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pwm: lpc32xx: Don't modify HW state in .probe() after the PWM chip was registered
commit3d2813fb17
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:acfd92fdfb
("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>
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commit
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1 changed files with 5 additions and 5 deletions
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@ -120,17 +120,17 @@ static int lpc32xx_pwm_probe(struct platform_device *pdev)
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lpc32xx->chip.npwm = 1;
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lpc32xx->chip.base = -1;
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/* If PWM is disabled, configure the output to the default value */
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val = readl(lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2));
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val &= ~PWM_PIN_LEVEL;
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writel(val, lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2));
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ret = pwmchip_add(&lpc32xx->chip);
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to add PWM chip, error %d\n", ret);
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return ret;
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}
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/* When PWM is disable, configure the output to the default value */
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val = readl(lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2));
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val &= ~PWM_PIN_LEVEL;
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writel(val, lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2));
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platform_set_drvdata(pdev, lpc32xx);
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return 0;
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