[PATCH] MMC: Clean up low voltage range handling
From: Philip Langdale
Date: Sat Mar 10 2007 - 18:47:00 EST
Clean up the handling of low voltage MMC cards.
The latest MMC and SD specs both agree that the low
voltage range is defined as 1.65-1.95V and is signified
by bit 7 in the OCR. An old Sandisk spec implied that
bits 7-0 represented voltages below 2.0V in 1V increments,
and the code was accordingly written with that expectation.
This confusion meant that host drivers attempting to support
the typical low voltage (1.8V) would set the wrong bits in
the host OCR mask (usually bits 5 and 6) resulting in the
the low voltage mode never being used.
This change switches the code to conform to the specs and
fixes the SDHCI driver. It also removes the explicit
defines for the host vdd and updates the SDHCI driver
to convert the bit number back to the mask value
for comparisons. Having only a single set of defines
ensures there's nothing to get out of sync.
Signed-off-by: Philip Langdale <philipl@xxxxxxxxx>
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index c87ce56..74ebd97 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -317,6 +317,24 @@ static u32 mmc_select_voltage(struct mmc
{
int bit;
+ /*
+ * Sanity check the voltages that the card claims to
+ * support.
+ */
+ if (ocr & 0x7F) {
+ printk("%s: card claims to support voltages below "
+ "the defined range. These will be ignored.\n",
+ mmc_hostname(host));
+ ocr &= ~0x7F;
+ }
+
+ if (host->mode == MMC_MODE_SD && (ocr & MMC_VDD_165_195)) {
+ printk("%s: SD card claims to support the incompletely "
+ "defined 'low voltage range'. This will be ignored.\n",
+ mmc_hostname(host));
+ ocr &= ~MMC_VDD_165_195;
+ }
+
ocr &= host->ocr_avail;
bit = ffs(ocr);
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 86d0957..a80c043 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -668,20 +668,16 @@ static void sdhci_set_power(struct sdhci
pwr = SDHCI_POWER_ON;
- switch (power) {
- case MMC_VDD_170:
- case MMC_VDD_180:
- case MMC_VDD_190:
+ switch (1 << power) {
+ case MMC_VDD_165_195:
pwr |= SDHCI_POWER_180;
break;
- case MMC_VDD_290:
- case MMC_VDD_300:
- case MMC_VDD_310:
+ case MMC_VDD_29_30:
+ case MMC_VDD_30_31:
pwr |= SDHCI_POWER_300;
break;
- case MMC_VDD_320:
- case MMC_VDD_330:
- case MMC_VDD_340:
+ case MMC_VDD_32_33:
+ case MMC_VDD_33_34:
pwr |= SDHCI_POWER_330;
break;
default:
@@ -1293,7 +1289,7 @@ static int __devinit sdhci_probe_slot(st
if (caps & SDHCI_CAN_VDD_300)
mmc->ocr_avail |= MMC_VDD_29_30|MMC_VDD_30_31;
if (caps & SDHCI_CAN_VDD_180)
- mmc->ocr_avail |= MMC_VDD_17_18|MMC_VDD_18_19;
+ mmc->ocr_avail |= MMC_VDD_165_195;
if (mmc->ocr_avail == 0) {
printk(KERN_ERR "%s: Hardware doesn't report any "
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 43bf6a5..89dbb91 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -16,30 +16,7 @@ struct mmc_ios {
unsigned int clock; /* clock rate */
unsigned short vdd;
-#define MMC_VDD_150 0
-#define MMC_VDD_155 1
-#define MMC_VDD_160 2
-#define MMC_VDD_165 3
-#define MMC_VDD_170 4
-#define MMC_VDD_180 5
-#define MMC_VDD_190 6
-#define MMC_VDD_200 7
-#define MMC_VDD_210 8
-#define MMC_VDD_220 9
-#define MMC_VDD_230 10
-#define MMC_VDD_240 11
-#define MMC_VDD_250 12
-#define MMC_VDD_260 13
-#define MMC_VDD_270 14
-#define MMC_VDD_280 15
-#define MMC_VDD_290 16
-#define MMC_VDD_300 17
-#define MMC_VDD_310 18
-#define MMC_VDD_320 19
-#define MMC_VDD_330 20
-#define MMC_VDD_340 21
-#define MMC_VDD_350 22
-#define MMC_VDD_360 23
+/* vdd stores the bit number of the selected voltage range from protocol.h */
unsigned char bus_mode; /* command output mode */
@@ -88,14 +65,7 @@ struct mmc_host {
unsigned int f_max;
u32 ocr_avail;
-#define MMC_VDD_145_150 0x00000001 /* VDD voltage 1.45 - 1.50 */
-#define MMC_VDD_150_155 0x00000002 /* VDD voltage 1.50 - 1.55 */
-#define MMC_VDD_155_160 0x00000004 /* VDD voltage 1.55 - 1.60 */
-#define MMC_VDD_160_165 0x00000008 /* VDD voltage 1.60 - 1.65 */
-#define MMC_VDD_165_170 0x00000010 /* VDD voltage 1.65 - 1.70 */
-#define MMC_VDD_17_18 0x00000020 /* VDD voltage 1.7 - 1.8 */
-#define MMC_VDD_18_19 0x00000040 /* VDD voltage 1.8 - 1.9 */
-#define MMC_VDD_19_20 0x00000080 /* VDD voltage 1.9 - 2.0 */
+#define MMC_VDD_165_195 0x00000080 /* VDD voltage 1.65 - 1.95 */
#define MMC_VDD_20_21 0x00000100 /* VDD voltage 2.0 ~ 2.1 */
#define MMC_VDD_21_22 0x00000200 /* VDD voltage 2.1 ~ 2.2 */
#define MMC_VDD_22_23 0x00000400 /* VDD voltage 2.2 ~ 2.3 */
-
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