[PATCH] ARM: SAMSUNG: Add clk enable/disable of pwm

[Kukjin Kim]

Joonyoung Shim wrote:
> 
> 11/03/2011 10:59 AM, Kukjin Kim 쓴 글:
> > Joonyoung Shim wrote:
> >> PWM timers use pclk("timers" clk) as parent clk. If this pclk is the
> >> disabled state when PWM driver is probed, then it causes wrong read and
> >> write operation about registers of PWM.
> >>
> >> Signed-off-by: Joonyoung Shim<jy0922.shim at samsung.com>
> >> Signed-off-by: Kyungmin Park<kyungmin.park at samsung.com>
> >> ---
> >>   arch/arm/plat-samsung/pwm.c |    7 +++++++
> >>   1 files changed, 7 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/arch/arm/plat-samsung/pwm.c b/arch/arm/plat-samsung/pwm.c
> >> index f37457c..dc1185d 100644
> >> --- a/arch/arm/plat-samsung/pwm.c
> >> +++ b/arch/arm/plat-samsung/pwm.c
> >> @@ -299,6 +299,9 @@ static int s3c_pwm_probe(struct platform_device *pdev)
> >>   		goto err_clk_tin;
> >>   	}
> >>
> >> +	clk_enable(pwm->clk);
> >> +	clk_enable(pwm->clk_div);
> >> +
> >>   	local_irq_save(flags);
> >>
> >>   	tcon = __raw_readl(S3C2410_TCON);
> >> @@ -326,6 +329,8 @@ static int s3c_pwm_probe(struct platform_device *pdev)
> >>   	return 0;
> >>
> >>    err_clk_tdiv:
> >> +	clk_disable(pwm->clk_div);
> >> +	clk_disable(pwm->clk);
> >>   	clk_put(pwm->clk_div);
> >>
> >>    err_clk_tin:
> >> @@ -340,6 +345,8 @@ static int __devexit s3c_pwm_remove(struct
> >> platform_device *pdev)
> >>   {
> >>   	struct pwm_device *pwm = platform_get_drvdata(pdev);
> >>
> >> +	clk_disable(pwm->clk_div);
> >> +	clk_disable(pwm->clk);
> >>   	clk_put(pwm->clk_div);
> >>   	clk_put(pwm->clk);
> >>   	kfree(pwm);
> >> --
> >> 1.7.5.4
> > Well, I wonder when this is needed. I think it should be enabled during
> > kernel booting...
> 
> The exynos4 machine using just timer turns on "timer" clock in the past,
> but "timer" clock is disable state when boot since MCT is used. MCT
> doesn't control "timer" clock.
> 
> I think pwm driver should control(enable/disable) using clocks
> regardless of their parents clock.
> 
I mean, why that is disabled when kernel boot...

Thanks.

Best regards,
Kgene.
--
Kukjin Kim <kgene.kim at samsung.com>, Senior Engineer,
SW Solution Development Team, Samsung Electronics Co., Ltd.