mmc: core: Export card RCA register via sysfs

This patch exports RCA register to sysfs which will help in reading the
disk identification information.

Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Harish Jenny K N <harish_kandiga@mentor.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/mmc.c

@@ -792,6 +792,7 @@ MMC_DEV_ATTR(enhanced_area_size, "%u\n", card->ext_csd.enhanced_area_size);
 MMC_DEV_ATTR(raw_rpmb_size_mult, "%#x\n", card->ext_csd.raw_rpmb_size_mult);
 MMC_DEV_ATTR(rel_sectors, "%#x\n", card->ext_csd.rel_sectors);
 MMC_DEV_ATTR(ocr, "0x%08x\n", card->ocr);
+MMC_DEV_ATTR(rca, "0x%04x\n", card->rca);
 MMC_DEV_ATTR(cmdq_en, "%d\n", card->ext_csd.cmdq_en);
 
 static ssize_t mmc_fwrev_show(struct device *dev,
@@ -848,6 +849,7 @@ static struct attribute *mmc_std_attrs[] = {
 	&dev_attr_raw_rpmb_size_mult.attr,
 	&dev_attr_rel_sectors.attr,
 	&dev_attr_ocr.attr,
+	&dev_attr_rca.attr,
 	&dev_attr_dsr.attr,
 	&dev_attr_cmdq_en.attr,
 	NULL,

drivers/mmc/core/sd.c

@@ -668,6 +668,7 @@ MMC_DEV_ATTR(name, "%s\n", card->cid.prod_name);
 MMC_DEV_ATTR(oemid, "0x%04x\n", card->cid.oemid);
 MMC_DEV_ATTR(serial, "0x%08x\n", card->cid.serial);
 MMC_DEV_ATTR(ocr, "0x%08x\n", card->ocr);
+MMC_DEV_ATTR(rca, "0x%04x\n", card->rca);
 
 
 static ssize_t mmc_dsr_show(struct device *dev,
@@ -701,6 +702,7 @@ static struct attribute *sd_std_attrs[] = {
 	&dev_attr_oemid.attr,
 	&dev_attr_serial.attr,
 	&dev_attr_ocr.attr,
+	&dev_attr_rca.attr,
 	&dev_attr_dsr.attr,
 	NULL,
 };