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

[Joonyoung Shim]

11/03/2011 04:46 PM, Kukjin Kim 쓴 글:
> 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...
>

Please see arch/arm/mach-exynos4/clock.c
There is "timers' clock in the clk init_clocks_off[].

Thanks.