From: Uwe Kleine-König u.kleine-koenig@pengutronix.de
stable inclusion from stable-5.10.69 commit 322b70b522abe03cd59712bb47a72eddd835d19d bugzilla: 182675 https://gitee.com/openeuler/kernel/issues/I4I3ED
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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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: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@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 710d9a207d2b..522f862eca52 100644 --- a/drivers/pwm/pwm-lpc32xx.c +++ b/drivers/pwm/pwm-lpc32xx.c @@ -120,17 +120,17 @@ 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;