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 <[email protected]>
---
 drivers/pwm/core.c  | 3 +++
 include/linux/pwm.h | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 3e830ce..236a8cf 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -264,6 +264,9 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip,
                pwm->hwpwm = i;
                pwm_set_default_polarity(pwm, polarity);
 
+               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 1e6e9d1..df78211 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -168,6 +168,9 @@ 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
  */
@@ -186,6 +189,8 @@ struct pwm_ops {
                                          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);
-- 
1.9.1

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