mmc: omap: follow TRM procedure to power on cards

Accorting to OMAP3 TRM, PBIASLITEPWRDNZ bits must be cleared while MMC
power supply is being enabled and is ramping up. It doesn't say what
happens if this procedure is violated, but better not to risk here and
do things as required.

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>

diff --git a/drivers/mmc/omap_hsmmc.c b/drivers/mmc/omap_hsmmc.c
index 3684335..547acd5 100644 (file)
--- a/drivers/mmc/omap_hsmmc.c
+++ b/drivers/mmc/omap_hsmmc.c
@@ -62,15 +62,21 @@ static void omap4_vmmc_pbias_config(struct mmc *mmc)
 
 unsigned char mmc_board_init(struct mmc *mmc)
 {
-#if defined(CONFIG_TWL4030_POWER)
-       twl4030_power_mmc_init();
-#endif
-
 #if defined(CONFIG_OMAP34XX)
        t2_t *t2_base = (t2_t *)T2_BASE;
        struct prcm *prcm_base = (struct prcm *)PRCM_BASE;
+       u32 pbias_lite;
 
-       writel(readl(&t2_base->pbias_lite) | PBIASLITEPWRDNZ1 |
+       pbias_lite = readl(&t2_base->pbias_lite);
+       pbias_lite &= ~(PBIASLITEPWRDNZ1 | PBIASLITEPWRDNZ0);
+       writel(pbias_lite, &t2_base->pbias_lite);
+#endif
+#if defined(CONFIG_TWL4030_POWER)
+       twl4030_power_mmc_init();
+       mdelay(100);    /* ramp-up delay from Linux code */
+#endif
+#if defined(CONFIG_OMAP34XX)
+       writel(pbias_lite | PBIASLITEPWRDNZ1 |
                PBIASSPEEDCTRL0 | PBIASLITEPWRDNZ0,
                &t2_base->pbias_lite);