[U-Boot] [PATCH v3 31/54] mmc: Support bypass mode with the get_mmc_clk() method

[Jaehoon Chung]

Hi, Simon.

On 06/24/2015 06:38 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.

I didn't see your other patches.
But i don't know this patch's purpose.
I think that @freq usage seems like host->bus_hz ("bus_hz" property), doesn't it?

Best Regards,
Jaehoon Chung

> 
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
> 
> 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 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;
>  };
>