diff options
Diffstat (limited to 'drivers/pwm/core.c')
| -rw-r--r-- | drivers/pwm/core.c | 1596 |
1 files changed, 1312 insertions, 284 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 18574857641e..cd06229db394 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> @@ -21,14 +23,464 @@ #include <dt-bindings/pwm/pwm.h> +#include <uapi/linux/pwm.h> + #define CREATE_TRACE_POINTS #include <trace/events/pwm.h> +#define PWM_MINOR_COUNT 256 + /* protects access to pwm_chips */ static DEFINE_MUTEX(pwm_lock); static DEFINE_IDR(pwm_chips); +static void pwmchip_lock(struct pwm_chip *chip) +{ + if (chip->atomic) + spin_lock(&chip->atomic_lock); + else + mutex_lock(&chip->nonatomic_lock); +} + +static void pwmchip_unlock(struct pwm_chip *chip) +{ + if (chip->atomic) + spin_unlock(&chip->atomic_lock); + else + mutex_unlock(&chip->nonatomic_lock); +} + +DEFINE_GUARD(pwmchip, struct pwm_chip *, pwmchip_lock(_T), pwmchip_unlock(_T)) + +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 (wf->duty_length_ns > wf->period_length_ns) + return false; + + /* + * .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 true; +} + +static void pwm_wf2state(const struct pwm_waveform *wf, struct pwm_state *state) +{ + 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, + }; + } +} + +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, + }; + } +} + +static int pwmwfcmp(const struct pwm_waveform *a, const struct pwm_waveform *b) +{ + if (a->period_length_ns > b->period_length_ns) + return 1; + + if (a->period_length_ns < b->period_length_ns) + return -1; + + if (a->duty_length_ns > b->duty_length_ns) + return 1; + + if (a->duty_length_ns < b->duty_length_ns) + return -1; + + if (a->duty_offset_ns > b->duty_offset_ns) + return 1; + + if (a->duty_offset_ns < b->duty_offset_ns) + return -1; + + return 0; +} + +static bool pwm_check_rounding(const struct pwm_waveform *wf, + const struct pwm_waveform *wf_rounded) +{ + if (!wf->period_length_ns) + return true; + + if (wf->period_length_ns < wf_rounded->period_length_ns) + return false; + + if (wf->duty_length_ns < wf_rounded->duty_length_ns) + return false; + + if (wf->duty_offset_ns < wf_rounded->duty_offset_ns) + return false; + + return true; +} + +static int __pwm_round_waveform_tohw(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_waveform *wf, void *wfhw) +{ + const struct pwm_ops *ops = chip->ops; + int ret; + + ret = ops->round_waveform_tohw(chip, pwm, wf, wfhw); + trace_pwm_round_waveform_tohw(pwm, wf, wfhw, ret); + + return ret; +} + +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); + + return ret; +} + +static int __pwm_read_waveform(struct pwm_chip *chip, struct pwm_device *pwm, void *wfhw) +{ + 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 int __pwm_write_waveform(struct pwm_chip *chip, struct pwm_device *pwm, const void *wfhw) +{ + const struct pwm_ops *ops = chip->ops; + int ret; + + ret = ops->write_waveform(chip, pwm, wfhw); + trace_pwm_write_waveform(pwm, wfhw, ret); + + return ret; +} + +/** + * pwm_round_waveform_might_sleep - Query hardware capabilities + * Cannot be used in atomic context. + * @pwm: PWM device + * @wf: waveform to round and output parameter + * + * 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. + * + * 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. + * + * Usually all values passed in @wf are rounded down to the nearest possible + * value (in the order period_length_ns, duty_length_ns and then + * duty_offset_ns). Only if this isn't possible, a value might grow. See the + * documentation for pwm_set_waveform_might_sleep() for a more formal + * description. + * + * Returns: 0 on success, 1 if at least one value had to be rounded up or a + * negative errno. + * Context: May sleep. + */ +int pwm_round_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform *wf) +{ + struct pwm_chip *chip = pwm->chip; + const struct pwm_ops *ops = chip->ops; + struct pwm_waveform wf_req = *wf; + char wfhw[PWM_WFHWSIZE]; + int ret_tohw, ret_fromhw; + + BUG_ON(PWM_WFHWSIZE < ops->sizeof_wfhw); + + if (!pwmchip_supports_waveform(chip)) + return -EOPNOTSUPP; + + if (!pwm_wf_valid(wf)) + return -EINVAL; + + guard(pwmchip)(chip); + + if (!chip->operational) + return -ENODEV; + + ret_tohw = __pwm_round_waveform_tohw(chip, pwm, wf, wfhw); + if (ret_tohw < 0) + return ret_tohw; + + 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); + + ret_fromhw = __pwm_round_waveform_fromhw(chip, pwm, wfhw, wf); + if (ret_fromhw < 0) + return ret_fromhw; + + 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_fromhw); + + 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], ret: %d\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, ret_tohw); + + return ret_tohw; +} +EXPORT_SYMBOL_GPL(pwm_round_waveform_might_sleep); + +/** + * pwm_get_waveform_might_sleep - Query hardware about current configuration + * Cannot be used in atomic context. + * @pwm: PWM device + * @wf: output parameter + * + * 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. + * + * Returns: 0 on success or a negative errno + * Context: May sleep. + */ +int pwm_get_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform *wf) +{ + struct pwm_chip *chip = pwm->chip; + const struct pwm_ops *ops = chip->ops; + char wfhw[PWM_WFHWSIZE]; + int err; + + BUG_ON(PWM_WFHWSIZE < ops->sizeof_wfhw); + + if (!pwmchip_supports_waveform(chip) || !ops->read_waveform) + return -EOPNOTSUPP; + + guard(pwmchip)(chip); + + if (!chip->operational) + return -ENODEV; + + err = __pwm_read_waveform(chip, pwm, &wfhw); + if (err) + return err; + + return __pwm_round_waveform_fromhw(chip, pwm, &wfhw, wf); +} +EXPORT_SYMBOL_GPL(pwm_get_waveform_might_sleep); + +/* 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 = pwm->chip; + const struct pwm_ops *ops = chip->ops; + char wfhw[PWM_WFHWSIZE]; + struct pwm_waveform wf_rounded; + int err, ret_tohw; + + BUG_ON(PWM_WFHWSIZE < ops->sizeof_wfhw); + + if (!pwmchip_supports_waveform(chip)) + return -EOPNOTSUPP; + + if (!pwm_wf_valid(wf)) + return -EINVAL; + + ret_tohw = __pwm_round_waveform_tohw(chip, pwm, wf, &wfhw); + if (ret_tohw < 0) + return ret_tohw; + + 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) && (ret_tohw == 0) != pwm_check_rounding(wf, &wf_rounded)) + dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu], ret: %d\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, ret_tohw); + + 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 ret_tohw; +} + +/** + * 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 + * + * 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 -EDOM. + * 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 ns 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. + * + * Let C be the set of possible hardware configurations for a given PWM device, + * consisting of tuples (p, d, o) where p is the period length, d is the duty + * length and o the duty offset. + * + * The following algorithm is implemented to pick the hardware setting + * (p, d, o) ∈ C for a given request (p', d', o') with @exact = false:: + * + * p = max( { ṗ | ∃ ḋ, ȯ : (ṗ, ḋ, ȯ) ∈ C ∧ ṗ ≤ p' } ∪ { min({ ṗ | ∃ ḋ, ȯ : (ṗ, ḋ, ȯ) ∈ C }) }) + * d = max( { ḋ | ∃ ȯ : (p, ḋ, ȯ) ∈ C ∧ ḋ ≤ d' } ∪ { min({ ḋ | ∃ ȯ : (p, ḋ, ȯ) ∈ C }) }) + * o = max( { ȯ | (p, d, ȯ) ∈ C ∧ ȯ ≤ o' } ∪ { min({ ȯ | (p, d, ȯ) ∈ C }) }) + * + * In words: The chosen period length is the maximal possible period length not + * bigger than the requested period length and if that doesn't exist, the + * minimal period length. The chosen duty length is the maximal possible duty + * length that is compatible with the chosen period length and isn't bigger than + * the requested duty length. Again if such a value doesn't exist, the minimal + * duty length compatible with the chosen period is picked. After that the duty + * offset compatible with the chosen period and duty length is chosen in the + * same way. + * + * Returns: 0 on success, -EDOM if setting failed due to the exact waveform not + * being possible (if @exact), or a different negative errno on failure. + * Context: May sleep. + */ +int pwm_set_waveform_might_sleep(struct pwm_device *pwm, + const struct pwm_waveform *wf, bool exact) +{ + struct pwm_chip *chip = pwm->chip; + int err; + + might_sleep(); + + 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. + */ + non_block_start(); + err = __pwm_set_waveform(pwm, wf, exact); + non_block_end(); + } else { + err = __pwm_set_waveform(pwm, wf, exact); + } + + /* + * map err == 1 to -EDOM for exact requests and 0 for !exact ones. Also + * make sure that -EDOM is only returned in exactly that case. Note that + * __pwm_set_waveform() should never return -EDOM which justifies the + * unlikely(). + */ + if (unlikely(err == -EDOM)) + err = -EINVAL; + else if (exact && err == 1) + err = -EDOM; + else if (err == 1) + err = 0; + + return err; +} +EXPORT_SYMBOL_GPL(pwm_set_waveform_might_sleep); + static void pwm_apply_debug(struct pwm_device *pwm, const struct pwm_state *state) { @@ -45,6 +497,13 @@ static void pwm_apply_debug(struct pwm_device *pwm, return; /* + * If a disabled PWM was requested the result is unspecified, so nothing + * to check. + */ + if (!state->enabled) + return; + + /* * *state was just applied. Read out the hardware state and do some * checks. */ @@ -56,38 +515,47 @@ static void pwm_apply_debug(struct pwm_device *pwm, return; /* + * If the PWM was disabled that's maybe strange but there is nothing + * that can be sensibly checked then. So return early. + */ + if (!s1.enabled) + return; + + /* * The lowlevel driver either ignored .polarity (which is a bug) or as * best effort inverted .polarity and fixed .duty_cycle respectively. * Undo this inversion and fixup for further tests. */ - if (s1.enabled && s1.polarity != state->polarity) { + if (s1.polarity != state->polarity) { s2.polarity = state->polarity; s2.duty_cycle = s1.period - s1.duty_cycle; s2.period = s1.period; - s2.enabled = s1.enabled; + s2.enabled = true; } else { s2 = s1; } if (s2.polarity != state->polarity && - state->duty_cycle < state->period) + s2.duty_cycle < s2.period) dev_warn(pwmchip_parent(chip), ".apply ignored .polarity\n"); - if (state->enabled && - last->polarity == state->polarity && + if (last->polarity == state->polarity && last->period > s2.period && last->period <= state->period) 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) + /* + * Rounding period up is fine only if duty_cycle is 0 then, because a + * flat line doesn't have a characteristic period. + */ + if (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); - if (state->enabled && - last->polarity == state->polarity && + if (last->polarity == state->polarity && last->period == s2.period && last->duty_cycle > s2.duty_cycle && last->duty_cycle <= state->duty_cycle) @@ -97,16 +565,12 @@ static void pwm_apply_debug(struct pwm_device *pwm, s2.duty_cycle, s2.period, last->duty_cycle, last->period); - if (state->enabled && state->duty_cycle < s2.duty_cycle) + if (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(pwmchip_parent(chip), - "requested disabled, but yielded enabled with duty > 0\n"); - /* reapply the state that the driver reported being configured. */ err = chip->ops->apply(chip, pwm, &s1); trace_pwm_apply(pwm, &s1, err); @@ -135,21 +599,53 @@ static void pwm_apply_debug(struct pwm_device *pwm, } } -/** - * __pwm_apply() - atomically apply a new state to a PWM device - * @pwm: PWM device - * @state: new state to apply - */ +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; +} + 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 && @@ -158,18 +654,69 @@ 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[PWM_WFHWSIZE]; - pwm->state = *state; + BUG_ON(PWM_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; } @@ -179,10 +726,14 @@ static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state) * Cannot be used in atomic context. * @pwm: PWM device * @state: new state to apply + * + * Returns: 0 on success, or a negative errno + * Context: May sleep. */ 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 @@ -193,7 +744,12 @@ 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. @@ -214,23 +770,85 @@ EXPORT_SYMBOL_GPL(pwm_apply_might_sleep); * Not all PWM devices support this function, check with pwm_might_sleep(). * @pwm: PWM device * @state: new state to apply + * + * Returns: 0 on success, or a negative errno + * Context: Any */ 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_get_state_hw() - get the current PWM state from hardware + * @pwm: PWM device + * @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_get_state_hw(struct pwm_device *pwm, struct pwm_state *state) +{ + struct pwm_chip *chip = pwm->chip; + const struct pwm_ops *ops = chip->ops; + int ret = -EOPNOTSUPP; + + might_sleep(); + + guard(pwmchip)(chip); + + if (!chip->operational) + return -ENODEV; + + if (pwmchip_supports_waveform(chip) && ops->read_waveform) { + char wfhw[PWM_WFHWSIZE]; + struct pwm_waveform wf; + + BUG_ON(PWM_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_get_state_hw); + +/** * pwm_adjust_config() - adjust the current PWM config to the PWM arguments * @pwm: PWM device * * This function will adjust the PWM config to the PWM arguments provided * by the DT or PWM lookup table. This is particularly useful to adapt * the bootloader config to the Linux one. + * + * Returns: 0 on success or a negative error code on failure. + * Context: May sleep. */ int pwm_adjust_config(struct pwm_device *pwm) { @@ -288,24 +906,29 @@ EXPORT_SYMBOL_GPL(pwm_adjust_config); * * Returns: 0 on success or a negative error code on failure. */ -int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, - unsigned long timeout) +static int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, + unsigned long timeout) { - int err; - - if (!pwm || !pwm->chip->ops) - return -EINVAL; + struct pwm_chip *chip = pwm->chip; + const struct pwm_ops *ops = chip->ops; - if (!pwm->chip->ops->capture) + if (!ops->capture) return -ENOSYS; - mutex_lock(&pwm_lock); - err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout); - mutex_unlock(&pwm_lock); + /* + * 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); - return err; + guard(pwmchip)(chip); + + if (!chip->operational) + return -ENODEV; + + return ops->capture(chip, pwm, result, timeout); } -EXPORT_SYMBOL_GPL(pwm_capture); static struct pwm_chip *pwmchip_find_by_name(const char *name) { @@ -315,19 +938,13 @@ static struct pwm_chip *pwmchip_find_by_name(const char *name) if (!name) return NULL; - mutex_lock(&pwm_lock); + guard(mutex)(&pwm_lock); idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) { - const char *chip_name = dev_name(pwmchip_parent(chip)); - - if (chip_name && strcmp(chip_name, name) == 0) { - mutex_unlock(&pwm_lock); + if (device_match_name(pwmchip_parent(chip), name)) return chip; - } } - mutex_unlock(&pwm_lock); - return NULL; } @@ -340,6 +957,14 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label) 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; @@ -358,7 +983,7 @@ err_get_device: } } - if (ops->get_state) { + 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 @@ -368,9 +993,7 @@ err_get_device: */ struct pwm_state state = { 0, }; - err = ops->get_state(chip, pwm, &state); - trace_pwm_get(pwm, &state, err); - + err = pwm_get_state_hw(pwm, &state); if (!err) pwm->state = state; @@ -394,9 +1017,9 @@ err_get_device: * 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. */ -struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, - unsigned int index, - const char *label) +static struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, + unsigned int index, + const char *label) { struct pwm_device *pwm; int err; @@ -404,18 +1027,16 @@ struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, if (!chip || index >= chip->npwm) return ERR_PTR(-EINVAL); - mutex_lock(&pwm_lock); + guard(mutex)(&pwm_lock); + pwm = &chip->pwms[index]; err = pwm_device_request(pwm, label); if (err < 0) - pwm = ERR_PTR(err); + return ERR_PTR(err); - mutex_unlock(&pwm_lock); return pwm; } -EXPORT_SYMBOL_GPL(pwm_request_from_chip); - struct pwm_device * of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args) @@ -441,11 +1062,27 @@ of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *arg } EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags); +/* + * This callback is used for PXA PWM chips that only have a single PWM line. + * For such chips you could argue that passing the line number (i.e. the first + * parameter in the common case) is useless as it's always zero. So compared to + * the default xlate function of_pwm_xlate_with_flags() the first parameter is + * the default period and the second are flags. + * + * Note that if #pwm-cells = <3>, the semantic is the same as for + * of_pwm_xlate_with_flags() to allow converting the affected driver to + * #pwm-cells = <3> without breaking the legacy binding. + * + * Don't use for new drivers. + */ struct pwm_device * of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args) { struct pwm_device *pwm; + if (args->args_count >= 3) + return of_pwm_xlate_with_flags(chip, args); + pwm = pwm_request_from_chip(chip, 0, NULL); if (IS_ERR(pwm)) return pwm; @@ -511,11 +1148,11 @@ static ssize_t period_store(struct device *pwm_dev, if (ret) return ret; - mutex_lock(&export->lock); + guard(mutex)(&export->lock); + pwm_get_state(pwm, &state); state.period = val; ret = pwm_apply_might_sleep(pwm, &state); - mutex_unlock(&export->lock); return ret ? : size; } @@ -546,11 +1183,11 @@ static ssize_t duty_cycle_store(struct device *pwm_dev, if (ret) return ret; - mutex_lock(&export->lock); + guard(mutex)(&export->lock); + pwm_get_state(pwm, &state); state.duty_cycle = val; ret = pwm_apply_might_sleep(pwm, &state); - mutex_unlock(&export->lock); return ret ? : size; } @@ -580,7 +1217,7 @@ static ssize_t enable_store(struct device *pwm_dev, if (ret) return ret; - mutex_lock(&export->lock); + guard(mutex)(&export->lock); pwm_get_state(pwm, &state); @@ -592,14 +1229,11 @@ static ssize_t enable_store(struct device *pwm_dev, state.enabled = true; break; default: - ret = -EINVAL; - goto unlock; + return -EINVAL; } ret = pwm_apply_might_sleep(pwm, &state); -unlock: - mutex_unlock(&export->lock); return ret ? : size; } @@ -643,11 +1277,11 @@ static ssize_t polarity_store(struct device *pwm_dev, else return -EINVAL; - mutex_lock(&export->lock); + guard(mutex)(&export->lock); + pwm_get_state(pwm, &state); state.polarity = polarity; ret = pwm_apply_might_sleep(pwm, &state); - mutex_unlock(&export->lock); return ret ? : size; } @@ -729,7 +1363,7 @@ static int pwm_export_child(struct device *pwmchip_dev, struct pwm_device *pwm) return 0; } -static int pwm_unexport_match(struct device *pwm_dev, void *data) +static int pwm_unexport_match(struct device *pwm_dev, const void *data) { return pwm_from_dev(pwm_dev) == data; } @@ -974,12 +1608,13 @@ void pwmchip_put(struct pwm_chip *chip) } EXPORT_SYMBOL_GPL(pwmchip_put); -static void pwmchip_release(struct device *pwmchip_dev) +void pwmchip_release(struct device *pwmchip_dev) { struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev); kfree(chip); } +EXPORT_SYMBOL_GPL(pwmchip_release); struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv) { @@ -997,6 +1632,7 @@ struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t chip->npwm = npwm; chip->uses_pwmchip_alloc = true; + chip->operational = false; pwmchip_dev = &chip->dev; device_initialize(pwmchip_dev); @@ -1061,122 +1697,27 @@ static bool pwm_ops_check(const struct pwm_chip *chip) { const struct pwm_ops *ops = chip->ops; - 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; -} - -/** - * __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; - - mutex_lock(&pwm_lock); - - ret = idr_alloc(&pwm_chips, chip, 0, 0, GFP_KERNEL); - if (ret < 0) - goto err_idr_alloc; - - chip->id = ret; - - dev_set_name(&chip->dev, "pwmchip%u", chip->id); - - if (IS_ENABLED(CONFIG_OF)) - of_pwmchip_add(chip); - - ret = device_add(&chip->dev); - if (ret) - goto err_device_add; - - mutex_unlock(&pwm_lock); - - return 0; - -err_device_add: - if (IS_ENABLED(CONFIG_OF)) - of_pwmchip_remove(chip); - - idr_remove(&pwm_chips, chip->id); -err_idr_alloc: - - mutex_unlock(&pwm_lock); - - 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); - - if (IS_ENABLED(CONFIG_OF)) - of_pwmchip_remove(chip); - - mutex_lock(&pwm_lock); - - idr_remove(&pwm_chips, chip->id); - - mutex_unlock(&pwm_lock); + if (ops->write_waveform) { + if (!ops->round_waveform_tohw || + !ops->round_waveform_fromhw || + !ops->write_waveform) + return false; - 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; + if (PWM_WFHWSIZE < ops->sizeof_wfhw) { + dev_warn(pwmchip_parent(chip), "PWM_WFHWSIZE < %zu\n", ops->sizeof_wfhw); + return false; + } + } else { + if (!ops->apply) + return false; - ret = __pwmchip_add(chip, owner); - if (ret) - return ret; + if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state) + dev_warn(pwmchip_parent(chip), + "Please implement the .get_state() callback\n"); + } - return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip); + return true; } -EXPORT_SYMBOL_GPL(__devm_pwmchip_add); static struct device_link *pwm_device_link_add(struct device *dev, struct pwm_device *pwm) @@ -1209,15 +1750,11 @@ static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode) struct pwm_chip *chip; unsigned long id, tmp; - mutex_lock(&pwm_lock); + 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)) { - mutex_unlock(&pwm_lock); + if (pwmchip_parent(chip) && device_match_fwnode(pwmchip_parent(chip), fwnode)) return chip; - } - - mutex_unlock(&pwm_lock); return ERR_PTR(-EPROBE_DEFER); } @@ -1258,8 +1795,7 @@ static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np, return ERR_PTR(index); } - err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index, - &args); + err = of_parse_phandle_with_args_map(np, "pwms", "pwm", index, &args); if (err) { pr_err("%s(): can't parse \"pwms\" property\n", __func__); return ERR_PTR(err); @@ -1360,40 +1896,6 @@ static DEFINE_MUTEX(pwm_lookup_lock); static LIST_HEAD(pwm_lookup_list); /** - * 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); -} - -/** * pwm_get() - look up and request a PWM device * @dev: device for PWM consumer * @con_id: consumer name @@ -1451,36 +1953,33 @@ 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); @@ -1519,27 +2018,21 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) } EXPORT_SYMBOL_GPL(pwm_get); -/** - * pwm_put() - release a PWM device - * @pwm: PWM device - */ -void pwm_put(struct pwm_device *pwm) +static void __pwm_put(struct pwm_device *pwm) { - struct pwm_chip *chip; - - if (!pwm) - return; - - chip = pwm->chip; - - mutex_lock(&pwm_lock); + struct pwm_chip *chip = pwm->chip; - if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) { + /* + * 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 (chip->ops->free) + if (chip->operational && chip->ops->free) pwm->chip->ops->free(pwm->chip, pwm); pwm->label = NULL; @@ -1547,8 +2040,20 @@ void pwm_put(struct pwm_device *pwm) put_device(&chip->dev); module_put(chip->owner); -out: - mutex_unlock(&pwm_lock); +} + +/** + * pwm_put() - release a PWM device + * @pwm: PWM device + */ +void pwm_put(struct pwm_device *pwm) +{ + if (!pwm) + return; + + guard(mutex)(&pwm_lock); + + __pwm_put(pwm); } EXPORT_SYMBOL_GPL(pwm_put); @@ -1619,31 +2124,540 @@ struct pwm_device *devm_fwnode_pwm_get(struct device *dev, } EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get); +struct pwm_cdev_data { + struct pwm_chip *chip; + struct pwm_device *pwm[]; +}; + +static int pwm_cdev_open(struct inode *inode, struct file *file) +{ + struct pwm_chip *chip = container_of(inode->i_cdev, struct pwm_chip, cdev); + struct pwm_cdev_data *cdata; + + guard(mutex)(&pwm_lock); + + if (!chip->operational) + return -ENXIO; + + cdata = kzalloc(struct_size(cdata, pwm, chip->npwm), GFP_KERNEL); + if (!cdata) + return -ENOMEM; + + cdata->chip = chip; + + file->private_data = cdata; + + return nonseekable_open(inode, file); +} + +static int pwm_cdev_release(struct inode *inode, struct file *file) +{ + struct pwm_cdev_data *cdata = file->private_data; + unsigned int i; + + for (i = 0; i < cdata->chip->npwm; ++i) { + struct pwm_device *pwm = cdata->pwm[i]; + + if (pwm) { + const char *label = pwm->label; + + pwm_put(cdata->pwm[i]); + kfree(label); + } + } + kfree(cdata); + + return 0; +} + +static int pwm_cdev_request(struct pwm_cdev_data *cdata, unsigned int hwpwm) +{ + struct pwm_chip *chip = cdata->chip; + + if (hwpwm >= chip->npwm) + return -EINVAL; + + if (!cdata->pwm[hwpwm]) { + struct pwm_device *pwm = &chip->pwms[hwpwm]; + const char *label; + int ret; + + label = kasprintf(GFP_KERNEL, "pwm-cdev (pid=%d)", current->pid); + if (!label) + return -ENOMEM; + + ret = pwm_device_request(pwm, label); + if (ret < 0) { + kfree(label); + return ret; + } + + cdata->pwm[hwpwm] = pwm; + } + + return 0; +} + +static int pwm_cdev_free(struct pwm_cdev_data *cdata, unsigned int hwpwm) +{ + struct pwm_chip *chip = cdata->chip; + + if (hwpwm >= chip->npwm) + return -EINVAL; + + if (cdata->pwm[hwpwm]) { + struct pwm_device *pwm = cdata->pwm[hwpwm]; + const char *label = pwm->label; + + __pwm_put(pwm); + + kfree(label); + + cdata->pwm[hwpwm] = NULL; + } + + return 0; +} + +static struct pwm_device *pwm_cdev_get_requested_pwm(struct pwm_cdev_data *cdata, + u32 hwpwm) +{ + struct pwm_chip *chip = cdata->chip; + + if (hwpwm >= chip->npwm) + return ERR_PTR(-EINVAL); + + if (cdata->pwm[hwpwm]) + return cdata->pwm[hwpwm]; + + return ERR_PTR(-EINVAL); +} + +static long pwm_cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + int ret = 0; + struct pwm_cdev_data *cdata = file->private_data; + struct pwm_chip *chip = cdata->chip; + + guard(mutex)(&pwm_lock); + + if (!chip->operational) + return -ENODEV; + + switch (cmd) { + case PWM_IOCTL_REQUEST: + { + unsigned int hwpwm = arg; + + return pwm_cdev_request(cdata, hwpwm); + } + + case PWM_IOCTL_FREE: + { + unsigned int hwpwm = arg; + + return pwm_cdev_free(cdata, hwpwm); + } + + case PWM_IOCTL_ROUNDWF: + { + struct pwmchip_waveform cwf; + struct pwm_waveform wf; + struct pwm_device *pwm; + + ret = copy_from_user(&cwf, + (struct pwmchip_waveform __user *)arg, + sizeof(cwf)); + if (ret) + return -EFAULT; + + if (cwf.__pad != 0) + return -EINVAL; + + pwm = pwm_cdev_get_requested_pwm(cdata, cwf.hwpwm); + if (IS_ERR(pwm)) + return PTR_ERR(pwm); + + wf = (struct pwm_waveform) { + .period_length_ns = cwf.period_length_ns, + .duty_length_ns = cwf.duty_length_ns, + .duty_offset_ns = cwf.duty_offset_ns, + }; + + ret = pwm_round_waveform_might_sleep(pwm, &wf); + if (ret < 0) + return ret; + + cwf = (struct pwmchip_waveform) { + .hwpwm = cwf.hwpwm, + .period_length_ns = wf.period_length_ns, + .duty_length_ns = wf.duty_length_ns, + .duty_offset_ns = wf.duty_offset_ns, + }; + + return copy_to_user((struct pwmchip_waveform __user *)arg, + &cwf, sizeof(cwf)); + } + + case PWM_IOCTL_GETWF: + { + struct pwmchip_waveform cwf; + struct pwm_waveform wf; + struct pwm_device *pwm; + + ret = copy_from_user(&cwf, + (struct pwmchip_waveform __user *)arg, + sizeof(cwf)); + if (ret) + return -EFAULT; + + if (cwf.__pad != 0) + return -EINVAL; + + pwm = pwm_cdev_get_requested_pwm(cdata, cwf.hwpwm); + if (IS_ERR(pwm)) + return PTR_ERR(pwm); + + ret = pwm_get_waveform_might_sleep(pwm, &wf); + if (ret) + return ret; + + cwf = (struct pwmchip_waveform) { + .hwpwm = cwf.hwpwm, + .period_length_ns = wf.period_length_ns, + .duty_length_ns = wf.duty_length_ns, + .duty_offset_ns = wf.duty_offset_ns, + }; + + return copy_to_user((struct pwmchip_waveform __user *)arg, + &cwf, sizeof(cwf)); + } + + case PWM_IOCTL_SETROUNDEDWF: + case PWM_IOCTL_SETEXACTWF: + { + struct pwmchip_waveform cwf; + struct pwm_waveform wf; + struct pwm_device *pwm; + + ret = copy_from_user(&cwf, + (struct pwmchip_waveform __user *)arg, + sizeof(cwf)); + if (ret) + return -EFAULT; + + if (cwf.__pad != 0) + return -EINVAL; + + wf = (struct pwm_waveform){ + .period_length_ns = cwf.period_length_ns, + .duty_length_ns = cwf.duty_length_ns, + .duty_offset_ns = cwf.duty_offset_ns, + }; + + if (!pwm_wf_valid(&wf)) + return -EINVAL; + + pwm = pwm_cdev_get_requested_pwm(cdata, cwf.hwpwm); + if (IS_ERR(pwm)) + return PTR_ERR(pwm); + + ret = pwm_set_waveform_might_sleep(pwm, &wf, + cmd == PWM_IOCTL_SETEXACTWF); + + /* + * If userspace cares about rounding deviations it has + * to check the values anyhow, so simplify handling for + * them and don't signal uprounding. This matches the + * behaviour of PWM_IOCTL_ROUNDWF which also returns 0 + * in that case. + */ + if (ret == 1) + ret = 0; + + return ret; + } + + default: + return -ENOTTY; + } +} + +static const struct file_operations pwm_cdev_fileops = { + .open = pwm_cdev_open, + .release = pwm_cdev_release, + .owner = THIS_MODULE, + .unlocked_ioctl = pwm_cdev_ioctl, +}; + +static dev_t pwm_devt; + +static int pwm_gpio_request(struct gpio_chip *gc, unsigned int offset) +{ + struct pwm_chip *chip = gpiochip_get_data(gc); + struct pwm_device *pwm; + + pwm = pwm_request_from_chip(chip, offset, "pwm-gpio"); + if (IS_ERR(pwm)) + return PTR_ERR(pwm); + + return 0; +} + +static void pwm_gpio_free(struct gpio_chip *gc, unsigned int offset) +{ + struct pwm_chip *chip = gpiochip_get_data(gc); + + pwm_put(&chip->pwms[offset]); +} + +static int pwm_gpio_get_direction(struct gpio_chip *gc, unsigned int offset) +{ + return GPIO_LINE_DIRECTION_OUT; +} + +static int pwm_gpio_set(struct gpio_chip *gc, unsigned int offset, int value) +{ + struct pwm_chip *chip = gpiochip_get_data(gc); + struct pwm_device *pwm = &chip->pwms[offset]; + int ret; + struct pwm_waveform wf = { + .period_length_ns = 1, + }; + + ret = pwm_round_waveform_might_sleep(pwm, &wf); + if (ret < 0) + return ret; + + if (value) + wf.duty_length_ns = wf.period_length_ns; + else + wf.duty_length_ns = 0; + + return pwm_set_waveform_might_sleep(pwm, &wf, true); +} + +/** + * __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; + + if (chip->ops->write_waveform) { + if (chip->id < PWM_MINOR_COUNT) + chip->dev.devt = MKDEV(MAJOR(pwm_devt), chip->id); + else + dev_warn(&chip->dev, "chip id too high to create a chardev\n"); + } + + cdev_init(&chip->cdev, &pwm_cdev_fileops); + chip->cdev.owner = owner; + + ret = cdev_device_add(&chip->cdev, &chip->dev); + if (ret) + goto err_device_add; + + if (IS_ENABLED(CONFIG_PWM_PROVIDE_GPIO) && chip->ops->write_waveform) { + struct device *parent = pwmchip_parent(chip); + + chip->gpio = (typeof(chip->gpio)){ + .label = dev_name(parent), + .parent = parent, + .request = pwm_gpio_request, + .free = pwm_gpio_free, + .get_direction = pwm_gpio_get_direction, + .set = pwm_gpio_set, + .base = -1, + .ngpio = chip->npwm, + .can_sleep = true, + }; + + ret = gpiochip_add_data(&chip->gpio, chip); + if (ret) + goto err_gpiochip_add; + } + + return 0; + +err_gpiochip_add: + + cdev_device_del(&chip->cdev, &chip->dev); +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) +{ + if (IS_ENABLED(CONFIG_PWM_PROVIDE_GPIO) && chip->ops->write_waveform) + gpiochip_remove(&chip->gpio); + + 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); + } + + cdev_device_del(&chip->cdev, &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; for (i = 0; i < chip->npwm; i++) { struct pwm_device *pwm = &chip->pwms[i]; - struct pwm_state state; + struct pwm_state state, hwstate; pwm_get_state(pwm, &state); + pwm_get_state_hw(pwm, &hwstate); seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label); if (test_bit(PWMF_REQUESTED, &pwm->flags)) seq_puts(s, " requested"); - if (state.enabled) - seq_puts(s, " enabled"); + seq_puts(s, "\n"); - seq_printf(s, " period: %llu ns", state.period); - seq_printf(s, " duty: %llu ns", state.duty_cycle); - seq_printf(s, " polarity: %s", + seq_printf(s, " requested configuration: %3sabled, %llu/%llu ns, %s polarity", + state.enabled ? "en" : "dis", state.duty_cycle, state.period, state.polarity ? "inverse" : "normal"); - if (state.usage_power) - seq_puts(s, " usage_power"); + seq_puts(s, ", usage_power"); + seq_puts(s, "\n"); + + seq_printf(s, " actual configuration: %3sabled, %llu/%llu ns, %s polarity", + hwstate.enabled ? "en" : "dis", hwstate.duty_cycle, hwstate.period, + hwstate.polarity ? "inverse" : "normal"); seq_puts(s, "\n"); } @@ -1683,11 +2697,10 @@ static int pwm_seq_show(struct seq_file *s, void *v) { struct pwm_chip *chip = v; - seq_printf(s, "%s%d: %s/%s, %d PWM device%s\n", + seq_printf(s, "%s%u: %s/%s, npwm: %u\n", (char *)s->private, chip->id, pwmchip_parent(chip)->bus ? pwmchip_parent(chip)->bus->name : "no-bus", - dev_name(pwmchip_parent(chip)), chip->npwm, - (chip->npwm != 1) ? "s" : ""); + dev_name(pwmchip_parent(chip)), chip->npwm); pwm_dbg_show(chip, s); @@ -1705,9 +2718,24 @@ DEFINE_SEQ_ATTRIBUTE(pwm_debugfs); static int __init pwm_init(void) { + int ret; + + ret = alloc_chrdev_region(&pwm_devt, 0, PWM_MINOR_COUNT, "pwm"); + if (ret) { + pr_err("Failed to initialize chrdev region for PWM usage\n"); + return ret; + } + + ret = class_register(&pwm_class); + if (ret) { + pr_err("Failed to initialize PWM class (%pe)\n", ERR_PTR(ret)); + unregister_chrdev_region(pwm_devt, 256); + return ret; + } + if (IS_ENABLED(CONFIG_DEBUG_FS)) debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops); - return class_register(&pwm_class); + return 0; } subsys_initcall(pwm_init); |