omap_hsmmc: only MMC1 allows HCTL.SDVS != 1.8V
Based on a patch from Tony Lindgren ... after initialization,
never change HCTL.SDVS except for MMC1. The other controller
instances only support 1.8V in that field, although they can
suport other card/SDIO/eMMC/... voltages with level shifting
solutions such as external transceivers.
MMC2 behavior sanity tested on Overo/WLAN, OMAP3430 SDP, and
custom hardware. MMC1 also sanity tested on those platforms
plus Beagle. This also fixes a bug preventing MMC2 (and also
presumably MMC3) from powering down when requested.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 4dba486..3bfd0fa 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -55,6 +55,7 @@
#define VS30 (1 << 25)
#define SDVS18 (0x5 << 9)
#define SDVS30 (0x6 << 9)
+#define SDVS33 (0x7 << 9)
#define SDVSCLR 0xFFFFF1FF
#define SDVSDET 0x00000400
#define AUTOIDLE 0x1
@@ -456,13 +457,20 @@
}
/*
- * Switch MMC operating voltage
+ * Switch MMC interface voltage ... only relevant for MMC1.
+ *
+ * MMC2 and MMC3 use fixed 1.8V levels, and maybe a transceiver.
+ * The MMC2 transceiver controls are used instead of DAT4..DAT7.
+ * Some chips, like eMMC ones, use internal transceivers.
*/
static int omap_mmc_switch_opcond(struct mmc_omap_host *host, int vdd)
{
u32 reg_val = 0;
int ret;
+ if (host->id != OMAP_MMC1_DEVID)
+ return 0;
+
/* Disable the clocks */
clk_disable(host->fclk);
clk_disable(host->iclk);
@@ -485,19 +493,26 @@
OMAP_HSMMC_WRITE(host->base, HCTL,
OMAP_HSMMC_READ(host->base, HCTL) & SDVSCLR);
reg_val = OMAP_HSMMC_READ(host->base, HCTL);
+
/*
* If a MMC dual voltage card is detected, the set_ios fn calls
* this fn with VDD bit set for 1.8V. Upon card removal from the
* slot, omap_mmc_set_ios sets the VDD back to 3V on MMC_POWER_OFF.
*
- * Only MMC1 supports 3.0V. MMC2 will not function if SDVS30 is
- * set in HCTL.
+ * Cope with a bit of slop in the range ... per data sheets:
+ * - "1.8V" for vdds_mmc1/vdds_mmc1a can be up to 2.45V max,
+ * but recommended values are 1.71V to 1.89V
+ * - "3.0V" for vdds_mmc1/vdds_mmc1a can be up to 3.5V max,
+ * but recommended values are 2.7V to 3.3V
+ *
+ * Board setup code shouldn't permit anything very out-of-range.
+ * TWL4030-family VMMC1 and VSIM regulators are fine (avoiding the
+ * middle range) but VSIM can't power DAT4..DAT7 at more than 3V.
*/
- if (host->id == OMAP_MMC1_DEVID && (((1 << vdd) == MMC_VDD_32_33) ||
- ((1 << vdd) == MMC_VDD_33_34)))
- reg_val |= SDVS30;
- if ((1 << vdd) == MMC_VDD_165_195)
+ if ((1 << vdd) <= MMC_VDD_23_24)
reg_val |= SDVS18;
+ else
+ reg_val |= SDVS30;
OMAP_HSMMC_WRITE(host->base, HCTL, reg_val);
@@ -759,10 +774,14 @@
case MMC_POWER_OFF:
mmc_slot(host).set_power(host->dev, host->slot_id, 0, 0);
/*
- * Reset bus voltage to 3V if it got set to 1.8V earlier.
+ * Reset interface voltage to 3V if it's 1.8V now;
+ * only relevant on MMC-1, the others always use 1.8V.
+ *
* REVISIT: If we are able to detect cards after unplugging
* a 1.8V card, this code should not be needed.
*/
+ if (host->id != OMAP_MMC1_DEVID)
+ break;
if (!(OMAP_HSMMC_READ(host->base, HCTL) & SDVSDET)) {
int vdd = fls(host->mmc->ocr_avail) - 1;
if (omap_mmc_switch_opcond(host, vdd) != 0)
@@ -786,7 +805,9 @@
}
if (host->id == OMAP_MMC1_DEVID) {
- /* Only MMC1 can operate at 3V/1.8V */
+ /* Only MMC1 can interface at 3V without some flavor
+ * of external transceiver; but they all handle 1.8V.
+ */
if ((OMAP_HSMMC_READ(host->base, HCTL) & SDVSDET) &&
(ios->vdd == DUAL_VOLT_OCR_BIT)) {
/*
@@ -1139,7 +1160,9 @@
" level suspend\n");
}
- if (!(OMAP_HSMMC_READ(host->base, HCTL) & SDVSDET)) {
+ if (host->id == OMAP_MMC1_DEVID
+ && !(OMAP_HSMMC_READ(host->base, HCTL)
+ & SDVSDET)) {
OMAP_HSMMC_WRITE(host->base, HCTL,
OMAP_HSMMC_READ(host->base, HCTL)
& SDVSCLR);