Re: [PATCH] sdhci: expose the SDCLK frq in sys ios

[Adrian Hunter <adrian.hunter@intel.com>]

On 19/10/11 16:45, Giuseppe CAVALLARO wrote:
> This patch is to expose the SDCLK frequency in the ios /sys entry.
> 
> For example, if the max clk for a normal speed card is 20MHz
> this will be reported in /sys/kernel/debug/mmc0/ios instead of
> the real SDCLK frequency (calculated as Baseclock / divisor;
> divisor used for programming the Clock Control Register).
> 
> Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
> ---
>  drivers/mmc/host/sdhci.c |    9 ++++++++-
>  1 files changed, 8 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 0e02cc1..6bdf64f 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1045,6 +1045,7 @@ static void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
>  	int div = 0; /* Initialized for compiler warning */
>  	u16 clk = 0;
>  	unsigned long timeout;
> +	unsigned int new_hc_clock = host->max_clk;
>  
>  	if (clock == host->clock)
>  		return;
> @@ -1134,7 +1135,10 @@ static void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
>  	sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
>  
>  out:
> -	host->clock = clock;
> +	if (div)
> +		new_hc_clock = host->max_clk / div;

At this point div is the value written to the register not the
divisor

> +
> +	host->clock = new_hc_clock;
>  }
>  
>  static void sdhci_set_power(struct sdhci_host *host, unsigned short power)
> @@ -1293,6 +1297,9 @@ static void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>  
>  	sdhci_set_clock(host, ios->clock);
>  
> +	/* Clock provided to the HC */
> +	ios->clock = host->clock;

It would be nicer to keep ios->clock as the target
frequency and add a new member to struct mmc_host for
the actual frequency.

> +
>  	if (ios->power_mode == MMC_POWER_OFF)
>  		sdhci_set_power(host, -1);
>  	else