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authorBoris Brezillon <boris.brezillon@free-electrons.com>2016-04-14 21:17:21 +0200
committerThierry Reding <thierry.reding@gmail.com>2016-05-03 13:44:37 +0200
commite39c0df1be5a97e0910b09af1530bdf3de057a06 (patch)
tree3299bb34c94cd6b989ecd54ff7cfcc9cc962d9ff
parentf55532a0c0b8bb6148f4e07853b876ef73bc69ca (diff)
pwm: Introduce the pwm_args concept
Currently the PWM core mixes the current PWM state with the per-platform reference config (specified through the PWM lookup table, DT definition or directly hardcoded in PWM drivers). Create a struct pwm_args to store this reference configuration, so that PWM users can differentiate between the current and reference configurations. Patch all places where pwm->args should be initialized. We keep the pwm_set_polarity/period() calls until all PWM users are patched to use pwm_args instead of pwm_get_period/polarity(). Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> [thierry.reding@gmail.com: reword kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
-rw-r--r--drivers/pwm/core.c21
-rw-r--r--drivers/pwm/pwm-clps711x.c2
-rw-r--r--drivers/pwm/pwm-pxa.c2
-rw-r--r--include/linux/pwm.h33
4 files changed, 49 insertions, 9 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 7831bc6..680fbc7 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -128,6 +128,13 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label)
set_bit(PWMF_REQUESTED, &pwm->flags);
pwm->label = label;
+ /*
+ * FIXME: This should be removed once all PWM users properly make use
+ * of struct pwm_args to initialize the PWM device. As long as this is
+ * here, the PWM state and hardware state can get out of sync.
+ */
+ pwm_apply_args(pwm);
+
return 0;
}
@@ -146,12 +153,12 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
if (IS_ERR(pwm))
return pwm;
- pwm_set_period(pwm, args->args[1]);
+ pwm->args.period = args->args[1];
if (args->args[2] & PWM_POLARITY_INVERTED)
- pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
+ pwm->args.polarity = PWM_POLARITY_INVERSED;
else
- pwm_set_polarity(pwm, PWM_POLARITY_NORMAL);
+ pwm->args.polarity = PWM_POLARITY_NORMAL;
return pwm;
}
@@ -172,7 +179,7 @@ of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
if (IS_ERR(pwm))
return pwm;
- pwm_set_period(pwm, args->args[1]);
+ pwm->args.period = args->args[1];
return pwm;
}
@@ -747,13 +754,13 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
if (!chip)
goto out;
+ pwm->args.period = chosen->period;
+ pwm->args.polarity = chosen->polarity;
+
pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
if (IS_ERR(pwm))
goto out;
- pwm_set_period(pwm, chosen->period);
- pwm_set_polarity(pwm, chosen->polarity);
-
out:
mutex_unlock(&pwm_lookup_lock);
return pwm;
diff --git a/drivers/pwm/pwm-clps711x.c b/drivers/pwm/pwm-clps711x.c
index a80c108..7d33542 100644
--- a/drivers/pwm/pwm-clps711x.c
+++ b/drivers/pwm/pwm-clps711x.c
@@ -60,7 +60,7 @@ static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
return -EINVAL;
/* Store constant period value */
- pwm_set_period(pwm, DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq));
+ pwm->args.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);
return 0;
}
diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c
index cb2f702..58b709f 100644
--- a/drivers/pwm/pwm-pxa.c
+++ b/drivers/pwm/pwm-pxa.c
@@ -160,7 +160,7 @@ pxa_pwm_of_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
if (IS_ERR(pwm))
return pwm;
- pwm_set_period(pwm, args->args[0]);
+ pwm->args.period = args->args[0];
return pwm;
}
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index cfc3ed4..b78d27c 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -74,6 +74,24 @@ enum pwm_polarity {
PWM_POLARITY_INVERSED,
};
+/**
+ * struct pwm_args - board-dependent PWM arguments
+ * @period: reference period
+ * @polarity: reference polarity
+ *
+ * This structure describes board-dependent arguments attached to a PWM
+ * device. These arguments are usually retrieved from the PWM lookup table or
+ * device tree.
+ *
+ * Do not confuse this with the PWM state: PWM arguments represent the initial
+ * configuration that users want to use on this PWM device rather than the
+ * current PWM hardware state.
+ */
+struct pwm_args {
+ unsigned int period;
+ enum pwm_polarity polarity;
+};
+
enum {
PWMF_REQUESTED = 1 << 0,
PWMF_ENABLED = 1 << 1,
@@ -92,6 +110,7 @@ enum {
* @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
*/
struct pwm_device {
const char *label;
@@ -105,6 +124,8 @@ struct pwm_device {
unsigned int period;
unsigned int duty_cycle;
enum pwm_polarity polarity;
+
+ struct pwm_args args;
};
static inline bool pwm_is_enabled(const struct pwm_device *pwm)
@@ -144,6 +165,18 @@ static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm)
return pwm ? pwm->polarity : PWM_POLARITY_NORMAL;
}
+static inline void pwm_get_args(const struct pwm_device *pwm,
+ struct pwm_args *args)
+{
+ *args = pwm->args;
+}
+
+static inline void pwm_apply_args(struct pwm_device *pwm)
+{
+ pwm_set_period(pwm, pwm->args.period);
+ pwm_set_polarity(pwm, pwm->args.polarity);
+}
+
/**
* struct pwm_ops - PWM controller operations
* @request: optional hook for requesting a PWM