linux-kernel - [PATCH 5.4 017/108] pwm: sprd: Ensure configuring period and duty

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Date:   Mon, 26 Jul 2021 17:38:18 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Thierry Reding <thierry.reding@...il.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.4 017/108] pwm: sprd: Ensure configuring period and duty_cycle isnt wrongly skipped

From: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>

[ Upstream commit 65e2e6c1c20104ed19060a38f4edbf14e9f9a9a5 ]

As the last call to sprd_pwm_apply() might have exited early if
state->enabled was false, the values for period and duty_cycle stored in
pwm->state might not have been written to hardware and it must be
ensured that they are configured before enabling the PWM.

Fixes: 8aae4b02e8a6 ("pwm: sprd: Add Spreadtrum PWM support")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@...il.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/pwm/pwm-sprd.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/pwm/pwm-sprd.c b/drivers/pwm/pwm-sprd.c
index be2394227423..892d853d48a1 100644
--- a/drivers/pwm/pwm-sprd.c
+++ b/drivers/pwm/pwm-sprd.c
@@ -180,13 +180,10 @@ static int sprd_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			}
 		}
 
-		if (state->period != cstate->period ||
-		    state->duty_cycle != cstate->duty_cycle) {
-			ret = sprd_pwm_config(spc, pwm, state->duty_cycle,
-					      state->period);
-			if (ret)
-				return ret;
-		}
+		ret = sprd_pwm_config(spc, pwm, state->duty_cycle,
+				      state->period);
+		if (ret)
+			return ret;
 
 		sprd_pwm_write(spc, pwm->hwpwm, SPRD_PWM_ENABLE, 1);
 	} else if (cstate->enabled) {
-- 
2.30.2