ARM: OMAP4: MMC: increase delay for pbias

1fcecf28 · Balaji T K <[email protected]> · 2011-06-01 16:45:22 +05:30

4 micro seconds is not enough for PBIAS if MMC regulator is
enabled from MMC regulator OFF.
Increase the delay for PBIAS to stabilize.
Wait for PBIAS and timeout if not.

Resolves MMC/SD failure on OMAP4
"Pbias Voltage is not same as LDO"

Signed-off-by: Balaji T K <[email protected]>
Acked-by:  Kishore Kadiyala <[email protected]>
Signed-off-by: Tony Lindgren <[email protected]>

Commit: 1fcecf281b99f9ca262ae7fbc3703c421be5c857
Parents: 1704bf15

Changes

1 files changed · +10 −3

File	Status	Add	Del	Content
arch/arm/mach-omap2/hsmmc.c	modified	+10	−3	View file

arch/arm/mach-omap2/hsmmc.c

View file

diff --git a/arch/arm/mach-omap2/hsmmc.c b/arch/arm/mach-omap2/hsmmc.c
index 857f7da..66868c5 100644
--- a/arch/arm/mach-omap2/hsmmc.c
+++ b/arch/arm/mach-omap2/hsmmc.c
@@ -145,6 +145,7 @@ static void omap4_hsmmc1_after_set_reg(struct device *dev, int slot,
 				 int power_on, int vdd)
 {
 	u32 reg;
+	unsigned long timeout;
 
 	if (power_on) {
 		reg = omap4_ctrl_pad_readl(control_pbias_offset);
@@ -157,9 +158,15 @@ static void omap4_hsmmc1_after_set_reg(struct device *dev, int slot,
 			OMAP4_MMC1_PWRDNZ_MASK |
 			OMAP4_USBC1_ICUSB_PWRDNZ_MASK);
 		omap4_ctrl_pad_writel(reg, control_pbias_offset);
-		/* 4 microsec delay for comparator to generate an error*/
-		udelay(4);
-		reg = omap4_ctrl_pad_readl(control_pbias_offset);
+
+		timeout = jiffies + msecs_to_jiffies(5);
+		do {
+			reg = omap4_ctrl_pad_readl(control_pbias_offset);
+			if (!(reg & OMAP4_MMC1_PBIASLITE_VMODE_ERROR_MASK))
+				break;
+			usleep_range(100, 200);
+		} while (!time_after(jiffies, timeout));
+
 		if (reg & OMAP4_MMC1_PBIASLITE_VMODE_ERROR_MASK) {
 			pr_err("Pbias Voltage is not same as LDO\n");
 			/* Caution : On VMODE_ERROR Power Down MMC IO */