Jae hoon Chung wrote:
> 2010/9/17 Matt Fleming <matt@xxxxxxxxxxxxxxxxx>:
>> On Thu, Sep 16, 2010 at 03:46:50PM +0900, Jaehoon Chung wrote:
>>> Hi all,
>>> This is a RFC patch that support clock-gating for saving power consumption.
>>> I found mmc_host_enable/mmc_host_disable function in core.c
>>> (using MMC_CAP_DSIABLE. i think that use when host enable/disable)
>>> So, i used that functions and implemented some functions in sdhci-s3c.c & sdhci.c
>>>
>>> i want any feedback. how do you think about this patch?
>>> Plz let me know...
>>>
>>> Thank you all
>>>
>>> Signed-off-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
>>> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
>>>
>>> ---
>>> drivers/mmc/host/sdhci-s3c.c | 36 ++++++++++++++++++++++++++++++++++++
>>> drivers/mmc/host/sdhci.c | 30 ++++++++++++++++++++++++++++++
>>> drivers/mmc/host/sdhci.h | 4 ++++
>>> 3 files changed, 70 insertions(+), 0 deletions(-)
>> [...]
>>
>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>> index 401527d..fa2e55d 100644
>>> --- a/drivers/mmc/host/sdhci.c
>>> +++ b/drivers/mmc/host/sdhci.c
>>> @@ -1245,7 +1245,37 @@ out:
>>> spin_unlock_irqrestore(&host->lock, flags);
>>> }
>>>
>>> +static int sdhci_enable_clk(struct mmc_host *mmc)
>>> +{
>>> + struct sdhci_host *host = mmc_priv(mmc);
>>> + int ret = 0;
>>> +
>>> + if (host->old_clock != 0 && host->clock == 0) {
>>> + if (host->ops->enable)
>>> + ret = host->ops->enable(host);
>>> + sdhci_set_clock(host, host->old_clock);
>>> + }
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +static int sdhci_disable_clk(struct mmc_host *mmc, int lazy)
>>> +{
>>> + struct sdhci_host *host = mmc_priv(mmc);
>>> + int ret = 0;
>>> +
>>> + if (host->clock != 0) {
>>> + host->old_clock = host->clock;
>>> + sdhci_set_clock(host, 0);
>>> + if (host->ops->disable)
>>> + ret = host->ops->disable(host, lazy);
>>> + }
>>> + return ret;
>>> +}
>>> +
>>> static const struct mmc_host_ops sdhci_ops = {
>>> + .enable = sdhci_enable_clk,
>>> + .disable = sdhci_disable_clk,
>>> .request = sdhci_request,
>>> .set_ios = sdhci_set_ios,
>>> .get_ro = sdhci_get_ro,
>>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>>> index d316bc7..0c6f143 100644
>>> --- a/drivers/mmc/host/sdhci.h
>>> +++ b/drivers/mmc/host/sdhci.h
>>> @@ -278,6 +278,8 @@ struct sdhci_host {
>>> unsigned int timeout_clk; /* Timeout freq (KHz) */
>>>
>>> unsigned int clock; /* Current clock (MHz) */
>>> + unsigned int old_clock; /* Old clock (MHz) */
>>> + unsigned int clk_cnt; /* Clock user count */
>>> u8 pwr; /* Current voltage */
>>>
>>> struct mmc_request *mrq; /* Current request */
>>> @@ -323,6 +325,8 @@ struct sdhci_ops {
>>> unsigned int (*get_max_clock)(struct sdhci_host *host);
>>> unsigned int (*get_min_clock)(struct sdhci_host *host);
>>> unsigned int (*get_timeout_clock)(struct sdhci_host *host);
>>> + int (*enable)(struct sdhci_host *host);
>>> + int (*disable)(struct sdhci_host *host, int lazy);
>>> };
>>>
>>> #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS
>> I could have misunderstood something, but do you really need this new
>> 'old_clock' member? Is the previous clock value not stored in
>> host->ios.clock?
>
> Thanks Matt for your comment.
> if host->ios.clock set zero, i think that need previous value (for
> example 52MHz..)
> So i add 'old_clock' member...i will test, after removed 'old_clock'
>
> anyother doubt? and problem?
> Thanks
>
Hi Chris.
I want to know how do you think about this patch.
If you have any doubt in this patch, let me know plz.
Thanks
Jaehoon Chung
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