path: root/drivers/pwm
diff options
authorSimon South <>2021-01-19 11:12:05 -0500
committerThierry Reding <>2021-01-20 18:12:31 +0100
commitd9b657a5cdbd960de35dee7e06473caf44a9016f (patch)
tree3e8e97ad8fd3d97f102f239320496a7b74566a91 /drivers/pwm
parenta2bc9b21fd3f89b1f9a5df46427855dcf344e6e7 (diff)
pwm: rockchip: Enable APB clock during register access while probing
Commit 457f74abbed0 ("pwm: rockchip: Keep enabled PWMs running while probing") modified rockchip_pwm_probe() to access a PWM device's registers directly to check whether or not the device is enabled, but did not also change the function so it first enables the device's APB clock to be certain the device can respond. This risks hanging the kernel on systems with PWM devices that use more than a single clock. Avoid this by enabling the device's APB clock before accessing its registers (and disabling the clock when register access is complete). Fixes: 457f74abbed0 ("pwm: rockchip: Keep enabled PWMs running while probing") Reported-by: Thierry Reding <> Suggested-by: Trent Piepho <> Signed-off-by: Simon South <> Signed-off-by: Thierry Reding <>
Diffstat (limited to 'drivers/pwm')
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
index 389a5e140412..e6929bc73968 100644
--- a/drivers/pwm/pwm-rockchip.c
+++ b/drivers/pwm/pwm-rockchip.c
@@ -330,9 +330,9 @@ static int rockchip_pwm_probe(struct platform_device *pdev)
return ret;
- ret = clk_prepare(pc->pclk);
+ ret = clk_prepare_enable(pc->pclk);
if (ret) {
- dev_err(&pdev->dev, "Can't prepare APB clk: %d\n", ret);
+ dev_err(&pdev->dev, "Can't prepare enable APB clk: %d\n", ret);
goto err_clk;
@@ -362,10 +362,12 @@ static int rockchip_pwm_probe(struct platform_device *pdev)
if ((ctrl & enable_conf) != enable_conf)
+ clk_disable(pc->pclk);
return 0;
- clk_unprepare(pc->pclk);
+ clk_disable_unprepare(pc->pclk);