On Fri, 3 Jun 2016 13:28:59 -0700
Brian Norris [off-list ref] wrote:

Hi,

Just noticed a few things:

On Fri, Jun 03, 2016 at 10:23:03AM +0200, Boris Brezillon wrote:

quoted

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: Boris Brezillon <redacted>
---
 drivers/pwm/pwm-rockchip.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
index dfacf7d..798a787 100644
--- a/drivers/pwm/pwm-rockchip.c
+++ b/drivers/pwm/pwm-rockchip.c

@@ -299,6 +299,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *id;
 	struct rockchip_pwm_chip *pc;
+	struct pwm_state state;
 	struct resource *r;
 	int ret;
 

@@ -319,7 +320,7 @@ 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;
 

@@ -342,12 +343,33 @@ 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. */
+	pwm_get_state(pc->chip.pwms, &state);
+	if (!state.enabled)  

Why not just if (!pwm_is_enabled())?

It's a leftover from a previous version where I was deprecating
pwm_enable(). I'll switch back to pwm_enable().

Thanks,

Boris

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com