[U-Boot] [PATCH v4 2/3] mmc: dw_mmc: Support bypass mode with the get_mmc_clk() method

Simon Glass
2015-08-07T02:16:28Z

Some SoCs want to adjust the input clock to the DWMMC block as a way of
controlling the MMC bus clock. Update the get_mmc_clk() method to support
this.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

Changes in v4:
- Update commit message to indicate this patch is for the dw_mmc driver

drivers/mmc/dw_mmc.c | 2 +-
drivers/mmc/exynos_dw_mmc.c | 2 +-
include/dwmmc.h | 16 +++++++++++++++-
3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
index 8f28d7e..a034c3f 100644
--- a/drivers/mmc/dw_mmc.c
+++ b/drivers/mmc/dw_mmc.c
@@ -248,7 +248,7 @@ static int dwmci_setup_bus(struct dwmci_host *host, u32 freq)
* host->bus_hz should be set by user.
*/
if (host->get_mmc_clk)
- sclk = host->get_mmc_clk(host);
+ sclk = host->get_mmc_clk(host, freq);
else if (host->bus_hz)
sclk = host->bus_hz;
else {
diff --git a/drivers/mmc/exynos_dw_mmc.c b/drivers/mmc/exynos_dw_mmc.c
index e083745..3f702ba 100644
--- a/drivers/mmc/exynos_dw_mmc.c
+++ b/drivers/mmc/exynos_dw_mmc.c
@@ -39,7 +39,7 @@ static void exynos_dwmci_clksel(struct dwmci_host *host)
dwmci_writel(host, DWMCI_CLKSEL, priv->sdr_timing);
}

-unsigned int exynos_dwmci_get_clk(struct dwmci_host *host)
+unsigned int exynos_dwmci_get_clk(struct dwmci_host *host, uint freq)
{
unsigned long sclk;
int8_t clk_div;
diff --git a/include/dwmmc.h b/include/dwmmc.h
index 7a7555a..25cf42c 100644
--- a/include/dwmmc.h
+++ b/include/dwmmc.h
@@ -163,7 +163,21 @@ struct dwmci_host {

void (*clksel)(struct dwmci_host *host);
void (*board_init)(struct dwmci_host *host);
- unsigned int (*get_mmc_clk)(struct dwmci_host *host);
+
+ /**
+ * Get / set a particular MMC clock frequency
+ *
+ * This is used to request the current clock frequency of the clock
+ * that drives the DWMMC peripheral. The caller will then use this
+ * information to work out the divider it needs to achieve the
+ * required MMC bus clock frequency. If you want to handle the
+ * clock external to DWMMC, use @freq to select the frequency and
+ * return that value too. Then DWMMC will put itself in bypass mode.
+ *
+ * @host: DWMMC host
+ * @freq: Frequency the host is trying to achieve
+ */
+ unsigned int (*get_mmc_clk)(struct dwmci_host *host, uint freq);

struct mmc_config cfg;
};
--
2.5.0.rc2.392.g76e840b