Hi Marek,
Is the regulator dedicated ? or is it shared ? Is it used for eMMC ?
If it cannot be turned off -- then just don't list it in the regulators list for vmmc.
If it CAN be turned off then need to get back to you.
Philip
On Nov 13, 2012, at 2:14 PM, Chris Ball <cjb@xxxxxxxxxx> wrote:
> Hi,
>
> On Tue, Nov 13 2012, Marek Szyprowski wrote:
>>> On Tue, Nov 13 2012, Marek Szyprowski wrote:
>>>> Fixed regulators cannot change their voltage, so disable all voltage
>>>> range checking for them, otherwise the driver fails to operate with
>>>> fixed regulators. Up to now it worked only by luck, because
>>>> regulator_is_supported_voltage() function returned incorrect values.
>>>> Commit "regulator: fix voltage check in regulator_is_supported_voltage()"
>>>> fixed that function and now additional check is needed for fixed
>>>> regulators.
>>>>
>>>> Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
>>>> ---
>>>> drivers/mmc/host/sdhci.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>>> index c7851c0..6f6534e 100644
>>>> --- a/drivers/mmc/host/sdhci.c
>>>> +++ b/drivers/mmc/host/sdhci.c
>>>> @@ -2923,7 +2923,7 @@ int sdhci_add_host(struct sdhci_host *host)
>>>> regulator_enable(host->vmmc);
>>>>
>>>> #ifdef CONFIG_REGULATOR
>>>> - if (host->vmmc) {
>>>> + if (host->vmmc && regulator_count_voltages(host->vmmc) > 1) {
>>>> ret = regulator_is_supported_voltage(host->vmmc, 3300000,
>>>> 3300000);
>>>> if ((ret <= 0) || (!(caps[0] & SDHCI_CAN_VDD_330)))
>>>
>>> Thanks for the longer explanation. I'm still missing something, though;
>>> what's wrong with running the check as it was with the new regulator code?
>>> (I haven't tried it yet.)
>>>
>>> #ifdef CONFIG_REGULATOR
>>> if (host->vmmc) {
>>> ret = regulator_is_supported_voltage(host->vmmc, 3300000,
>>> 3300000);
>>> if ((ret <= 0) || (!(caps[0] & SDHCI_CAN_VDD_330)))
>>> caps[0] &= ~SDHCI_CAN_VDD_330;
>>> ret = regulator_is_supported_voltage(host->vmmc, 3000000,
>>> 3000000);
>>> if ((ret <= 0) || (!(caps[0] & SDHCI_CAN_VDD_300)))
>>> caps[0] &= ~SDHCI_CAN_VDD_300;
>>> ret = regulator_is_supported_voltage(host->vmmc, 1800000,
>>> 1800000);
>>> if ((ret <= 0) || (!(caps[0] & SDHCI_CAN_VDD_180)))
>>> caps[0] &= ~SDHCI_CAN_VDD_180;
>>> }
>>> #endif /* CONFIG_REGULATOR */
>>>
>>> The point is to remove unsupported voltages, so if someone sets up a
>>> fixed regulator at 3300000, all of the other caps are disabled. Why
>>> wouldn't that work without this change, and how are we supposed to
>>> remove those caps on a fixed regulator after your patchset?
>>>
>>> Thanks, sorry if I'm missing something obvious,
>>
>> On our boards eMMC is connected to fixed 2.8V regulator, what results in
>> clearing all available voltages and fail. The same situation is when one
>> enable dummy regulator and try to use sdhci with it. My patch fixes this
>> and restores sdhci to working state as it was before (before fixing
>> regulator regulator_is_supported_voltage() function and earlier when
>> MMC_BROKEN_VOLATGE capability was used).
>
> I see. Sounds like a separate bug -- Philip (or anyone else), any
> idea how we should be treating eMMCs with a fixed voltage here?
>
> Thanks,
>
> - Chris.
> --
> Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/>
> One Laptop Per Child
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