On May 11, 2011, at 2:28 AM, zhangfei gao wrote:
> On Wed, May 11, 2011 at 4:52 AM, Philip Rakity <prakity@xxxxxxxxxxx> wrote:
>>
>> \
>> On May 11, 2011, at 1:48 AM, zhangfei gao wrote:
>>
>>> On Thu, May 5, 2011 at 2:49 AM, Arindam Nath <arindam.nath@xxxxxxx> wrote:
>>>> Marvell controller requires 1.8V bit in UHS control register 2
>>>> be set when doing UHS. eMMC does not require 1.8V for DDR.
>>>> add platform code to handle this.
>>>>
>>>> Signed-off-by: Philip Rakity <prakity@xxxxxxxxxxx>
>>>> Reviewed-by: Arindam Nath <arindam.nath@xxxxxxx>
>>>> ---
>>>> drivers/mmc/host/sdhci-pxa.c | 36 ++++++++++++++++++++++++++++++++++++
>>>> 1 files changed, 36 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/drivers/mmc/host/sdhci-pxa.c b/drivers/mmc/host/sdhci-pxa.c
>>>> index 5a61208..b52c3e6 100644
>>>> --- a/drivers/mmc/host/sdhci-pxa.c
>>>> +++ b/drivers/mmc/host/sdhci-pxa.c
>>>> @@ -69,7 +69,40 @@ static void set_clock(struct sdhci_host *host, unsigned int clock)
>>>> }
>>>> }
>>>>
>>>> +static int set_uhs_signaling(struct sdhci_host *host, unsigned int uhs)
>>>> +{
>>>> + u16 ctrl_2;
>>>> +
>>>> + /*
>>>> + * Set V18_EN -- UHS modes do not work without this.
>>>> + * does not change signaling voltage
>>>> + */
>>>> + ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>>>> +
>>>> + /* Select Bus Speed Mode for host */
>>>> + ctrl_2 &= ~SDHCI_CTRL_UHS_MASK;
>>>> + if (uhs == MMC_TIMING_UHS_SDR12)
>>>> + ctrl_2 |= SDHCI_CTRL_UHS_SDR12;
>>>> + else if (uhs == MMC_TIMING_UHS_SDR25)
>>>> + ctrl_2 |= SDHCI_CTRL_UHS_SDR25;
>>>> + else if (uhs == MMC_TIMING_UHS_SDR50) {
>>>> + ctrl_2 |= SDHCI_CTRL_UHS_SDR50;
>>>> + ctrl_2 |= SDHCI_CTRL_VDD_180;
>>>> + } else if (uhs == MMC_TIMING_UHS_SDR104) {
>>>> + ctrl_2 |= SDHCI_CTRL_UHS_SDR104;
>>>> + ctrl_2 |= SDHCI_CTRL_VDD_180;
>>>> + } else if (uhs == MMC_TIMING_UHS_DDR50) {
>>>> + ctrl_2 |= SDHCI_CTRL_UHS_DDR50;
>>>> + ctrl_2 |= SDHCI_CTRL_VDD_180;
>>>> + }
>>>> + sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
>>>> + pr_debug("%s:%s uhs = %d, ctrl_2 = %04X\n",
>>>> + __func__, mmc_hostname(host->mmc), uhs, ctrl_2);
>>>> + return 0;
>>>> +}
>>>
>>> Why move common register accessing from sdhci.c to specific driver?
>>
>> In general case you do not know what the specific host controller work arounds are required.
>> on mmp2 this code works (no need for V18 for low speed UHS)
>> but other controllers it could be different
>
> Sorry, not understand, the patch is for sd uhs card or for emmc?
> For sd uhs card, no workaround is needed on mmp2, but require external
> pmic to provide 1.8v io voltage.
require 1.8V when setting UHS modes. See latest MMP2 Documentation.
>
>>
>>>
>>>> +
>>>> static struct sdhci_ops sdhci_pxa_ops = {
>>>> + .set_uhs_signaling = set_uhs_signaling,
>>>> .set_clock = set_clock,
>>>> };
>>>>
>>>> @@ -141,6 +174,9 @@ static int __devinit sdhci_pxa_probe(struct platform_device *pdev)
>>>> if (pdata->quirks)
>>>> host->quirks |= pdata->quirks;
>>>>
>>>> + /* enable 1/8V DDR capable */
>>>> + host->mmc->caps |= MMC_CAP_1_8V_DDR;
>>>> +
>>>> /* If slot design supports 8 bit data, indicate this to MMC. */
>>>> if (pdata->flags & PXA_FLAG_SD_8_BIT_CAPABLE_SLOT)
>>>> host->mmc->caps |= MMC_CAP_8_BIT_DATA;
>>>> --
>>>> 1.7.1
>>>>
>>>>
>>
>>
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