From mboxrd@z Thu Jan 1 00:00:00 1970 From: shawn.lin@rock-chips.com (Shawn Lin) Date: Sun, 7 Aug 2016 10:07:00 +0800 Subject: [PATCH RFC 2/3] mmc: core: add new cap for 3.3V only DDR MMCs In-Reply-To: <16443443.114784.752d0f22-93a7-46e8-bb14-c884787aaea3.open-xchange@email.1und1.de> References: <1470488140-10104-1-git-send-email-stefan.wahren@i2se.com> <1470488140-10104-3-git-send-email-stefan.wahren@i2se.com> <0e38d62a-b3d0-30ca-fca9-bb740ae54d0a@denx.de> <16443443.114784.752d0f22-93a7-46e8-bb14-c884787aaea3.open-xchange@email.1und1.de> Message-ID: <7284d9a4-164d-dd2d-b9a0-dd1de6c76274@rock-chips.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org ? 2016/8/6 22:18, Stefan Wahren ??: > Hi Marek, > >> Marek Vasut hat am 6. August 2016 um 15:14 geschrieben: >> >> >> On 08/06/2016 02:55 PM, Stefan Wahren wrote: >>> This patch based on the work of Fabio Estevam: >>> "[PATCH v2] mmc: core: Do not set mmc voltage to 1.8V when >>> 'no-1-8-v' is present" >>> >>> It adds the support for 3.3V only DDR MMC hosts. >> >> Do such cards even exist ? Do you have a link where I can find some ? > > i never said anything about SD cards. I mean eMMC modules which usually have 8 > data pins like this one [1]. > > Please don't blame me if it's not compatible to i.MX28. It's only an example. > > [1] - > http://datasheet.octopart.com/THGBM3G4D1FBAIGH2H-Toshiba-datasheet-20748880.pdf I download the datasheet you mentioned, and I explicitly see it describe 1V8 everywhere, especially for the section of "ELECTRICAL CHARACTERISTICS". I never see one eMMC claiming DDR52 capability but doesn't support 1V8 so far. Could you kindly share me the part number of the eMMC you are using? :) > >> >>> Signed-off-by: Stefan Wahren >>> --- >>> drivers/mmc/core/host.c | 2 ++ >>> drivers/mmc/core/mmc.c | 6 ++++++ >>> include/linux/mmc/host.h | 1 + >>> 3 files changed, 9 insertions(+) >>> >>> Changes to Fabio's patch: >>> - rebase to current linux-next >>> - rename DT property to mmc-ddr-3_3v >>> - use EXT_CSD_CARD_TYPE_DDR_52 instead of new define >>> >>> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c >>> index 98f25ff..4c971de 100644 >>> --- a/drivers/mmc/core/host.c >>> +++ b/drivers/mmc/core/host.c >>> @@ -301,6 +301,8 @@ int mmc_of_parse(struct mmc_host *host) >>> if (of_property_read_bool(np, "wakeup-source") || >>> of_property_read_bool(np, "enable-sdio-wakeup")) /* legacy */ >>> host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ; >>> + if (of_property_read_bool(np, "mmc-ddr-3_3v")) >>> + host->caps2 |= MMC_CAP2_3_3V_ONLY_DDR; >>> if (of_property_read_bool(np, "mmc-ddr-1_8v")) >>> host->caps |= MMC_CAP_1_8V_DDR; >>> if (of_property_read_bool(np, "mmc-ddr-1_2v")) >>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c >>> index f2d185c..8a933d5 100644 >>> --- a/drivers/mmc/core/mmc.c >>> +++ b/drivers/mmc/core/mmc.c >>> @@ -210,6 +210,12 @@ static void mmc_select_card_type(struct mmc_card *card) >>> avail_type |= EXT_CSD_CARD_TYPE_HS_52; >>> } >>> >>> + if (caps2 & MMC_CAP2_3_3V_ONLY_DDR && >>> + card_type & EXT_CSD_CARD_TYPE_DDR_1_8V) { >>> + hs_max_dtr = MMC_HIGH_DDR_MAX_DTR; >>> + avail_type |= EXT_CSD_CARD_TYPE_DDR_52; >>> + } >>> + >>> if (caps & MMC_CAP_1_8V_DDR && >>> card_type & EXT_CSD_CARD_TYPE_DDR_1_8V) { >>> hs_max_dtr = MMC_HIGH_DDR_MAX_DTR; >>> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h >>> index aa4bfbf..db0775d 100644 >>> --- a/include/linux/mmc/host.h >>> +++ b/include/linux/mmc/host.h >>> @@ -311,6 +311,7 @@ struct mmc_host { >>> #define MMC_CAP2_HS400_ES (1 << 20) /* Host supports enhanced strobe */ >>> #define MMC_CAP2_NO_SD (1 << 21) /* Do not send SD commands during >>> initialization */ >>> #define MMC_CAP2_NO_MMC (1 << 22) /* Do not send (e)MMC commands during >>> initialization */ >>> +#define MMC_CAP2_3_3V_ONLY_DDR (1 << 23) /* Only supports 3.3V DDR */ >>> >>> mmc_pm_flag_t pm_caps; /* supported pm features */ >>> >>> >> >> >> -- >> Best regards, >> Marek Vasut > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo at vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Best Regards Shawn Lin