2005-06-04 01:03:27 +08:00
|
|
|
/*
|
|
|
|
max6875.c - driver for MAX6874/MAX6875
|
|
|
|
|
|
|
|
Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
|
|
|
|
|
2009-06-16 00:01:49 +08:00
|
|
|
Based on eeprom.c
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
The MAX6875 has a bank of registers and two banks of EEPROM.
|
|
|
|
Address ranges are defined as follows:
|
|
|
|
* 0x0000 - 0x0046 = configuration registers
|
|
|
|
* 0x8000 - 0x8046 = configuration EEPROM
|
|
|
|
* 0x8100 - 0x82FF = user EEPROM
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
This driver makes the user EEPROM available for read.
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
The registers & config EEPROM should be accessed via i2c-dev.
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
The MAX6875 ignores the lowest address bit, so each chip responds to
|
|
|
|
two addresses - 0x50/0x51 and 0x52/0x53.
|
|
|
|
|
|
|
|
Note that the MAX6875 uses i2c_smbus_write_byte_data() to set the read
|
|
|
|
address, so this driver is destructive if loaded for the wrong EEPROM chip.
|
2005-06-04 01:03:27 +08:00
|
|
|
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
|
|
it under the terms of the GNU General Public License as published by
|
|
|
|
the Free Software Foundation; version 2 of the License.
|
|
|
|
*/
|
|
|
|
|
|
|
|
#include <linux/kernel.h>
|
|
|
|
#include <linux/init.h>
|
|
|
|
#include <linux/module.h>
|
|
|
|
#include <linux/slab.h>
|
|
|
|
#include <linux/i2c.h>
|
2006-01-19 06:16:04 +08:00
|
|
|
#include <linux/mutex.h>
|
2005-06-04 01:03:27 +08:00
|
|
|
|
|
|
|
/* The MAX6875 can only read/write 16 bytes at a time */
|
|
|
|
#define SLICE_SIZE 16
|
|
|
|
#define SLICE_BITS 4
|
|
|
|
|
|
|
|
/* USER EEPROM is at addresses 0x8100 - 0x82FF */
|
|
|
|
#define USER_EEPROM_BASE 0x8100
|
|
|
|
#define USER_EEPROM_SIZE 0x0200
|
|
|
|
#define USER_EEPROM_SLICES 32
|
|
|
|
|
|
|
|
/* MAX6875 commands */
|
2005-07-13 02:21:11 +08:00
|
|
|
#define MAX6875_CMD_BLK_READ 0x84
|
2005-06-04 01:03:27 +08:00
|
|
|
|
|
|
|
/* Each client has this additional data */
|
|
|
|
struct max6875_data {
|
2008-07-17 01:30:07 +08:00
|
|
|
struct i2c_client *fake_client;
|
2006-01-19 06:16:04 +08:00
|
|
|
struct mutex update_lock;
|
2005-07-13 02:21:11 +08:00
|
|
|
|
|
|
|
u32 valid;
|
|
|
|
u8 data[USER_EEPROM_SIZE];
|
|
|
|
unsigned long last_updated[USER_EEPROM_SLICES];
|
2005-06-04 01:03:27 +08:00
|
|
|
};
|
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
static void max6875_update_slice(struct i2c_client *client, int slice)
|
2005-06-04 01:03:27 +08:00
|
|
|
{
|
|
|
|
struct max6875_data *data = i2c_get_clientdata(client);
|
2005-07-13 02:21:11 +08:00
|
|
|
int i, j, addr;
|
|
|
|
u8 *buf;
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
if (slice >= USER_EEPROM_SLICES)
|
|
|
|
return;
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2006-01-19 06:16:04 +08:00
|
|
|
mutex_lock(&data->update_lock);
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
buf = &data->data[slice << SLICE_BITS];
|
|
|
|
|
|
|
|
if (!(data->valid & (1 << slice)) ||
|
|
|
|
time_after(jiffies, data->last_updated[slice])) {
|
|
|
|
|
2005-07-28 01:43:03 +08:00
|
|
|
dev_dbg(&client->dev, "Starting update of slice %u\n", slice);
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
data->valid &= ~(1 << slice);
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
addr = USER_EEPROM_BASE + (slice << SLICE_BITS);
|
|
|
|
|
|
|
|
/* select the eeprom address */
|
|
|
|
if (i2c_smbus_write_byte_data(client, addr >> 8, addr & 0xFF)) {
|
|
|
|
dev_err(&client->dev, "address set failed\n");
|
|
|
|
goto exit_up;
|
2005-06-04 01:03:27 +08:00
|
|
|
}
|
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
if (i2c_check_functionality(client->adapter,
|
|
|
|
I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
|
|
|
|
if (i2c_smbus_read_i2c_block_data(client,
|
|
|
|
MAX6875_CMD_BLK_READ,
|
i2c: Fix the i2c_smbus_read_i2c_block_data() prototype
Let the drivers specify how many bytes they want to read with
i2c_smbus_read_i2c_block_data(). So far, the block count was
hard-coded to I2C_SMBUS_BLOCK_MAX (32), which did not make much sense.
Many driver authors complained about this before, and I believe it's
about time to fix it. Right now, authors have to do technically stupid
things, such as individual byte reads or full-fledged I2C messaging,
to work around the problem. We do not want to encourage that.
I even found that some bus drivers (e.g. i2c-amd8111) already
implemented I2C block read the "right" way, that is, they didn't
follow the old, broken standard. The fact that it was never noticed
before just shows how little i2c_smbus_read_i2c_block_data() was used,
which isn't that surprising given how broken its prototype was so far.
There are some obvious compatiblity considerations:
* This changes the i2c_smbus_read_i2c_block_data() prototype. Users
outside the kernel tree will notice at compilation time, and will
have to update their code.
* User-space has access to i2c_smbus_xfer() directly using i2c-dev, so
the changed expectations would affect tools such as i2cdump. In order
to preserve binary compatibility, we give I2C_SMBUS_I2C_BLOCK_DATA
a new numeric value, and define I2C_SMBUS_I2C_BLOCK_BROKEN with the
old numeric value. When i2c-dev receives a transaction with the
old value, it can convert it to the new format on the fly.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-07-12 20:12:29 +08:00
|
|
|
SLICE_SIZE,
|
2005-07-13 02:21:11 +08:00
|
|
|
buf) != SLICE_SIZE) {
|
|
|
|
goto exit_up;
|
2005-06-04 01:03:27 +08:00
|
|
|
}
|
|
|
|
} else {
|
2005-07-13 02:21:11 +08:00
|
|
|
for (i = 0; i < SLICE_SIZE; i++) {
|
2005-06-04 01:03:27 +08:00
|
|
|
j = i2c_smbus_read_byte(client);
|
2005-07-13 02:21:11 +08:00
|
|
|
if (j < 0) {
|
|
|
|
goto exit_up;
|
2005-06-04 01:03:27 +08:00
|
|
|
}
|
2005-07-13 02:21:11 +08:00
|
|
|
buf[i] = j;
|
2005-06-04 01:03:27 +08:00
|
|
|
}
|
|
|
|
}
|
2005-07-13 02:21:11 +08:00
|
|
|
data->last_updated[slice] = jiffies;
|
|
|
|
data->valid |= (1 << slice);
|
2005-06-04 01:03:27 +08:00
|
|
|
}
|
2005-07-13 02:21:11 +08:00
|
|
|
exit_up:
|
2006-01-19 06:16:04 +08:00
|
|
|
mutex_unlock(&data->update_lock);
|
2005-06-04 01:03:27 +08:00
|
|
|
}
|
|
|
|
|
2007-06-09 13:57:22 +08:00
|
|
|
static ssize_t max6875_read(struct kobject *kobj,
|
|
|
|
struct bin_attribute *bin_attr,
|
|
|
|
char *buf, loff_t off, size_t count)
|
2005-06-04 01:03:27 +08:00
|
|
|
{
|
2005-07-13 02:21:11 +08:00
|
|
|
struct i2c_client *client = kobj_to_i2c_client(kobj);
|
2005-06-04 01:03:27 +08:00
|
|
|
struct max6875_data *data = i2c_get_clientdata(client);
|
2005-07-13 02:21:11 +08:00
|
|
|
int slice, max_slice;
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
if (off > USER_EEPROM_SIZE)
|
2005-06-04 01:03:27 +08:00
|
|
|
return 0;
|
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
if (off + count > USER_EEPROM_SIZE)
|
|
|
|
count = USER_EEPROM_SIZE - off;
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
/* refresh slices which contain requested bytes */
|
|
|
|
max_slice = (off + count - 1) >> SLICE_BITS;
|
|
|
|
for (slice = (off >> SLICE_BITS); slice <= max_slice; slice++)
|
|
|
|
max6875_update_slice(client, slice);
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
memcpy(buf, &data->data[off], count);
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
return count;
|
2005-06-04 01:03:27 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
static struct bin_attribute user_eeprom_attr = {
|
|
|
|
.attr = {
|
2005-07-13 02:21:11 +08:00
|
|
|
.name = "eeprom",
|
|
|
|
.mode = S_IRUGO,
|
2005-06-04 01:03:27 +08:00
|
|
|
},
|
2005-07-13 02:21:11 +08:00
|
|
|
.size = USER_EEPROM_SIZE,
|
|
|
|
.read = max6875_read,
|
2005-06-04 01:03:27 +08:00
|
|
|
};
|
|
|
|
|
2009-10-05 04:53:41 +08:00
|
|
|
static int max6875_probe(struct i2c_client *client,
|
|
|
|
const struct i2c_device_id *id)
|
2005-06-04 01:03:27 +08:00
|
|
|
{
|
2008-07-17 01:30:07 +08:00
|
|
|
struct i2c_adapter *adapter = client->adapter;
|
2009-10-05 04:53:41 +08:00
|
|
|
struct max6875_data *data;
|
|
|
|
int err;
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-28 01:43:14 +08:00
|
|
|
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE_DATA
|
2005-07-13 02:21:11 +08:00
|
|
|
| I2C_FUNC_SMBUS_READ_BYTE))
|
2008-07-17 01:30:07 +08:00
|
|
|
return -ENODEV;
|
2005-07-13 02:21:11 +08:00
|
|
|
|
2009-10-05 04:53:41 +08:00
|
|
|
/* Only bind to even addresses */
|
2008-07-17 01:30:07 +08:00
|
|
|
if (client->addr & 1)
|
|
|
|
return -ENODEV;
|
|
|
|
|
2005-10-18 05:09:43 +08:00
|
|
|
if (!(data = kzalloc(sizeof(struct max6875_data), GFP_KERNEL)))
|
2005-07-13 02:21:11 +08:00
|
|
|
return -ENOMEM;
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2005-07-13 02:21:11 +08:00
|
|
|
/* A fake client is created on the odd address */
|
2008-07-17 01:30:07 +08:00
|
|
|
data->fake_client = i2c_new_dummy(client->adapter, client->addr + 1);
|
|
|
|
if (!data->fake_client) {
|
2005-07-13 02:21:11 +08:00
|
|
|
err = -ENOMEM;
|
2008-07-17 01:30:07 +08:00
|
|
|
goto exit_kfree;
|
2005-07-13 02:21:11 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
/* Init real i2c_client */
|
2008-07-17 01:30:07 +08:00
|
|
|
i2c_set_clientdata(client, data);
|
2006-01-19 06:16:04 +08:00
|
|
|
mutex_init(&data->update_lock);
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2008-07-17 01:30:07 +08:00
|
|
|
err = sysfs_create_bin_file(&client->dev.kobj, &user_eeprom_attr);
|
2006-09-04 04:20:24 +08:00
|
|
|
if (err)
|
2008-07-17 01:30:07 +08:00
|
|
|
goto exit_remove_fake;
|
2005-06-04 01:03:27 +08:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
2008-07-17 01:30:07 +08:00
|
|
|
exit_remove_fake:
|
|
|
|
i2c_unregister_device(data->fake_client);
|
|
|
|
exit_kfree:
|
2005-06-04 01:03:27 +08:00
|
|
|
kfree(data);
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
2008-07-17 01:30:07 +08:00
|
|
|
static int max6875_remove(struct i2c_client *client)
|
2005-06-04 01:03:27 +08:00
|
|
|
{
|
2006-09-04 04:20:24 +08:00
|
|
|
struct max6875_data *data = i2c_get_clientdata(client);
|
|
|
|
|
2008-07-17 01:30:07 +08:00
|
|
|
i2c_unregister_device(data->fake_client);
|
2005-06-04 01:03:27 +08:00
|
|
|
|
2008-07-17 01:30:07 +08:00
|
|
|
sysfs_remove_bin_file(&client->dev.kobj, &user_eeprom_attr);
|
|
|
|
kfree(data);
|
2006-09-04 04:20:24 +08:00
|
|
|
|
2005-06-04 01:03:27 +08:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2008-07-17 01:30:07 +08:00
|
|
|
static const struct i2c_device_id max6875_id[] = {
|
|
|
|
{ "max6875", 0 },
|
|
|
|
{ }
|
|
|
|
};
|
|
|
|
|
|
|
|
static struct i2c_driver max6875_driver = {
|
|
|
|
.driver = {
|
|
|
|
.name = "max6875",
|
|
|
|
},
|
|
|
|
.probe = max6875_probe,
|
|
|
|
.remove = max6875_remove,
|
|
|
|
.id_table = max6875_id,
|
|
|
|
};
|
|
|
|
|
2005-06-04 01:03:27 +08:00
|
|
|
static int __init max6875_init(void)
|
|
|
|
{
|
|
|
|
return i2c_add_driver(&max6875_driver);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void __exit max6875_exit(void)
|
|
|
|
{
|
|
|
|
i2c_del_driver(&max6875_driver);
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
|
|
|
|
MODULE_DESCRIPTION("MAX6875 driver");
|
|
|
|
MODULE_LICENSE("GPL");
|
|
|
|
|
|
|
|
module_init(max6875_init);
|
|
|
|
module_exit(max6875_exit);
|