| 1 | /* |
|---|
| 2 | * i2c-amd756-s4882.c - i2c-amd756 extras for the Tyan S4882 motherboard |
|---|
| 3 | * |
|---|
| 4 | * Copyright (C) 2004 Jean Delvare <khali@linux-fr.org> |
|---|
| 5 | * |
|---|
| 6 | * This program is free software; you can redistribute it and/or modify |
|---|
| 7 | * it under the terms of the GNU General Public License as published by |
|---|
| 8 | * the Free Software Foundation; either version 2 of the License, or |
|---|
| 9 | * (at your option) any later version. |
|---|
| 10 | * |
|---|
| 11 | * This program is distributed in the hope that it will be useful, |
|---|
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
|---|
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
|---|
| 14 | * GNU General Public License for more details. |
|---|
| 15 | * |
|---|
| 16 | * You should have received a copy of the GNU General Public License |
|---|
| 17 | * along with this program; if not, write to the Free Software |
|---|
| 18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
|---|
| 19 | */ |
|---|
| 20 | |
|---|
| 21 | /* |
|---|
| 22 | * We select the channels by sending commands to the Philips |
|---|
| 23 | * PCA9556 chip at I2C address 0x18. The main adapter is used for |
|---|
| 24 | * the non-multiplexed part of the bus, and 4 virtual adapters |
|---|
| 25 | * are defined for the multiplexed addresses: 0x50-0x53 (memory |
|---|
| 26 | * module EEPROM) located on channels 1-4, and 0x4c (LM63) |
|---|
| 27 | * located on multiplexed channels 0 and 5-7. We define one |
|---|
| 28 | * virtual adapter per CPU, which corresponds to two multiplexed |
|---|
| 29 | * channels: |
|---|
| 30 | * CPU0: virtual adapter 1, channels 1 and 0 |
|---|
| 31 | * CPU1: virtual adapter 2, channels 2 and 5 |
|---|
| 32 | * CPU2: virtual adapter 3, channels 3 and 6 |
|---|
| 33 | * CPU3: virtual adapter 4, channels 4 and 7 |
|---|
| 34 | */ |
|---|
| 35 | |
|---|
| 36 | #include <linux/module.h> |
|---|
| 37 | #include <linux/kernel.h> |
|---|
| 38 | #include <linux/slab.h> |
|---|
| 39 | #include <linux/init.h> |
|---|
| 40 | #include <linux/i2c.h> |
|---|
| 41 | #include <asm/semaphore.h> |
|---|
| 42 | |
|---|
| 43 | #define DRV_NAME "i2c-amd756-s4882" |
|---|
| 44 | |
|---|
| 45 | extern struct i2c_adapter amd756_smbus; |
|---|
| 46 | |
|---|
| 47 | static struct i2c_adapter *s4882_adapter; |
|---|
| 48 | static struct i2c_algorithm *s4882_algo; |
|---|
| 49 | |
|---|
| 50 | /* Wrapper access functions for multiplexed SMBus */ |
|---|
| 51 | static struct semaphore amd756_lock; |
|---|
| 52 | |
|---|
| 53 | static s32 amd756_access_virt0(struct i2c_adapter * adap, u16 addr, |
|---|
| 54 | unsigned short flags, char read_write, |
|---|
| 55 | u8 command, int size, |
|---|
| 56 | union i2c_smbus_data * data) |
|---|
| 57 | { |
|---|
| 58 | int error; |
|---|
| 59 | |
|---|
| 60 | /* We exclude the multiplexed addresses */ |
|---|
| 61 | if (addr == 0x4c || (addr & 0xfc) == 0x50 || (addr & 0xfc) == 0x30 |
|---|
| 62 | || addr == 0x18) |
|---|
| 63 | return -1; |
|---|
| 64 | |
|---|
| 65 | down(&amd756_lock); |
|---|
| 66 | |
|---|
| 67 | error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write, |
|---|
| 68 | command, size, data); |
|---|
| 69 | |
|---|
| 70 | up(&amd756_lock); |
|---|
| 71 | |
|---|
| 72 | return error; |
|---|
| 73 | } |
|---|
| 74 | |
|---|
| 75 | /* We remember the last used channels combination so as to only switch |
|---|
| 76 | channels when it is really needed. This greatly reduces the SMBus |
|---|
| 77 | overhead, but also assumes that nobody will be writing to the PCA9556 |
|---|
| 78 | in our back. */ |
|---|
| 79 | static u8 last_channels; |
|---|
| 80 | |
|---|
| 81 | static inline s32 amd756_access_channel(struct i2c_adapter * adap, u16 addr, |
|---|
| 82 | unsigned short flags, char read_write, |
|---|
| 83 | u8 command, int size, |
|---|
| 84 | union i2c_smbus_data * data, |
|---|
| 85 | u8 channels) |
|---|
| 86 | { |
|---|
| 87 | int error; |
|---|
| 88 | |
|---|
| 89 | /* We exclude the non-multiplexed addresses */ |
|---|
| 90 | if (addr != 0x4c && (addr & 0xfc) != 0x50 && (addr & 0xfc) != 0x30) |
|---|
| 91 | return -1; |
|---|
| 92 | |
|---|
| 93 | down(&amd756_lock); |
|---|
| 94 | |
|---|
| 95 | if (last_channels != channels) { |
|---|
| 96 | union i2c_smbus_data mplxdata; |
|---|
| 97 | mplxdata.byte = channels; |
|---|
| 98 | |
|---|
| 99 | error = amd756_smbus.algo->smbus_xfer(adap, 0x18, 0, |
|---|
| 100 | I2C_SMBUS_WRITE, 0x01, |
|---|
| 101 | I2C_SMBUS_BYTE_DATA, |
|---|
| 102 | &mplxdata); |
|---|
| 103 | if (error) |
|---|
| 104 | goto UNLOCK; |
|---|
| 105 | last_channels = channels; |
|---|
| 106 | } |
|---|
| 107 | error = amd756_smbus.algo->smbus_xfer(adap, addr, flags, read_write, |
|---|
| 108 | command, size, data); |
|---|
| 109 | |
|---|
| 110 | UNLOCK: |
|---|
| 111 | up(&amd756_lock); |
|---|
| 112 | return error; |
|---|
| 113 | } |
|---|
| 114 | |
|---|
| 115 | static s32 amd756_access_virt1(struct i2c_adapter * adap, u16 addr, |
|---|
| 116 | unsigned short flags, char read_write, |
|---|
| 117 | u8 command, int size, |
|---|
| 118 | union i2c_smbus_data * data) |
|---|
| 119 | { |
|---|
| 120 | /* CPU0: channels 1 and 0 enabled */ |
|---|
| 121 | return amd756_access_channel(adap, addr, flags, read_write, command, |
|---|
| 122 | size, data, 0x03); |
|---|
| 123 | } |
|---|
| 124 | |
|---|
| 125 | static s32 amd756_access_virt2(struct i2c_adapter * adap, u16 addr, |
|---|
| 126 | unsigned short flags, char read_write, |
|---|
| 127 | u8 command, int size, |
|---|
| 128 | union i2c_smbus_data * data) |
|---|
| 129 | { |
|---|
| 130 | /* CPU1: channels 2 and 5 enabled */ |
|---|
| 131 | return amd756_access_channel(adap, addr, flags, read_write, command, |
|---|
| 132 | size, data, 0x24); |
|---|
| 133 | } |
|---|
| 134 | |
|---|
| 135 | static s32 amd756_access_virt3(struct i2c_adapter * adap, u16 addr, |
|---|
| 136 | unsigned short flags, char read_write, |
|---|
| 137 | u8 command, int size, |
|---|
| 138 | union i2c_smbus_data * data) |
|---|
| 139 | { |
|---|
| 140 | /* CPU2: channels 3 and 6 enabled */ |
|---|
| 141 | return amd756_access_channel(adap, addr, flags, read_write, command, |
|---|
| 142 | size, data, 0x48); |
|---|
| 143 | } |
|---|
| 144 | |
|---|
| 145 | static s32 amd756_access_virt4(struct i2c_adapter * adap, u16 addr, |
|---|
| 146 | unsigned short flags, char read_write, |
|---|
| 147 | u8 command, int size, |
|---|
| 148 | union i2c_smbus_data * data) |
|---|
| 149 | { |
|---|
| 150 | /* CPU3: channels 4 and 7 enabled */ |
|---|
| 151 | return amd756_access_channel(adap, addr, flags, read_write, command, |
|---|
| 152 | size, data, 0x90); |
|---|
| 153 | } |
|---|
| 154 | |
|---|
| 155 | static int __init amd756_s4882_init(void) |
|---|
| 156 | { |
|---|
| 157 | int i, error; |
|---|
| 158 | union i2c_smbus_data ioconfig; |
|---|
| 159 | |
|---|
| 160 | /* Unregister physical bus */ |
|---|
| 161 | error = i2c_del_adapter(&amd756_smbus); |
|---|
| 162 | if (error) { |
|---|
| 163 | if (error != -ENODEV) |
|---|
| 164 | printk(KERN_ERR DRV_NAME ": Physical bus removal " |
|---|
| 165 | "failed\n"); |
|---|
| 166 | goto ERROR0; |
|---|
| 167 | } |
|---|
| 168 | |
|---|
| 169 | printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4882\n"); |
|---|
| 170 | init_MUTEX(&amd756_lock); |
|---|
| 171 | |
|---|
| 172 | /* Define the 5 virtual adapters and algorithms structures */ |
|---|
| 173 | if (!(s4882_adapter = kmalloc(5 * sizeof(struct i2c_adapter), |
|---|
| 174 | GFP_KERNEL))) { |
|---|
| 175 | error = -ENOMEM; |
|---|
| 176 | goto ERROR1; |
|---|
| 177 | } |
|---|
| 178 | if (!(s4882_algo = kmalloc(5 * sizeof(struct i2c_algorithm), |
|---|
| 179 | GFP_KERNEL))) { |
|---|
| 180 | error = -ENOMEM; |
|---|
| 181 | goto ERROR2; |
|---|
| 182 | } |
|---|
| 183 | |
|---|
| 184 | /* Fill in the new structures */ |
|---|
| 185 | s4882_algo[0] = *(amd756_smbus.algo); |
|---|
| 186 | s4882_algo[0].smbus_xfer = amd756_access_virt0; |
|---|
| 187 | s4882_adapter[0] = amd756_smbus; |
|---|
| 188 | s4882_adapter[0].algo = s4882_algo; |
|---|
| 189 | for (i = 1; i < 5; i++) { |
|---|
| 190 | s4882_algo[i] = *(amd756_smbus.algo); |
|---|
| 191 | s4882_adapter[i] = amd756_smbus; |
|---|
| 192 | sprintf(s4882_adapter[i].name, |
|---|
| 193 | "SMBus 8111 adapter (CPU%d)", i-1); |
|---|
| 194 | s4882_adapter[i].algo = s4882_algo+i; |
|---|
| 195 | } |
|---|
| 196 | s4882_algo[1].smbus_xfer = amd756_access_virt1; |
|---|
| 197 | s4882_algo[2].smbus_xfer = amd756_access_virt2; |
|---|
| 198 | s4882_algo[3].smbus_xfer = amd756_access_virt3; |
|---|
| 199 | s4882_algo[4].smbus_xfer = amd756_access_virt4; |
|---|
| 200 | |
|---|
| 201 | /* Configure the PCA9556 multiplexer */ |
|---|
| 202 | ioconfig.byte = 0x00; /* All I/O to output mode */ |
|---|
| 203 | error = amd756_smbus.algo->smbus_xfer(&amd756_smbus, 0x18, 0, |
|---|
| 204 | I2C_SMBUS_WRITE, 0x03, |
|---|
| 205 | I2C_SMBUS_BYTE_DATA, &ioconfig); |
|---|
| 206 | if (error) { |
|---|
| 207 | printk(KERN_ERR DRV_NAME ": PCA9556 configuration failed\n"); |
|---|
| 208 | error = -EIO; |
|---|
| 209 | goto ERROR3; |
|---|
| 210 | } |
|---|
| 211 | |
|---|
| 212 | /* Register virtual adapters */ |
|---|
| 213 | for (i = 0; i < 5; i++) { |
|---|
| 214 | error = i2c_add_adapter(s4882_adapter+i); |
|---|
| 215 | if (error) { |
|---|
| 216 | printk(KERN_ERR DRV_NAME |
|---|
| 217 | ": Virtual adapter %d registration " |
|---|
| 218 | "failed, module not inserted\n", i); |
|---|
| 219 | for (i--; i >= 0; i--) |
|---|
| 220 | i2c_del_adapter(s4882_adapter+i); |
|---|
| 221 | goto ERROR3; |
|---|
| 222 | } |
|---|
| 223 | } |
|---|
| 224 | |
|---|
| 225 | return 0; |
|---|
| 226 | |
|---|
| 227 | ERROR3: |
|---|
| 228 | kfree(s4882_algo); |
|---|
| 229 | s4882_algo = NULL; |
|---|
| 230 | ERROR2: |
|---|
| 231 | kfree(s4882_adapter); |
|---|
| 232 | s4882_adapter = NULL; |
|---|
| 233 | ERROR1: |
|---|
| 234 | i2c_del_adapter(&amd756_smbus); |
|---|
| 235 | ERROR0: |
|---|
| 236 | return error; |
|---|
| 237 | } |
|---|
| 238 | |
|---|
| 239 | static void __exit amd756_s4882_exit(void) |
|---|
| 240 | { |
|---|
| 241 | if (s4882_adapter) { |
|---|
| 242 | int i; |
|---|
| 243 | |
|---|
| 244 | for (i = 0; i < 5; i++) |
|---|
| 245 | i2c_del_adapter(s4882_adapter+i); |
|---|
| 246 | kfree(s4882_adapter); |
|---|
| 247 | s4882_adapter = NULL; |
|---|
| 248 | } |
|---|
| 249 | if (s4882_algo) { |
|---|
| 250 | kfree(s4882_algo); |
|---|
| 251 | s4882_algo = NULL; |
|---|
| 252 | } |
|---|
| 253 | |
|---|
| 254 | /* Restore physical bus */ |
|---|
| 255 | if (i2c_add_adapter(&amd756_smbus)) |
|---|
| 256 | printk(KERN_ERR DRV_NAME ": Physical bus restoration " |
|---|
| 257 | "failed\n"); |
|---|
| 258 | } |
|---|
| 259 | |
|---|
| 260 | MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); |
|---|
| 261 | MODULE_DESCRIPTION("S4882 SMBus multiplexing"); |
|---|
| 262 | MODULE_LICENSE("GPL"); |
|---|
| 263 | |
|---|
| 264 | module_init(amd756_s4882_init); |
|---|
| 265 | module_exit(amd756_s4882_exit); |
|---|
