1 /* 2 i2c-isch.c - Linux kernel driver for Intel SCH chipset SMBus 3 - Based on i2c-piix4.c 4 Copyright (c) 1998 - 2002 Frodo Looijaard <frodol@dds.nl> and 5 Philip Edelbrock <phil@netroedge.com> 6 - Intel SCH support 7 Copyright (c) 2007 - 2008 Jacob Jun Pan <jacob.jun.pan@intel.com> 8 9 This program is free software; you can redistribute it and/or modify 10 it under the terms of the GNU General Public License version 2 as 11 published by the Free Software Foundation. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 */ 18 19 /* 20 Supports: 21 Intel SCH chipsets (AF82US15W, AF82US15L, AF82UL11L) 22 Note: we assume there can only be one device, with one SMBus interface. 23 */ 24 25 #include <linux/module.h> 26 #include <linux/platform_device.h> 27 #include <linux/kernel.h> 28 #include <linux/delay.h> 29 #include <linux/stddef.h> 30 #include <linux/ioport.h> 31 #include <linux/i2c.h> 32 #include <linux/io.h> 33 #include <linux/acpi.h> 34 35 /* SCH SMBus address offsets */ 36 #define SMBHSTCNT (0 + sch_smba) 37 #define SMBHSTSTS (1 + sch_smba) 38 #define SMBHSTCLK (2 + sch_smba) 39 #define SMBHSTADD (4 + sch_smba) /* TSA */ 40 #define SMBHSTCMD (5 + sch_smba) 41 #define SMBHSTDAT0 (6 + sch_smba) 42 #define SMBHSTDAT1 (7 + sch_smba) 43 #define SMBBLKDAT (0x20 + sch_smba) 44 45 /* Other settings */ 46 #define MAX_RETRIES 5000 47 48 /* I2C constants */ 49 #define SCH_QUICK 0x00 50 #define SCH_BYTE 0x01 51 #define SCH_BYTE_DATA 0x02 52 #define SCH_WORD_DATA 0x03 53 #define SCH_BLOCK_DATA 0x05 54 55 static unsigned short sch_smba; 56 static struct i2c_adapter sch_adapter; 57 static int backbone_speed = 33000; /* backbone speed in kHz */ 58 module_param(backbone_speed, int, S_IRUSR | S_IWUSR); 59 MODULE_PARM_DESC(backbone_speed, "Backbone speed in kHz, (default = 33000)"); 60 61 /* 62 * Start the i2c transaction -- the i2c_access will prepare the transaction 63 * and this function will execute it. 64 * return 0 for success and others for failure. 65 */ 66 static int sch_transaction(void) 67 { 68 int temp; 69 int result = 0; 70 int retries = 0; 71 72 dev_dbg(&sch_adapter.dev, "Transaction (pre): CNT=%02x, CMD=%02x, " 73 "ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT), 74 inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0), 75 inb(SMBHSTDAT1)); 76 77 /* Make sure the SMBus host is ready to start transmitting */ 78 temp = inb(SMBHSTSTS) & 0x0f; 79 if (temp) { 80 /* Can not be busy since we checked it in sch_access */ 81 if (temp & 0x01) { 82 dev_dbg(&sch_adapter.dev, "Completion (%02x). " 83 "Clear...\n", temp); 84 } 85 if (temp & 0x06) { 86 dev_dbg(&sch_adapter.dev, "SMBus error (%02x). " 87 "Resetting...\n", temp); 88 } 89 outb(temp, SMBHSTSTS); 90 temp = inb(SMBHSTSTS) & 0x0f; 91 if (temp) { 92 dev_err(&sch_adapter.dev, 93 "SMBus is not ready: (%02x)\n", temp); 94 return -EAGAIN; 95 } 96 } 97 98 /* start the transaction by setting bit 4 */ 99 outb(inb(SMBHSTCNT) | 0x10, SMBHSTCNT); 100 101 do { 102 usleep_range(100, 200); 103 temp = inb(SMBHSTSTS) & 0x0f; 104 } while ((temp & 0x08) && (retries++ < MAX_RETRIES)); 105 106 /* If the SMBus is still busy, we give up */ 107 if (retries > MAX_RETRIES) { 108 dev_err(&sch_adapter.dev, "SMBus Timeout!\n"); 109 result = -ETIMEDOUT; 110 } 111 if (temp & 0x04) { 112 result = -EIO; 113 dev_dbg(&sch_adapter.dev, "Bus collision! SMBus may be " 114 "locked until next hard reset. (sorry!)\n"); 115 /* Clock stops and slave is stuck in mid-transmission */ 116 } else if (temp & 0x02) { 117 result = -EIO; 118 dev_err(&sch_adapter.dev, "Error: no response!\n"); 119 } else if (temp & 0x01) { 120 dev_dbg(&sch_adapter.dev, "Post complete!\n"); 121 outb(temp, SMBHSTSTS); 122 temp = inb(SMBHSTSTS) & 0x07; 123 if (temp & 0x06) { 124 /* Completion clear failed */ 125 dev_dbg(&sch_adapter.dev, "Failed reset at end of " 126 "transaction (%02x), Bus error!\n", temp); 127 } 128 } else { 129 result = -ENXIO; 130 dev_dbg(&sch_adapter.dev, "No such address.\n"); 131 } 132 dev_dbg(&sch_adapter.dev, "Transaction (post): CNT=%02x, CMD=%02x, " 133 "ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT), 134 inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0), 135 inb(SMBHSTDAT1)); 136 return result; 137 } 138 139 /* 140 * This is the main access entry for i2c-sch access 141 * adap is i2c_adapter pointer, addr is the i2c device bus address, read_write 142 * (0 for read and 1 for write), size is i2c transaction type and data is the 143 * union of transaction for data to be transferred or data read from bus. 144 * return 0 for success and others for failure. 145 */ 146 static s32 sch_access(struct i2c_adapter *adap, u16 addr, 147 unsigned short flags, char read_write, 148 u8 command, int size, union i2c_smbus_data *data) 149 { 150 int i, len, temp, rc; 151 152 /* Make sure the SMBus host is not busy */ 153 temp = inb(SMBHSTSTS) & 0x0f; 154 if (temp & 0x08) { 155 dev_dbg(&sch_adapter.dev, "SMBus busy (%02x)\n", temp); 156 return -EAGAIN; 157 } 158 temp = inw(SMBHSTCLK); 159 if (!temp) { 160 /* 161 * We can't determine if we have 33 or 25 MHz clock for 162 * SMBus, so expect 33 MHz and calculate a bus clock of 163 * 100 kHz. If we actually run at 25 MHz the bus will be 164 * run ~75 kHz instead which should do no harm. 165 */ 166 dev_notice(&sch_adapter.dev, 167 "Clock divider unitialized. Setting defaults\n"); 168 outw(backbone_speed / (4 * 100), SMBHSTCLK); 169 } 170 171 dev_dbg(&sch_adapter.dev, "access size: %d %s\n", size, 172 (read_write)?"READ":"WRITE"); 173 switch (size) { 174 case I2C_SMBUS_QUICK: 175 outb((addr << 1) | read_write, SMBHSTADD); 176 size = SCH_QUICK; 177 break; 178 case I2C_SMBUS_BYTE: 179 outb((addr << 1) | read_write, SMBHSTADD); 180 if (read_write == I2C_SMBUS_WRITE) 181 outb(command, SMBHSTCMD); 182 size = SCH_BYTE; 183 break; 184 case I2C_SMBUS_BYTE_DATA: 185 outb((addr << 1) | read_write, SMBHSTADD); 186 outb(command, SMBHSTCMD); 187 if (read_write == I2C_SMBUS_WRITE) 188 outb(data->byte, SMBHSTDAT0); 189 size = SCH_BYTE_DATA; 190 break; 191 case I2C_SMBUS_WORD_DATA: 192 outb((addr << 1) | read_write, SMBHSTADD); 193 outb(command, SMBHSTCMD); 194 if (read_write == I2C_SMBUS_WRITE) { 195 outb(data->word & 0xff, SMBHSTDAT0); 196 outb((data->word & 0xff00) >> 8, SMBHSTDAT1); 197 } 198 size = SCH_WORD_DATA; 199 break; 200 case I2C_SMBUS_BLOCK_DATA: 201 outb((addr << 1) | read_write, SMBHSTADD); 202 outb(command, SMBHSTCMD); 203 if (read_write == I2C_SMBUS_WRITE) { 204 len = data->block[0]; 205 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX) 206 return -EINVAL; 207 outb(len, SMBHSTDAT0); 208 for (i = 1; i <= len; i++) 209 outb(data->block[i], SMBBLKDAT+i-1); 210 } 211 size = SCH_BLOCK_DATA; 212 break; 213 default: 214 dev_warn(&adap->dev, "Unsupported transaction %d\n", size); 215 return -EOPNOTSUPP; 216 } 217 dev_dbg(&sch_adapter.dev, "write size %d to 0x%04x\n", size, SMBHSTCNT); 218 outb((inb(SMBHSTCNT) & 0xb0) | (size & 0x7), SMBHSTCNT); 219 220 rc = sch_transaction(); 221 if (rc) /* Error in transaction */ 222 return rc; 223 224 if ((read_write == I2C_SMBUS_WRITE) || (size == SCH_QUICK)) 225 return 0; 226 227 switch (size) { 228 case SCH_BYTE: 229 case SCH_BYTE_DATA: 230 data->byte = inb(SMBHSTDAT0); 231 break; 232 case SCH_WORD_DATA: 233 data->word = inb(SMBHSTDAT0) + (inb(SMBHSTDAT1) << 8); 234 break; 235 case SCH_BLOCK_DATA: 236 data->block[0] = inb(SMBHSTDAT0); 237 if (data->block[0] == 0 || data->block[0] > I2C_SMBUS_BLOCK_MAX) 238 return -EPROTO; 239 for (i = 1; i <= data->block[0]; i++) 240 data->block[i] = inb(SMBBLKDAT+i-1); 241 break; 242 } 243 return 0; 244 } 245 246 static u32 sch_func(struct i2c_adapter *adapter) 247 { 248 return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | 249 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | 250 I2C_FUNC_SMBUS_BLOCK_DATA; 251 } 252 253 static const struct i2c_algorithm smbus_algorithm = { 254 .smbus_xfer = sch_access, 255 .functionality = sch_func, 256 }; 257 258 static struct i2c_adapter sch_adapter = { 259 .owner = THIS_MODULE, 260 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD, 261 .algo = &smbus_algorithm, 262 }; 263 264 static int smbus_sch_probe(struct platform_device *dev) 265 { 266 struct resource *res; 267 int retval; 268 269 res = platform_get_resource(dev, IORESOURCE_IO, 0); 270 if (!res) 271 return -EBUSY; 272 273 if (!devm_request_region(&dev->dev, res->start, resource_size(res), 274 dev->name)) { 275 dev_err(&dev->dev, "SMBus region 0x%x already in use!\n", 276 sch_smba); 277 return -EBUSY; 278 } 279 280 sch_smba = res->start; 281 282 dev_dbg(&dev->dev, "SMBA = 0x%X\n", sch_smba); 283 284 /* set up the sysfs linkage to our parent device */ 285 sch_adapter.dev.parent = &dev->dev; 286 287 snprintf(sch_adapter.name, sizeof(sch_adapter.name), 288 "SMBus SCH adapter at %04x", sch_smba); 289 290 retval = i2c_add_adapter(&sch_adapter); 291 if (retval) { 292 dev_err(&dev->dev, "Couldn't register adapter!\n"); 293 sch_smba = 0; 294 } 295 296 return retval; 297 } 298 299 static int smbus_sch_remove(struct platform_device *pdev) 300 { 301 if (sch_smba) { 302 i2c_del_adapter(&sch_adapter); 303 sch_smba = 0; 304 } 305 306 return 0; 307 } 308 309 static struct platform_driver smbus_sch_driver = { 310 .driver = { 311 .name = "isch_smbus", 312 }, 313 .probe = smbus_sch_probe, 314 .remove = smbus_sch_remove, 315 }; 316 317 module_platform_driver(smbus_sch_driver); 318 319 MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@intel.com>"); 320 MODULE_DESCRIPTION("Intel SCH SMBus driver"); 321 MODULE_LICENSE("GPL"); 322 MODULE_ALIAS("platform:isch_smbus"); 323