1 /* 2 * Hardware monitoring driver for ZL6100 and compatibles 3 * 4 * Copyright (c) 2011 Ericsson AB. 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 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/init.h> 24 #include <linux/err.h> 25 #include <linux/slab.h> 26 #include <linux/i2c.h> 27 #include <linux/ktime.h> 28 #include <linux/delay.h> 29 #include "pmbus.h" 30 31 enum chips { zl2004, zl2006, zl2008, zl2105, zl2106, zl6100, zl6105 }; 32 33 struct zl6100_data { 34 int id; 35 ktime_t access; /* chip access time */ 36 struct pmbus_driver_info info; 37 }; 38 39 #define to_zl6100_data(x) container_of(x, struct zl6100_data, info) 40 41 #define ZL6100_DEVICE_ID 0xe4 42 43 #define ZL6100_WAIT_TIME 1000 /* uS */ 44 45 static ushort delay = ZL6100_WAIT_TIME; 46 module_param(delay, ushort, 0644); 47 MODULE_PARM_DESC(delay, "Delay between chip accesses in uS"); 48 49 /* Some chips need a delay between accesses */ 50 static inline void zl6100_wait(const struct zl6100_data *data) 51 { 52 if (delay) { 53 s64 delta = ktime_us_delta(ktime_get(), data->access); 54 if (delta < delay) 55 udelay(delay - delta); 56 } 57 } 58 59 static int zl6100_read_word_data(struct i2c_client *client, int page, int reg) 60 { 61 const struct pmbus_driver_info *info = pmbus_get_driver_info(client); 62 struct zl6100_data *data = to_zl6100_data(info); 63 int ret; 64 65 if (page || reg >= PMBUS_VIRT_BASE) 66 return -ENXIO; 67 68 zl6100_wait(data); 69 ret = pmbus_read_word_data(client, page, reg); 70 data->access = ktime_get(); 71 72 return ret; 73 } 74 75 static int zl6100_read_byte_data(struct i2c_client *client, int page, int reg) 76 { 77 const struct pmbus_driver_info *info = pmbus_get_driver_info(client); 78 struct zl6100_data *data = to_zl6100_data(info); 79 int ret; 80 81 if (page > 0) 82 return -ENXIO; 83 84 zl6100_wait(data); 85 ret = pmbus_read_byte_data(client, page, reg); 86 data->access = ktime_get(); 87 88 return ret; 89 } 90 91 static int zl6100_write_word_data(struct i2c_client *client, int page, int reg, 92 u16 word) 93 { 94 const struct pmbus_driver_info *info = pmbus_get_driver_info(client); 95 struct zl6100_data *data = to_zl6100_data(info); 96 int ret; 97 98 if (page || reg >= PMBUS_VIRT_BASE) 99 return -ENXIO; 100 101 zl6100_wait(data); 102 ret = pmbus_write_word_data(client, page, reg, word); 103 data->access = ktime_get(); 104 105 return ret; 106 } 107 108 static int zl6100_write_byte(struct i2c_client *client, int page, u8 value) 109 { 110 const struct pmbus_driver_info *info = pmbus_get_driver_info(client); 111 struct zl6100_data *data = to_zl6100_data(info); 112 int ret; 113 114 if (page > 0) 115 return -ENXIO; 116 117 zl6100_wait(data); 118 ret = pmbus_write_byte(client, page, value); 119 data->access = ktime_get(); 120 121 return ret; 122 } 123 124 static const struct i2c_device_id zl6100_id[] = { 125 {"zl2004", zl2004}, 126 {"zl2006", zl2006}, 127 {"zl2008", zl2008}, 128 {"zl2105", zl2105}, 129 {"zl2106", zl2106}, 130 {"zl6100", zl6100}, 131 {"zl6105", zl6105}, 132 { } 133 }; 134 MODULE_DEVICE_TABLE(i2c, zl6100_id); 135 136 static int zl6100_probe(struct i2c_client *client, 137 const struct i2c_device_id *id) 138 { 139 int ret; 140 struct zl6100_data *data; 141 struct pmbus_driver_info *info; 142 u8 device_id[I2C_SMBUS_BLOCK_MAX + 1]; 143 const struct i2c_device_id *mid; 144 145 if (!i2c_check_functionality(client->adapter, 146 I2C_FUNC_SMBUS_READ_BYTE_DATA 147 | I2C_FUNC_SMBUS_READ_BLOCK_DATA)) 148 return -ENODEV; 149 150 ret = i2c_smbus_read_block_data(client, ZL6100_DEVICE_ID, 151 device_id); 152 if (ret < 0) { 153 dev_err(&client->dev, "Failed to read device ID\n"); 154 return ret; 155 } 156 device_id[ret] = '\0'; 157 dev_info(&client->dev, "Device ID %s\n", device_id); 158 159 mid = NULL; 160 for (mid = zl6100_id; mid->name[0]; mid++) { 161 if (!strncasecmp(mid->name, device_id, strlen(mid->name))) 162 break; 163 } 164 if (!mid->name[0]) { 165 dev_err(&client->dev, "Unsupported device\n"); 166 return -ENODEV; 167 } 168 if (id->driver_data != mid->driver_data) 169 dev_notice(&client->dev, 170 "Device mismatch: Configured %s, detected %s\n", 171 id->name, mid->name); 172 173 data = kzalloc(sizeof(struct zl6100_data), GFP_KERNEL); 174 if (!data) 175 return -ENOMEM; 176 177 data->id = mid->driver_data; 178 179 /* 180 * ZL2008, ZL2105, and ZL6100 are known to require a wait time 181 * between I2C accesses. ZL2004 and ZL6105 are known to be safe. 182 * 183 * Only clear the wait time for chips known to be safe. The wait time 184 * can be cleared later for additional chips if tests show that it 185 * is not needed (in other words, better be safe than sorry). 186 */ 187 if (data->id == zl2004 || data->id == zl6105) 188 delay = 0; 189 190 /* 191 * Since there was a direct I2C device access above, wait before 192 * accessing the chip again. 193 * Set the timestamp, wait, then set it again. This should provide 194 * enough buffer time to be safe. 195 */ 196 data->access = ktime_get(); 197 zl6100_wait(data); 198 data->access = ktime_get(); 199 200 info = &data->info; 201 202 info->pages = 1; 203 info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT 204 | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT 205 | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT 206 | PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP; 207 208 info->read_word_data = zl6100_read_word_data; 209 info->read_byte_data = zl6100_read_byte_data; 210 info->write_word_data = zl6100_write_word_data; 211 info->write_byte = zl6100_write_byte; 212 213 ret = pmbus_do_probe(client, mid, info); 214 if (ret) 215 goto err_mem; 216 return 0; 217 218 err_mem: 219 kfree(data); 220 return ret; 221 } 222 223 static int zl6100_remove(struct i2c_client *client) 224 { 225 const struct pmbus_driver_info *info = pmbus_get_driver_info(client); 226 const struct zl6100_data *data = to_zl6100_data(info); 227 228 pmbus_do_remove(client); 229 kfree(data); 230 return 0; 231 } 232 233 static struct i2c_driver zl6100_driver = { 234 .driver = { 235 .name = "zl6100", 236 }, 237 .probe = zl6100_probe, 238 .remove = zl6100_remove, 239 .id_table = zl6100_id, 240 }; 241 242 static int __init zl6100_init(void) 243 { 244 return i2c_add_driver(&zl6100_driver); 245 } 246 247 static void __exit zl6100_exit(void) 248 { 249 i2c_del_driver(&zl6100_driver); 250 } 251 252 MODULE_AUTHOR("Guenter Roeck"); 253 MODULE_DESCRIPTION("PMBus driver for ZL6100 and compatibles"); 254 MODULE_LICENSE("GPL"); 255 module_init(zl6100_init); 256 module_exit(zl6100_exit); 257