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 boris.brezillon@free-electrons.com --- 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 6a1087c..5c7e79c 100644 --- a/drivers/pwm/pwm-rockchip.c +++ b/drivers/pwm/pwm-rockchip.c @@ -302,6 +302,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev) { const struct of_device_id *id; struct rockchip_pwm_chip *pc; + struct pwm_state pstate; struct resource *r; int ret;
@@ -322,7 +323,7 @@ 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;
@@ -345,12 +346,33 @@ 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, &pstate); + if (!pstate.enabled) + clk_disable(pc->clk); + return ret; }
static int rockchip_pwm_remove(struct platform_device *pdev) { struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev); + struct pwm_state pstate; + + /* + * 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(). + * + */ + pwm_get_state(pc->chip.pwms, &pstate); + if (pstate.enabled) + clk_disable(pc->clk);
clk_unprepare(pc->clk);