Re: [PATCH 1/3] mmc: sdhci-s3c: Enable only required bus clock

[Jaehoon Chung <jh80.chung@samsung.com>]

Acked-by: Jaehoon Chung <jh80.chung@samsung.com>

On 09/14/2012 07:46 PM, Chander Kashyap wrote:
> Hi Jaehoon Chung,
> 
> On 14 September 2012 15:25, Jaehoon Chung <jh80.chung@samsung.com> wrote:
>> Hi Chander,
>>
>> Could you add the error control for clk_enable()?
> It is maintained as original and clk is already checked for error using IS_ERR.
>>
>> On 09/14/2012 06:08 PM, Chander Kashyap wrote:
>>> In case of multiple bus clock sources, all the clock sources were
>>> getting enabled. As only one clock source is needed at the time hence
>>> enable only the required bus clock.
>>>
>>> This patch does as follows:
>>> 1.    In sdhci_s3c_probe enable only required bus clock source.
>>>
>>> 2.    Handle the disabling of old bus clock and enables the
>>>       best clock selected in sdhci_s3c_set_clock().
>>>
>>> Signed-off-by: Chander Kashyap <chander.kashyap@linaro.org>
>>> ---
>>>  drivers/mmc/host/sdhci-s3c.c |   12 +++++++-----
>>>  1 file changed, 7 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
>>> index 00969ba..0cbb4c2 100644
>>> --- a/drivers/mmc/host/sdhci-s3c.c
>>> +++ b/drivers/mmc/host/sdhci-s3c.c
>>> @@ -203,10 +203,12 @@ static void sdhci_s3c_set_clock(struct sdhci_host *host, unsigned int clock)
>>>                best_src, clock, best);
>>>
>>>       /* select the new clock source */
>>> -
>>>       if (ourhost->cur_clk != best_src) {
>>>               struct clk *clk = ourhost->clk_bus[best_src];
>>>
>>> +             clk_enable(clk);
>>> +             clk_disable(ourhost->clk_bus[ourhost->cur_clk]);
>>> +
>> Did you consider the case that set_clock is assigned the sdhci_cmu_set_clock()?
> Yes considered.
>>
>>>               /* turn clock off to card before changing clock source */
>>>               writew(0, host->ioaddr + SDHCI_CLOCK_CONTROL);
>>>
>>> @@ -501,8 +503,6 @@ static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
>>>                */
>>>               sc->cur_clk = ptr;
>>>
>>> -             clk_enable(clk);
>>> -
>>>               dev_info(dev, "clock source %d: %s (%ld Hz)\n",
>>>                        ptr, name, clk_get_rate(clk));
>>>       }
>>> @@ -513,6 +513,8 @@ static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
>>>               goto err_no_busclks;
>>>       }
>>>
>>> +     clk_enable(sc->clk_bus[sc->cur_clk]);
>>> +
>>>       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>>       host->ioaddr = devm_request_and_ioremap(&pdev->dev, res);
>>>       if (!host->ioaddr) {
>>> @@ -621,9 +623,9 @@ static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
>>>       return 0;
>>>
>>>   err_req_regs:
>>> +     clk_disable(sc->clk_bus[sc->cur_clk]);
>>>       for (ptr = 0; ptr < MAX_BUS_CLK; ptr++) {
>>>               if (sc->clk_bus[ptr]) {
>>> -                     clk_disable(sc->clk_bus[ptr]);
>>>                       clk_put(sc->clk_bus[ptr]);
>>>               }
>>>       }
>>> @@ -658,9 +660,9 @@ static int __devexit sdhci_s3c_remove(struct platform_device *pdev)
>>>
>>>       pm_runtime_disable(&pdev->dev);
>>>
>>> +     clk_disable(sc->clk_bus[sc->cur_clk]);
>>>       for (ptr = 0; ptr < 3; ptr++) {
>>>               if (sc->clk_bus[ptr]) {
>>> -                     clk_disable(sc->clk_bus[ptr]);
>>>                       clk_put(sc->clk_bus[ptr]);
>>>               }
>>>       }
>>>
>>
> 
> 
>