This patch adds a check whether the host supports maximum current value
obtained from the device's extended csd register for a selected interface
voltage and frequency.
cc: Chris Ball <cjb@xxxxxxxxxx>
Signed-off-by: Girish K S <girish.shivananjappa@xxxxxxxxxx>
---
Changes in v2:
deleted a unnecessary if else condition identified by subhash J
Changes in v1:
reduced the number of comparisons as per Hein's suggestion
drivers/mmc/core/mmc.c | 19 +++++++++++++++++++
include/linux/mmc/card.h | 4 ++++
2 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 006e932..b9ef777 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -688,6 +688,25 @@ static int mmc_select_powerclass(struct mmc_card *card,
pwrclass_val = (pwrclass_val & EXT_CSD_PWR_CL_4BIT_MASK) >>
EXT_CSD_PWR_CL_4BIT_SHIFT;
+ if (pwrclass_val >= MMC_MAX_CURRENT_800)
+ pwrclass_val = MMC_MAX_CURRENT_800;
+ else if (pwrclass_val >= MMC_MAX_CURRENT_600)
+ pwrclass_val = MMC_MAX_CURRENT_600;
+ else if (pwrclass_val >= MMC_MAX_CURRENT_400)
+ pwrclass_val = MMC_MAX_CURRENT_400;
+ else
+ pwrclass_val = MMC_MAX_CURRENT_200;
+
+ if ((pwrclass_val == MMC_MAX_CURRENT_800) &&
+ !(card->host->caps & MMC_CAP_MAX_CURRENT_800))
+ pwrclass_val = MMC_MAX_CURRENT_600;
+ if ((pwrclass_val == MMC_MAX_CURRENT_600) &&
+ !(card->host->caps & MMC_CAP_MAX_CURRENT_600))
+ pwrclass_val = MMC_MAX_CURRENT_400;
+ if ((pwrclass_val == MMC_MAX_CURRENT_400) &&
+ !(card->host->caps & MMC_CAP_MAX_CURRENT_400))
+ pwrclass_val = MMC_MAX_CURRENT_200;
+
/* If the power class is different from the default value */
if (pwrclass_val > 0) {
err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 9478a6b..c5e031a 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -195,6 +195,10 @@ struct mmc_part {
#define MMC_BLK_DATA_AREA_GP (1<<2)
};
+#define MMC_MAX_CURRENT_200 (0)
+#define MMC_MAX_CURRENT_400 (7)
+#define MMC_MAX_CURRENT_600 (11)
+#define MMC_MAX_CURRENT_800 (13)
/*
* MMC device
*/
--
1.7.1
--
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