[PATCH] mmc: tmio: Disable 1/1024 clock divider on Renesas R-Car platforms

[Paul Barker]

On Sun, Oct 22, 2023 at 11:40:43PM +0200, Marek Vasut wrote:
> The R-Car Gen3 SD_CLK_CTRL register does not use BIT(16) to implement
> divider 1/1024, instead BIT(16) is reserved bit and divider 1/1024 is
> not supported. The divider 1/1024 is specific to Socionext variant of
> the IP, as is indicated by Linux commit:
> 
> 0196c8db8363 ("mmc: tmio: move tmio_mmc_set_clock() to platform hook")
> "
> Socionext (and Panasonic) uses bit 10 (CLKSEL) for 1/1.  Also, newer
> versions of UniPhier SoC variants use bit 16 for 1/1024.
> "
> 
> Do not set the TMIO_SD_CAP_DIV1024 on Renesas R-Car platforms even if
> the IP VERSION register does exist, and indicates IP version is newer
> or equal to version 1.0 . The IP version 1.0 or newer does not imply
> presence of the 1/1024 divider.
> 
> Since the TMIO driver is used exactly by two supported platforms, that
> is Renesas R-Car and Socionext UniPhier, it is OK to check whether the
> TMIO_SD_CAP_RCAR capability is not set to identify the UniPhier platform
> and add the capability only on that platform.
> 
> Fixes: 58c35b17aa8f ("mmc: matsushita-common: Always check controller version")
> Signed-off-by: Marek Vasut <marek.vasut+renesas at mailbox.org>

I've confirmed that the 1/1024 divider doesn't exist in the RZ/G2L
datasheet.

Acked-by: Paul Barker <paul.barker.ct at bp.renesas.com>
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