xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

mmc: sdio: fix setting card data bus width as 4-bit

Browse Source 
SDIO_CCCR_IF[1:0] in SDIO card is used for card data bus width
setting as below:

     00b: 1-bit bus
     01b: Reserved
     10b: 4-bit bus
     11b: 8-bit bus (only for embedded SDIO)

And sdio_enable_wide is for setting data bus width as 4-bit.
But currently, it first reads the register, second OR' 1b with
SDIO_CCCR_IF[1], and then writes it back.

As we can see, this is based on such assumption that the
SDIO_CCCR_IF[0] is always 0. Apparently, this is not right.

Signed-off-by: Yong Ding <yongd@marvell.com>
Acked-by: Philip Rakity <prakity@marvell.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Yong Ding
2012-05-15 13:09:43 +08:00
committed by Chris Ball
parent 693e5e2025
commit 2a0fe914a3
2 changed files with 8 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/mmc/core/sdio.c
View File

@@ -218,6 +218,12 @@ static int sdio_enable_wide(struct mmc_card *card)
if (ret)
return ret;
if ((ctrl & SDIO_BUS_WIDTH_MASK) == SDIO_BUS_WIDTH_RESERVED)
pr_warning("%s: SDIO_CCCR_IF is invalid: 0x%02x\n",
mmc_hostname(card->host), ctrl);
/* set as 4-bit bus width */
ctrl &= ~SDIO_BUS_WIDTH_MASK;
ctrl |= SDIO_BUS_WIDTH_4BIT;
ret = mmc_io_rw_direct(card, 1, 0, SDIO_CCCR_IF, ctrl, NULL);