1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Hardware monitoring driver for the STPDDC60 controller 4 * 5 * Copyright (c) 2021 Flextronics International Sweden AB. 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/module.h> 10 #include <linux/init.h> 11 #include <linux/err.h> 12 #include <linux/i2c.h> 13 #include <linux/pmbus.h> 14 #include "pmbus.h" 15 16 #define STPDDC60_MFR_READ_VOUT 0xd2 17 #define STPDDC60_MFR_OV_LIMIT_OFFSET 0xe5 18 #define STPDDC60_MFR_UV_LIMIT_OFFSET 0xe6 19 20 static const struct i2c_device_id stpddc60_id[] = { 21 {"stpddc60", 0}, 22 {"bmr481", 0}, 23 {} 24 }; 25 MODULE_DEVICE_TABLE(i2c, stpddc60_id); 26 27 static struct pmbus_driver_info stpddc60_info = { 28 .pages = 1, 29 .func[0] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT 30 | PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT 31 | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP 32 | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT 33 | PMBUS_HAVE_POUT, 34 }; 35 36 /* 37 * Calculate the closest absolute offset between commanded vout value 38 * and limit value in steps of 50mv in the range 0 (50mv) to 7 (400mv). 39 * Return 0 if the upper limit is lower than vout or if the lower limit 40 * is higher than vout. 41 */ 42 static u8 stpddc60_get_offset(int vout, u16 limit, bool over) 43 { 44 int offset; 45 long v, l; 46 47 v = 250 + (vout - 1) * 5; /* Convert VID to mv */ 48 l = (limit * 1000L) >> 8; /* Convert LINEAR to mv */ 49 50 if (over == (l < v)) 51 return 0; 52 53 offset = DIV_ROUND_CLOSEST(abs(l - v), 50); 54 55 if (offset > 0) 56 offset--; 57 58 return clamp_val(offset, 0, 7); 59 } 60 61 /* 62 * Adjust the linear format word to use the given fixed exponent. 63 */ 64 static u16 stpddc60_adjust_linear(u16 word, s16 fixed) 65 { 66 s16 e, m, d; 67 68 e = ((s16)word) >> 11; 69 m = ((s16)((word & 0x7ff) << 5)) >> 5; 70 d = e - fixed; 71 72 if (d >= 0) 73 m <<= d; 74 else 75 m >>= -d; 76 77 return clamp_val(m, 0, 0x3ff) | ((fixed << 11) & 0xf800); 78 } 79 80 /* 81 * The VOUT_COMMAND register uses the VID format but the vout alarm limit 82 * registers use the LINEAR format so we override VOUT_MODE here to force 83 * LINEAR format for all registers. 84 */ 85 static int stpddc60_read_byte_data(struct i2c_client *client, int page, int reg) 86 { 87 int ret; 88 89 if (page > 0) 90 return -ENXIO; 91 92 switch (reg) { 93 case PMBUS_VOUT_MODE: 94 ret = 0x18; 95 break; 96 default: 97 ret = -ENODATA; 98 break; 99 } 100 101 return ret; 102 } 103 104 /* 105 * The vout related registers return values in LINEAR11 format when LINEAR16 106 * is expected. Clear the top 5 bits to set the exponent part to zero to 107 * convert the value to LINEAR16 format. 108 */ 109 static int stpddc60_read_word_data(struct i2c_client *client, int page, 110 int phase, int reg) 111 { 112 int ret; 113 114 if (page > 0) 115 return -ENXIO; 116 117 switch (reg) { 118 case PMBUS_READ_VOUT: 119 ret = pmbus_read_word_data(client, page, phase, 120 STPDDC60_MFR_READ_VOUT); 121 if (ret < 0) 122 return ret; 123 ret &= 0x7ff; 124 break; 125 case PMBUS_VOUT_OV_FAULT_LIMIT: 126 case PMBUS_VOUT_UV_FAULT_LIMIT: 127 ret = pmbus_read_word_data(client, page, phase, reg); 128 if (ret < 0) 129 return ret; 130 ret &= 0x7ff; 131 break; 132 default: 133 ret = -ENODATA; 134 break; 135 } 136 137 return ret; 138 } 139 140 /* 141 * The vout under- and over-voltage limits are set as an offset relative to 142 * the commanded vout voltage. The vin, iout, pout and temp limits must use 143 * the same fixed exponent the chip uses to encode the data when read. 144 */ 145 static int stpddc60_write_word_data(struct i2c_client *client, int page, 146 int reg, u16 word) 147 { 148 int ret; 149 u8 offset; 150 151 if (page > 0) 152 return -ENXIO; 153 154 switch (reg) { 155 case PMBUS_VOUT_OV_FAULT_LIMIT: 156 ret = pmbus_read_word_data(client, page, 0xff, 157 PMBUS_VOUT_COMMAND); 158 if (ret < 0) 159 return ret; 160 offset = stpddc60_get_offset(ret, word, true); 161 ret = pmbus_write_byte_data(client, page, 162 STPDDC60_MFR_OV_LIMIT_OFFSET, 163 offset); 164 break; 165 case PMBUS_VOUT_UV_FAULT_LIMIT: 166 ret = pmbus_read_word_data(client, page, 0xff, 167 PMBUS_VOUT_COMMAND); 168 if (ret < 0) 169 return ret; 170 offset = stpddc60_get_offset(ret, word, false); 171 ret = pmbus_write_byte_data(client, page, 172 STPDDC60_MFR_UV_LIMIT_OFFSET, 173 offset); 174 break; 175 case PMBUS_VIN_OV_FAULT_LIMIT: 176 case PMBUS_VIN_UV_FAULT_LIMIT: 177 case PMBUS_OT_FAULT_LIMIT: 178 case PMBUS_OT_WARN_LIMIT: 179 case PMBUS_IOUT_OC_FAULT_LIMIT: 180 case PMBUS_IOUT_OC_WARN_LIMIT: 181 case PMBUS_POUT_OP_FAULT_LIMIT: 182 ret = pmbus_read_word_data(client, page, 0xff, reg); 183 if (ret < 0) 184 return ret; 185 word = stpddc60_adjust_linear(word, ret >> 11); 186 ret = pmbus_write_word_data(client, page, reg, word); 187 break; 188 default: 189 ret = -ENODATA; 190 break; 191 } 192 193 return ret; 194 } 195 196 static int stpddc60_probe(struct i2c_client *client) 197 { 198 int status; 199 u8 device_id[I2C_SMBUS_BLOCK_MAX + 1]; 200 const struct i2c_device_id *mid; 201 struct pmbus_driver_info *info = &stpddc60_info; 202 203 if (!i2c_check_functionality(client->adapter, 204 I2C_FUNC_SMBUS_READ_BYTE_DATA 205 | I2C_FUNC_SMBUS_BLOCK_DATA)) 206 return -ENODEV; 207 208 status = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, device_id); 209 if (status < 0) { 210 dev_err(&client->dev, "Failed to read Manufacturer Model\n"); 211 return status; 212 } 213 for (mid = stpddc60_id; mid->name[0]; mid++) { 214 if (!strncasecmp(mid->name, device_id, strlen(mid->name))) 215 break; 216 } 217 if (!mid->name[0]) { 218 dev_err(&client->dev, "Unsupported device\n"); 219 return -ENODEV; 220 } 221 222 info->read_byte_data = stpddc60_read_byte_data; 223 info->read_word_data = stpddc60_read_word_data; 224 info->write_word_data = stpddc60_write_word_data; 225 226 status = pmbus_do_probe(client, info); 227 if (status < 0) 228 return status; 229 230 pmbus_set_update(client, PMBUS_VOUT_OV_FAULT_LIMIT, true); 231 pmbus_set_update(client, PMBUS_VOUT_UV_FAULT_LIMIT, true); 232 233 return 0; 234 } 235 236 static struct i2c_driver stpddc60_driver = { 237 .driver = { 238 .name = "stpddc60", 239 }, 240 .probe_new = stpddc60_probe, 241 .id_table = stpddc60_id, 242 }; 243 244 module_i2c_driver(stpddc60_driver); 245 246 MODULE_AUTHOR("Erik Rosen <erik.rosen@metormote.com>"); 247 MODULE_DESCRIPTION("PMBus driver for ST STPDDC60"); 248 MODULE_LICENSE("GPL"); 249 MODULE_IMPORT_NS(PMBUS); 250