[U-Boot] [PATCH v4 04/33] mmc: Support bypass mode with the get_mmc_clk() method

Jaehoon Chung
2015-08-25T02:18:28Z

Hi, Simon.

Acked-by: Jaehoon Chung <jh80.chung@samsung.com>

Best Regards,
Jaehoon Chung

On 08/25/2015 12:12 AM, Simon Glass wrote:
> 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: None
> Changes in v3: None
> Changes in v2: None
>
> 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 77b87e0..1117fed 100644
> --- a/drivers/mmc/dw_mmc.c
> +++ b/drivers/mmc/dw_mmc.c
> @@ -266,7 +266,7 @@ 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 cde2ba7..863bbb3 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;
> };
>