[PATCH 1/2] mmc: fsl_esdhc: Set fallback mode to 1-bit
Jaehoon Chung
jh80.chung at samsung.com
Tue May 17 01:39:14 CEST 2022
On 5/12/22 03:27, Pali Rohár wrote:
> 8-bit mode is not supported by SD cards and on P2020 are four SDHC pins
> shared with SPI (so if P2020 board have also SPI then only 4-bit SDHC mode
> is provided). So 8-bit SDHC mode is really bad default.
>
> When max bus width is not provided then set mode to 1-bit. This mode is
> supported by all cards, so it is the best option for fallback mode.
>
> Also P2020 bootrom sets mode to 1-bit when booting from SD/MMC card.
>
> Signed-off-by: Pali Rohár <pali at kernel.org>
Reviewed-by: Jaehoon Chung <jh80.chung at samsung.com>
Add minor comment.
> ---
> drivers/mmc/fsl_esdhc.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
> index 3b3587bd8d72..834f8933b0c6 100644
> --- a/drivers/mmc/fsl_esdhc.c
> +++ b/drivers/mmc/fsl_esdhc.c
> @@ -963,9 +963,8 @@ int fsl_esdhc_initialize(struct bd_info *bis, struct fsl_esdhc_cfg *cfg)
> } else if (cfg->max_bus_width == 1) {
> mmc_cfg->host_caps |= MMC_MODE_1BIT;
> } else {
> - mmc_cfg->host_caps |= MMC_MODE_1BIT | MMC_MODE_4BIT |
> - MMC_MODE_8BIT;
> - printf("No max bus width provided. Assume 8-bit supported.\n");
> + mmc_cfg->host_caps |= MMC_MODE_1BIT;
I'm not sure that it really needs to use "|".
Best Regards,
Jaehoon Chung
> + printf("No max bus width provided. Fallback to 1-bit mode.\n");
> }
>
> if (IS_ENABLED(CONFIG_ESDHC_DETECT_8_BIT_QUIRK))
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