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Commit af1fdbbb authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Greg Kroah-Hartman
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pwm: lpc18xx-sct: Initialize driver data and hardware before pwmchip_add() 



[ Upstream commit 0401f24cd238ae200a23a13925f98de3d2c883b8 ]

When a driver calls pwmchip_add() it has to be prepared to immediately
get its callbacks called. So move allocation of driver data and hardware
initialization before the call to pwmchip_add().

This fixes a potential NULL pointer exception and a race condition on
register writes.

Fixes: 841e6f90 ("pwm: NXP LPC18xx PWM/SCT driver")
Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 996291d0

drivers/pwm/pwm-lpc18xx-sct.c

+9 −11
Original line number Diff line number Diff line
@@ -400,12 +400,6 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev) 
	lpc18xx_pwm_writel(lpc18xx_pwm, LPC18XX_PWM_LIMIT,

			   BIT(lpc18xx_pwm->period_event));



	ret = pwmchip_add(&lpc18xx_pwm->chip);

	if (ret < 0) {

		dev_err(&pdev->dev, "pwmchip_add failed: %d\n", ret);

		goto disable_pwmclk;

	}



	for (i = 0; i < lpc18xx_pwm->chip.npwm; i++) {

		struct lpc18xx_pwm_data *data;
@@ -415,14 +409,12 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev) 
				    GFP_KERNEL);

		if (!data) {

			ret = -ENOMEM;

			goto remove_pwmchip;

			goto disable_pwmclk;

		}



		pwm_set_chip_data(pwm, data);

	}



	platform_set_drvdata(pdev, lpc18xx_pwm);



	val = lpc18xx_pwm_readl(lpc18xx_pwm, LPC18XX_PWM_CTRL);

	val &= ~LPC18XX_PWM_BIDIR;

	val &= ~LPC18XX_PWM_CTRL_HALT;
@@ -430,10 +422,16 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev) 
	val |= LPC18XX_PWM_PRE(0);

	lpc18xx_pwm_writel(lpc18xx_pwm, LPC18XX_PWM_CTRL, val);



	ret = pwmchip_add(&lpc18xx_pwm->chip);

	if (ret < 0) {

		dev_err(&pdev->dev, "pwmchip_add failed: %d\n", ret);

		goto disable_pwmclk;

	}



	platform_set_drvdata(pdev, lpc18xx_pwm);



	return 0;



remove_pwmchip:

	pwmchip_remove(&lpc18xx_pwm->chip);

disable_pwmclk:

	clk_disable_unprepare(lpc18xx_pwm->pwm_clk);

	return ret;