[PATCH v4 2/4] rockchip: sdhci: Fix RK3399 eMMC PHY power cycling

[Simon Glass]

On Fri, 28 Jan 2022 at 15:43, Alper Nebi Yasak <alpernebiyasak at gmail.com> wrote:
>
> The Rockchip RK3399 eMMC PHY has to be power-cycled while changing its
> clock speed to some higher speeds. This is dependent on the desired
> SDHCI clock speed, and it looks like the PHY should be powered off while
> setting the SDHCI clock in these cases.
>
> Commit ac804143cfd1 ("mmc: rockchip_sdhci: add phy and clock config for
> rk3399") attempts to do this in the set_ios_post() hook by setting the
> SDHCI clock once more while the PHY is turned off/on as necessary, as
> the SDHCI framework does not provide a way to override how it sets its
> clock. However, the commit breaks reinitializing the eMMC on a few
> boards including chromebook_kevin and reportedly ROCKPro64.
>
> This patch reworks the power cycling to utilize the SDHCI framework
> slightly better (using the set_control_reg() hook to power off the PHY
> and set_ios_post() hook to power it back on) which happens to fix the
> issue, at least on a chromebook_kevin.
>
> Signed-off-by: Alper Nebi Yasak <alpernebiyasak at gmail.com>
> ---
> RK3568 parts only build-tested as I don't have a RK3568 board.
>
> Changes in v4:
> - Add comment for Rockchip SDHCI set_control_reg() driver data op
> - Add comment for Rockchip SDHCI set_ios_post() driver data op
>
> Changes in v2:
> - Add this patch
>
>  drivers/mmc/rockchip_sdhci.c | 76 +++++++++++++++++++++++++++++++-----
>  1 file changed, 66 insertions(+), 10 deletions(-)

Reviewed-by: Simon Glass <sjg at chromium.org>