Chris, Thanks, and very glad to hear this:-) Best Wishes, Yong Ding Operating Systems Engineering, Application Processor Systems Engineering -----Original Message----- From: Chris Ball [mailto:cjb@xxxxxxxxxx] Sent: Wednesday, June 06, 2012 9:24 PM To: Yong Ding Cc: linux-mmc@xxxxxxxxxxxxxxx; Philip Rakity; ohad@xxxxxxxxxx; linus.walleij@xxxxxxxxxx; ulf.hansson@xxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx Subject: Re: [PATCH v2] mmc:sdio:guarantee setting card data bus width as 4-bit Hi, On Tue, May 15 2012, yongd wrote: > 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 1stly read the register, 2ndly OR' 1b with SDIO_CCCR_IF[1], > and then write it back. > As we can see, such way is based on such assumption that the > SDIO_CCCR_IF[0] is always 0. Apparently, this is not right. > > Signed-off-by: yongd <yongd@xxxxxxxxxxx> > --- > drivers/mmc/core/sdio.c | 7 +++++++ > include/linux/mmc/sdio.h | 2 ++ > 2 files changed, 9 insertions(+) > > diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c > index 13d0e95..7b528cf 100644 > --- a/drivers/mmc/core/sdio.c > +++ b/drivers/mmc/core/sdio.c > @@ -218,6 +218,13 @@ static int sdio_enable_wide(struct mmc_card *card) > if (ret) > return ret; > > + if ((ctrl & SDIO_BUS_WIDTH_MASK) > + == SDIO_BUS_WIDTH_RESERVED) > + printk(KERN_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); > diff --git a/include/linux/mmc/sdio.h b/include/linux/mmc/sdio.h > index c9fe66c..17446d3 100644 > --- a/include/linux/mmc/sdio.h > +++ b/include/linux/mmc/sdio.h > @@ -98,7 +98,9 @@ > > #define SDIO_CCCR_IF 0x07 /* bus interface controls */ > > +#define SDIO_BUS_WIDTH_MASK 0x03 /* data bus width setting */ > #define SDIO_BUS_WIDTH_1BIT 0x00 > +#define SDIO_BUS_WIDTH_RESERVED 0x01 > #define SDIO_BUS_WIDTH_4BIT 0x02 > #define SDIO_BUS_ECSI 0x20 /* Enable continuous SPI interrupt */ > #define SDIO_BUS_SCSI 0x40 /* Support continuous SPI interrupt */ Thanks, pushed to mmc-next for 3.5. - Chris. -- Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/> One Laptop Per Child -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
