[U-Boot] [PATCH] MMC: DWMMC: Correct the CLKDIV register value

[Simon Glass]

On Thu, Aug 29, 2013 at 5:04 AM, Rajeshwari Birje
<rajeshwari.birje at gmail.com> wrote:
> CCing the MMC Maintainer.
>
> On Thu, Aug 29, 2013 at 4:22 PM, Rajeshwari S Shinde
> <rajeshwari.s at samsung.com> wrote:
>> This patch corrects the divider value written to CLKDIV register.
>> Since SDCLKIN is divided inside controller by the DIVRATIO value set
>> in the CLKSEL register, we need to use the same output clock value to
>> calculate the CLKDIV value.
>> as per user manual: cclk_in = SDCLKIN / (DIVRATIO + 1)
>>
>> Input parameter to mmc_clk is changed to dwmci_host, since
>> we need the same to read DWMCI_CLKSEL register.
>>
>> This improves the read timing values for channel 0 on SMDK5250
>> from 0.288sec to 0.144sec
>>
>> Signed-off-by: Rajeshwari S Shinde <rajeshwari.s at samsung.com>
>> ---
>>  arch/arm/include/asm/arch-exynos/dwmmc.h |  4 ++++
>>  drivers/mmc/dw_mmc.c                     |  2 +-
>>  drivers/mmc/exynos_dw_mmc.c              | 17 +++++++++++++++--
>>  include/dwmmc.h                          |  2 +-
>>  4 files changed, 21 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/arm/include/asm/arch-exynos/dwmmc.h b/arch/arm/include/asm/arch-exynos/dwmmc.h
>> index b9eca76..f1c8d8a 100644
>> --- a/arch/arm/include/asm/arch-exynos/dwmmc.h
>> +++ b/arch/arm/include/asm/arch-exynos/dwmmc.h
>> @@ -14,6 +14,10 @@
>>  #define DWMCI_SET_DRV_CLK(x)   ((x) << 16)
>>  #define DWMCI_SET_DIV_RATIO(x) ((x) << 24)
>>
>> +/* CLKSEL Register */
>> +#define DWMCI_DIVRATIO_BIT             24
>> +#define DWMCI_DIVRATIO_MASK            0x7
>> +
>>  #ifdef CONFIG_OF_CONTROL
>>  int exynos_dwmmc_init(const void *blob);
>>  #endif
>> diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
>> index a82ee17..3406bdd 100644
>> --- a/drivers/mmc/dw_mmc.c
>> +++ b/drivers/mmc/dw_mmc.c
>> @@ -224,7 +224,7 @@ static int dwmci_setup_bus(struct dwmci_host *host, u32 freq)
>>          * host->bus_hz should be set from user.
>>          */
>>         if (host->mmc_clk)
>> -               sclk = host->mmc_clk(host->dev_index);
>> +               sclk = host->mmc_clk(host);

Do you need to change dw_mmc_simple.c as well?

Regards,
Simon