pwm: Introduce the pwm_state concept

The PWM state, represented by its period, duty_cycle and polarity is
currently directly stored in the PWM device. Declare a pwm_state
structure embedding those field so that we can later use this struct
to atomically update all the PWM parameters at once.

All pwm_get_xxx() helpers are now implemented as wrappers around
pwm_get_state().

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 6433059..f3f91e7 100644 (file)
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -268,7 +268,7 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip,
                pwm->chip = chip;
                pwm->pwm = chip->base + i;
                pwm->hwpwm = i;
-               pwm->polarity = polarity;
+               pwm->state.polarity = polarity;
 
                radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
        }
@@ -446,8 +446,8 @@ int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
        if (err)
                return err;
 
-       pwm->duty_cycle = duty_ns;
-       pwm->period = period_ns;
+       pwm->state.duty_cycle = duty_ns;
+       pwm->state.period = period_ns;
 
        return 0;
 }
@@ -480,7 +480,7 @@ int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
        if (err)
                return err;
 
-       pwm->polarity = polarity;
+       pwm->state.polarity = polarity;
 
        return 0;
 }

diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 7caf549..51d4005 100644 (file)
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -98,6 +98,18 @@ enum {
        PWMF_EXPORTED = 1 << 2,
 };
 
+/*
+ * struct pwm_state - state of a PWM channel
+ * @period: PWM period (in nanoseconds)
+ * @duty_cycle: PWM duty cycle (in nanoseconds)
+ * @polarity: PWM polarity
+ */
+struct pwm_state {
+       unsigned int period;
+       unsigned int duty_cycle;
+       enum pwm_polarity polarity;
+};
+
 /**
  * struct pwm_device - PWM channel object
  * @label: name of the PWM device
@@ -106,10 +118,8 @@ enum {
  * @pwm: global index of the PWM device
  * @chip: PWM chip providing this PWM device
  * @chip_data: chip-private data associated with the PWM device
- * @period: period of the PWM signal (in nanoseconds)
- * @duty_cycle: duty cycle of the PWM signal (in nanoseconds)
- * @polarity: polarity of the PWM signal
  * @args: PWM arguments
+ * @state: curent PWM channel state
  */
 struct pwm_device {
        const char *label;
@@ -119,13 +129,21 @@ struct pwm_device {
        struct pwm_chip *chip;
        void *chip_data;
 
-       unsigned int period;
-       unsigned int duty_cycle;
-       enum pwm_polarity polarity;
-
        struct pwm_args args;
+       struct pwm_state state;
 };
 
+/**
+ * pwm_get_state() - retrieve the current PWM state
+ * @pwm: PWM device
+ * @state: state to fill with the current PWM state
+ */
+static inline void pwm_get_state(const struct pwm_device *pwm,
+                                struct pwm_state *state)
+{
+       *state = pwm->state;
+}
+
 static inline bool pwm_is_enabled(const struct pwm_device *pwm)
 {
        return test_bit(PWMF_ENABLED, &pwm->flags);
@@ -134,23 +152,31 @@ static inline bool pwm_is_enabled(const struct pwm_device *pwm)
 static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period)
 {
        if (pwm)
-               pwm->period = period;
+               pwm->state.period = period;
 }
 
 static inline unsigned int pwm_get_period(const struct pwm_device *pwm)
 {
-       return pwm ? pwm->period : 0;
+       struct pwm_state state;
+
+       pwm_get_state(pwm, &state);
+
+       return state.period;
 }
 
 static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty)
 {
        if (pwm)
-               pwm->duty_cycle = duty;
+               pwm->state.duty_cycle = duty;
 }
 
 static inline unsigned int pwm_get_duty_cycle(const struct pwm_device *pwm)
 {
-       return pwm ? pwm->duty_cycle : 0;
+       struct pwm_state state;
+
+       pwm_get_state(pwm, &state);
+
+       return state.duty_cycle;
 }
 
 /*
@@ -160,7 +186,11 @@ int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity);
 
 static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm)
 {
-       return pwm ? pwm->polarity : PWM_POLARITY_NORMAL;
+       struct pwm_state state;
+
+       pwm_get_state(pwm, &state);
+
+       return state.polarity;
 }
 
 static inline void pwm_get_args(const struct pwm_device *pwm,