1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 Copyright (c) 2003 Mark M. Hoffman <mhoffman@lightlink.com> 4 5 */ 6 7 /* 8 This module must be considered BETA unless and until 9 the chipset manufacturer releases a datasheet. 10 The register definitions are based on the SiS630. 11 12 This module relies on quirk_sis_96x_smbus (drivers/pci/quirks.c) 13 for just about every machine for which users have reported. 14 If this module isn't detecting your 96x south bridge, have a 15 look there. 16 17 We assume there can only be one SiS96x with one SMBus interface. 18 */ 19 20 #include <linux/module.h> 21 #include <linux/pci.h> 22 #include <linux/kernel.h> 23 #include <linux/delay.h> 24 #include <linux/stddef.h> 25 #include <linux/ioport.h> 26 #include <linux/i2c.h> 27 #include <linux/acpi.h> 28 #include <linux/io.h> 29 30 /* base address register in PCI config space */ 31 #define SIS96x_BAR 0x04 32 33 /* SiS96x SMBus registers */ 34 #define SMB_STS 0x00 35 #define SMB_EN 0x01 36 #define SMB_CNT 0x02 37 #define SMB_HOST_CNT 0x03 38 #define SMB_ADDR 0x04 39 #define SMB_CMD 0x05 40 #define SMB_PCOUNT 0x06 41 #define SMB_COUNT 0x07 42 #define SMB_BYTE 0x08 43 #define SMB_DEV_ADDR 0x10 44 #define SMB_DB0 0x11 45 #define SMB_DB1 0x12 46 #define SMB_SAA 0x13 47 48 /* register count for request_region */ 49 #define SMB_IOSIZE 0x20 50 51 /* Other settings */ 52 #define MAX_TIMEOUT 500 53 54 /* SiS96x SMBus constants */ 55 #define SIS96x_QUICK 0x00 56 #define SIS96x_BYTE 0x01 57 #define SIS96x_BYTE_DATA 0x02 58 #define SIS96x_WORD_DATA 0x03 59 #define SIS96x_PROC_CALL 0x04 60 #define SIS96x_BLOCK_DATA 0x05 61 62 static struct pci_driver sis96x_driver; 63 static struct i2c_adapter sis96x_adapter; 64 static u16 sis96x_smbus_base; 65 66 static inline u8 sis96x_read(u8 reg) 67 { 68 return inb(sis96x_smbus_base + reg) ; 69 } 70 71 static inline void sis96x_write(u8 reg, u8 data) 72 { 73 outb(data, sis96x_smbus_base + reg) ; 74 } 75 76 /* Execute a SMBus transaction. 77 int size is from SIS96x_QUICK to SIS96x_BLOCK_DATA 78 */ 79 static int sis96x_transaction(int size) 80 { 81 int temp; 82 int result = 0; 83 int timeout = 0; 84 85 dev_dbg(&sis96x_adapter.dev, "SMBus transaction %d\n", size); 86 87 /* Make sure the SMBus host is ready to start transmitting */ 88 if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) { 89 90 dev_dbg(&sis96x_adapter.dev, "SMBus busy (0x%02x). " 91 "Resetting...\n", temp); 92 93 /* kill the transaction */ 94 sis96x_write(SMB_HOST_CNT, 0x20); 95 96 /* check it again */ 97 if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) { 98 dev_dbg(&sis96x_adapter.dev, "Failed (0x%02x)\n", temp); 99 return -EBUSY; 100 } else { 101 dev_dbg(&sis96x_adapter.dev, "Successful\n"); 102 } 103 } 104 105 /* Turn off timeout interrupts, set fast host clock */ 106 sis96x_write(SMB_CNT, 0x20); 107 108 /* clear all (sticky) status flags */ 109 temp = sis96x_read(SMB_STS); 110 sis96x_write(SMB_STS, temp & 0x1e); 111 112 /* start the transaction by setting bit 4 and size bits */ 113 sis96x_write(SMB_HOST_CNT, 0x10 | (size & 0x07)); 114 115 /* We will always wait for a fraction of a second! */ 116 do { 117 msleep(1); 118 temp = sis96x_read(SMB_STS); 119 } while (!(temp & 0x0e) && (timeout++ < MAX_TIMEOUT)); 120 121 /* If the SMBus is still busy, we give up */ 122 if (timeout > MAX_TIMEOUT) { 123 dev_dbg(&sis96x_adapter.dev, "SMBus Timeout! (0x%02x)\n", temp); 124 result = -ETIMEDOUT; 125 } 126 127 /* device error - probably missing ACK */ 128 if (temp & 0x02) { 129 dev_dbg(&sis96x_adapter.dev, "Failed bus transaction!\n"); 130 result = -ENXIO; 131 } 132 133 /* bus collision */ 134 if (temp & 0x04) { 135 dev_dbg(&sis96x_adapter.dev, "Bus collision!\n"); 136 result = -EIO; 137 } 138 139 /* Finish up by resetting the bus */ 140 sis96x_write(SMB_STS, temp); 141 if ((temp = sis96x_read(SMB_STS))) { 142 dev_dbg(&sis96x_adapter.dev, "Failed reset at " 143 "end of transaction! (0x%02x)\n", temp); 144 } 145 146 return result; 147 } 148 149 /* Return negative errno on error. */ 150 static s32 sis96x_access(struct i2c_adapter * adap, u16 addr, 151 unsigned short flags, char read_write, 152 u8 command, int size, union i2c_smbus_data * data) 153 { 154 int status; 155 156 switch (size) { 157 case I2C_SMBUS_QUICK: 158 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01)); 159 size = SIS96x_QUICK; 160 break; 161 162 case I2C_SMBUS_BYTE: 163 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01)); 164 if (read_write == I2C_SMBUS_WRITE) 165 sis96x_write(SMB_CMD, command); 166 size = SIS96x_BYTE; 167 break; 168 169 case I2C_SMBUS_BYTE_DATA: 170 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01)); 171 sis96x_write(SMB_CMD, command); 172 if (read_write == I2C_SMBUS_WRITE) 173 sis96x_write(SMB_BYTE, data->byte); 174 size = SIS96x_BYTE_DATA; 175 break; 176 177 case I2C_SMBUS_PROC_CALL: 178 case I2C_SMBUS_WORD_DATA: 179 sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01)); 180 sis96x_write(SMB_CMD, command); 181 if (read_write == I2C_SMBUS_WRITE) { 182 sis96x_write(SMB_BYTE, data->word & 0xff); 183 sis96x_write(SMB_BYTE + 1, (data->word & 0xff00) >> 8); 184 } 185 size = (size == I2C_SMBUS_PROC_CALL ? 186 SIS96x_PROC_CALL : SIS96x_WORD_DATA); 187 break; 188 189 default: 190 dev_warn(&adap->dev, "Unsupported transaction %d\n", size); 191 return -EOPNOTSUPP; 192 } 193 194 status = sis96x_transaction(size); 195 if (status) 196 return status; 197 198 if ((size != SIS96x_PROC_CALL) && 199 ((read_write == I2C_SMBUS_WRITE) || (size == SIS96x_QUICK))) 200 return 0; 201 202 switch (size) { 203 case SIS96x_BYTE: 204 case SIS96x_BYTE_DATA: 205 data->byte = sis96x_read(SMB_BYTE); 206 break; 207 208 case SIS96x_WORD_DATA: 209 case SIS96x_PROC_CALL: 210 data->word = sis96x_read(SMB_BYTE) + 211 (sis96x_read(SMB_BYTE + 1) << 8); 212 break; 213 } 214 return 0; 215 } 216 217 static u32 sis96x_func(struct i2c_adapter *adapter) 218 { 219 return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | 220 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | 221 I2C_FUNC_SMBUS_PROC_CALL; 222 } 223 224 static const struct i2c_algorithm smbus_algorithm = { 225 .smbus_xfer = sis96x_access, 226 .functionality = sis96x_func, 227 }; 228 229 static struct i2c_adapter sis96x_adapter = { 230 .owner = THIS_MODULE, 231 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD, 232 .algo = &smbus_algorithm, 233 }; 234 235 static const struct pci_device_id sis96x_ids[] = { 236 { PCI_DEVICE(PCI_VENDOR_ID_SI, PCI_DEVICE_ID_SI_SMBUS) }, 237 { 0, } 238 }; 239 240 MODULE_DEVICE_TABLE (pci, sis96x_ids); 241 242 static int sis96x_probe(struct pci_dev *dev, 243 const struct pci_device_id *id) 244 { 245 u16 ww = 0; 246 int retval; 247 248 if (sis96x_smbus_base) { 249 dev_err(&dev->dev, "Only one device supported.\n"); 250 return -EBUSY; 251 } 252 253 pci_read_config_word(dev, PCI_CLASS_DEVICE, &ww); 254 if (PCI_CLASS_SERIAL_SMBUS != ww) { 255 dev_err(&dev->dev, "Unsupported device class 0x%04x!\n", ww); 256 return -ENODEV; 257 } 258 259 sis96x_smbus_base = pci_resource_start(dev, SIS96x_BAR); 260 if (!sis96x_smbus_base) { 261 dev_err(&dev->dev, "SiS96x SMBus base address " 262 "not initialized!\n"); 263 return -EINVAL; 264 } 265 dev_info(&dev->dev, "SiS96x SMBus base address: 0x%04x\n", 266 sis96x_smbus_base); 267 268 retval = acpi_check_resource_conflict(&dev->resource[SIS96x_BAR]); 269 if (retval) 270 return -ENODEV; 271 272 /* Everything is happy, let's grab the memory and set things up. */ 273 if (!request_region(sis96x_smbus_base, SMB_IOSIZE, 274 sis96x_driver.name)) { 275 dev_err(&dev->dev, "SMBus registers 0x%04x-0x%04x " 276 "already in use!\n", sis96x_smbus_base, 277 sis96x_smbus_base + SMB_IOSIZE - 1); 278 279 sis96x_smbus_base = 0; 280 return -EINVAL; 281 } 282 283 /* set up the sysfs linkage to our parent device */ 284 sis96x_adapter.dev.parent = &dev->dev; 285 286 snprintf(sis96x_adapter.name, sizeof(sis96x_adapter.name), 287 "SiS96x SMBus adapter at 0x%04x", sis96x_smbus_base); 288 289 if ((retval = i2c_add_adapter(&sis96x_adapter))) { 290 dev_err(&dev->dev, "Couldn't register adapter!\n"); 291 release_region(sis96x_smbus_base, SMB_IOSIZE); 292 sis96x_smbus_base = 0; 293 } 294 295 return retval; 296 } 297 298 static void sis96x_remove(struct pci_dev *dev) 299 { 300 if (sis96x_smbus_base) { 301 i2c_del_adapter(&sis96x_adapter); 302 release_region(sis96x_smbus_base, SMB_IOSIZE); 303 sis96x_smbus_base = 0; 304 } 305 } 306 307 static struct pci_driver sis96x_driver = { 308 .name = "sis96x_smbus", 309 .id_table = sis96x_ids, 310 .probe = sis96x_probe, 311 .remove = sis96x_remove, 312 }; 313 314 module_pci_driver(sis96x_driver); 315 316 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>"); 317 MODULE_DESCRIPTION("SiS96x SMBus driver"); 318 MODULE_LICENSE("GPL"); 319