[MMC] ios for mmc chip select

Adds a new ios for setting the chip select pin on MMC cards. Needed on
SD controllers which use this pin for other things and therefore cannot
have it pulled high at all times.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/mmc/mmc.c

@@ -457,13 +457,23 @@ static void mmc_idle_cards(struct mmc_host *host)
 {
 	struct mmc_command cmd;
 
+	host->ios.chip_select = MMC_CS_HIGH;
+	host->ops->set_ios(host, &host->ios);
+
+	mmc_delay(1);
+
 	cmd.opcode = MMC_GO_IDLE_STATE;
 	cmd.arg = 0;
 	cmd.flags = MMC_RSP_NONE;
 
 	mmc_wait_for_cmd(host, &cmd, 0);
 
 	mmc_delay(1);
+
+	host->ios.chip_select = MMC_CS_DONTCARE;
+	host->ops->set_ios(host, &host->ios);
+
+	mmc_delay(1);
 }
 
 /*
@@ -475,6 +485,7 @@ static void mmc_power_up(struct mmc_host *host)
 
 	host->ios.vdd = bit;
 	host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
+	host->ios.chip_select = MMC_CS_DONTCARE;
 	host->ios.power_mode = MMC_POWER_UP;
 	host->ops->set_ios(host, &host->ios);
 
@@ -492,6 +503,7 @@ static void mmc_power_off(struct mmc_host *host)
 	host->ios.clock = 0;
 	host->ios.vdd = 0;
 	host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
+	host->ios.chip_select = MMC_CS_DONTCARE;
 	host->ios.power_mode = MMC_POWER_OFF;
 	host->ops->set_ios(host, &host->ios);
 }

include/linux/mmc/host.h

@@ -46,6 +46,12 @@ struct mmc_ios {
 #define MMC_BUSMODE_OPENDRAIN	1
 #define MMC_BUSMODE_PUSHPULL	2
 
+	unsigned char	chip_select;		/* SPI chip select */
+
+#define MMC_CS_DONTCARE		0
+#define MMC_CS_HIGH		1
+#define MMC_CS_LOW		2
+
 	unsigned char	power_mode;		/* power supply mode */
 
 #define MMC_POWER_OFF		0