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 <boris.brezil...@free-electrons.com>
---
 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 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
-- 
2.5.0

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