diff options
Diffstat (limited to 'drivers/pwm/core.c')
| -rw-r--r-- | drivers/pwm/core.c | 1818 |
1 files changed, 1493 insertions, 325 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index f2728ee787d7..ccd54c089bab 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -6,6 +6,8 @@ * Copyright (C) 2011-2012 Avionic Design GmbH */ +#define DEFAULT_SYMBOL_NAMESPACE "PWM" + #include <linux/acpi.h> #include <linux/module.h> #include <linux/idr.h> @@ -24,309 +26,410 @@ #define CREATE_TRACE_POINTS #include <trace/events/pwm.h> -static DEFINE_MUTEX(pwm_lookup_lock); -static LIST_HEAD(pwm_lookup_list); - /* protects access to pwm_chips */ static DEFINE_MUTEX(pwm_lock); static DEFINE_IDR(pwm_chips); -static struct pwm_chip *pwmchip_find_by_name(const char *name) +static void pwmchip_lock(struct pwm_chip *chip) { - struct pwm_chip *chip; - unsigned long id, tmp; + if (chip->atomic) + spin_lock(&chip->atomic_lock); + else + mutex_lock(&chip->nonatomic_lock); +} - if (!name) - return NULL; +static void pwmchip_unlock(struct pwm_chip *chip) +{ + if (chip->atomic) + spin_unlock(&chip->atomic_lock); + else + mutex_unlock(&chip->nonatomic_lock); +} - mutex_lock(&pwm_lock); +DEFINE_GUARD(pwmchip, struct pwm_chip *, pwmchip_lock(_T), pwmchip_unlock(_T)) - idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) { - const char *chip_name = dev_name(chip->dev); +static bool pwm_wf_valid(const struct pwm_waveform *wf) +{ + /* + * For now restrict waveforms to period_length_ns <= S64_MAX to provide + * some space for future extensions. One possibility is to simplify + * representing waveforms with inverted polarity using negative values + * somehow. + */ + if (wf->period_length_ns > S64_MAX) + return false; - if (chip_name && strcmp(chip_name, name) == 0) { - mutex_unlock(&pwm_lock); - return chip; - } - } + if (wf->duty_length_ns > wf->period_length_ns) + return false; - mutex_unlock(&pwm_lock); + /* + * .duty_offset_ns is supposed to be smaller than .period_length_ns, apart + * from the corner case .duty_offset_ns == 0 && .period_length_ns == 0. + */ + if (wf->duty_offset_ns && wf->duty_offset_ns >= wf->period_length_ns) + return false; - return NULL; + return true; } -static int pwm_device_request(struct pwm_device *pwm, const char *label) +static void pwm_wf2state(const struct pwm_waveform *wf, struct pwm_state *state) { - int err; - struct pwm_chip *chip = pwm->chip; - const struct pwm_ops *ops = chip->ops; - - if (test_bit(PWMF_REQUESTED, &pwm->flags)) - return -EBUSY; - - if (!try_module_get(chip->owner)) - return -ENODEV; - - if (ops->request) { - err = ops->request(chip, pwm); - if (err) { - module_put(chip->owner); - return err; - } + if (wf->period_length_ns) { + if (wf->duty_length_ns + wf->duty_offset_ns < wf->period_length_ns) + *state = (struct pwm_state){ + .enabled = true, + .polarity = PWM_POLARITY_NORMAL, + .period = wf->period_length_ns, + .duty_cycle = wf->duty_length_ns, + }; + else + *state = (struct pwm_state){ + .enabled = true, + .polarity = PWM_POLARITY_INVERSED, + .period = wf->period_length_ns, + .duty_cycle = wf->period_length_ns - wf->duty_length_ns, + }; + } else { + *state = (struct pwm_state){ + .enabled = false, + }; } +} - if (ops->get_state) { - /* - * Zero-initialize state because most drivers are unaware of - * .usage_power. The other members of state are supposed to be - * set by lowlevel drivers. We still initialize the whole - * structure for simplicity even though this might paper over - * faulty implementations of .get_state(). - */ - struct pwm_state state = { 0, }; - - err = ops->get_state(chip, pwm, &state); - trace_pwm_get(pwm, &state, err); - - if (!err) - pwm->state = state; - - if (IS_ENABLED(CONFIG_PWM_DEBUG)) - pwm->last = pwm->state; +static void pwm_state2wf(const struct pwm_state *state, struct pwm_waveform *wf) +{ + if (state->enabled) { + if (state->polarity == PWM_POLARITY_NORMAL) + *wf = (struct pwm_waveform){ + .period_length_ns = state->period, + .duty_length_ns = state->duty_cycle, + .duty_offset_ns = 0, + }; + else + *wf = (struct pwm_waveform){ + .period_length_ns = state->period, + .duty_length_ns = state->period - state->duty_cycle, + .duty_offset_ns = state->duty_cycle, + }; + } else { + *wf = (struct pwm_waveform){ + .period_length_ns = 0, + }; } - - set_bit(PWMF_REQUESTED, &pwm->flags); - pwm->label = label; - - return 0; } -struct pwm_device * -of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args) +static int pwmwfcmp(const struct pwm_waveform *a, const struct pwm_waveform *b) { - struct pwm_device *pwm; + if (a->period_length_ns > b->period_length_ns) + return 1; - if (chip->of_pwm_n_cells < 2) - return ERR_PTR(-EINVAL); + if (a->period_length_ns < b->period_length_ns) + return -1; - /* flags in the third cell are optional */ - if (args->args_count < 2) - return ERR_PTR(-EINVAL); - - if (args->args[0] >= chip->npwm) - return ERR_PTR(-EINVAL); + if (a->duty_length_ns > b->duty_length_ns) + return 1; - pwm = pwm_request_from_chip(chip, args->args[0], NULL); - if (IS_ERR(pwm)) - return pwm; + if (a->duty_length_ns < b->duty_length_ns) + return -1; - pwm->args.period = args->args[1]; - pwm->args.polarity = PWM_POLARITY_NORMAL; + if (a->duty_offset_ns > b->duty_offset_ns) + return 1; - if (chip->of_pwm_n_cells >= 3) { - if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED) - pwm->args.polarity = PWM_POLARITY_INVERSED; - } + if (a->duty_offset_ns < b->duty_offset_ns) + return -1; - return pwm; + return 0; } -EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags); -struct pwm_device * -of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args) +static bool pwm_check_rounding(const struct pwm_waveform *wf, + const struct pwm_waveform *wf_rounded) { - struct pwm_device *pwm; - - if (chip->of_pwm_n_cells < 1) - return ERR_PTR(-EINVAL); - - /* validate that one cell is specified, optionally with flags */ - if (args->args_count != 1 && args->args_count != 2) - return ERR_PTR(-EINVAL); + if (!wf->period_length_ns) + return true; - pwm = pwm_request_from_chip(chip, 0, NULL); - if (IS_ERR(pwm)) - return pwm; + if (wf->period_length_ns < wf_rounded->period_length_ns) + return false; - pwm->args.period = args->args[0]; - pwm->args.polarity = PWM_POLARITY_NORMAL; + if (wf->duty_length_ns < wf_rounded->duty_length_ns) + return false; - if (args->args_count == 2 && args->args[1] & PWM_POLARITY_INVERTED) - pwm->args.polarity = PWM_POLARITY_INVERSED; + if (wf->duty_offset_ns < wf_rounded->duty_offset_ns) + return false; - return pwm; + return true; } -EXPORT_SYMBOL_GPL(of_pwm_single_xlate); -static void of_pwmchip_add(struct pwm_chip *chip) +static int __pwm_round_waveform_tohw(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_waveform *wf, void *wfhw) { - if (!chip->dev || !chip->dev->of_node) - return; + const struct pwm_ops *ops = chip->ops; + int ret; - if (!chip->of_xlate) { - u32 pwm_cells; + ret = ops->round_waveform_tohw(chip, pwm, wf, wfhw); + trace_pwm_round_waveform_tohw(pwm, wf, wfhw, ret); - if (of_property_read_u32(chip->dev->of_node, "#pwm-cells", - &pwm_cells)) - pwm_cells = 2; + return ret; +} - chip->of_xlate = of_pwm_xlate_with_flags; - chip->of_pwm_n_cells = pwm_cells; - } +static int __pwm_round_waveform_fromhw(struct pwm_chip *chip, struct pwm_device *pwm, + const void *wfhw, struct pwm_waveform *wf) +{ + const struct pwm_ops *ops = chip->ops; + int ret; + + ret = ops->round_waveform_fromhw(chip, pwm, wfhw, wf); + trace_pwm_round_waveform_fromhw(pwm, wfhw, wf, ret); - of_node_get(chip->dev->of_node); + return ret; } -static void of_pwmchip_remove(struct pwm_chip *chip) +static int __pwm_read_waveform(struct pwm_chip *chip, struct pwm_device *pwm, void *wfhw) { - if (chip->dev) - of_node_put(chip->dev->of_node); + const struct pwm_ops *ops = chip->ops; + int ret; + + ret = ops->read_waveform(chip, pwm, wfhw); + trace_pwm_read_waveform(pwm, wfhw, ret); + + return ret; } -static bool pwm_ops_check(const struct pwm_chip *chip) +static int __pwm_write_waveform(struct pwm_chip *chip, struct pwm_device *pwm, const void *wfhw) { const struct pwm_ops *ops = chip->ops; + int ret; - if (!ops->apply) - return false; - - if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state) - dev_warn(chip->dev, - "Please implement the .get_state() callback\n"); + ret = ops->write_waveform(chip, pwm, wfhw); + trace_pwm_write_waveform(pwm, wfhw, ret); - return true; + return ret; } +#define WFHWSIZE 20 + /** - * __pwmchip_add() - register a new PWM chip - * @chip: the PWM chip to add - * @owner: reference to the module providing the chip. + * pwm_round_waveform_might_sleep - Query hardware capabilities + * Cannot be used in atomic context. + * @pwm: PWM device + * @wf: waveform to round and output parameter * - * Register a new PWM chip. @owner is supposed to be THIS_MODULE, use the - * pwmchip_add wrapper to do this right. + * Typically a given waveform cannot be implemented exactly by hardware, e.g. + * because hardware only supports coarse period resolution or no duty_offset. + * This function returns the actually implemented waveform if you pass wf to + * pwm_set_waveform_might_sleep now. * - * Returns: 0 on success or a negative error code on failure. + * Note however that the world doesn't stop turning when you call it, so when + * doing + * + * pwm_round_waveform_might_sleep(mypwm, &wf); + * pwm_set_waveform_might_sleep(mypwm, &wf, true); + * + * the latter might fail, e.g. because an input clock changed its rate between + * these two calls and the waveform determined by + * pwm_round_waveform_might_sleep() cannot be implemented any more. + * + * Returns 0 on success, 1 if there is no valid hardware configuration matching + * the input waveform under the PWM rounding rules or a negative errno. */ -int __pwmchip_add(struct pwm_chip *chip, struct module *owner) +int pwm_round_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform *wf) { - unsigned int i; - int ret; - - if (!chip || !chip->dev || !chip->ops || !chip->npwm) - return -EINVAL; - - if (!pwm_ops_check(chip)) - return -EINVAL; + struct pwm_chip *chip = pwm->chip; + const struct pwm_ops *ops = chip->ops; + struct pwm_waveform wf_req = *wf; + char wfhw[WFHWSIZE]; + int ret_tohw, ret_fromhw; - chip->owner = owner; + BUG_ON(WFHWSIZE < ops->sizeof_wfhw); - chip->pwms = kcalloc(chip->npwm, sizeof(*chip->pwms), GFP_KERNEL); - if (!chip->pwms) - return -ENOMEM; + if (!pwmchip_supports_waveform(chip)) + return -EOPNOTSUPP; - mutex_lock(&pwm_lock); + if (!pwm_wf_valid(wf)) + return -EINVAL; - ret = idr_alloc(&pwm_chips, chip, 0, 0, GFP_KERNEL); - if (ret < 0) { - mutex_unlock(&pwm_lock); - kfree(chip->pwms); - return ret; - } + guard(pwmchip)(chip); - chip->id = ret; + if (!chip->operational) + return -ENODEV; - for (i = 0; i < chip->npwm; i++) { - struct pwm_device *pwm = &chip->pwms[i]; + ret_tohw = __pwm_round_waveform_tohw(chip, pwm, wf, wfhw); + if (ret_tohw < 0) + return ret_tohw; - pwm->chip = chip; - pwm->hwpwm = i; - } + if (IS_ENABLED(CONFIG_PWM_DEBUG) && ret_tohw > 1) + dev_err(&chip->dev, "Unexpected return value from __pwm_round_waveform_tohw: requested %llu/%llu [+%llu], return value %d\n", + wf_req.duty_length_ns, wf_req.period_length_ns, wf_req.duty_offset_ns, ret_tohw); - mutex_unlock(&pwm_lock); + ret_fromhw = __pwm_round_waveform_fromhw(chip, pwm, wfhw, wf); + if (ret_fromhw < 0) + return ret_fromhw; - if (IS_ENABLED(CONFIG_OF)) - of_pwmchip_add(chip); + if (IS_ENABLED(CONFIG_PWM_DEBUG) && ret_fromhw > 0) + dev_err(&chip->dev, "Unexpected return value from __pwm_round_waveform_fromhw: requested %llu/%llu [+%llu], return value %d\n", + wf_req.duty_length_ns, wf_req.period_length_ns, wf_req.duty_offset_ns, ret_tohw); - pwmchip_sysfs_export(chip); + if (IS_ENABLED(CONFIG_PWM_DEBUG) && + ret_tohw == 0 && !pwm_check_rounding(&wf_req, wf)) + dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu]\n", + wf_req.duty_length_ns, wf_req.period_length_ns, wf_req.duty_offset_ns, + wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns); - return 0; + return ret_tohw; } -EXPORT_SYMBOL_GPL(__pwmchip_add); +EXPORT_SYMBOL_GPL(pwm_round_waveform_might_sleep); /** - * pwmchip_remove() - remove a PWM chip - * @chip: the PWM chip to remove + * pwm_get_waveform_might_sleep - Query hardware about current configuration + * Cannot be used in atomic context. + * @pwm: PWM device + * @wf: output parameter * - * Removes a PWM chip. + * Stores the current configuration of the PWM in @wf. Note this is the + * equivalent of pwm_get_state_hw() (and not pwm_get_state()) for pwm_waveform. */ -void pwmchip_remove(struct pwm_chip *chip) +int pwm_get_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform *wf) { - pwmchip_sysfs_unexport(chip); + struct pwm_chip *chip = pwm->chip; + const struct pwm_ops *ops = chip->ops; + char wfhw[WFHWSIZE]; + int err; - if (IS_ENABLED(CONFIG_OF)) - of_pwmchip_remove(chip); + BUG_ON(WFHWSIZE < ops->sizeof_wfhw); - mutex_lock(&pwm_lock); + if (!pwmchip_supports_waveform(chip) || !ops->read_waveform) + return -EOPNOTSUPP; - idr_remove(&pwm_chips, chip->id); + guard(pwmchip)(chip); - mutex_unlock(&pwm_lock); + if (!chip->operational) + return -ENODEV; + + err = __pwm_read_waveform(chip, pwm, &wfhw); + if (err) + return err; - kfree(chip->pwms); + return __pwm_round_waveform_fromhw(chip, pwm, &wfhw, wf); } -EXPORT_SYMBOL_GPL(pwmchip_remove); +EXPORT_SYMBOL_GPL(pwm_get_waveform_might_sleep); -static void devm_pwmchip_remove(void *data) +/* Called with the pwmchip lock held */ +static int __pwm_set_waveform(struct pwm_device *pwm, + const struct pwm_waveform *wf, + bool exact) { - struct pwm_chip *chip = data; + struct pwm_chip *chip = pwm->chip; + const struct pwm_ops *ops = chip->ops; + char wfhw[WFHWSIZE]; + struct pwm_waveform wf_rounded; + int err; - pwmchip_remove(chip); -} + BUG_ON(WFHWSIZE < ops->sizeof_wfhw); -int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner) -{ - int ret; + if (!pwmchip_supports_waveform(chip)) + return -EOPNOTSUPP; - ret = __pwmchip_add(chip, owner); - if (ret) - return ret; + if (!pwm_wf_valid(wf)) + return -EINVAL; - return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip); + err = __pwm_round_waveform_tohw(chip, pwm, wf, &wfhw); + if (err) + return err; + + if ((IS_ENABLED(CONFIG_PWM_DEBUG) || exact) && wf->period_length_ns) { + err = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf_rounded); + if (err) + return err; + + if (IS_ENABLED(CONFIG_PWM_DEBUG) && !pwm_check_rounding(wf, &wf_rounded)) + dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu]\n", + wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns, + wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns); + + if (exact && pwmwfcmp(wf, &wf_rounded)) { + dev_dbg(&chip->dev, "Requested no rounding, but %llu/%llu [+%llu] -> %llu/%llu [+%llu]\n", + wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns, + wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns); + + return 1; + } + } + + err = __pwm_write_waveform(chip, pwm, &wfhw); + if (err) + return err; + + /* update .state */ + pwm_wf2state(wf, &pwm->state); + + if (IS_ENABLED(CONFIG_PWM_DEBUG) && ops->read_waveform && wf->period_length_ns) { + struct pwm_waveform wf_set; + + err = __pwm_read_waveform(chip, pwm, &wfhw); + if (err) + /* maybe ignore? */ + return err; + + err = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf_set); + if (err) + /* maybe ignore? */ + return err; + + if (pwmwfcmp(&wf_set, &wf_rounded) != 0) + dev_err(&chip->dev, + "Unexpected setting: requested %llu/%llu [+%llu], expected %llu/%llu [+%llu], set %llu/%llu [+%llu]\n", + wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns, + wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns, + wf_set.duty_length_ns, wf_set.period_length_ns, wf_set.duty_offset_ns); + } + return 0; } -EXPORT_SYMBOL_GPL(__devm_pwmchip_add); /** - * pwm_request_from_chip() - request a PWM device relative to a PWM chip - * @chip: PWM chip - * @index: per-chip index of the PWM to request - * @label: a literal description string of this PWM + * pwm_set_waveform_might_sleep - Apply a new waveform + * Cannot be used in atomic context. + * @pwm: PWM device + * @wf: The waveform to apply + * @exact: If true no rounding is allowed * - * Returns: A pointer to the PWM device at the given index of the given PWM - * chip. A negative error code is returned if the index is not valid for the - * specified PWM chip or if the PWM device cannot be requested. + * Typically a requested waveform cannot be implemented exactly, e.g. because + * you requested .period_length_ns = 100 ns, but the hardware can only set + * periods that are a multiple of 8.5 ns. With that hardware passing exact = + * true results in pwm_set_waveform_might_sleep() failing and returning 1. If + * exact = false you get a period of 93.5 ns (i.e. the biggest period not bigger + * than the requested value). + * Note that even with exact = true, some rounding by less than 1 is + * possible/needed. In the above example requesting .period_length_ns = 94 and + * exact = true, you get the hardware configured with period = 93.5 ns. */ -struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, - unsigned int index, - const char *label) +int pwm_set_waveform_might_sleep(struct pwm_device *pwm, + const struct pwm_waveform *wf, bool exact) { - struct pwm_device *pwm; + struct pwm_chip *chip = pwm->chip; int err; - if (!chip || index >= chip->npwm) - return ERR_PTR(-EINVAL); + might_sleep(); - mutex_lock(&pwm_lock); - pwm = &chip->pwms[index]; + guard(pwmchip)(chip); - err = pwm_device_request(pwm, label); - if (err < 0) - pwm = ERR_PTR(err); + if (!chip->operational) + return -ENODEV; - mutex_unlock(&pwm_lock); - return pwm; + if (IS_ENABLED(CONFIG_PWM_DEBUG) && chip->atomic) { + /* + * Catch any drivers that have been marked as atomic but + * that will sleep anyway. + */ + non_block_start(); + err = __pwm_set_waveform(pwm, wf, exact); + non_block_end(); + } else { + err = __pwm_set_waveform(pwm, wf, exact); + } + + return err; } -EXPORT_SYMBOL_GPL(pwm_request_from_chip); +EXPORT_SYMBOL_GPL(pwm_set_waveform_might_sleep); static void pwm_apply_debug(struct pwm_device *pwm, const struct pwm_state *state) @@ -370,18 +473,22 @@ static void pwm_apply_debug(struct pwm_device *pwm, if (s2.polarity != state->polarity && state->duty_cycle < state->period) - dev_warn(chip->dev, ".apply ignored .polarity\n"); + dev_warn(pwmchip_parent(chip), ".apply ignored .polarity\n"); - if (state->enabled && + if (state->enabled && s2.enabled && last->polarity == state->polarity && last->period > s2.period && last->period <= state->period) - dev_warn(chip->dev, + dev_warn(pwmchip_parent(chip), ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n", state->period, s2.period, last->period); - if (state->enabled && state->period < s2.period) - dev_warn(chip->dev, + /* + * Rounding period up is fine only if duty_cycle is 0 then, because a + * flat line doesn't have a characteristic period. + */ + if (state->enabled && s2.enabled && state->period < s2.period && s2.duty_cycle) + dev_warn(pwmchip_parent(chip), ".apply is supposed to round down period (requested: %llu, applied: %llu)\n", state->period, s2.period); @@ -390,20 +497,20 @@ static void pwm_apply_debug(struct pwm_device *pwm, last->period == s2.period && last->duty_cycle > s2.duty_cycle && last->duty_cycle <= state->duty_cycle) - dev_warn(chip->dev, + dev_warn(pwmchip_parent(chip), ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n", state->duty_cycle, state->period, s2.duty_cycle, s2.period, last->duty_cycle, last->period); - if (state->enabled && state->duty_cycle < s2.duty_cycle) - dev_warn(chip->dev, + if (state->enabled && s2.enabled && state->duty_cycle < s2.duty_cycle) + dev_warn(pwmchip_parent(chip), ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n", state->duty_cycle, state->period, s2.duty_cycle, s2.period); if (!state->enabled && s2.enabled && s2.duty_cycle > 0) - dev_warn(chip->dev, + dev_warn(pwmchip_parent(chip), "requested disabled, but yielded enabled with duty > 0\n"); /* reapply the state that the driver reported being configured. */ @@ -411,7 +518,7 @@ static void pwm_apply_debug(struct pwm_device *pwm, trace_pwm_apply(pwm, &s1, err); if (err) { *last = s1; - dev_err(chip->dev, "failed to reapply current setting\n"); + dev_err(pwmchip_parent(chip), "failed to reapply current setting\n"); return; } @@ -426,7 +533,7 @@ static void pwm_apply_debug(struct pwm_device *pwm, s1.polarity != last->polarity || (s1.enabled && s1.period != last->period) || (s1.enabled && s1.duty_cycle != last->duty_cycle)) { - dev_err(chip->dev, + dev_err(pwmchip_parent(chip), ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n", s1.enabled, s1.polarity, s1.duty_cycle, s1.period, last->enabled, last->polarity, last->duty_cycle, @@ -434,6 +541,25 @@ static void pwm_apply_debug(struct pwm_device *pwm, } } +static bool pwm_state_valid(const struct pwm_state *state) +{ + /* + * For a disabled state all other state description is irrelevant and + * and supposed to be ignored. So also ignore any strange values and + * consider the state ok. + */ + if (state->enabled) + return true; + + if (!state->period) + return false; + + if (state->duty_cycle > state->period) + return false; + + return true; +} + /** * __pwm_apply() - atomically apply a new state to a PWM device * @pwm: PWM device @@ -442,13 +568,31 @@ static void pwm_apply_debug(struct pwm_device *pwm, static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state) { struct pwm_chip *chip; + const struct pwm_ops *ops; int err; - if (!pwm || !state || !state->period || - state->duty_cycle > state->period) + if (!pwm || !state) return -EINVAL; + if (!pwm_state_valid(state)) { + /* + * Allow to transition from one invalid state to another. + * This ensures that you can e.g. change the polarity while + * the period is zero. (This happens on stm32 when the hardware + * is in its poweron default state.) This greatly simplifies + * working with the sysfs API where you can only change one + * parameter at a time. + */ + if (!pwm_state_valid(&pwm->state)) { + pwm->state = *state; + return 0; + } + + return -EINVAL; + } + chip = pwm->chip; + ops = chip->ops; if (state->period == pwm->state.period && state->duty_cycle == pwm->state.duty_cycle && @@ -457,18 +601,69 @@ static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state) state->usage_power == pwm->state.usage_power) return 0; - err = chip->ops->apply(chip, pwm, state); - trace_pwm_apply(pwm, state, err); - if (err) - return err; + if (pwmchip_supports_waveform(chip)) { + struct pwm_waveform wf; + char wfhw[WFHWSIZE]; - pwm->state = *state; + BUG_ON(WFHWSIZE < ops->sizeof_wfhw); - /* - * only do this after pwm->state was applied as some - * implementations of .get_state depend on this - */ - pwm_apply_debug(pwm, state); + pwm_state2wf(state, &wf); + + /* + * The rounding is wrong here for states with inverted polarity. + * While .apply() rounds down duty_cycle (which represents the + * time from the start of the period to the inner edge), + * .round_waveform_tohw() rounds down the time the PWM is high. + * Can be fixed if the need arises, until reported otherwise + * let's assume that consumers don't care. + */ + + err = __pwm_round_waveform_tohw(chip, pwm, &wf, &wfhw); + if (err) { + if (err > 0) + /* + * This signals an invalid request, typically + * the requested period (or duty_offset) is + * smaller than possible with the hardware. + */ + return -EINVAL; + + return err; + } + + if (IS_ENABLED(CONFIG_PWM_DEBUG)) { + struct pwm_waveform wf_rounded; + + err = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf_rounded); + if (err) + return err; + + if (!pwm_check_rounding(&wf, &wf_rounded)) + dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu]\n", + wf.duty_length_ns, wf.period_length_ns, wf.duty_offset_ns, + wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns); + } + + err = __pwm_write_waveform(chip, pwm, &wfhw); + if (err) + return err; + + pwm->state = *state; + + } else { + err = ops->apply(chip, pwm, state); + trace_pwm_apply(pwm, state, err); + if (err) + return err; + + pwm->state = *state; + + /* + * only do this after pwm->state was applied as some + * implementations of .get_state() depend on this + */ + pwm_apply_debug(pwm, state); + } return 0; } @@ -482,6 +677,7 @@ static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state) int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state) { int err; + struct pwm_chip *chip = pwm->chip; /* * Some lowlevel driver's implementations of .apply() make use of @@ -492,7 +688,12 @@ int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state) */ might_sleep(); - if (IS_ENABLED(CONFIG_PWM_DEBUG) && pwm->chip->atomic) { + guard(pwmchip)(chip); + + if (!chip->operational) + return -ENODEV; + + if (IS_ENABLED(CONFIG_PWM_DEBUG) && chip->atomic) { /* * Catch any drivers that have been marked as atomic but * that will sleep anyway. @@ -516,39 +717,68 @@ EXPORT_SYMBOL_GPL(pwm_apply_might_sleep); */ int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state) { - WARN_ONCE(!pwm->chip->atomic, + struct pwm_chip *chip = pwm->chip; + + WARN_ONCE(!chip->atomic, "sleeping PWM driver used in atomic context\n"); + guard(pwmchip)(chip); + + if (!chip->operational) + return -ENODEV; + return __pwm_apply(pwm, state); } EXPORT_SYMBOL_GPL(pwm_apply_atomic); /** - * pwm_capture() - capture and report a PWM signal + * pwm_get_state_hw() - get the current PWM state from hardware * @pwm: PWM device - * @result: structure to fill with capture result - * @timeout: time to wait, in milliseconds, before giving up on capture + * @state: state to fill with the current PWM state + * + * Similar to pwm_get_state() but reads the current PWM state from hardware + * instead of the requested state. * * Returns: 0 on success or a negative error code on failure. + * Context: May sleep. */ -int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, - unsigned long timeout) +int pwm_get_state_hw(struct pwm_device *pwm, struct pwm_state *state) { - int err; + struct pwm_chip *chip = pwm->chip; + const struct pwm_ops *ops = chip->ops; + int ret = -EOPNOTSUPP; - if (!pwm || !pwm->chip->ops) - return -EINVAL; + might_sleep(); - if (!pwm->chip->ops->capture) - return -ENOSYS; + guard(pwmchip)(chip); - mutex_lock(&pwm_lock); - err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout); - mutex_unlock(&pwm_lock); + if (!chip->operational) + return -ENODEV; - return err; + if (pwmchip_supports_waveform(chip) && ops->read_waveform) { + char wfhw[WFHWSIZE]; + struct pwm_waveform wf; + + BUG_ON(WFHWSIZE < ops->sizeof_wfhw); + + ret = __pwm_read_waveform(chip, pwm, &wfhw); + if (ret) + return ret; + + ret = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf); + if (ret) + return ret; + + pwm_wf2state(&wf, state); + + } else if (ops->get_state) { + ret = ops->get_state(chip, pwm, state); + trace_pwm_get(pwm, state, ret); + } + + return ret; } -EXPORT_SYMBOL_GPL(pwm_capture); +EXPORT_SYMBOL_GPL(pwm_get_state_hw); /** * pwm_adjust_config() - adjust the current PWM config to the PWM arguments @@ -606,22 +836,808 @@ int pwm_adjust_config(struct pwm_device *pwm) } EXPORT_SYMBOL_GPL(pwm_adjust_config); -static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode) +/** + * pwm_capture() - capture and report a PWM signal + * @pwm: PWM device + * @result: structure to fill with capture result + * @timeout: time to wait, in milliseconds, before giving up on capture + * + * Returns: 0 on success or a negative error code on failure. + */ +static int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, + unsigned long timeout) +{ + struct pwm_chip *chip = pwm->chip; + const struct pwm_ops *ops = chip->ops; + + if (!ops->capture) + return -ENOSYS; + + /* + * Holding the pwm_lock is probably not needed. If you use pwm_capture() + * and you're interested to speed it up, please convince yourself it's + * really not needed, test and then suggest a patch on the mailing list. + */ + guard(mutex)(&pwm_lock); + + guard(pwmchip)(chip); + + if (!chip->operational) + return -ENODEV; + + return ops->capture(chip, pwm, result, timeout); +} + +static struct pwm_chip *pwmchip_find_by_name(const char *name) { struct pwm_chip *chip; unsigned long id, tmp; - mutex_lock(&pwm_lock); + if (!name) + return NULL; - idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) - if (chip->dev && device_match_fwnode(chip->dev, fwnode)) { - mutex_unlock(&pwm_lock); + guard(mutex)(&pwm_lock); + + idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) { + if (device_match_name(pwmchip_parent(chip), name)) return chip; + } + + return NULL; +} + +static int pwm_device_request(struct pwm_device *pwm, const char *label) +{ + int err; + struct pwm_chip *chip = pwm->chip; + const struct pwm_ops *ops = chip->ops; + + if (test_bit(PWMF_REQUESTED, &pwm->flags)) + return -EBUSY; + + /* + * This function is called while holding pwm_lock. As .operational only + * changes while holding this lock, checking it here without holding the + * chip lock is fine. + */ + if (!chip->operational) + return -ENODEV; + + if (!try_module_get(chip->owner)) + return -ENODEV; + + if (!get_device(&chip->dev)) { + err = -ENODEV; + goto err_get_device; + } + + if (ops->request) { + err = ops->request(chip, pwm); + if (err) { + put_device(&chip->dev); +err_get_device: + module_put(chip->owner); + return err; } + } - mutex_unlock(&pwm_lock); + if (ops->read_waveform || ops->get_state) { + /* + * Zero-initialize state because most drivers are unaware of + * .usage_power. The other members of state are supposed to be + * set by lowlevel drivers. We still initialize the whole + * structure for simplicity even though this might paper over + * faulty implementations of .get_state(). + */ + struct pwm_state state = { 0, }; - return ERR_PTR(-EPROBE_DEFER); + err = pwm_get_state_hw(pwm, &state); + if (!err) + pwm->state = state; + + if (IS_ENABLED(CONFIG_PWM_DEBUG)) + pwm->last = pwm->state; + } + + set_bit(PWMF_REQUESTED, &pwm->flags); + pwm->label = label; + + return 0; +} + +/** + * pwm_request_from_chip() - request a PWM device relative to a PWM chip + * @chip: PWM chip + * @index: per-chip index of the PWM to request + * @label: a literal description string of this PWM + * + * Returns: A pointer to the PWM device at the given index of the given PWM + * chip. A negative error code is returned if the index is not valid for the + * specified PWM chip or if the PWM device cannot be requested. + */ +static struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, + unsigned int index, + const char *label) +{ + struct pwm_device *pwm; + int err; + + if (!chip || index >= chip->npwm) + return ERR_PTR(-EINVAL); + + guard(mutex)(&pwm_lock); + + pwm = &chip->pwms[index]; + + err = pwm_device_request(pwm, label); + if (err < 0) + return ERR_PTR(err); + + return pwm; +} + +struct pwm_device * +of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args) +{ + struct pwm_device *pwm; + + /* period in the second cell and flags in the third cell are optional */ + if (args->args_count < 1) + return ERR_PTR(-EINVAL); + + pwm = pwm_request_from_chip(chip, args->args[0], NULL); + if (IS_ERR(pwm)) + return pwm; + + if (args->args_count > 1) + pwm->args.period = args->args[1]; + + pwm->args.polarity = PWM_POLARITY_NORMAL; + if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED) + pwm->args.polarity = PWM_POLARITY_INVERSED; + + return pwm; +} +EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags); + +struct pwm_device * +of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args) +{ + struct pwm_device *pwm; + + pwm = pwm_request_from_chip(chip, 0, NULL); + if (IS_ERR(pwm)) + return pwm; + + if (args->args_count > 0) + pwm->args.period = args->args[0]; + + pwm->args.polarity = PWM_POLARITY_NORMAL; + if (args->args_count > 1 && args->args[1] & PWM_POLARITY_INVERTED) + pwm->args.polarity = PWM_POLARITY_INVERSED; + + return pwm; +} +EXPORT_SYMBOL_GPL(of_pwm_single_xlate); + +struct pwm_export { + struct device pwm_dev; + struct pwm_device *pwm; + struct mutex lock; + struct pwm_state suspend; +}; + +static inline struct pwm_chip *pwmchip_from_dev(struct device *pwmchip_dev) +{ + return container_of(pwmchip_dev, struct pwm_chip, dev); +} + +static inline struct pwm_export *pwmexport_from_dev(struct device *pwm_dev) +{ + return container_of(pwm_dev, struct pwm_export, pwm_dev); +} + +static inline struct pwm_device *pwm_from_dev(struct device *pwm_dev) +{ + struct pwm_export *export = pwmexport_from_dev(pwm_dev); + + return export->pwm; +} + +static ssize_t period_show(struct device *pwm_dev, + struct device_attribute *attr, + char *buf) +{ + const struct pwm_device *pwm = pwm_from_dev(pwm_dev); + struct pwm_state state; + + pwm_get_state(pwm, &state); + + return sysfs_emit(buf, "%llu\n", state.period); +} + +static ssize_t period_store(struct device *pwm_dev, + struct device_attribute *attr, + const char *buf, size_t size) +{ + struct pwm_export *export = pwmexport_from_dev(pwm_dev); + struct pwm_device *pwm = export->pwm; + struct pwm_state state; + u64 val; + int ret; + + ret = kstrtou64(buf, 0, &val); + if (ret) + return ret; + + guard(mutex)(&export->lock); + + pwm_get_state(pwm, &state); + state.period = val; + ret = pwm_apply_might_sleep(pwm, &state); + + return ret ? : size; +} + +static ssize_t duty_cycle_show(struct device *pwm_dev, + struct device_attribute *attr, + char *buf) +{ + const struct pwm_device *pwm = pwm_from_dev(pwm_dev); + struct pwm_state state; + + pwm_get_state(pwm, &state); + + return sysfs_emit(buf, "%llu\n", state.duty_cycle); +} + +static ssize_t duty_cycle_store(struct device *pwm_dev, + struct device_attribute *attr, + const char *buf, size_t size) +{ + struct pwm_export *export = pwmexport_from_dev(pwm_dev); + struct pwm_device *pwm = export->pwm; + struct pwm_state state; + u64 val; + int ret; + + ret = kstrtou64(buf, 0, &val); + if (ret) + return ret; + + guard(mutex)(&export->lock); + + pwm_get_state(pwm, &state); + state.duty_cycle = val; + ret = pwm_apply_might_sleep(pwm, &state); + + return ret ? : size; +} + +static ssize_t enable_show(struct device *pwm_dev, + struct device_attribute *attr, + char *buf) +{ + const struct pwm_device *pwm = pwm_from_dev(pwm_dev); + struct pwm_state state; + + pwm_get_state(pwm, &state); + + return sysfs_emit(buf, "%d\n", state.enabled); +} + +static ssize_t enable_store(struct device *pwm_dev, + struct device_attribute *attr, + const char *buf, size_t size) +{ + struct pwm_export *export = pwmexport_from_dev(pwm_dev); + struct pwm_device *pwm = export->pwm; + struct pwm_state state; + int val, ret; + + ret = kstrtoint(buf, 0, &val); + if (ret) + return ret; + + guard(mutex)(&export->lock); + + pwm_get_state(pwm, &state); + + switch (val) { + case 0: + state.enabled = false; + break; + case 1: + state.enabled = true; + break; + default: + return -EINVAL; + } + + ret = pwm_apply_might_sleep(pwm, &state); + + return ret ? : size; +} + +static ssize_t polarity_show(struct device *pwm_dev, + struct device_attribute *attr, + char *buf) +{ + const struct pwm_device *pwm = pwm_from_dev(pwm_dev); + const char *polarity = "unknown"; + struct pwm_state state; + + pwm_get_state(pwm, &state); + + switch (state.polarity) { + case PWM_POLARITY_NORMAL: + polarity = "normal"; + break; + + case PWM_POLARITY_INVERSED: + polarity = "inversed"; + break; + } + + return sysfs_emit(buf, "%s\n", polarity); +} + +static ssize_t polarity_store(struct device *pwm_dev, + struct device_attribute *attr, + const char *buf, size_t size) +{ + struct pwm_export *export = pwmexport_from_dev(pwm_dev); + struct pwm_device *pwm = export->pwm; + enum pwm_polarity polarity; + struct pwm_state state; + int ret; + + if (sysfs_streq(buf, "normal")) + polarity = PWM_POLARITY_NORMAL; + else if (sysfs_streq(buf, "inversed")) + polarity = PWM_POLARITY_INVERSED; + else + return -EINVAL; + + guard(mutex)(&export->lock); + + pwm_get_state(pwm, &state); + state.polarity = polarity; + ret = pwm_apply_might_sleep(pwm, &state); + + return ret ? : size; +} + +static ssize_t capture_show(struct device *pwm_dev, + struct device_attribute *attr, + char *buf) +{ + struct pwm_device *pwm = pwm_from_dev(pwm_dev); + struct pwm_capture result; + int ret; + + ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ)); + if (ret) + return ret; + + return sysfs_emit(buf, "%u %u\n", result.period, result.duty_cycle); +} + +static DEVICE_ATTR_RW(period); +static DEVICE_ATTR_RW(duty_cycle); +static DEVICE_ATTR_RW(enable); +static DEVICE_ATTR_RW(polarity); +static DEVICE_ATTR_RO(capture); + +static struct attribute *pwm_attrs[] = { + &dev_attr_period.attr, + &dev_attr_duty_cycle.attr, + &dev_attr_enable.attr, + &dev_attr_polarity.attr, + &dev_attr_capture.attr, + NULL +}; +ATTRIBUTE_GROUPS(pwm); + +static void pwm_export_release(struct device *pwm_dev) +{ + struct pwm_export *export = pwmexport_from_dev(pwm_dev); + + kfree(export); +} + +static int pwm_export_child(struct device *pwmchip_dev, struct pwm_device *pwm) +{ + struct pwm_export *export; + char *pwm_prop[2]; + int ret; + + if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags)) + return -EBUSY; + + export = kzalloc(sizeof(*export), GFP_KERNEL); + if (!export) { + clear_bit(PWMF_EXPORTED, &pwm->flags); + return -ENOMEM; + } + + export->pwm = pwm; + mutex_init(&export->lock); + + export->pwm_dev.release = pwm_export_release; + export->pwm_dev.parent = pwmchip_dev; + export->pwm_dev.devt = MKDEV(0, 0); + export->pwm_dev.groups = pwm_groups; + dev_set_name(&export->pwm_dev, "pwm%u", pwm->hwpwm); + + ret = device_register(&export->pwm_dev); + if (ret) { + clear_bit(PWMF_EXPORTED, &pwm->flags); + put_device(&export->pwm_dev); + export = NULL; + return ret; + } + pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm); + pwm_prop[1] = NULL; + kobject_uevent_env(&pwmchip_dev->kobj, KOBJ_CHANGE, pwm_prop); + kfree(pwm_prop[0]); + + return 0; +} + +static int pwm_unexport_match(struct device *pwm_dev, const void *data) +{ + return pwm_from_dev(pwm_dev) == data; +} + +static int pwm_unexport_child(struct device *pwmchip_dev, struct pwm_device *pwm) +{ + struct device *pwm_dev; + char *pwm_prop[2]; + + if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags)) + return -ENODEV; + + pwm_dev = device_find_child(pwmchip_dev, pwm, pwm_unexport_match); + if (!pwm_dev) + return -ENODEV; + + pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm); + pwm_prop[1] = NULL; + kobject_uevent_env(&pwmchip_dev->kobj, KOBJ_CHANGE, pwm_prop); + kfree(pwm_prop[0]); + + /* for device_find_child() */ + put_device(pwm_dev); + device_unregister(pwm_dev); + pwm_put(pwm); + + return 0; +} + +static ssize_t export_store(struct device *pwmchip_dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev); + struct pwm_device *pwm; + unsigned int hwpwm; + int ret; + + ret = kstrtouint(buf, 0, &hwpwm); + if (ret < 0) + return ret; + + if (hwpwm >= chip->npwm) + return -ENODEV; + + pwm = pwm_request_from_chip(chip, hwpwm, "sysfs"); + if (IS_ERR(pwm)) + return PTR_ERR(pwm); + + ret = pwm_export_child(pwmchip_dev, pwm); + if (ret < 0) + pwm_put(pwm); + + return ret ? : len; +} +static DEVICE_ATTR_WO(export); + +static ssize_t unexport_store(struct device *pwmchip_dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev); + unsigned int hwpwm; + int ret; + + ret = kstrtouint(buf, 0, &hwpwm); + if (ret < 0) + return ret; + + if (hwpwm >= chip->npwm) + return -ENODEV; + + ret = pwm_unexport_child(pwmchip_dev, &chip->pwms[hwpwm]); + + return ret ? : len; +} +static DEVICE_ATTR_WO(unexport); + +static ssize_t npwm_show(struct device *pwmchip_dev, struct device_attribute *attr, + char *buf) +{ + const struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev); + + return sysfs_emit(buf, "%u\n", chip->npwm); +} +static DEVICE_ATTR_RO(npwm); + +static struct attribute *pwm_chip_attrs[] = { + &dev_attr_export.attr, + &dev_attr_unexport.attr, + &dev_attr_npwm.attr, + NULL, +}; +ATTRIBUTE_GROUPS(pwm_chip); + +/* takes export->lock on success */ +static struct pwm_export *pwm_class_get_state(struct device *pwmchip_dev, + struct pwm_device *pwm, + struct pwm_state *state) +{ + struct device *pwm_dev; + struct pwm_export *export; + + if (!test_bit(PWMF_EXPORTED, &pwm->flags)) + return NULL; + + pwm_dev = device_find_child(pwmchip_dev, pwm, pwm_unexport_match); + if (!pwm_dev) + return NULL; + + export = pwmexport_from_dev(pwm_dev); + put_device(pwm_dev); /* for device_find_child() */ + + mutex_lock(&export->lock); + pwm_get_state(pwm, state); + + return export; +} + +static int pwm_class_apply_state(struct pwm_export *export, + struct pwm_device *pwm, + struct pwm_state *state) +{ + int ret = pwm_apply_might_sleep(pwm, state); + + /* release lock taken in pwm_class_get_state */ + mutex_unlock(&export->lock); + + return ret; +} + +static int pwm_class_resume_npwm(struct device *pwmchip_dev, unsigned int npwm) +{ + struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev); + unsigned int i; + int ret = 0; + + for (i = 0; i < npwm; i++) { + struct pwm_device *pwm = &chip->pwms[i]; + struct pwm_state state; + struct pwm_export *export; + + export = pwm_class_get_state(pwmchip_dev, pwm, &state); + if (!export) + continue; + + /* If pwmchip was not enabled before suspend, do nothing. */ + if (!export->suspend.enabled) { + /* release lock taken in pwm_class_get_state */ + mutex_unlock(&export->lock); + continue; + } + + state.enabled = export->suspend.enabled; + ret = pwm_class_apply_state(export, pwm, &state); + if (ret < 0) + break; + } + + return ret; +} + +static int pwm_class_suspend(struct device *pwmchip_dev) +{ + struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev); + unsigned int i; + int ret = 0; + + for (i = 0; i < chip->npwm; i++) { + struct pwm_device *pwm = &chip->pwms[i]; + struct pwm_state state; + struct pwm_export *export; + + export = pwm_class_get_state(pwmchip_dev, pwm, &state); + if (!export) + continue; + + /* + * If pwmchip was not enabled before suspend, save + * state for resume time and do nothing else. + */ + export->suspend = state; + if (!state.enabled) { + /* release lock taken in pwm_class_get_state */ + mutex_unlock(&export->lock); + continue; + } + + state.enabled = false; + ret = pwm_class_apply_state(export, pwm, &state); + if (ret < 0) { + /* + * roll back the PWM devices that were disabled by + * this suspend function. + */ + pwm_class_resume_npwm(pwmchip_dev, i); + break; + } + } + + return ret; +} + +static int pwm_class_resume(struct device *pwmchip_dev) +{ + struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev); + + return pwm_class_resume_npwm(pwmchip_dev, chip->npwm); +} + +static DEFINE_SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume); + +static struct class pwm_class = { + .name = "pwm", + .dev_groups = pwm_chip_groups, + .pm = pm_sleep_ptr(&pwm_class_pm_ops), +}; + +static void pwmchip_sysfs_unexport(struct pwm_chip *chip) +{ + unsigned int i; + + for (i = 0; i < chip->npwm; i++) { + struct pwm_device *pwm = &chip->pwms[i]; + + if (test_bit(PWMF_EXPORTED, &pwm->flags)) + pwm_unexport_child(&chip->dev, pwm); + } +} + +#define PWMCHIP_ALIGN ARCH_DMA_MINALIGN + +static void *pwmchip_priv(struct pwm_chip *chip) +{ + return (void *)chip + ALIGN(struct_size(chip, pwms, chip->npwm), PWMCHIP_ALIGN); +} + +/* This is the counterpart to pwmchip_alloc() */ +void pwmchip_put(struct pwm_chip *chip) +{ + put_device(&chip->dev); +} +EXPORT_SYMBOL_GPL(pwmchip_put); + +static void pwmchip_release(struct device *pwmchip_dev) +{ + struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev); + + kfree(chip); +} + +struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv) +{ + struct pwm_chip *chip; + struct device *pwmchip_dev; + size_t alloc_size; + unsigned int i; + + alloc_size = size_add(ALIGN(struct_size(chip, pwms, npwm), PWMCHIP_ALIGN), + sizeof_priv); + + chip = kzalloc(alloc_size, GFP_KERNEL); + if (!chip) + return ERR_PTR(-ENOMEM); + + chip->npwm = npwm; + chip->uses_pwmchip_alloc = true; + chip->operational = false; + + pwmchip_dev = &chip->dev; + device_initialize(pwmchip_dev); + pwmchip_dev->class = &pwm_class; + pwmchip_dev->parent = parent; + pwmchip_dev->release = pwmchip_release; + + pwmchip_set_drvdata(chip, pwmchip_priv(chip)); + + for (i = 0; i < chip->npwm; i++) { + struct pwm_device *pwm = &chip->pwms[i]; + pwm->chip = chip; + pwm->hwpwm = i; + } + + return chip; +} +EXPORT_SYMBOL_GPL(pwmchip_alloc); + +static void devm_pwmchip_put(void *data) +{ + struct pwm_chip *chip = data; + + pwmchip_put(chip); +} + +struct pwm_chip *devm_pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv) +{ + struct pwm_chip *chip; + int ret; + + chip = pwmchip_alloc(parent, npwm, sizeof_priv); + if (IS_ERR(chip)) + return chip; + + ret = devm_add_action_or_reset(parent, devm_pwmchip_put, chip); + if (ret) + return ERR_PTR(ret); + + return chip; +} +EXPORT_SYMBOL_GPL(devm_pwmchip_alloc); + +static void of_pwmchip_add(struct pwm_chip *chip) +{ + if (!pwmchip_parent(chip) || !pwmchip_parent(chip)->of_node) + return; + + if (!chip->of_xlate) + chip->of_xlate = of_pwm_xlate_with_flags; + + of_node_get(pwmchip_parent(chip)->of_node); +} + +static void of_pwmchip_remove(struct pwm_chip *chip) +{ + if (pwmchip_parent(chip)) + of_node_put(pwmchip_parent(chip)->of_node); +} + +static bool pwm_ops_check(const struct pwm_chip *chip) +{ + const struct pwm_ops *ops = chip->ops; + + if (ops->write_waveform) { + if (!ops->round_waveform_tohw || + !ops->round_waveform_fromhw || + !ops->write_waveform) + return false; + + if (WFHWSIZE < ops->sizeof_wfhw) { + dev_warn(pwmchip_parent(chip), "WFHWSIZE < %zu\n", ops->sizeof_wfhw); + return false; + } + } else { + if (!ops->apply) + return false; + + if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state) + dev_warn(pwmchip_parent(chip), + "Please implement the .get_state() callback\n"); + } + + return true; } static struct device_link *pwm_device_link_add(struct device *dev, @@ -635,21 +1651,35 @@ static struct device_link *pwm_device_link_add(struct device *dev, * impact the PM sequence ordering: the PWM supplier may get * suspended before the consumer. */ - dev_warn(pwm->chip->dev, + dev_warn(pwmchip_parent(pwm->chip), "No consumer device specified to create a link to\n"); return NULL; } - dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER); + dl = device_link_add(dev, pwmchip_parent(pwm->chip), DL_FLAG_AUTOREMOVE_CONSUMER); if (!dl) { dev_err(dev, "failed to create device link to %s\n", - dev_name(pwm->chip->dev)); + dev_name(pwmchip_parent(pwm->chip))); return ERR_PTR(-EINVAL); } return dl; } +static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode) +{ + struct pwm_chip *chip; + unsigned long id, tmp; + + guard(mutex)(&pwm_lock); + + idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) + if (pwmchip_parent(chip) && device_match_fwnode(pwmchip_parent(chip), fwnode)) + return chip; + + return ERR_PTR(-EPROBE_DEFER); +} + /** * of_pwm_get() - request a PWM via the PWM framework * @dev: device for PWM consumer @@ -784,39 +1814,8 @@ static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode) return pwm; } -/** - * pwm_add_table() - register PWM device consumers - * @table: array of consumers to register - * @num: number of consumers in table - */ -void pwm_add_table(struct pwm_lookup *table, size_t num) -{ - mutex_lock(&pwm_lookup_lock); - - while (num--) { - list_add_tail(&table->list, &pwm_lookup_list); - table++; - } - - mutex_unlock(&pwm_lookup_lock); -} - -/** - * pwm_remove_table() - unregister PWM device consumers - * @table: array of consumers to unregister - * @num: number of consumers in table - */ -void pwm_remove_table(struct pwm_lookup *table, size_t num) -{ - mutex_lock(&pwm_lookup_lock); - - while (num--) { - list_del(&table->list); - table++; - } - - mutex_unlock(&pwm_lookup_lock); -} +static DEFINE_MUTEX(pwm_lookup_lock); +static LIST_HEAD(pwm_lookup_list); /** * pwm_get() - look up and request a PWM device @@ -876,36 +1875,33 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) * Then we take the most specific entry - with the following order * of precedence: dev+con > dev only > con only. */ - mutex_lock(&pwm_lookup_lock); + scoped_guard(mutex, &pwm_lookup_lock) + list_for_each_entry(p, &pwm_lookup_list, list) { + match = 0; - list_for_each_entry(p, &pwm_lookup_list, list) { - match = 0; + if (p->dev_id) { + if (!dev_id || strcmp(p->dev_id, dev_id)) + continue; - if (p->dev_id) { - if (!dev_id || strcmp(p->dev_id, dev_id)) - continue; + match += 2; + } - match += 2; - } + if (p->con_id) { + if (!con_id || strcmp(p->con_id, con_id)) + continue; - if (p->con_id) { - if (!con_id || strcmp(p->con_id, con_id)) - continue; + match += 1; + } - match += 1; - } + if (match > best) { + chosen = p; - if (match > best) { - chosen = p; - - if (match != 3) - best = match; - else - break; + if (match != 3) + best = match; + else + break; + } } - } - - mutex_unlock(&pwm_lookup_lock); if (!chosen) return ERR_PTR(-ENODEV); @@ -950,24 +1946,33 @@ EXPORT_SYMBOL_GPL(pwm_get); */ void pwm_put(struct pwm_device *pwm) { + struct pwm_chip *chip; + if (!pwm) return; - mutex_lock(&pwm_lock); + chip = pwm->chip; - if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) { + guard(mutex)(&pwm_lock); + + /* + * Trigger a warning if a consumer called pwm_put() twice. + * If the chip isn't operational, PWMF_REQUESTED was already cleared in + * pwmchip_remove(). So don't warn in this case. + */ + if (chip->operational && !test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) { pr_warn("PWM device already freed\n"); - goto out; + return; } - if (pwm->chip->ops->free) + if (chip->operational && chip->ops->free) pwm->chip->ops->free(pwm->chip, pwm); pwm->label = NULL; - module_put(pwm->chip->owner); -out: - mutex_unlock(&pwm_lock); + put_device(&chip->dev); + + module_put(chip->owner); } EXPORT_SYMBOL_GPL(pwm_put); @@ -1038,7 +2043,162 @@ struct pwm_device *devm_fwnode_pwm_get(struct device *dev, } EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get); -#ifdef CONFIG_DEBUG_FS +/** + * __pwmchip_add() - register a new PWM chip + * @chip: the PWM chip to add + * @owner: reference to the module providing the chip. + * + * Register a new PWM chip. @owner is supposed to be THIS_MODULE, use the + * pwmchip_add wrapper to do this right. + * + * Returns: 0 on success or a negative error code on failure. + */ +int __pwmchip_add(struct pwm_chip *chip, struct module *owner) +{ + int ret; + + if (!chip || !pwmchip_parent(chip) || !chip->ops || !chip->npwm) + return -EINVAL; + + /* + * a struct pwm_chip must be allocated using (devm_)pwmchip_alloc, + * otherwise the embedded struct device might disappear too early + * resulting in memory corruption. + * Catch drivers that were not converted appropriately. + */ + if (!chip->uses_pwmchip_alloc) + return -EINVAL; + + if (!pwm_ops_check(chip)) + return -EINVAL; + + chip->owner = owner; + + if (chip->atomic) + spin_lock_init(&chip->atomic_lock); + else + mutex_init(&chip->nonatomic_lock); + + guard(mutex)(&pwm_lock); + + ret = idr_alloc(&pwm_chips, chip, 0, 0, GFP_KERNEL); + if (ret < 0) + return ret; + + chip->id = ret; + + dev_set_name(&chip->dev, "pwmchip%u", chip->id); + + if (IS_ENABLED(CONFIG_OF)) + of_pwmchip_add(chip); + + scoped_guard(pwmchip, chip) + chip->operational = true; + + ret = device_add(&chip->dev); + if (ret) + goto err_device_add; + + return 0; + +err_device_add: + scoped_guard(pwmchip, chip) + chip->operational = false; + + if (IS_ENABLED(CONFIG_OF)) + of_pwmchip_remove(chip); + + idr_remove(&pwm_chips, chip->id); + + return ret; +} +EXPORT_SYMBOL_GPL(__pwmchip_add); + +/** + * pwmchip_remove() - remove a PWM chip + * @chip: the PWM chip to remove + * + * Removes a PWM chip. + */ +void pwmchip_remove(struct pwm_chip *chip) +{ + pwmchip_sysfs_unexport(chip); + + scoped_guard(mutex, &pwm_lock) { + unsigned int i; + + scoped_guard(pwmchip, chip) + chip->operational = false; + + for (i = 0; i < chip->npwm; ++i) { + struct pwm_device *pwm = &chip->pwms[i]; + + if (test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) { + dev_warn(&chip->dev, "Freeing requested PWM #%u\n", i); + if (pwm->chip->ops->free) + pwm->chip->ops->free(pwm->chip, pwm); + } + } + + if (IS_ENABLED(CONFIG_OF)) + of_pwmchip_remove(chip); + + idr_remove(&pwm_chips, chip->id); + } + + device_del(&chip->dev); +} +EXPORT_SYMBOL_GPL(pwmchip_remove); + +static void devm_pwmchip_remove(void *data) +{ + struct pwm_chip *chip = data; + + pwmchip_remove(chip); +} + +int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner) +{ + int ret; + + ret = __pwmchip_add(chip, owner); + if (ret) + return ret; + + return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip); +} +EXPORT_SYMBOL_GPL(__devm_pwmchip_add); + +/** + * pwm_add_table() - register PWM device consumers + * @table: array of consumers to register + * @num: number of consumers in table + */ +void pwm_add_table(struct pwm_lookup *table, size_t num) +{ + guard(mutex)(&pwm_lookup_lock); + + while (num--) { + list_add_tail(&table->list, &pwm_lookup_list); + table++; + } +} + +/** + * pwm_remove_table() - unregister PWM device consumers + * @table: array of consumers to unregister + * @num: number of consumers in table + */ +void pwm_remove_table(struct pwm_lookup *table, size_t num) +{ + guard(mutex)(&pwm_lookup_lock); + + while (num--) { + list_del(&table->list); + table++; + } +} + static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s) { unsigned int i; @@ -1105,8 +2265,8 @@ static int pwm_seq_show(struct seq_file *s, void *v) seq_printf(s, "%s%d: %s/%s, %d PWM device%s\n", (char *)s->private, chip->id, - chip->dev->bus ? chip->dev->bus->name : "no-bus", - dev_name(chip->dev), chip->npwm, + pwmchip_parent(chip)->bus ? pwmchip_parent(chip)->bus->name : "no-bus", + dev_name(pwmchip_parent(chip)), chip->npwm, (chip->npwm != 1) ? "s" : ""); pwm_dbg_show(chip, s); @@ -1123,11 +2283,19 @@ static const struct seq_operations pwm_debugfs_sops = { DEFINE_SEQ_ATTRIBUTE(pwm_debugfs); -static int __init pwm_debugfs_init(void) +static int __init pwm_init(void) { - debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops); + int ret; + + ret = class_register(&pwm_class); + if (ret) { + pr_err("Failed to initialize PWM class (%pe)\n", ERR_PTR(ret)); + return ret; + } + + if (IS_ENABLED(CONFIG_DEBUG_FS)) + debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops); return 0; } -subsys_initcall(pwm_debugfs_init); -#endif /* CONFIG_DEBUG_FS */ +subsys_initcall(pwm_init); |