linux-kernel - [RFC PATCH 2/4] pwm: sun4i: Disable pwm before turning off clock gate

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Date:   Tue, 17 Mar 2020 16:59:04 +0100
From:   Pascal Roeleven <dev@...calroeleven.nl>
To:     Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Maxime Ripard <mripard@...nel.org>,
        Chen-Yu Tsai <wens@...e.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        linux-pwm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Cc:     linux-sunxi@...glegroups.com,
        Pascal Roeleven <dev@...calroeleven.nl>
Subject: [RFC PATCH 2/4] pwm: sun4i: Disable pwm before turning off clock gate

The clock gate must stay on when disabling to ensure proper turning off.
After one period it will still be disabled anyway.

Signed-off-by: Pascal Roeleven <dev@...calroeleven.nl>
---
 drivers/pwm/pwm-sun4i.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 5c677c563..56942036b 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -292,13 +292,12 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	else
 		ctrl |= BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
 
-	ctrl |= BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
-
 	if (state->enabled) {
 		ctrl |= BIT_CH(PWM_EN, pwm->hwpwm);
+		ctrl |= BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
 	} else {
+		/* Turn gate off after delay to ensure proper turning off */
 		ctrl &= ~BIT_CH(PWM_EN, pwm->hwpwm);
-		ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
 	}
 
 	sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
-- 
2.20.1