diff options
| author | Pierre Ossman <drzeus-list@drzeus.cx> | 2005-09-06 15:18:55 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-07 16:57:51 -0700 |
| commit | f218278a456b3c272b480443c89004c3d2a49f18 (patch) | |
| tree | 8d9558816488311e06a7ad2434e342418f2c79d5 /drivers/mmc/mmc.c | |
| parent | a9c4342beb4cd28b3a05c3401195e2536c37c150 (diff) | |
| download | linux-f218278a456b3c272b480443c89004c3d2a49f18.tar.bz2 | |
[PATCH] sd: SD 4-bit bus
Infrastructure for 4-bit bus transfers with SD cards.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/mmc/mmc.c')
| -rw-r--r-- | drivers/mmc/mmc.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index 21d4fb3314f8..6414f071a2a4 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -335,6 +335,40 @@ static int mmc_select_card(struct mmc_host *host, struct mmc_card *card) if (err != MMC_ERR_NONE) return err; + /* + * Default bus width is 1 bit. + */ + host->ios.bus_width = MMC_BUS_WIDTH_1; + + /* + * We can only change the bus width of the selected + * card so therefore we have to put the handling + * here. + */ + if (host->caps & MMC_CAP_4_BIT_DATA) { + /* + * The card is in 1 bit mode by default so + * we only need to change if it supports the + * wider version. + */ + if (mmc_card_sd(card) && + (card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) { + struct mmc_command cmd; + cmd.opcode = SD_APP_SET_BUS_WIDTH; + cmd.arg = SD_BUS_WIDTH_4; + cmd.flags = MMC_RSP_R1; + + err = mmc_wait_for_app_cmd(host, card->rca, &cmd, + CMD_RETRIES); + if (err != MMC_ERR_NONE) + return err; + + host->ios.bus_width = MMC_BUS_WIDTH_4; + } + } + + host->ops->set_ios(host, &host->ios); + return MMC_ERR_NONE; } @@ -653,6 +687,7 @@ static void mmc_power_up(struct mmc_host *host) host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN; host->ios.chip_select = MMC_CS_DONTCARE; host->ios.power_mode = MMC_POWER_UP; + host->ios.bus_width = MMC_BUS_WIDTH_1; host->ops->set_ios(host, &host->ios); mmc_delay(1); @@ -671,6 +706,7 @@ static void mmc_power_off(struct mmc_host *host) host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN; host->ios.chip_select = MMC_CS_DONTCARE; host->ios.power_mode = MMC_POWER_OFF; + host->ios.bus_width = MMC_BUS_WIDTH_1; host->ops->set_ios(host, &host->ios); } |