[PATCH v3 2/6] pwm: let pwm_get_state() return the last implemented state - Uwe Kleine-König

From: "Uwe Kleine-König" <uwe-rXY34ruvC2xidJT2blvkqNi2O/JbrIOy@public.gmane.org>
To: Thierry Reding
	<thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>,
	Maxime Ripard
	<maxime.ripard-LDxbnhwyfcJBDgjK7y7TUQ@public.gmane.org>,
	Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>,
	Patrick Havelange
	<patrick.havelange-buIOx9BAs4sybS5Ee8rs3A@public.gmane.org>
Cc: linux-pwm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org,
	linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: [PATCH v3 2/6] pwm: let pwm_get_state() return the last implemented state
Date: Sat, 24 Aug 2019 17:37:03 +0200	[thread overview]
Message-ID: <20190824153707.13746-3-uwe@kleine-koenig.org> (raw)
In-Reply-To: <20190824153707.13746-1-uwe-rXY34ruvC2xidJT2blvkqNi2O/JbrIOy@public.gmane.org>

When pwm_apply_state() is called the lowlevel driver usually has to
apply some rounding because the hardware doesn't support nanosecond
resolution. So let pwm_get_state() return the actually implemented state
instead of the last applied one if possible.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
---
 drivers/pwm/core.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 72347ca4a647..92333b89bf02 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -473,7 +473,14 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
 		if (err)
 			return err;
 
-		pwm->state = *state;
+		/*
+		 * .apply might have to round some values in *state, if possible
+		 * read the actually implemented value back.
+		 */
+		if (chip->ops->get_state)
+			chip->ops->get_state(chip, pwm, &pwm->state);
+		else
+			pwm->state = *state;
 	} else {
 		/*
 		 * FIXME: restore the initial state in case of error.
-- 
2.20.1


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