2 files changed, 55 insertions, 6 deletions

diff --git a/Documentation/powerpc/dts-bindings/eeprom.txt b/Documentation/powerpc/dts-bindings/eeprom.txt
new file mode 100644
index 000000000000..4342c10de1bf
--- /dev/null
+++ b/Documentation/powerpc/dts-bindings/eeprom.txt
@@ -0,0 +1,28 @@
+EEPROMs (I2C)
+
+Required properties:
+
+  - compatible : should be "<manufacturer>,<type>"
+                 If there is no specific driver for <manufacturer>, a generic
+                 driver based on <type> is selected. Possible types are:
+                 24c00, 24c01, 24c02, 24c04, 24c08, 24c16, 24c32, 24c64,
+                 24c128, 24c256, 24c512, 24c1024, spd
+
+  - reg : the I2C address of the EEPROM
+
+Optional properties:
+
+  - pagesize : the length of the pagesize for writing. Please consult the
+               manual of your device, that value varies a lot. A wrong value
+               may result in data loss! If not specified, a safety value of
+               '1' is used which will be very slow.
+
+  - read-only: this parameterless property disables writes to the eeprom
+
+Example:
+
+eeprom@52 {
+        compatible = "atmel,24c32";
+        reg = <0x52>;
+        pagesize = <32>;
+};
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 559b0b3c16c3..3a53efc28821 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -20,6 +20,7 @@
 #include <linux/log2.h>
 #include <linux/bitops.h>
 #include <linux/jiffies.h>
+#include <linux/of.h>
 #include <linux/i2c.h>
 #include <linux/i2c/at24.h>
 
@@ -457,6 +458,27 @@ static ssize_t at24_macc_write(struct memory_accessor *macc, const char *buf,
 
 /*-------------------------------------------------------------------------*/
 
+#ifdef CONFIG_OF
+static void at24_get_ofdata(struct i2c_client *client,
+                struct at24_platform_data *chip)
+{
+        const __be32 *val;
+        struct device_node *node = client->dev.of_node;
+
+        if (node) {
+                if (of_get_property(node, "read-only", NULL))
+                        chip->flags |= AT24_FLAG_READONLY;
+                val = of_get_property(node, "pagesize", NULL);
+                if (val)
+                        chip->page_size = be32_to_cpup(val);
+        }
+}
+#else
+static void at24_get_ofdata(struct i2c_client *client,
+                struct at24_platform_data *chip)
+{ }
+#endif /* CONFIG_OF */
+
 static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
         struct at24_platform_data chip;
@@ -485,6 +507,9 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
                  */
                 chip.page_size = 1;
 
+                /* update chipdata if OF is present */
+                at24_get_ofdata(client, &chip);
+
                 chip.setup = NULL;
                 chip.context = NULL;
         }
@@ -597,19 +622,15 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
         i2c_set_clientdata(client, at24);
 
-        dev_info(&client->dev, "%zu byte %s EEPROM %s\n",
+        dev_info(&client->dev, "%zu byte %s EEPROM, %s, %u bytes/write\n",
                 at24->bin.size, client->name,
-                writable ? "(writable)" : "(read-only)");
+                writable ? "writable" : "read-only", at24->write_max);
         if (use_smbus == I2C_SMBUS_WORD_DATA ||
             use_smbus == I2C_SMBUS_BYTE_DATA) {
                 dev_notice(&client->dev, "Falling back to %s reads, "
                            "performance will suffer\n", use_smbus ==
                            I2C_SMBUS_WORD_DATA ? "word" : "byte");
         }
-        dev_dbg(&client->dev,
-                "page_size %d, num_addresses %d, write_max %d, use_smbus %d\n",
-                chip.page_size, num_addresses,
-                at24->write_max, use_smbus);
 
         /* export data to kernel code */
         if (chip.setup)