mmc: core: parse voltage from device-tree

Add function to support getting voltage from device-tree.
If voltage-range is specified in device-tree node, this function
will parse it and return the available voltage mask.

Signed-off-by: Haijun Zhang <haijun.zhang@freescale.com>
Acked-by: Anton Vorontsov <anton@enomsg.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

diff --git a/Documentation/devicetree/bindings/mmc/fsl-esdhc.txt b/Documentation/devicetree/bindings/mmc/fsl-esdhc.txt
index bd9be0b5bc2034279d628f07eece8a3d9c2b394d..b7943f3f999546cbaa1ec4170299c9221030427d 100644 (file)
--- a/Documentation/devicetree/bindings/mmc/fsl-esdhc.txt
+++ b/Documentation/devicetree/bindings/mmc/fsl-esdhc.txt
@@ -19,6 +19,9 @@ Optional properties:
     "bus-width = <1>" property.
   - sdhci,auto-cmd12: specifies that a controller can only handle auto
     CMD12.
+  - voltage-ranges : two cells are required, first cell specifies minimum
+    slot voltage (mV), second cell specifies maximum slot voltage (mV).
+    Several ranges could be specified.
 
 Example:
 
@@ -29,4 +32,5 @@ sdhci@2e000 {
        interrupt-parent = <&ipic>;
        /* Filled in by U-Boot */
        clock-frequency = <0>;
+       voltage-ranges = <3300 3300>;
 };

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 49a5bca418bdb7a6edf24669a9821851b9593aa9..b9b9fb6e449609137b3811f7c7435aa34aa18e52 100644 (file)
--- 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
 
 /**

diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 443243b241d5fcce816f4f269a95bed7c16a6878..da51bec578c33043c156d6661668e8957f5cb86f 100644 (file)
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -208,6 +208,8 @@ static inline void mmc_claim_host(struct mmc_host *host)
        __mmc_claim_host(host, NULL);
 }
 
+struct device_node;
 extern u32 mmc_vddrange_to_ocrmask(int vdd_min, int vdd_max);
+extern int mmc_of_parse_voltage(struct device_node *np, u32 *mask);
 
 #endif /* LINUX_MMC_CORE_H */