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Commit 48cf973c authored by Boris Brezillon's avatar Boris Brezillon Committed by Thierry Reding
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pwm: rockchip: Avoid glitches on already running PWMs 



The current logic will disable the PWM clk even if the PWM was left
enabled by the bootloader (because it's controlling a critical device
like a regulator for example).
Keep the PWM clk enabled if the PWM is enabled to avoid any glitches.

Signed-off-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: default avatarBrian Norris <briannorris@chromium.org>
Tested-by: default avatarBrian Norris <briannorris@chromium.org>
Tested-by: default avatarHeiko Stuebner <heiko@sntech.de>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent 1ebb74cf

drivers/pwm/pwm-rockchip.c

+19 −1
Original line number Diff line number Diff line
@@ -319,7 +319,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev) 
	if (IS_ERR(pc->clk))

		return PTR_ERR(pc->clk);



	ret = clk_prepare(pc->clk);

	ret = clk_prepare_enable(pc->clk);

	if (ret)

		return ret;
@@ -342,6 +342,10 @@ static int rockchip_pwm_probe(struct platform_device *pdev) 
		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);

	}



	/* Keep the PWM clk enabled if the PWM appears to be up and running. */

	if (!pwm_is_enabled(pc->chip.pwms))

		clk_disable(pc->clk);



	return ret;

}
@@ -349,6 +353,20 @@ static int rockchip_pwm_remove(struct platform_device *pdev) 
{

	struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev);



	/*

	 * Disable the PWM clk before unpreparing it if the PWM device is still

	 * running. This should only happen when the last PWM user left it

	 * enabled, or when nobody requested a PWM that was previously enabled

	 * by the bootloader.

	 *

	 * FIXME: Maybe the core should disable all PWM devices in

	 * pwmchip_remove(). In this case we'd only have to call

	 * clk_unprepare() after pwmchip_remove().

	 *

	 */

	if (pwm_is_enabled(pc->chip.pwms))

		clk_disable(pc->clk);



	clk_unprepare(pc->clk);



	return pwmchip_remove(&pc->chip);