1 files changed, 44 insertions, 0 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 5d088551196b..bf18b6bfce48 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -27,6 +27,7 @@
 #include <linux/fault-inject.h>
 #include <linux/random.h>
 #include <linux/slab.h>
+#include <linux/of.h>
 
 #include <linux/mmc/card.h>
 #include <linux/mmc/host.h>
@@ -1196,6 +1197,49 @@ u32 mmc_vddrange_to_ocrmask(int vdd_min, int vdd_max)
 }
 EXPORT_SYMBOL(mmc_vddrange_to_ocrmask);
 
+#ifdef CONFIG_OF
+
+/**
+ * mmc_of_parse_voltage - return mask of supported voltages
+ * @np: The device node need to be parsed.
+ * @mask: mask of voltages available for MMC/SD/SDIO
+ *
+ * 1. Return zero on success.
+ * 2. Return negative errno: voltage-range is invalid.
+ */
+int mmc_of_parse_voltage(struct device_node *np, u32 *mask)
+{
+        const u32 *voltage_ranges;
+        int num_ranges, i;
+
+        voltage_ranges = of_get_property(np, "voltage-ranges", &num_ranges);
+        num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
+        if (!voltage_ranges || !num_ranges) {
+                pr_info("%s: voltage-ranges unspecified\n", np->full_name);
+                return -EINVAL;
+        }
+
+        for (i = 0; i < num_ranges; i++) {
+                const int j = i * 2;
+                u32 ocr_mask;
+
+                ocr_mask = mmc_vddrange_to_ocrmask(
+                                be32_to_cpu(voltage_ranges[j]),
+                                be32_to_cpu(voltage_ranges[j + 1]));
+                if (!ocr_mask) {
+                        pr_err("%s: voltage-range #%d is invalid\n",
+                                np->full_name, i);
+                        return -EINVAL;
+                }
+                *mask |= ocr_mask;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL(mmc_of_parse_voltage);
+
+#endif /* CONFIG_OF */
+
 #ifdef CONFIG_REGULATOR
 
 /**