mmc: Support bypass mode with the get_mmc_clk() method
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>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
index 77b87e0..1117fed 100644
--- a/drivers/mmc/dw_mmc.c
+++ b/drivers/mmc/dw_mmc.c
@@ -266,7 +266,7 @@
* 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 cde2ba7..863bbb3 100644
--- a/drivers/mmc/exynos_dw_mmc.c
+++ b/drivers/mmc/exynos_dw_mmc.c
@@ -39,7 +39,7 @@
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 @@
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;
};