From mboxrd@z Thu Jan 1 00:00:00 1970 From: stefan.wahren@i2se.com (Stefan Wahren) Date: Thu, 11 Aug 2016 13:57:50 +0200 Subject: [PATCH RFC 2/3] mmc: core: add new cap for 3.3V only DDR MMCs In-Reply-To: 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> <7284d9a4-164d-dd2d-b9a0-dd1de6c76274@rock-chips.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Am 11.08.2016 um 13:12 schrieb Jaehoon Chung: > On 08/07/2016 11:07 AM, Shawn Lin wrote: >> ? 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; >>>>> + } > > did you know EXT_CSD_CARD_TYPE_DDR_52 -> TYPE_DDR_1_8V and TYPE_DDR_1_2V? Thanks for pointing out. Fabio's patch was better here. As i wrote to Shawn the subject line is incorrect. I want to add 3.3V only support for hosts not for "card". According to the comments EXT_CSD_CARD_TYPE_DDR_1_8V stands for 1.8V or 3.3V. So i better add EXT_CSD_CARD_TYPE_DDR_3_3V_ONLY even the "card" supports 1.8V.