Commit 7274ec8b authored by Kevin Hilman's avatar Kevin Hilman Committed by Linus Torvalds
Browse files

memory_accessor: implement the new memory_accessor interface for I2C EEPROM 



In the case of at24, the platform code registers a 'setup' callback with
the at24_platform_data.  When the at24 driver detects an EEPROM, it fills
out the read and write functions of the memory_accessor and calls the
setup callback passing the memory_accessor struct.  The platform code can
then use the read/write functions in the memory_accessor struct for
reading and writing the EEPROM.

Signed-off-by: default avatarKevin Hilman <khilman@deeprootsystems.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 06c421ee

drivers/misc/eeprom/at24.c

+54 −13
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ 


struct at24_data {

	struct at24_platform_data chip;

	struct memory_accessor macc;

	bool use_smbus;



	/*
@@ -225,14 +226,11 @@ static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf, 
		return status;

}



static ssize_t at24_bin_read(struct kobject *kobj, struct bin_attribute *attr,

static ssize_t at24_read(struct at24_data *at24,

		char *buf, loff_t off, size_t count)

{

	struct at24_data *at24;

	ssize_t retval = 0;



	at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));



	if (unlikely(!count))

		return count;
@@ -262,12 +260,14 @@ static ssize_t at24_bin_read(struct kobject *kobj, struct bin_attribute *attr, 
	return retval;

}



static ssize_t at24_bin_read(struct kobject *kobj, struct bin_attribute *attr,

		char *buf, loff_t off, size_t count)

{

	struct at24_data *at24;



/*

 * REVISIT: export at24_bin{read,write}() to let other kernel code use

 * eeprom data. For example, it might hold a board's Ethernet address, or

 * board-specific calibration data generated on the manufacturing floor.

 */

	at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));

	return at24_read(at24, buf, off, count);

}





/*
@@ -347,14 +347,11 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, char *buf, 
	return -ETIMEDOUT;

}



static ssize_t at24_bin_write(struct kobject *kobj, struct bin_attribute *attr,

static ssize_t at24_write(struct at24_data *at24,

		char *buf, loff_t off, size_t count)

{

	struct at24_data *at24;

	ssize_t retval = 0;



	at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));



	if (unlikely(!count))

		return count;
@@ -384,6 +381,39 @@ static ssize_t at24_bin_write(struct kobject *kobj, struct bin_attribute *attr, 
	return retval;

}



static ssize_t at24_bin_write(struct kobject *kobj, struct bin_attribute *attr,

		char *buf, loff_t off, size_t count)

{

	struct at24_data *at24;



	at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));

	return at24_write(at24, buf, off, count);

}



/*-------------------------------------------------------------------------*/



/*

 * This lets other kernel code access the eeprom data. For example, it

 * might hold a board's Ethernet address, or board-specific calibration

 * data generated on the manufacturing floor.

 */



static ssize_t at24_macc_read(struct memory_accessor *macc, char *buf,

			 off_t offset, size_t count)

{

	struct at24_data *at24 = container_of(macc, struct at24_data, macc);



	return at24_read(at24, buf, offset, count);

}



static ssize_t at24_macc_write(struct memory_accessor *macc, char *buf,

			  off_t offset, size_t count)

{

	struct at24_data *at24 = container_of(macc, struct at24_data, macc);



	return at24_write(at24, buf, offset, count);

}



/*-------------------------------------------------------------------------*/



static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
@@ -413,6 +443,9 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) 
		 * is recommended anyhow.

		 */

		chip.page_size = 1;



		chip.setup = NULL;

		chip.context = NULL;

	}



	if (!is_power_of_2(chip.byte_len))
@@ -463,6 +496,8 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) 
	at24->bin.read = at24_bin_read;

	at24->bin.size = chip.byte_len;



	at24->macc.read = at24_macc_read;



	writable = !(chip.flags & AT24_FLAG_READONLY);

	if (writable) {

		if (!use_smbus || i2c_check_functionality(client->adapter,
@@ -470,6 +505,8 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) 


			unsigned write_max = chip.page_size;



			at24->macc.write = at24_macc_write;



			at24->bin.write = at24_bin_write;

			at24->bin.attr.mode |= S_IWUSR;
@@ -520,6 +557,10 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) 
		at24->write_max,

		use_smbus ? ", use_smbus" : "");



	/* export data to kernel code */

	if (chip.setup)

		chip.setup(&at24->macc, chip.context);



	return 0;



err_clients:

include/linux/i2c/at24.h

+4 −0
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ 
#define _LINUX_AT24_H



#include <linux/types.h>

#include <linux/memory.h>



/*

 * As seen through Linux I2C, differences between the most common types of I2C
@@ -23,6 +24,9 @@ struct at24_platform_data { 
#define AT24_FLAG_READONLY	0x40	/* sysfs-entry will be read-only */

#define AT24_FLAG_IRUGO		0x20	/* sysfs-entry will be world-readable */

#define AT24_FLAG_TAKE8ADDR	0x10	/* take always 8 addresses (24c00) */



	void		(*setup)(struct memory_accessor *, void *context);

	void		*context;

};



#endif /* _LINUX_AT24_H */

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