On 4 June 2015 at 11:56, Lu Y.B. <yangbo.lu@xxxxxxxxxxxxx> wrote: > Pls see my comments below. > >> -----Original Message----- >> From: Ulf Hansson [mailto:ulf.hansson@xxxxxxxxxx] >> Sent: Thursday, June 04, 2015 3:51 PM >> To: Lu Yangbo-B47093 >> Cc: linux-mmc; Chris Ball >> Subject: Re: [PATCH 2/2] mmc: esdhc: add quirk to support 3.3v for T4240 >> >> On 2 June 2015 at 09:09, Yangbo Lu <yangbo.lu@xxxxxxxxxxxxx> wrote: >> > Add SDHCI_QUIRK2_CIRCUIT_SUPPORT_VS33 for T4240 >> > >> > Signed-off-by: Yangbo Lu <yangbo.lu@xxxxxxxxxxxxx> >> > --- >> > drivers/mmc/host/sdhci-of-esdhc.c | 3 +++ >> > 1 file changed, 3 insertions(+) >> > >> > diff --git a/drivers/mmc/host/sdhci-of-esdhc.c >> b/drivers/mmc/host/sdhci-of-esdhc.c >> > index 22e9111..4f5fe42 100644 >> > --- a/drivers/mmc/host/sdhci-of-esdhc.c >> > +++ b/drivers/mmc/host/sdhci-of-esdhc.c >> > @@ -369,6 +369,9 @@ static int sdhci_esdhc_probe(struct platform_device >> *pdev) >> > host->quirks2 |= SDHCI_QUIRK2_BROKEN_HOST_CONTROL; >> > } >> > >> > + if (of_device_is_compatible(np, "fsl,t4240-esdhc")) >> > + host->quirks2 |= SDHCI_QUIRK2_CIRCUIT_SUPPORT_VS33; >> > + >> >> Instead of checking the compatible, could you check the "ocr_avail" >> mask which mmc_of_parse() create from the vmmc regulator? > > It could get ocr_mask value supporting 3.3v from dts, and get ocr_avail not supporting 3.3v from capability register. > But in sdhci.c, the ocr_avail will "&" the ocr_mask value, this makes 3.3v supporting bit cleaned. > > if (host->ocr_mask) > ocr_avail &= host->ocr_mask; I have to admit that this looks a bit odd... Anyway, as long as you don't specify the "host->ocr_mask" the above "if" will not change the ocr_avail mask. Looking a bit further up in the code in sdhci_add_host(), you will find that the ocr_avail mask is created by calling mmc_regulator_get_supply() (and not mmc_of_parse() as told you before). If there are external regulators, the ocr_avail mask will then override the values from SDHCI's caps register. Anyway, as this patch seems to intended fixing something related to the IO voltage, it all looks wrong. [...] Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
