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authorWolfram Sang <w.sang@pengutronix.de>2010-11-17 13:00:48 +0100
committerGrant Likely <grant.likely@secretlab.ca>2010-12-24 02:13:36 -0700
commit9ed030d728f3bd03b6e869357da02725afda19a7 (patch)
tree2dfe452c10e5562a817197d686e7bed61d946fe4
parent194588604765ac803f98fb9d19a36f6b835f4620 (diff)
downloadlinux-9ed030d728f3bd03b6e869357da02725afda19a7.tar.bz2
misc/at24: parse device tree data
Information about the pagesize and read-only-status may also come from the devicetree. Parse this data, too, and act accordingly. While we are here, change the initialization printout a bit. write_max is useful to know to detect performance bottlenecks, the rest is superfluous. Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
-rw-r--r--Documentation/powerpc/dts-bindings/eeprom.txt28
-rw-r--r--drivers/misc/eeprom/at24.c33
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)