[PATCH 3/5] clk: meson: reset mmc clock on probe

[Neil Armstrong]

On 19/12/2019 19:36, Jerome Brunet wrote:
> On some SoCs, depending on the boot device, the MMC clock block may be
> left in a weird state by the ROM code, in which no decent clock may be
> provided. Reset the related register to make sure a sane MMC clock is
> ready for the controller.
> 
> Signed-off-by: Jerome Brunet <jbrunet at baylibre.com>
> ---
>  drivers/clk/meson/axg.c  | 7 +++++++
>  drivers/clk/meson/g12a.c | 7 +++++++
>  drivers/clk/meson/gxbb.c | 7 +++++++
>  3 files changed, 21 insertions(+)
> 
> diff --git a/drivers/clk/meson/axg.c b/drivers/clk/meson/axg.c
> index 32cbf752aed8..0ba6c303e122 100644
> --- a/drivers/clk/meson/axg.c
> +++ b/drivers/clk/meson/axg.c
> @@ -290,6 +290,13 @@ static int meson_clk_probe(struct udevice *dev)
>  	if (IS_ERR(priv->map))
>  		return PTR_ERR(priv->map);
>  
> +	/*
> +	 * Depending on the boot src, the state of the MMC clock might
> +	 * be different. Reset it to make sure we won't get stuck
> +	 */
> +	regmap_write(priv->map, HHI_NAND_CLK_CNTL, 0);
> +	regmap_write(priv->map, HHI_SD_EMMC_CLK_CNTL, 0);
> +
>  	debug("meson-clk-axg: probed\n");
>  
>  	return 0;
> diff --git a/drivers/clk/meson/g12a.c b/drivers/clk/meson/g12a.c
> index 1b2523bbf1fe..03d885d986b8 100644
> --- a/drivers/clk/meson/g12a.c
> +++ b/drivers/clk/meson/g12a.c
> @@ -976,6 +976,13 @@ static int meson_clk_probe(struct udevice *dev)
>  	if (IS_ERR(priv->map))
>  		return PTR_ERR(priv->map);
>  
> +	/*
> +	 * Depending on the boot src, the state of the MMC clock might
> +	 * be different. Reset it to make sure we won't get stuck
> +	 */
> +	regmap_write(priv->map, HHI_NAND_CLK_CNTL, 0);
> +	regmap_write(priv->map, HHI_SD_EMMC_CLK_CNTL, 0);
> +
>  	debug("meson-clk-g12a: probed\n");
>  
>  	return 0;
> diff --git a/drivers/clk/meson/gxbb.c b/drivers/clk/meson/gxbb.c
> index abb5337e7829..aedba991603f 100644
> --- a/drivers/clk/meson/gxbb.c
> +++ b/drivers/clk/meson/gxbb.c
> @@ -886,6 +886,13 @@ static int meson_clk_probe(struct udevice *dev)
>  	if (IS_ERR(priv->map))
>  		return PTR_ERR(priv->map);
>  
> +	/*
> +	 * Depending on the boot src, the state of the MMC clock might
> +	 * be different. Reset it to make sure we won't get stuck
> +	 */
> +	regmap_write(priv->map, HHI_NAND_CLK_CNTL, 0);
> +	regmap_write(priv->map, HHI_SD_EMMC_CLK_CNTL, 0);
> +
>  	debug("meson-clk: probed\n");
>  
>  	return 0;
> 

looks sane, but should be tested on other platforms to make sure
it still works.

Reviewed-by: Neil Armstrong <narmstrong at baylibre.com>