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pwm: lpc18xx-sct: Initialize driver data and hardware before pwmchip_add()

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[ 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: 841e6f90bb ("pwm: NXP LPC18xx PWM/SCT driver")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Uwe Kleine-König 2021-11-10 09:49:48 +01:00 committed by Greg Kroah-Hartman
parent 996291d068
commit af1fdbbb7b
1 changed files with 9 additions and 11 deletions
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20
drivers/pwm/pwm-lpc18xx-sct.c
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@ -400,12 +400,6 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev)
lpc18xx_pwm_writel(lpc18xx_pwm, LPC18XX_PWM_LIMIT, lpc18xx_pwm_writel(lpc18xx_pwm, LPC18XX_PWM_LIMIT,
BIT(lpc18xx_pwm->period_event)); 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++) { for (i = 0; i < lpc18xx_pwm->chip.npwm; i++) {
struct lpc18xx_pwm_data *data; struct lpc18xx_pwm_data *data;
@ -415,14 +409,12 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev)
GFP_KERNEL); GFP_KERNEL);
if (!data) { if (!data) {
ret = -ENOMEM; ret = -ENOMEM;
goto remove_pwmchip; goto disable_pwmclk;
} }
pwm_set_chip_data(pwm, data); pwm_set_chip_data(pwm, data);
} }
platform_set_drvdata(pdev, lpc18xx_pwm);
val = lpc18xx_pwm_readl(lpc18xx_pwm, LPC18XX_PWM_CTRL); val = lpc18xx_pwm_readl(lpc18xx_pwm, LPC18XX_PWM_CTRL);
val &= ~LPC18XX_PWM_BIDIR; val &= ~LPC18XX_PWM_BIDIR;
val &= ~LPC18XX_PWM_CTRL_HALT; val &= ~LPC18XX_PWM_CTRL_HALT;
@ -430,10 +422,16 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev)
val |= LPC18XX_PWM_PRE(0); val |= LPC18XX_PWM_PRE(0);
lpc18xx_pwm_writel(lpc18xx_pwm, LPC18XX_PWM_CTRL, val); 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; return 0;
remove_pwmchip:
pwmchip_remove(&lpc18xx_pwm->chip);
disable_pwmclk: disable_pwmclk:
clk_disable_unprepare(lpc18xx_pwm->pwm_clk); clk_disable_unprepare(lpc18xx_pwm->pwm_clk);
return ret; return ret;