[v5,17/46] pwm: add the PWM initial state retrieval infra

Commit Message

Boris BREZILLON March 30, 2016, 8:03 p.m. UTC

Add a ->get_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 <[e-mail]>
---
 drivers/pwm/core.c  | 3 +++
 include/linux/pwm.h | 5 +++++
 2 files changed, 8 insertions(+)

Patch

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index c240b54..a909c64 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -270,6 +270,9 @@  int pwmchip_add_with_polarity(struct pwm_chip *chip,
 		pwm->hwpwm = i;
 		pwm->state.polarity = polarity;
 
+		if (chip->ops->get_state)
+			chip->ops->get_state(chip, pwm, &pwm->state);
+
 		radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
 	}
 
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 55bf463..ceedcf8 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -211,6 +211,9 @@  static inline void pwm_get_args(const struct pwm_device *pwm,
  * @set_polarity: configure the polarity of this PWM
  * @enable: enable PWM output toggling
  * @disable: disable PWM output toggling
+ * @get_state: get the current PWM 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
  */
@@ -223,6 +226,8 @@  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 (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
+			  struct pwm_state *pstate);
 #ifdef CONFIG_DEBUG_FS
 	void (*dbg_show)(struct pwm_chip *chip, struct seq_file *s);
 #endif