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 <[email protected]> Signed-off-by: Kyungmin Park <[email protected]> --- 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-s3c.c b/drivers/mmc/host/sdhci-s3c.c index 71ad416..9b430fb 100644 --- a/drivers/mmc/host/sdhci-s3c.c +++ b/drivers/mmc/host/sdhci-s3c.c @@ -47,6 +47,7 @@ struct sdhci_s3c { unsigned int cur_clk; int ext_cd_irq; int ext_cd_gpio; + int flag; struct clk *clk_io; struct clk *clk_bus[MAX_BUS_CLK]; @@ -232,10 +233,45 @@ static unsigned int sdhci_s3c_get_min_clock(struct sdhci_host *host) return min; } +static int sdhci_s3c_enable_clk(struct sdhci_host *host) +{ + struct sdhci_s3c *sc = to_s3c(host); + + if (sc->flag != 1) { + clk_disable(sc->clk_io); + clk_disable(sc->clk_bus[sc->cur_clk]); + } + + if (sc->host->clk_cnt == 0) { + clk_enable(sc->clk_io); + clk_enable(sc->clk_bus[sc->cur_clk]); + sc->host->clk_cnt++; + sc->flag = 1; + } + + return 0; +} + +static int sdhci_s3c_disable_clk(struct sdhci_host *host, int lazy) +{ + struct sdhci_s3c *sc = to_s3c(host); + + if (sc->host->clk_cnt) { + clk_disable(sc->clk_io); + clk_disable(sc->clk_bus[sc->cur_clk]); + if (sc->host->clk_cnt) + sc->host->clk_cnt--; + } + + return 0; +} + static struct sdhci_ops sdhci_s3c_ops = { .get_max_clock = sdhci_s3c_get_max_clk, .set_clock = sdhci_s3c_set_clock, .get_min_clock = sdhci_s3c_get_min_clock, + .enable = sdhci_s3c_enable_clk, + .disable = sdhci_s3c_disable_clk, }; static void sdhci_s3c_notify_change(struct platform_device *dev, int state) 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 -- 1.6.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
