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
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