diff options
Diffstat (limited to 'drivers/pwm/core.c')
| -rw-r--r-- | drivers/pwm/core.c | 479 |
1 files changed, 412 insertions, 67 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index a40c511e0096..0d66376a83ec 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -23,9 +23,13 @@ #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); @@ -206,8 +210,6 @@ static int __pwm_write_waveform(struct pwm_chip *chip, struct pwm_device *pwm, c return ret; } -#define WFHWSIZE 20 - /** * pwm_round_waveform_might_sleep - Query hardware capabilities * Cannot be used in atomic context. @@ -216,31 +218,38 @@ static int __pwm_write_waveform(struct pwm_chip *chip, struct pwm_device *pwm, c * * 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. + * 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 + * doing:: * - * pwm_round_waveform_might_sleep(mypwm, &wf); - * pwm_set_waveform_might_sleep(mypwm, &wf, true); + * 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. + * 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[WFHWSIZE]; + char wfhw[PWM_WFHWSIZE]; int ret_tohw, ret_fromhw; - BUG_ON(WFHWSIZE < ops->sizeof_wfhw); + BUG_ON(PWM_WFHWSIZE < ops->sizeof_wfhw); if (!pwmchip_supports_waveform(chip)) return -EOPNOTSUPP; @@ -270,10 +279,10 @@ int pwm_round_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform * wf_req.duty_length_ns, wf_req.period_length_ns, wf_req.duty_offset_ns, ret_tohw); 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", + (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); + wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns, ret_tohw); return ret_tohw; } @@ -287,15 +296,18 @@ EXPORT_SYMBOL_GPL(pwm_round_waveform_might_sleep); * * 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[WFHWSIZE]; + char wfhw[PWM_WFHWSIZE]; int err; - BUG_ON(WFHWSIZE < ops->sizeof_wfhw); + BUG_ON(PWM_WFHWSIZE < ops->sizeof_wfhw); if (!pwmchip_supports_waveform(chip) || !ops->read_waveform) return -EOPNOTSUPP; @@ -320,11 +332,11 @@ static int __pwm_set_waveform(struct pwm_device *pwm, { struct pwm_chip *chip = pwm->chip; const struct pwm_ops *ops = chip->ops; - char wfhw[WFHWSIZE]; + char wfhw[PWM_WFHWSIZE]; struct pwm_waveform wf_rounded; - int err; + int err, ret_tohw; - BUG_ON(WFHWSIZE < ops->sizeof_wfhw); + BUG_ON(PWM_WFHWSIZE < ops->sizeof_wfhw); if (!pwmchip_supports_waveform(chip)) return -EOPNOTSUPP; @@ -332,19 +344,19 @@ static int __pwm_set_waveform(struct pwm_device *pwm, if (!pwm_wf_valid(wf)) return -EINVAL; - err = __pwm_round_waveform_tohw(chip, pwm, wf, &wfhw); - if (err) - return err; + 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) && !pwm_check_rounding(wf, &wf_rounded)) - dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu]\n", + 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); + 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", @@ -382,7 +394,8 @@ static int __pwm_set_waveform(struct pwm_device *pwm, 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; + + return ret_tohw; } /** @@ -394,13 +407,37 @@ static int __pwm_set_waveform(struct pwm_device *pwm, * * 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 + * 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. + * @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) @@ -427,6 +464,19 @@ int pwm_set_waveform_might_sleep(struct pwm_device *pwm, 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); @@ -548,7 +598,7 @@ static bool pwm_state_valid(const struct pwm_state *state) * and supposed to be ignored. So also ignore any strange values and * consider the state ok. */ - if (state->enabled) + if (!state->enabled) return true; if (!state->period) @@ -560,11 +610,6 @@ static bool pwm_state_valid(const struct pwm_state *state) return true; } -/** - * __pwm_apply() - atomically apply a new state to a PWM device - * @pwm: PWM device - * @state: new state to apply - */ static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state) { struct pwm_chip *chip; @@ -603,9 +648,9 @@ static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state) if (pwmchip_supports_waveform(chip)) { struct pwm_waveform wf; - char wfhw[WFHWSIZE]; + char wfhw[PWM_WFHWSIZE]; - BUG_ON(WFHWSIZE < ops->sizeof_wfhw); + BUG_ON(PWM_WFHWSIZE < ops->sizeof_wfhw); pwm_state2wf(state, &wf); @@ -673,6 +718,9 @@ 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) { @@ -714,6 +762,9 @@ 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) { @@ -756,10 +807,10 @@ int pwm_get_state_hw(struct pwm_device *pwm, struct pwm_state *state) return -ENODEV; if (pwmchip_supports_waveform(chip) && ops->read_waveform) { - char wfhw[WFHWSIZE]; + char wfhw[PWM_WFHWSIZE]; struct pwm_waveform wf; - BUG_ON(WFHWSIZE < ops->sizeof_wfhw); + BUG_ON(PWM_WFHWSIZE < ops->sizeof_wfhw); ret = __pwm_read_waveform(chip, pwm, &wfhw); if (ret) @@ -787,6 +838,9 @@ EXPORT_SYMBOL_GPL(pwm_get_state_hw); * 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) { @@ -1640,8 +1694,8 @@ static bool pwm_ops_check(const struct pwm_chip *chip) !ops->write_waveform) return false; - if (WFHWSIZE < ops->sizeof_wfhw) { - dev_warn(pwmchip_parent(chip), "WFHWSIZE < %zu\n", ops->sizeof_wfhw); + if (PWM_WFHWSIZE < ops->sizeof_wfhw) { + dev_warn(pwmchip_parent(chip), "PWM_WFHWSIZE < %zu\n", ops->sizeof_wfhw); return false; } } else { @@ -1955,20 +2009,9 @@ 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; - - guard(mutex)(&pwm_lock); + struct pwm_chip *chip = pwm->chip; /* * Trigger a warning if a consumer called pwm_put() twice. @@ -1989,6 +2032,20 @@ void pwm_put(struct pwm_device *pwm) module_put(chip->owner); } + +/** + * 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); static void devm_pwm_release(void *pwm) @@ -2058,6 +2115,274 @@ 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; + /** * __pwmchip_add() - register a new PWM chip * @chip: the PWM chip to add @@ -2110,7 +2435,17 @@ int __pwmchip_add(struct pwm_chip *chip, struct module *owner) scoped_guard(pwmchip, chip) chip->operational = true; - ret = device_add(&chip->dev); + 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; @@ -2161,7 +2496,7 @@ void pwmchip_remove(struct pwm_chip *chip) idr_remove(&pwm_chips, chip->id); } - device_del(&chip->dev); + cdev_device_del(&chip->cdev, &chip->dev); } EXPORT_SYMBOL_GPL(pwmchip_remove); @@ -2220,25 +2555,28 @@ static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s) 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"); } @@ -2302,9 +2640,16 @@ 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; } |