From: Uwe Kleine-König u.kleine-koenig@pengutronix.de
stable inclusion from linux-4.19.208 commit 4459118977665f681017e1299933895d54b6e87b
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commit 3d2813fb17e5fd0d73c1d1442ca0192bde4af10e upstream.
This fixes a race condition: After pwmchip_add() is called there might already be a consumer and then modifying the hardware behind the consumer's back is bad. So set the default before.
(Side-note: I don't know what this register setting actually does, if this modifies the polarity there is an inconsistency because the inversed polarity isn't considered if the PWM is already running during .probe().)
Fixes: acfd92fdfb93 ("pwm: lpc32xx: Set PWM_PIN_LEVEL bit to default value") Cc: Sylvain Lemieux slemieux@tycoint.com Signed-off-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Signed-off-by: Thierry Reding thierry.reding@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/pwm/pwm-lpc32xx.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/pwm/pwm-lpc32xx.c b/drivers/pwm/pwm-lpc32xx.c index a9b3cff96aaca..ed8e9406b4af2 100644 --- a/drivers/pwm/pwm-lpc32xx.c +++ b/drivers/pwm/pwm-lpc32xx.c @@ -124,17 +124,17 @@ static int lpc32xx_pwm_probe(struct platform_device *pdev) lpc32xx->chip.npwm = 1; lpc32xx->chip.base = -1;
+ /* If PWM is disabled, configure the output to the default value */ + val = readl(lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2)); + val &= ~PWM_PIN_LEVEL; + writel(val, lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2)); + ret = pwmchip_add(&lpc32xx->chip); if (ret < 0) { dev_err(&pdev->dev, "failed to add PWM chip, error %d\n", ret); return ret; }
- /* When PWM is disable, configure the output to the default value */ - val = readl(lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2)); - val &= ~PWM_PIN_LEVEL; - writel(val, lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2)); - platform_set_drvdata(pdev, lpc32xx);
return 0;