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pwm: mtk-disp: Disable shadow registers before setting backlight values

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[ Upstream commit 36dd7f530ae7d9ce9e853ffb8aa337de65c6600b ]

If shadow registers usage is not desired, disable that before performing
any write to CON0/1 registers in the .apply() callback, otherwise we may
lose clkdiv or period/width updates.

Fixes: cd4b45ac449a ("pwm: Add MediaTek MT2701 display PWM driver support")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Tested-by: Alexandre Mergnat <amergnat@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
AngeloGioacchino Del Regno 2023-04-03 15:30:53 +02:00 committed by Greg Kroah-Hartman
parent 6d13804388
commit 45e4c00940
1 changed files with 13 additions and 11 deletions
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24
drivers/pwm/pwm-mtk-disp.c
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@ -114,6 +114,19 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
high_width = div64_u64(rate * duty_ns, div);
value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
if (mdp->data->bls_debug && !mdp->data->has_commit) {
/*
* For MT2701, disable double buffer before writing register
* and select manual mode and use PWM_PERIOD/PWM_HIGH_WIDTH.
*/
mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
mdp->data->bls_debug_mask,
mdp->data->bls_debug_mask);
mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
mdp->data->con0_sel,
mdp->data->con0_sel);
}
mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
PWM_CLKDIV_MASK,
clk_div << PWM_CLKDIV_SHIFT);
@ -128,17 +141,6 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
mdp->data->commit_mask,
0x0);
} else {
/*
* For MT2701, disable double buffer before writing register
* and select manual mode and use PWM_PERIOD/PWM_HIGH_WIDTH.
*/
mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
mdp->data->bls_debug_mask,
mdp->data->bls_debug_mask);
mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
mdp->data->con0_sel,
mdp->data->con0_sel);
}
clk_disable_unprepare(mdp->clk_mm);