Re: [PATCH v4 2/7] mmc: mediatek: Add Mediatek MMC driver

[Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>]

On Tue, May 19, 2015 at 02:36:46PM +0800, Chaotian Jing wrote:
> Add Mediatek MMC driver code
> Support eMMC/SD/SDIO
> 
> Signed-off-by: Chaotian Jing <chaotian.jing@xxxxxxxxxxxx>
> ---
>  drivers/mmc/host/Kconfig  |    8 +
>  drivers/mmc/host/Makefile |    1 +
>  drivers/mmc/host/mtk-sd.c | 1422 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1431 insertions(+)
>  create mode 100644 drivers/mmc/host/mtk-sd.c
> 
> +
> +	host->src_clk = devm_clk_get(&pdev->dev, "source");
> +	if (IS_ERR(host->src_clk)) {
> +		ret = PTR_ERR(host->src_clk);
> +		goto host_free;
> +	}
> +
> +	host->h_clk = devm_clk_get(&pdev->dev, "hclk");
> +	if (IS_ERR(host->h_clk)) {
> +		/* host->h_clk is optional, Only for MSDC0/3 at MT8173 */
> +		dev_dbg(&pdev->dev,
> +				"Invalied hclk from the device tree!\n");
> +	}

s/Invalied/Invalid/

According to my reference manual the controller always needs a hclk. It
seems on some controllers it is just not software controllable. If
that's the case you should always provide a hclk to the driver and make
this clock mandatory.

Sascha

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