Re: [PATCH v1] mtd: rawnand: meson: initialize clock register

[Arseniy Krasnov]

On 09.11.2023 08:40, Arseniy Krasnov wrote:
> Clock register must be also initialized during controller probing. If
> this is not performed (for example by bootloader before) - controller
> will not work.
> 
> Signed-off-by: Arseniy Krasnov <avkrasnov@xxxxxxxxxxxxxxxxx>
> ---
>  drivers/mtd/nand/raw/meson_nand.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
> index 0d4d358152d7..4e7fa943928c 100644
> --- a/drivers/mtd/nand/raw/meson_nand.c
> +++ b/drivers/mtd/nand/raw/meson_nand.c
> @@ -91,6 +91,8 @@
>  
>  /* eMMC clock register, misc control */
>  #define CLK_SELECT_NAND		BIT(31)
> +#define CLK_ALWAYS_ON_NAND      BIT(24)
> +#define CLK_ENABLE_VALUE        0x245
                                   ^^^^^^

Hi,

@Liang, it will be great, if You'll give some details about this magic value. I get it
from vendor's driver and it makes NAND controller alive, but I don't have any docs.

Thanks, Arseniy

>  
>  #define NFC_CLK_CYCLE		6
>  
> @@ -1152,7 +1154,7 @@ static int meson_nfc_clk_init(struct meson_nfc *nfc)
>  		return PTR_ERR(nfc->nand_clk);
>  
>  	/* init SD_EMMC_CLOCK to sane defaults w/min clock rate */
> -	writel(CLK_SELECT_NAND | readl(nfc->reg_clk),
> +	writel(CLK_ALWAYS_ON_NAND | CLK_SELECT_NAND | CLK_ENABLE_VALUE,
>  	       nfc->reg_clk);
>  
>  	ret = clk_prepare_enable(nfc->core_clk);