Re: [PATCH 03/12] mci: arasan: implement 25MHz quirk for zynqmp

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 08.03.24 12:17, Steffen Trumtrar wrote:
> The Arasan on the zynqmp in version 8.9a doesn't meet the timing
> requirements at 25MHz. It works at 19MHz instead.
> 
> Add the quirk from linux kernel v6.8-rc4.
> 
> Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

> ---
>  drivers/mci/arasan-sdhci.c | 28 +++++++++++++++++++++++++++-
>  1 file changed, 27 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mci/arasan-sdhci.c b/drivers/mci/arasan-sdhci.c
> index 59afac7372..cc1bad8b62 100644
> --- a/drivers/mci/arasan-sdhci.c
> +++ b/drivers/mci/arasan-sdhci.c
> @@ -37,6 +37,12 @@ struct arasan_sdhci_host {
>  /* Controller does not have CD wired and will not function normally without */
>  #define SDHCI_ARASAN_QUIRK_FORCE_CDTEST		BIT(0)
>  #define SDHCI_ARASAN_QUIRK_NO_1_8_V		BIT(1)
> +/*
> + * Some of the Arasan variations might not have timing requirements
> + * met at 25MHz for Default Speed mode, those controllers work at
> + * 19MHz instead
> + */
> +#define SDHCI_ARASAN_QUIRK_CLOCK_25_BROKEN	BIT(2)
>  };
>  
>  static inline
> @@ -110,13 +116,30 @@ static int arasan_sdhci_init(struct mci_host *mci, struct device *dev)
>  	return 0;
>  }
>  
> +static void arasan_sdhci_set_clock(struct mci_host *mci, unsigned int clock)
> +{
> +	struct arasan_sdhci_host *host = to_arasan_sdhci_host(mci);
> +
> +	if (host->quirks & SDHCI_ARASAN_QUIRK_CLOCK_25_BROKEN) {
> +		/*
> +		 * Some of the Arasan variations might not have timing
> +		 * requirements met at 25MHz for Default Speed mode,
> +		 * those controllers work at 19MHz instead.
> +		 */
> +		if (clock == 25000000)
> +			clock = (25000000 * 19) / 25;
> +	}
> +
> +	sdhci_set_clock(&host->sdhci, clock, host->sdhci.max_clk);
> +}
> +
>  static void arasan_sdhci_set_ios(struct mci_host *mci, struct mci_ios *ios)
>  {
>  	struct arasan_sdhci_host *host = to_arasan_sdhci_host(mci);
>  	u16 val;
>  
>  	if (ios->clock)
> -		sdhci_set_clock(&host->sdhci, ios->clock, host->sdhci.max_clk);
> +		arasan_sdhci_set_clock(mci, ios->clock);
>  
>  	sdhci_set_bus_width(&host->sdhci, ios->bus_width);
>  
> @@ -243,6 +266,9 @@ static int arasan_sdhci_probe(struct device *dev)
>  	if (of_property_read_bool(np, "no-1-8-v"))
>  		arasan_sdhci->quirks |= SDHCI_ARASAN_QUIRK_NO_1_8_V;
>  
> +	if (of_device_is_compatible(np, "xlnx,zynqmp-8.9a"))
> +		arasan_sdhci->quirks |= SDHCI_ARASAN_QUIRK_CLOCK_25_BROKEN;
> +
>  	arasan_sdhci->sdhci.base = IOMEM(iores->start);
>  	arasan_sdhci->sdhci.mci = mci;
>  	mci->send_cmd = arasan_sdhci_send_cmd;
> 

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