linux-kernel - [PATCH] pwm: mtk_disp: Fix the disable flow of disp

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Message-ID: <20230515061845.10241-1-shuijing.li@mediatek.com>
Date:   Mon, 15 May 2023 14:18:45 +0800
From:   Shuijing Li <shuijing.li@...iatek.com>
To:     <thierry.reding@...il.com>, <matthias.bgg@...il.com>,
        <angelogioacchino.delregno@...labora.com>
CC:     <devicetree@...r.kernel.org>, <linux-pwm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>,
        <Project_Global_Chrome_Upstream_Group@...iatek.com>,
        <jitao.shi@...iatek.com>, Shuijing Li <shuijing.li@...iatek.com>
Subject: [PATCH] pwm: mtk_disp: Fix the disable flow of disp_pwm

There is a flow error in the original mtk_disp_pwm_apply() function.
If this function is called when the clock is disabled, there will be a
chance to operate the disp_pwm register, resulting in disp_pwm exception.
Fix this accordingly.

Signed-off-by: Shuijing Li <shuijing.li@...iatek.com>
---
 drivers/pwm/pwm-mtk-disp.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
index 79e321e96f56..cb699fa9a5ae 100644
--- a/drivers/pwm/pwm-mtk-disp.c
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -80,10 +80,9 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 		return -EINVAL;
 
 	if (!state->enabled) {
-		mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
-					 0x0);
-
 		if (mdp->enabled) {
+			mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN,
+						 mdp->data->enable_mask, 0x0);
 			clk_disable_unprepare(mdp->clk_mm);
 			clk_disable_unprepare(mdp->clk_main);
 		}
-- 
2.40.1