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 <c...@laptop.org>
Signed-off-by: Girish K S <girish.shivananja...@linaro.org>
---
 drivers/mmc/core/mmc.c   |   27 +++++++++++++++++++++++++++
 include/linux/mmc/card.h |    4 ++++
 2 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 006e932..30d1cbc 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -688,6 +688,33 @@ 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 (card->host->caps & MMC_CAP_MAX_CURRENT_800) {
+               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 if (pwrclass_val >= MMC_MAX_CURRENT_200)
+                       pwrclass_val = MMC_MAX_CURRENT_200;
+       } else if (card->host->caps & MMC_CAP_MAX_CURRENT_600) {
+               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 if (pwrclass_val >= MMC_MAX_CURRENT_200)
+                       pwrclass_val = MMC_MAX_CURRENT_200;
+       } else if (card->host->caps & MMC_CAP_MAX_CURRENT_400) {
+               if (pwrclass_val >= MMC_MAX_CURRENT_400)
+                       pwrclass_val = MMC_MAX_CURRENT_400;
+               else if (pwrclass_val >= MMC_MAX_CURRENT_200)
+                       pwrclass_val = MMC_MAX_CURRENT_200;
+       } else if (card->host->caps & MMC_CAP_MAX_CURRENT_200) {
+               if (pwrclass_val >= MMC_MAX_CURRENT_200)
+                       pwrclass_val = MMC_MAX_CURRENT_200;
+       } else
+               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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