From: Uwe Kleine-König u.kleine-koenig@pengutronix.de
[ 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: 841e6f90bb78 ("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 --- drivers/pwm/pwm-lpc18xx-sct.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-)
diff --git a/drivers/pwm/pwm-lpc18xx-sct.c b/drivers/pwm/pwm-lpc18xx-sct.c index 8e461f3baa05..8cc8ae16553c 100644 --- a/drivers/pwm/pwm-lpc18xx-sct.c +++ b/drivers/pwm/pwm-lpc18xx-sct.c @@ -395,12 +395,6 @@ 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;
@@ -410,14 +404,12 @@ 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; @@ -425,10 +417,16 @@ 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;