Re: [PATCH] Revert "mmc: fsl_esdhc_imx: add wait_dat0() support"

[Jaehoon Chung]

Hi Marek,

On 1/28/22 12:40, Marek Vasut wrote:
> This reverts commit b5874b552ffa09bc1dc5dec6b5dd376c62dab45d.
> 
> It seems the iMX8MM SDHC controller always reports DAT0 line status
> as zero after voltage switch at the end of mmc_switch_voltage(), even
> if it is supposed to be high and scope confirms the DAT0 is high.
> Reverting this patch makes SDR104 work on iMX8MM, however, it is
> not clear why the DAT0 status is not correctly reported by the
> controller.

I didn't have an imx8mm board, so I wonder that other boards which is using 
fsl_esdhci_imx driver have same problem.
I'm not sure...I remember that some controller doesn't support a busy signal.
In kernel driver, also doesn't report correct status?

Best Regards,
Jaehoon Chung

> 
> Signed-off-by: Marek Vasut <ma...@denx.de>
> Cc: Haibo Chen <haibo.c...@nxp.com>
> Cc: Igor Opaniuk <igor.opan...@foundries.io>
> Cc: Jaehoon Chung <jh80.ch...@samsung.com>
> Cc: Peng Fan <peng....@nxp.com>
> Cc: Stefano Babic <sba...@denx.de>
> ---
>  drivers/mmc/fsl_esdhc_imx.c | 15 ---------------
>  1 file changed, 15 deletions(-)
> 
> diff --git a/drivers/mmc/fsl_esdhc_imx.c b/drivers/mmc/fsl_esdhc_imx.c
> index 9299635f509..5465992ec95 100644
> --- a/drivers/mmc/fsl_esdhc_imx.c
> +++ b/drivers/mmc/fsl_esdhc_imx.c
> @@ -1552,20 +1552,6 @@ static int __maybe_unused 
> fsl_esdhc_set_enhanced_strobe(struct udevice *dev)
>       return 0;
>  }
>  
> -static int fsl_esdhc_wait_dat0(struct udevice *dev, int state,
> -                             int timeout_us)
> -{
> -     int ret;
> -     u32 tmp;
> -     struct fsl_esdhc_priv *priv = dev_get_priv(dev);
> -     struct fsl_esdhc *regs = priv->esdhc_regs;
> -
> -     ret = readx_poll_timeout(esdhc_read32, &regs->prsstat, tmp,
> -                             !!(tmp & PRSSTAT_DAT0) == !!state,
> -                             timeout_us);
> -     return ret;
> -}
> -
>  static const struct dm_mmc_ops fsl_esdhc_ops = {
>       .get_cd         = fsl_esdhc_get_cd,
>       .send_cmd       = fsl_esdhc_send_cmd,
> @@ -1576,7 +1562,6 @@ static const struct dm_mmc_ops fsl_esdhc_ops = {
>  #if CONFIG_IS_ENABLED(MMC_HS400_ES_SUPPORT)
>       .set_enhanced_strobe = fsl_esdhc_set_enhanced_strobe,
>  #endif
> -     .wait_dat0 = fsl_esdhc_wait_dat0,
>  };
>  
>  static struct esdhc_soc_data usdhc_imx7d_data = {