Am 11.08.2016 um 13:12 schrieb Jaehoon Chung:
On 08/07/2016 11:07 AM, Shawn Lin wrote:
在 2016/8/6 22:18, Stefan Wahren 写道:
Hi Marek,
Marek Vasut <marex@xxxxxxx> 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 <stefan.wahren@xxxxxxxx>
---
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.
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