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misc/at24: parse device tree data

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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>
This commit is contained in:
Wolfram Sang 2010-11-17 13:00:48 +01:00 committed by Grant Likely
parent 1945886047
commit 9ed030d728
2 changed files with 55 additions and 6 deletions
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28
Documentation/powerpc/dts-bindings/eeprom.txt Normal file
View File

@ -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>;
};

33
drivers/misc/eeprom/at24.c
View File

@ -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)