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memory_accessor: implement the new memory_accessor interface for I2C EEPROM

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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: Kevin Hilman <khilman@deeprootsystems.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kevin Hilman 2009-04-02 16:56:57 -07:00 committed by Linus Torvalds
parent 06c421ee0d
commit 7274ec8bd7
2 changed files with 58 additions and 13 deletions
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67
drivers/misc/eeprom/at24.c
View file

@ -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:

4
include/linux/i2c/at24.h
View file

@ -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 */