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>

1 files changed, 14 insertions, 7 deletions

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 7831bc6b51dd..680fbc795a0a 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;