Commit 9ed030d7 authored by Wolfram Sang's avatar Wolfram Sang Committed by Grant Likely
Browse files

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: default avatarWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent 19458860

Documentation/powerpc/dts-bindings/eeprom.txt

0 → 100644
+28 −0
Original line number Diff line number Diff line 
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>;

};

drivers/misc/eeprom/at24.c

+27 −6
Original line number Diff line number Diff line
@@ -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)

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