BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 1 | /* |
Arce, Abraham | 6858d49 | 2010-05-13 15:05:47 -0500 | [diff] [blame] | 2 | * max6875.c - driver for MAX6874/MAX6875 |
| 3 | * |
| 4 | * Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com> |
| 5 | * |
| 6 | * Based on eeprom.c |
| 7 | * |
| 8 | * The MAX6875 has a bank of registers and two banks of EEPROM. |
| 9 | * Address ranges are defined as follows: |
| 10 | * * 0x0000 - 0x0046 = configuration registers |
| 11 | * * 0x8000 - 0x8046 = configuration EEPROM |
| 12 | * * 0x8100 - 0x82FF = user EEPROM |
| 13 | * |
| 14 | * This driver makes the user EEPROM available for read. |
| 15 | * |
| 16 | * The registers & config EEPROM should be accessed via i2c-dev. |
| 17 | * |
| 18 | * The MAX6875 ignores the lowest address bit, so each chip responds to |
| 19 | * two addresses - 0x50/0x51 and 0x52/0x53. |
| 20 | * |
| 21 | * Note that the MAX6875 uses i2c_smbus_write_byte_data() to set the read |
| 22 | * address, so this driver is destructive if loaded for the wrong EEPROM chip. |
| 23 | * |
| 24 | * This program is free software; you can redistribute it and/or modify |
| 25 | * it under the terms of the GNU General Public License as published by |
| 26 | * the Free Software Foundation; version 2 of the License. |
| 27 | */ |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 28 | |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 29 | #include <linux/kernel.h> |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 30 | #include <linux/module.h> |
| 31 | #include <linux/slab.h> |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 32 | #include <linux/i2c.h> |
Ingo Molnar | 5c085d3 | 2006-01-18 23:16:04 +0100 | [diff] [blame] | 33 | #include <linux/mutex.h> |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 34 | |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 35 | /* The MAX6875 can only read/write 16 bytes at a time */ |
| 36 | #define SLICE_SIZE 16 |
| 37 | #define SLICE_BITS 4 |
| 38 | |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 39 | /* USER EEPROM is at addresses 0x8100 - 0x82FF */ |
| 40 | #define USER_EEPROM_BASE 0x8100 |
| 41 | #define USER_EEPROM_SIZE 0x0200 |
| 42 | #define USER_EEPROM_SLICES 32 |
| 43 | |
| 44 | /* MAX6875 commands */ |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 45 | #define MAX6875_CMD_BLK_READ 0x84 |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 46 | |
| 47 | /* Each client has this additional data */ |
| 48 | struct max6875_data { |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 49 | struct i2c_client *fake_client; |
Ingo Molnar | 5c085d3 | 2006-01-18 23:16:04 +0100 | [diff] [blame] | 50 | struct mutex update_lock; |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 51 | |
| 52 | u32 valid; |
| 53 | u8 data[USER_EEPROM_SIZE]; |
| 54 | unsigned long last_updated[USER_EEPROM_SLICES]; |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 55 | }; |
| 56 | |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 57 | static void max6875_update_slice(struct i2c_client *client, int slice) |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 58 | { |
| 59 | struct max6875_data *data = i2c_get_clientdata(client); |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 60 | int i, j, addr; |
| 61 | u8 *buf; |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 62 | |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 63 | if (slice >= USER_EEPROM_SLICES) |
| 64 | return; |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 65 | |
Ingo Molnar | 5c085d3 | 2006-01-18 23:16:04 +0100 | [diff] [blame] | 66 | mutex_lock(&data->update_lock); |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 67 | |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 68 | buf = &data->data[slice << SLICE_BITS]; |
| 69 | |
| 70 | if (!(data->valid & (1 << slice)) || |
| 71 | time_after(jiffies, data->last_updated[slice])) { |
| 72 | |
Greg Kroah-Hartman | a8decc6 | 2005-07-27 12:43:03 -0500 | [diff] [blame] | 73 | dev_dbg(&client->dev, "Starting update of slice %u\n", slice); |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 74 | |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 75 | data->valid &= ~(1 << slice); |
| 76 | |
| 77 | addr = USER_EEPROM_BASE + (slice << SLICE_BITS); |
| 78 | |
| 79 | /* select the eeprom address */ |
| 80 | if (i2c_smbus_write_byte_data(client, addr >> 8, addr & 0xFF)) { |
| 81 | dev_err(&client->dev, "address set failed\n"); |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 82 | goto exit_up; |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 83 | } |
| 84 | |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 85 | if (i2c_check_functionality(client->adapter, |
| 86 | I2C_FUNC_SMBUS_READ_I2C_BLOCK)) { |
| 87 | if (i2c_smbus_read_i2c_block_data(client, |
| 88 | MAX6875_CMD_BLK_READ, |
Jean Delvare | 4b2643d | 2007-07-12 14:12:29 +0200 | [diff] [blame] | 89 | SLICE_SIZE, |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 90 | buf) != SLICE_SIZE) { |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 91 | goto exit_up; |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 92 | } |
| 93 | } else { |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 94 | for (i = 0; i < SLICE_SIZE; i++) { |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 95 | j = i2c_smbus_read_byte(client); |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 96 | if (j < 0) { |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 97 | goto exit_up; |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 98 | } |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 99 | buf[i] = j; |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 100 | } |
| 101 | } |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 102 | data->last_updated[slice] = jiffies; |
| 103 | data->valid |= (1 << slice); |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 104 | } |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 105 | exit_up: |
Ingo Molnar | 5c085d3 | 2006-01-18 23:16:04 +0100 | [diff] [blame] | 106 | mutex_unlock(&data->update_lock); |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 107 | } |
| 108 | |
Chris Wright | 2c3c8be | 2010-05-12 18:28:57 -0700 | [diff] [blame] | 109 | static ssize_t max6875_read(struct file *filp, struct kobject *kobj, |
Zhang Rui | 91a6902 | 2007-06-09 13:57:22 +0800 | [diff] [blame] | 110 | struct bin_attribute *bin_attr, |
| 111 | char *buf, loff_t off, size_t count) |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 112 | { |
| 113 | struct i2c_client *client = kobj_to_i2c_client(kobj); |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 114 | struct max6875_data *data = i2c_get_clientdata(client); |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 115 | int slice, max_slice; |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 116 | |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 117 | /* refresh slices which contain requested bytes */ |
| 118 | max_slice = (off + count - 1) >> SLICE_BITS; |
| 119 | for (slice = (off >> SLICE_BITS); slice <= max_slice; slice++) |
| 120 | max6875_update_slice(client, slice); |
| 121 | |
| 122 | memcpy(buf, &data->data[off], count); |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 123 | |
| 124 | return count; |
| 125 | } |
| 126 | |
Bhumika Goyal | 57daedf | 2017-08-02 14:40:06 +0530 | [diff] [blame] | 127 | static const struct bin_attribute user_eeprom_attr = { |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 128 | .attr = { |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 129 | .name = "eeprom", |
| 130 | .mode = S_IRUGO, |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 131 | }, |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 132 | .size = USER_EEPROM_SIZE, |
| 133 | .read = max6875_read, |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 134 | }; |
| 135 | |
Jean Delvare | b835d7f | 2009-10-04 22:53:41 +0200 | [diff] [blame] | 136 | static int max6875_probe(struct i2c_client *client, |
| 137 | const struct i2c_device_id *id) |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 138 | { |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 139 | struct i2c_adapter *adapter = client->adapter; |
Jean Delvare | b835d7f | 2009-10-04 22:53:41 +0200 | [diff] [blame] | 140 | struct max6875_data *data; |
| 141 | int err; |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 142 | |
bgardner@wabtec.com | 17f990c | 2005-07-27 12:43:14 -0500 | [diff] [blame] | 143 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 144 | | I2C_FUNC_SMBUS_READ_BYTE)) |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 145 | return -ENODEV; |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 146 | |
Jean Delvare | b835d7f | 2009-10-04 22:53:41 +0200 | [diff] [blame] | 147 | /* Only bind to even addresses */ |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 148 | if (client->addr & 1) |
| 149 | return -ENODEV; |
| 150 | |
Deepak Saxena | 5263ebb | 2005-10-17 23:09:43 +0200 | [diff] [blame] | 151 | if (!(data = kzalloc(sizeof(struct max6875_data), GFP_KERNEL))) |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 152 | return -ENOMEM; |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 153 | |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 154 | /* A fake client is created on the odd address */ |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 155 | data->fake_client = i2c_new_dummy(client->adapter, client->addr + 1); |
| 156 | if (!data->fake_client) { |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 157 | err = -ENOMEM; |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 158 | goto exit_kfree; |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 159 | } |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 160 | |
bgardner@wabtec.com | bc769ff | 2005-07-12 13:21:11 -0500 | [diff] [blame] | 161 | /* Init real i2c_client */ |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 162 | i2c_set_clientdata(client, data); |
Ingo Molnar | 5c085d3 | 2006-01-18 23:16:04 +0100 | [diff] [blame] | 163 | mutex_init(&data->update_lock); |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 164 | |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 165 | err = sysfs_create_bin_file(&client->dev.kobj, &user_eeprom_attr); |
Jean Delvare | 7d9db67 | 2006-09-03 22:20:24 +0200 | [diff] [blame] | 166 | if (err) |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 167 | goto exit_remove_fake; |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 168 | |
| 169 | return 0; |
| 170 | |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 171 | exit_remove_fake: |
| 172 | i2c_unregister_device(data->fake_client); |
| 173 | exit_kfree: |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 174 | kfree(data); |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 175 | return err; |
| 176 | } |
| 177 | |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 178 | static int max6875_remove(struct i2c_client *client) |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 179 | { |
Jean Delvare | 7d9db67 | 2006-09-03 22:20:24 +0200 | [diff] [blame] | 180 | struct max6875_data *data = i2c_get_clientdata(client); |
| 181 | |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 182 | i2c_unregister_device(data->fake_client); |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 183 | |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 184 | sysfs_remove_bin_file(&client->dev.kobj, &user_eeprom_attr); |
| 185 | kfree(data); |
Jean Delvare | 7d9db67 | 2006-09-03 22:20:24 +0200 | [diff] [blame] | 186 | |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 187 | return 0; |
| 188 | } |
| 189 | |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 190 | static const struct i2c_device_id max6875_id[] = { |
| 191 | { "max6875", 0 }, |
| 192 | { } |
| 193 | }; |
Javier Martinez Canillas | c49c1f0 | 2015-08-07 14:04:19 +0200 | [diff] [blame] | 194 | MODULE_DEVICE_TABLE(i2c, max6875_id); |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 195 | |
| 196 | static struct i2c_driver max6875_driver = { |
| 197 | .driver = { |
| 198 | .name = "max6875", |
| 199 | }, |
| 200 | .probe = max6875_probe, |
| 201 | .remove = max6875_remove, |
| 202 | .id_table = max6875_id, |
Jean Delvare | bd8d421 | 2008-07-16 19:30:07 +0200 | [diff] [blame] | 203 | }; |
| 204 | |
Axel Lin | a64fe2e | 2012-01-22 15:36:45 +0800 | [diff] [blame] | 205 | module_i2c_driver(max6875_driver); |
BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 206 | |
| 207 | MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>"); |
| 208 | MODULE_DESCRIPTION("MAX6875 driver"); |
| 209 | MODULE_LICENSE("GPL"); |