This removes the default clocking for the MMCI controller so that the external MCI card clock does not activate until the first .set_ios() call is issued. It will further handle the transitions from a clock != 0 to 0 and vice versa by gating/ungating the clock with clk_disable()/clk_enable().
This assures that the MCI clock will not be active unless there is a card in the MMC slot. By default the MMC core will not gate off the clock to a card once it's enabled, but with the separate patch for aggressive clocking this can optionally be enabled for the system. Signed-off-by: Linus Walleij <[email protected]> --- drivers/mmc/host/mmci.c | 35 +++++++++++++++++++++++------------ drivers/mmc/host/mmci.h | 1 + 2 files changed, 24 insertions(+), 12 deletions(-) diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c index d4081d5..ea5e320 100644 --- a/drivers/mmc/host/mmci.c +++ b/drivers/mmc/host/mmci.c @@ -924,7 +924,23 @@ static void mmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) spin_lock_irqsave(&host->lock, flags); - mmci_set_clkreg(host, ios->clock); + /* + * Turn on clock whenever ios->clock transitions + * from 0 to !=0 and gate it off whenever ios->clock + * transitions from !=0 to 0. + */ + if (host->iosclock == 0 && ios->clock != 0) { + dev_dbg(mmc_dev(mmc), "enable clock f=%d\n", ios->clock); + clk_enable(host->clk); + mmci_set_clkreg(host, ios->clock); + } else if (host->iosclock != 0 && ios->clock == 0) { + dev_dbg(mmc_dev(mmc), "disable clock\n"); + clk_disable(host->clk); + } else if (ios->clock != 0) { + mmci_set_clkreg(host, ios->clock); + dev_dbg(mmc_dev(mmc), "set clock f=%d\n", ios->clock); + } + host->iosclock = ios->clock; if (host->pwr != pwr) { host->pwr = pwr; @@ -1009,6 +1025,8 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id) host = mmc_priv(mmc); host->mmc = mmc; + host->plat = plat; + host->variant = variant; host->gpio_wp = -ENOSYS; host->gpio_cd = -ENOSYS; @@ -1019,19 +1037,14 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id) dev_dbg(mmc_dev(mmc), "designer ID = 0x%02x\n", host->hw_designer); dev_dbg(mmc_dev(mmc), "revision = 0x%01x\n", host->hw_revision); + /* This clock will be enabled/disabled by set_ios() calls later */ host->clk = clk_get(&dev->dev, NULL); if (IS_ERR(host->clk)) { ret = PTR_ERR(host->clk); host->clk = NULL; goto host_free; } - - ret = clk_enable(host->clk); - if (ret) - goto clk_free; - - host->plat = plat; - host->variant = variant; + host->iosclock = 0; host->mclk = clk_get_rate(host->clk); /* * According to the spec, mclk is max 100 MHz, @@ -1041,7 +1054,7 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id) if (host->mclk > 100000000) { ret = clk_set_rate(host->clk, 100000000); if (ret < 0) - goto clk_disable; + goto clk_free; host->mclk = clk_get_rate(host->clk); dev_dbg(mmc_dev(mmc), "eventual mclk rate: %u Hz\n", host->mclk); @@ -1050,7 +1063,7 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id) host->base = ioremap(dev->res.start, resource_size(&dev->res)); if (!host->base) { ret = -ENOMEM; - goto clk_disable; + goto clk_free; } mmc->ops = &mmci_ops; @@ -1203,8 +1216,6 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id) gpio_free(host->gpio_cd); err_gpio_cd: iounmap(host->base); - clk_disable: - clk_disable(host->clk); clk_free: clk_put(host->clk); host_free: diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h index bc3b71e..5701d33 100644 --- a/drivers/mmc/host/mmci.h +++ b/drivers/mmc/host/mmci.h @@ -170,6 +170,7 @@ struct mmci_host { unsigned int mclk; unsigned int cclk; + unsigned int iosclock; u32 pwr; struct mmci_platform_data *plat; struct variant_data *variant; -- 1.7.2.3 -- 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
