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/include/linux/pwm.h b/include/linux/pwm.h
index 7caf549..51d4005 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -98,6 +98,18 @@
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 @@
* @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_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 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 @@
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,