On 3 August 2017 at 12:55, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: > On 03/08/17 13:40, Ulf Hansson wrote: >> +Adrian >> >> On 20 July 2017 at 15:36, Kishon Vijay Abraham I <kishon@xxxxxx> wrote: >>> Hi Ulf, >>> >>> On Tuesday 11 July 2017 07:27 PM, Kishon Vijay Abraham I wrote: >>>> Hi Ulf, >>>> >>>> On Tuesday 11 July 2017 06:40 PM, Ulf Hansson wrote: >>>>> On 16 June 2017 at 14:45, Kishon Vijay Abraham I <kishon@xxxxxx> wrote: >>>>>> This is the final part of the series originally sent as >>>>>> part of [2]. >>>>>> >>>>>> This series adds UHS, HS200, DDR mode and ADMA support to >>>>>> omap_hsmmc driver used to improve the throughput of MMC/SD in dra7 >>>>>> SoCs. >>>>>> >>>>>> Changes from [2]: >>>>>> *) No more updating omap2plus_defconfig or multi_v7_defconfig is >>>>>> required, so those patches are removed. >>>>>> *) Addressed Rob Herring's comment on implementing a function >>>>>> instead of having a macro while getting pinctrl state. >>>>>> >>>>>> This series is created on top of [3], [4], [5] AND [6] >>>>>> (i.e after >>>>>> ARM: dts: omap3-overo: Remove "vqmmc-supply" property from MMC dt node >>>>>> omap_hsmmc: use mmc_regulator_get_supply() to get regulators >>>>>> omap*: Fixes/Cleanups for MMC devicetree node >>>>>> ARM: dts: Add iodelay data for MMC) >>>>>> >>>>>> The functionality implemented in this series was sent before ([1]) but >>>>>> was never followed up since supporting high speed modes in dra7 required >>>>>> IODelay values to be configured. With IODelay driver being merged into >>>>>> kernel, sending it as a fresh series with support for configuring IODelay >>>>>> values. >>>>> >>>>> Is it safe to queue this via mmc tree for 4.14 or is there a >>>>> dependency I must consider? The above didn't quite tell me that, could >>>>> you please elaborate. >>>> >>>> There is a dependency with https://www.spinics.net/lists/arm-kernel/msg586215.html. >>>> >>>> I'll resend the series after all the platform data specific stuff is merged. >>>>> >>>>>> >>>>>> Suggestions of migrating to sdhci driver (from omap_hsmmc driver) is not >>>>>> addressed since >>>>>> *) tuning ratio of MMC in dra7 is different from sdhci >>>>>> *) IOdelay is required for dra7 >>>>>> *) GPIO based card detect is not supported in sdhci >>>>> >>>>> Lots of sdhci drivers calls mmc_of_parse(), and uses the mmc slot gpio >>>>> APIs, so I don't this this is correct statement. >>>>> >>>>>> *) Some of the registers don't always have correct values as in sdhci >>>>>> (like PSTATE). >>>>>> Supporting all of these in sdhci will result in adding lot of quirks in >>>>>> sdhci driver. >>>>> >>>>> Is it really that much different? It would be nice if some really took >>>>> on the challenge of converting omap_hsmmc into an sdhci variant. >>>> >>>> Okay. I'll give that a shot and see how far I can get. >>> >>> I created a sdhci variant and was able to get it working with high speed mode >>> in dra7. >> >> That's very nice! >> >>> >>> I have a query on sdhci_set_power_noreg() in sdhci.c. sdhci_set_power_noreg >>> sets SDHCI_POWER_CONTROL based on *vdd* value. However SDHCI_POWER_CONTROL is >>> for setting bus voltage and need not be based on *vdd*. IMHO >>> SDHCI_POWER_CONTROL should be set based on "ios->signal_voltage". >> >> According to the implementation in sdhci_set_power_noreg(), I >> understand it as the SDHCI_POWER_CONTROL register actually controls >> the power to the card (VDD) and the not the I/O voltage level >> (ios->signal_voltage). >> >> However, if I read the SDHCI spec, it seems to be mentioning the "SD >> bus voltage", which to me is about the I/O voltage level. So either >> the spec is unclear or the code is wrong. :-) >> >> Are you saying that the omap_hsmmc variant is using the >> SDHCI_POWER_CONTROL to control the I/O voltage level? >> >> I am wondering how other variants use it. Perhaps most variants >> actually have an external regulator and thus calls >> sdhci_set_power_reg() instead. >> >> Looping in Adrian, to see if he has some thoughts on this. > > The spec is clear enough. SDHCI_POWER_CONTROL is set based on the card's OCR. > > Signal voltage is defined by "1.8V Signaling Enable" in "Host Control 2 > Register". Thanks for clarifying this! 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
