diff options
Diffstat (limited to 'kernel/drivers/pwm/core.c')
| -rw-r--r-- | kernel/drivers/pwm/core.c | 124 |
1 files changed, 105 insertions, 19 deletions
diff --git a/kernel/drivers/pwm/core.c b/kernel/drivers/pwm/core.c index ba34c7d89..d24ca5f28 100644 --- a/kernel/drivers/pwm/core.c +++ b/kernel/drivers/pwm/core.c @@ -200,6 +200,8 @@ static void of_pwmchip_remove(struct pwm_chip *chip) * pwm_set_chip_data() - set private chip data for a PWM * @pwm: PWM device * @data: pointer to chip-specific data + * + * Returns: 0 on success or a negative error code on failure. */ int pwm_set_chip_data(struct pwm_device *pwm, void *data) { @@ -215,6 +217,8 @@ EXPORT_SYMBOL_GPL(pwm_set_chip_data); /** * pwm_get_chip_data() - get private chip data for a PWM * @pwm: PWM device + * + * Returns: A pointer to the chip-private data for the PWM device. */ void *pwm_get_chip_data(struct pwm_device *pwm) { @@ -223,13 +227,18 @@ void *pwm_get_chip_data(struct pwm_device *pwm) EXPORT_SYMBOL_GPL(pwm_get_chip_data); /** - * pwmchip_add() - register a new PWM chip + * pwmchip_add_with_polarity() - register a new PWM chip * @chip: the PWM chip to add + * @polarity: initial polarity of PWM channels * * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base - * will be used. + * will be used. The initial polarity for all channels is specified by the + * @polarity parameter. + * + * Returns: 0 on success or a negative error code on failure. */ -int pwmchip_add(struct pwm_chip *chip) +int pwmchip_add_with_polarity(struct pwm_chip *chip, + enum pwm_polarity polarity) { struct pwm_device *pwm; unsigned int i; @@ -259,6 +268,8 @@ int pwmchip_add(struct pwm_chip *chip) pwm->chip = chip; pwm->pwm = chip->base + i; pwm->hwpwm = i; + pwm->polarity = polarity; + mutex_init(&pwm->lock); radix_tree_insert(&pwm_tree, pwm->pwm, pwm); } @@ -279,6 +290,21 @@ out: mutex_unlock(&pwm_lock); return ret; } +EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity); + +/** + * pwmchip_add() - register a new PWM chip + * @chip: the PWM chip to add + * + * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base + * will be used. The initial polarity for all channels is normal. + * + * Returns: 0 on success or a negative error code on failure. + */ +int pwmchip_add(struct pwm_chip *chip) +{ + return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL); +} EXPORT_SYMBOL_GPL(pwmchip_add); /** @@ -287,6 +313,8 @@ EXPORT_SYMBOL_GPL(pwmchip_add); * * Removes a PWM chip. This function may return busy if the PWM chip provides * a PWM device that is still requested. + * + * Returns: 0 on success or a negative error code on failure. */ int pwmchip_remove(struct pwm_chip *chip) { @@ -321,10 +349,13 @@ EXPORT_SYMBOL_GPL(pwmchip_remove); /** * pwm_request() - request a PWM device - * @pwm_id: global PWM device index + * @pwm: global PWM device index * @label: PWM device label * * This function is deprecated, use pwm_get() instead. + * + * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on + * failure. */ struct pwm_device *pwm_request(int pwm, const char *label) { @@ -359,9 +390,9 @@ EXPORT_SYMBOL_GPL(pwm_request); * @index: per-chip index of the PWM to request * @label: a literal description string of this PWM * - * Returns the PWM 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. + * 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. */ struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, unsigned int index, @@ -402,6 +433,8 @@ EXPORT_SYMBOL_GPL(pwm_free); * @pwm: PWM device * @duty_ns: "on" time (in nanoseconds) * @period_ns: duration (in nanoseconds) of one cycle + * + * Returns: 0 on success or a negative error code on failure. */ int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) { @@ -426,7 +459,10 @@ EXPORT_SYMBOL_GPL(pwm_config); * @pwm: PWM device * @polarity: new polarity of the PWM signal * - * Note that the polarity cannot be configured while the PWM device is enabled + * Note that the polarity cannot be configured while the PWM device is + * enabled. + * + * Returns: 0 on success or a negative error code on failure. */ int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity) { @@ -438,29 +474,49 @@ int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity) if (!pwm->chip->ops->set_polarity) return -ENOSYS; - if (test_bit(PWMF_ENABLED, &pwm->flags)) - return -EBUSY; + mutex_lock(&pwm->lock); + + if (pwm_is_enabled(pwm)) { + err = -EBUSY; + goto unlock; + } err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity); if (err) - return err; + goto unlock; pwm->polarity = polarity; - return 0; +unlock: + mutex_unlock(&pwm->lock); + return err; } EXPORT_SYMBOL_GPL(pwm_set_polarity); /** * pwm_enable() - start a PWM output toggling * @pwm: PWM device + * + * Returns: 0 on success or a negative error code on failure. */ int pwm_enable(struct pwm_device *pwm) { - if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags)) - return pwm->chip->ops->enable(pwm->chip, pwm); + int err = 0; - return pwm ? 0 : -EINVAL; + if (!pwm) + return -EINVAL; + + mutex_lock(&pwm->lock); + + if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) { + err = pwm->chip->ops->enable(pwm->chip, pwm); + if (err) + clear_bit(PWMF_ENABLED, &pwm->flags); + } + + mutex_unlock(&pwm->lock); + + return err; } EXPORT_SYMBOL_GPL(pwm_enable); @@ -507,6 +563,9 @@ static struct pwm_chip *of_node_to_pwmchip(struct device_node *np) * lookup of the PWM index. This also means that the "pwm-names" property * becomes mandatory for devices that look up the PWM device via the con_id * parameter. + * + * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded + * error code on failure. */ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id) { @@ -586,6 +645,23 @@ void pwm_add_table(struct pwm_lookup *table, size_t num) } /** + * 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 @@ -596,6 +672,9 @@ void pwm_add_table(struct pwm_lookup *table, size_t num) * * Once a PWM chip has been found the specified PWM device will be requested * and is ready to be used. + * + * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded + * error code on failure. */ struct pwm_device *pwm_get(struct device *dev, const char *con_id) { @@ -659,8 +738,10 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) } } - if (!chosen) + if (!chosen) { + pwm = ERR_PTR(-ENODEV); goto out; + } chip = pwmchip_find_by_name(chosen->provider); if (!chip) @@ -718,6 +799,9 @@ static void devm_pwm_release(struct device *dev, void *res) * * This function performs like pwm_get() but the acquired PWM device will * automatically be released on driver detach. + * + * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded + * error code on failure. */ struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id) { @@ -747,6 +831,9 @@ EXPORT_SYMBOL_GPL(devm_pwm_get); * * This function performs like of_pwm_get() but the acquired PWM device will * automatically be released on driver detach. + * + * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded + * error code on failure. */ struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np, const char *con_id) @@ -798,7 +885,7 @@ EXPORT_SYMBOL_GPL(devm_pwm_put); * pwm_can_sleep() - report whether PWM access will sleep * @pwm: PWM device * - * It returns true if accessing the PWM can sleep, false otherwise. + * Returns: True if accessing the PWM can sleep, false otherwise. */ bool pwm_can_sleep(struct pwm_device *pwm) { @@ -819,7 +906,7 @@ static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s) if (test_bit(PWMF_REQUESTED, &pwm->flags)) seq_puts(s, " requested"); - if (test_bit(PWMF_ENABLED, &pwm->flags)) + if (pwm_is_enabled(pwm)) seq_puts(s, " enabled"); seq_puts(s, "\n"); @@ -890,6 +977,5 @@ static int __init pwm_debugfs_init(void) return 0; } - subsys_initcall(pwm_debugfs_init); #endif /* CONFIG_DEBUG_FS */ |