mmc: core: Extend sysfs with DSR register

Export DSR register through sysfs same as we did for the CID, CSD and
OCR registers.
Signed-off-by: Bojan Prtvar <prtvar.b@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/mmc/mmc-dev-attrs.txt

@@ -29,6 +29,7 @@ All attributes are read-only.
 	raw_rpmb_size_mult	RPMB partition size
 	rel_sectors		Reliable write sector count
 	ocr 			Operation Conditions Register
+	dsr			Driver Stage Register
 
 Note on Erase Size and Preferred Erase Size:
 

drivers/mmc/core/mmc.c

@@ -767,6 +767,22 @@ static ssize_t mmc_fwrev_show(struct device *dev,
 
 static DEVICE_ATTR(fwrev, S_IRUGO, mmc_fwrev_show, NULL);
 
+static ssize_t mmc_dsr_show(struct device *dev,
+			    struct device_attribute *attr,
+			    char *buf)
+{
+	struct mmc_card *card = mmc_dev_to_card(dev);
+	struct mmc_host *host = card->host;
+
+	if (card->csd.dsr_imp && host->dsr_req)
+		return sprintf(buf, "0x%x\n", host->dsr);
+	else
+		/* return default DSR value */
+		return sprintf(buf, "0x%x\n", 0x404);
+}
+
+static DEVICE_ATTR(dsr, S_IRUGO, mmc_dsr_show, NULL);
+
 static struct attribute *mmc_std_attrs[] = {
 	&dev_attr_cid.attr,
 	&dev_attr_csd.attr,
@@ -786,6 +802,7 @@ static struct attribute *mmc_std_attrs[] = {
 	&dev_attr_raw_rpmb_size_mult.attr,
 	&dev_attr_rel_sectors.attr,
 	&dev_attr_ocr.attr,
+	&dev_attr_dsr.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(mmc_std);

drivers/mmc/core/sd.c

@@ -678,6 +678,22 @@ MMC_DEV_ATTR(serial, "0x%08x\n", card->cid.serial);
 MMC_DEV_ATTR(ocr, "%08x\n", card->ocr);
 
 
+static ssize_t mmc_dsr_show(struct device *dev,
+                           struct device_attribute *attr,
+                           char *buf)
+{
+       struct mmc_card *card = mmc_dev_to_card(dev);
+       struct mmc_host *host = card->host;
+
+       if (card->csd.dsr_imp && host->dsr_req)
+               return sprintf(buf, "0x%x\n", host->dsr);
+       else
+               /* return default DSR value */
+               return sprintf(buf, "0x%x\n", 0x404);
+}
+
+static DEVICE_ATTR(dsr, S_IRUGO, mmc_dsr_show, NULL);
+
 static struct attribute *sd_std_attrs[] = {
 	&dev_attr_cid.attr,
 	&dev_attr_csd.attr,
@@ -692,6 +708,7 @@ static struct attribute *sd_std_attrs[] = {
 	&dev_attr_oemid.attr,
 	&dev_attr_serial.attr,
 	&dev_attr_ocr.attr,
+	&dev_attr_dsr.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(sd_std);