From: Uwe Kleine-König u.kleine-koenig@pengutronix.de
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 --- drivers/pwm/pwm-lpc32xx.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
--- a/drivers/pwm/pwm-lpc32xx.c +++ b/drivers/pwm/pwm-lpc32xx.c @@ -120,17 +120,17 @@ static int lpc32xx_pwm_probe(struct plat 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;