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pwm: rockchip: Enable APB clock during register access while probing

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[ 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>
This commit is contained in:
Simon South 2021-01-19 11:12:05 -05:00 committed by Greg Kroah-Hartman
parent 7c0c9081f8
commit 39ab0927e7
1 changed files with 5 additions and 3 deletions
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8
drivers/pwm/pwm-rockchip.c
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@ -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);