Dear Marek Vasut,
On 04/08/2013 06:28 PM, Marek Vasut wrote:
Dear Shawn Guo,
On Mon, Apr 08, 2013 at 03:58:05PM +0200, Hector Palacios wrote:
On 04/08/2013 02:48 PM, Shawn Guo wrote:
On Mon, Apr 08, 2013 at 12:12:20PM +0200, Hector Palacios wrote:
MicroSD card sockets don't usually have card detect line. This pin
is actually not needed for the MMC to work and it is more of a
platform design decission to have it.
The card detect pin already has a configuration entry of its own:
'mmc0_cd_cfg' so we complete the iomux configuration here and let
platforms to include it or not depending on whether the card detect
line is routed to the SD socket.
Sounds sensible.
Signed-off-by: Hector Palacios <hector.palacios@xxxxxxxx>
---
Hello,
All imx28 based platforms except 'bluegiga,apx4devkit' and
'schulercontrol,imx28-sps1', use 'mmc0_cd_cfg' in their mmc
configuration so please check whether this patch would break these
platforms.
I just tested the patch on imx28-evk and card-detection still works. So
patches applied, thanks.
The EVK and most platforms will work because they are using
'mmc0_cd_cfg' so actually this patch does not change anything on
them.
Platforms 'bluegiga,apx4devkit' and 'schulercontrol,imx28-sps1'
however are not referencing 'mmc0_cd_cfg' so after applying this
patch they will have unconfigured CD line and they may break.
Ah, yes. I thought that any board that has CD support has to reference
'mmc0_cd_cfg'. That's not necessarily true.
The driver will call get_cd() upon probing, which returns the status of
the CD line. Please check these two platforms before applying.
Ok, let's wait for people owning the boards to confirm.
Maybe you want to use MMC_CAP_NEEDS_POLL as was noted by someone before on the
olinuxino -- the slot is there, it's just the CD line that's missing.
I'm not sure of what you mean. The mxs-mmc.c driver already sets the
MMC_CAP_NEEDS_POLL flag by default in the probe() function. My platform does not even
route the CD line because the microSD socket does not have it.
So what I have done is modify the driver to parse the property 'non-removable' from
the device tree in order to set the MMC_CAP_NONREMOVABLE flag:
diff --git a/drivers/mmc/host/mxs-mmc.c b/drivers/mmc/host/mxs-mmc.c
index 206fe49..2a3b9c9 100644
--- a/drivers/mmc/host/mxs-mmc.c
+++ b/drivers/mmc/host/mxs-mmc.c
@@ -679,15 +682,20 @@ static int mxs_mmc_probe(struct platform_device *pdev)
/* set mmc core parameters */
mmc->ops = &mxs_mmc_ops;
mmc->caps = MMC_CAP_SD_HIGHSPEED | MMC_CAP_MMC_HIGHSPEED |
- MMC_CAP_SDIO_IRQ | MMC_CAP_NEEDS_POLL;
+ MMC_CAP_SDIO_IRQ;
of_property_read_u32(np, "bus-width", &bus_width);
if (bus_width == 4)
mmc->caps |= MMC_CAP_4_BIT_DATA;
else if (bus_width == 8)
mmc->caps |= MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA;
- host->wp_gpio = of_get_named_gpio_flags(np, "wp-gpios", 0, &flags);
+ if (of_find_property(np, "non-removable", NULL))
+ mmc->caps |= MMC_CAP_NONREMOVABLE;
+ else
+ mmc->caps |= MMC_CAP_NEEDS_POLL;
+
+ host->wp_gpio = of_get_named_gpio_flags(np, "wp-gpios", 0, &flags);
if (flags & OF_GPIO_ACTIVE_LOW)
host->wp_inverted = 1;
In theory, and according to the mmc bindings doc, this flag must assume the card is
always present. However the MMC core function mmc_rescan() will still call at least
once the get_cd() hook, which in the mxs-mmc.c returns the value of the CD line. In my
platform (where the CD line is not connected) this is returning 0, so I needed to do
the following:
diff --git a/drivers/mmc/host/mxs-mmc.c b/drivers/mmc/host/mxs-mmc.c
index 206fe49..2a3b9c9 100644
--- a/drivers/mmc/host/mxs-mmc.c
+++ b/drivers/mmc/host/mxs-mmc.c
@@ -95,6 +95,9 @@ static int mxs_mmc_get_cd(struct mmc_host *mmc)
struct mxs_mmc_host *host = mmc_priv(mmc);
struct mxs_ssp *ssp = &host->ssp;
+ if (mmc->caps & MMC_CAP_NONREMOVABLE)
+ return 1;
+
return !(readl(ssp->base + HW_SSP_STATUS(ssp)) &
BM_SSP_STATUS_CARD_DETECT);
}
to return a 1 when the driver should assume that the card is there. I wonder however
if this should be a global mmc patch instead, and have mmc_rescan() not call the host
get_cd() hook at all if MMC_CAP_NONREMOVABLE is set.
Regards,
--
Héctor Palacios
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