[PATCH v4 19/24] pwm: add the PWM initial state retrieval infra

Boris Brezillon
2015-11-16T08:56:42Z

Add a ->reset_state() function to the pwm_ops struct to let PWM drivers
initialize the PWM state attached to a PWM device.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
---
drivers/pwm/core.c | 3 +++
include/linux/pwm.h | 4 ++++
2 files changed, 7 insertions(+)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 6bbda6c..ce8b373 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -271,6 +271,9 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip,
pwm_set_default_polarity(pwm, polarity);
mutex_init(&pwm->lock);

+ if (chip->ops->reset_state)
+ chip->ops->reset_state(chip, pwm);
+
radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
}

diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 292e7da..caa0ffe 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -182,6 +182,9 @@ static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm)
* @set_polarity: configure the polarity of this PWM
* @enable: enable PWM output toggling
* @disable: disable PWM output toggling
+ * @reset_state: reset the current PWM state (pwm->state) to the actual
+ * hardware state. This function is only called once per
+ * PWM device when the PWM chip is registered.
* @dbg_show: optional routine to show contents in debugfs
* @owner: helps prevent removal of modules exporting active PWMs
*/
@@ -194,6 +197,7 @@ struct pwm_ops {
enum pwm_polarity polarity);
int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm);
void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm);
+ void (*reset_state)(struct pwm_chip *chip, struct pwm_device *pwm);
#ifdef CONFIG_DEBUG_FS
void (*dbg_show)(struct pwm_chip *chip, struct seq_file *s);
#endif
--
2.1.4