From: Uwe Kleine-König <uwe@kleine-koenig.org>
Date: Sat, 24 Aug 2019 15:37:03 +0000 (+0200)
Subject: pwm: Let pwm_get_state() return the last implemented state
X-Git-Tag: v5.4-rc1~27^2~18
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=01ccf903edd65f6421612321648fa5a7f4b7cb10;p=linux.git

pwm: Let pwm_get_state() return the last implemented state

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>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
---

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 4ab683a30629..449ba161877d 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -474,7 +474,14 @@ 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.