From: Simon South simon@simonsouth.net
[ Upstream commit d9b657a5cdbd960de35dee7e06473caf44a9016f ]
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 thierry.reding@gmail.com Suggested-by: Trent Piepho tpiepho@gmail.com Signed-off-by: Simon South simon@simonsouth.net Signed-off-by: Thierry Reding thierry.reding@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pwm/pwm-rockchip.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c index 77c23a2c6d71e..7b9cdefb3daa3 100644 --- a/drivers/pwm/pwm-rockchip.c +++ b/drivers/pwm/pwm-rockchip.c @@ -332,9 +332,9 @@ 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; }
@@ -364,10 +364,12 @@ static int rockchip_pwm_probe(struct platform_device *pdev) if ((ctrl & enable_conf) != enable_conf) clk_disable(pc->clk);
+ clk_disable(pc->pclk); + return 0;
err_pclk: - clk_unprepare(pc->pclk); + clk_disable_unprepare(pc->pclk); err_clk: clk_disable_unprepare(pc->clk);