1 /* 2 * max8973-regulator.c -- Maxim max8973 3 * 4 * Regulator driver for MAXIM 8973 DC-DC step-down switching regulator. 5 * 6 * Copyright (c) 2012, NVIDIA Corporation. 7 * 8 * Author: Laxman Dewangan <ldewangan@nvidia.com> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License as 12 * published by the Free Software Foundation version 2. 13 * 14 * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind, 15 * whether express or implied; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, write to the Free Software 21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 22 * 02111-1307, USA 23 */ 24 25 #include <linux/kernel.h> 26 #include <linux/module.h> 27 #include <linux/init.h> 28 #include <linux/err.h> 29 #include <linux/platform_device.h> 30 #include <linux/regulator/driver.h> 31 #include <linux/regulator/machine.h> 32 #include <linux/regulator/max8973-regulator.h> 33 #include <linux/gpio.h> 34 #include <linux/i2c.h> 35 #include <linux/slab.h> 36 #include <linux/regmap.h> 37 38 /* Register definitions */ 39 #define MAX8973_VOUT 0x0 40 #define MAX8973_VOUT_DVS 0x1 41 #define MAX8973_CONTROL1 0x2 42 #define MAX8973_CONTROL2 0x3 43 #define MAX8973_CHIPID1 0x4 44 #define MAX8973_CHIPID2 0x5 45 46 #define MAX8973_MAX_VOUT_REG 2 47 48 /* MAX8973_VOUT */ 49 #define MAX8973_VOUT_ENABLE BIT(7) 50 #define MAX8973_VOUT_MASK 0x7F 51 52 /* MAX8973_VOUT_DVS */ 53 #define MAX8973_DVS_VOUT_MASK 0x7F 54 55 /* MAX8973_CONTROL1 */ 56 #define MAX8973_SNS_ENABLE BIT(7) 57 #define MAX8973_FPWM_EN_M BIT(6) 58 #define MAX8973_NFSR_ENABLE BIT(5) 59 #define MAX8973_AD_ENABLE BIT(4) 60 #define MAX8973_BIAS_ENABLE BIT(3) 61 #define MAX8973_FREQSHIFT_9PER BIT(2) 62 63 #define MAX8973_RAMP_12mV_PER_US 0x0 64 #define MAX8973_RAMP_25mV_PER_US 0x1 65 #define MAX8973_RAMP_50mV_PER_US 0x2 66 #define MAX8973_RAMP_200mV_PER_US 0x3 67 68 /* MAX8973_CONTROL2 */ 69 #define MAX8973_WDTMR_ENABLE BIT(6) 70 #define MAX8973_DISCH_ENBABLE BIT(5) 71 #define MAX8973_FT_ENABLE BIT(4) 72 73 #define MAX8973_CKKADV_TRIP_DISABLE 0xC 74 #define MAX8973_CKKADV_TRIP_75mV_PER_US 0x0 75 #define MAX8973_CKKADV_TRIP_150mV_PER_US 0x4 76 #define MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS 0x8 77 #define MAX8973_CONTROL_CLKADV_TRIP_MASK 0x00030000 78 79 #define MAX8973_INDUCTOR_MIN_30_PER 0x0 80 #define MAX8973_INDUCTOR_NOMINAL 0x1 81 #define MAX8973_INDUCTOR_PLUS_30_PER 0x2 82 #define MAX8973_INDUCTOR_PLUS_60_PER 0x3 83 #define MAX8973_CONTROL_INDUCTOR_VALUE_MASK 0x00300000 84 85 #define MAX8973_MIN_VOLATGE 606250 86 #define MAX8973_MAX_VOLATGE 1400000 87 #define MAX8973_VOLATGE_STEP 6250 88 #define MAX8973_BUCK_N_VOLTAGE 0x80 89 90 /* Maxim 8973 chip information */ 91 struct max8973_chip { 92 struct device *dev; 93 struct regulator_desc desc; 94 struct regulator_dev *rdev; 95 struct regmap *regmap; 96 bool enable_external_control; 97 int dvs_gpio; 98 int lru_index[MAX8973_MAX_VOUT_REG]; 99 int curr_vout_val[MAX8973_MAX_VOUT_REG]; 100 int curr_vout_reg; 101 int curr_gpio_val; 102 bool valid_dvs_gpio; 103 }; 104 105 /* 106 * find_voltage_set_register: Find new voltage configuration register (VOUT). 107 * The finding of the new VOUT register will be based on the LRU mechanism. 108 * Each VOUT register will have different voltage configured . This 109 * Function will look if any of the VOUT register have requested voltage set 110 * or not. 111 * - If it is already there then it will make that register as most 112 * recently used and return as found so that caller need not to set 113 * the VOUT register but need to set the proper gpios to select this 114 * VOUT register. 115 * - If requested voltage is not found then it will use the least 116 * recently mechanism to get new VOUT register for new configuration 117 * and will return not_found so that caller need to set new VOUT 118 * register and then gpios (both). 119 */ 120 static bool find_voltage_set_register(struct max8973_chip *tps, 121 int req_vsel, int *vout_reg, int *gpio_val) 122 { 123 int i; 124 bool found = false; 125 int new_vout_reg = tps->lru_index[MAX8973_MAX_VOUT_REG - 1]; 126 int found_index = MAX8973_MAX_VOUT_REG - 1; 127 128 for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) { 129 if (tps->curr_vout_val[tps->lru_index[i]] == req_vsel) { 130 new_vout_reg = tps->lru_index[i]; 131 found_index = i; 132 found = true; 133 goto update_lru_index; 134 } 135 } 136 137 update_lru_index: 138 for (i = found_index; i > 0; i--) 139 tps->lru_index[i] = tps->lru_index[i - 1]; 140 141 tps->lru_index[0] = new_vout_reg; 142 *gpio_val = new_vout_reg; 143 *vout_reg = MAX8973_VOUT + new_vout_reg; 144 return found; 145 } 146 147 static int max8973_dcdc_get_voltage_sel(struct regulator_dev *rdev) 148 { 149 struct max8973_chip *max = rdev_get_drvdata(rdev); 150 unsigned int data; 151 int ret; 152 153 ret = regmap_read(max->regmap, max->curr_vout_reg, &data); 154 if (ret < 0) { 155 dev_err(max->dev, "register %d read failed, err = %d\n", 156 max->curr_vout_reg, ret); 157 return ret; 158 } 159 return data & MAX8973_VOUT_MASK; 160 } 161 162 static int max8973_dcdc_set_voltage_sel(struct regulator_dev *rdev, 163 unsigned vsel) 164 { 165 struct max8973_chip *max = rdev_get_drvdata(rdev); 166 int ret; 167 bool found = false; 168 int vout_reg = max->curr_vout_reg; 169 int gpio_val = max->curr_gpio_val; 170 171 /* 172 * If gpios are available to select the VOUT register then least 173 * recently used register for new configuration. 174 */ 175 if (max->valid_dvs_gpio) 176 found = find_voltage_set_register(max, vsel, 177 &vout_reg, &gpio_val); 178 179 if (!found) { 180 ret = regmap_update_bits(max->regmap, vout_reg, 181 MAX8973_VOUT_MASK, vsel); 182 if (ret < 0) { 183 dev_err(max->dev, "register %d update failed, err %d\n", 184 vout_reg, ret); 185 return ret; 186 } 187 max->curr_vout_reg = vout_reg; 188 max->curr_vout_val[gpio_val] = vsel; 189 } 190 191 /* Select proper VOUT register vio gpios */ 192 if (max->valid_dvs_gpio) { 193 gpio_set_value_cansleep(max->dvs_gpio, gpio_val & 0x1); 194 max->curr_gpio_val = gpio_val; 195 } 196 return 0; 197 } 198 199 static int max8973_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode) 200 { 201 struct max8973_chip *max = rdev_get_drvdata(rdev); 202 int ret; 203 int pwm; 204 205 /* Enable force PWM mode in FAST mode only. */ 206 switch (mode) { 207 case REGULATOR_MODE_FAST: 208 pwm = MAX8973_FPWM_EN_M; 209 break; 210 211 case REGULATOR_MODE_NORMAL: 212 pwm = 0; 213 break; 214 215 default: 216 return -EINVAL; 217 } 218 219 ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1, 220 MAX8973_FPWM_EN_M, pwm); 221 if (ret < 0) 222 dev_err(max->dev, "register %d update failed, err %d\n", 223 MAX8973_CONTROL1, ret); 224 return ret; 225 } 226 227 static unsigned int max8973_dcdc_get_mode(struct regulator_dev *rdev) 228 { 229 struct max8973_chip *max = rdev_get_drvdata(rdev); 230 unsigned int data; 231 int ret; 232 233 ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data); 234 if (ret < 0) { 235 dev_err(max->dev, "register %d read failed, err %d\n", 236 MAX8973_CONTROL1, ret); 237 return ret; 238 } 239 return (data & MAX8973_FPWM_EN_M) ? 240 REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL; 241 } 242 243 static struct regulator_ops max8973_dcdc_ops = { 244 .get_voltage_sel = max8973_dcdc_get_voltage_sel, 245 .set_voltage_sel = max8973_dcdc_set_voltage_sel, 246 .list_voltage = regulator_list_voltage_linear, 247 .set_mode = max8973_dcdc_set_mode, 248 .get_mode = max8973_dcdc_get_mode, 249 }; 250 251 static int max8973_init_dcdc(struct max8973_chip *max, 252 struct max8973_regulator_platform_data *pdata) 253 { 254 int ret; 255 uint8_t control1 = 0; 256 uint8_t control2 = 0; 257 258 if (pdata->control_flags & MAX8973_CONTROL_REMOTE_SENSE_ENABLE) 259 control1 |= MAX8973_SNS_ENABLE; 260 261 if (!(pdata->control_flags & MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE)) 262 control1 |= MAX8973_NFSR_ENABLE; 263 264 if (pdata->control_flags & MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE) 265 control1 |= MAX8973_AD_ENABLE; 266 267 if (pdata->control_flags & MAX8973_CONTROL_BIAS_ENABLE) 268 control1 |= MAX8973_BIAS_ENABLE; 269 270 if (pdata->control_flags & MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE) 271 control1 |= MAX8973_FREQSHIFT_9PER; 272 273 /* Set ramp delay */ 274 if (pdata->reg_init_data && 275 pdata->reg_init_data->constraints.ramp_delay) { 276 if (pdata->reg_init_data->constraints.ramp_delay < 25000) 277 control1 |= MAX8973_RAMP_12mV_PER_US; 278 else if (pdata->reg_init_data->constraints.ramp_delay < 50000) 279 control1 |= MAX8973_RAMP_25mV_PER_US; 280 else if (pdata->reg_init_data->constraints.ramp_delay < 200000) 281 control1 |= MAX8973_RAMP_50mV_PER_US; 282 else 283 control1 |= MAX8973_RAMP_200mV_PER_US; 284 } else { 285 control1 |= MAX8973_RAMP_12mV_PER_US; 286 max->desc.ramp_delay = 12500; 287 } 288 289 if (!(pdata->control_flags & MAX8973_CONTROL_PULL_DOWN_ENABLE)) 290 control2 |= MAX8973_DISCH_ENBABLE; 291 292 /* Clock advance trip configuration */ 293 switch (pdata->control_flags & MAX8973_CONTROL_CLKADV_TRIP_MASK) { 294 case MAX8973_CONTROL_CLKADV_TRIP_DISABLED: 295 control2 |= MAX8973_CKKADV_TRIP_DISABLE; 296 break; 297 298 case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US: 299 control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US; 300 break; 301 302 case MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US: 303 control2 |= MAX8973_CKKADV_TRIP_150mV_PER_US; 304 break; 305 306 case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US_HIST_DIS: 307 control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS; 308 break; 309 } 310 311 /* Configure inductor value */ 312 switch (pdata->control_flags & MAX8973_CONTROL_INDUCTOR_VALUE_MASK) { 313 case MAX8973_CONTROL_INDUCTOR_VALUE_NOMINAL: 314 control2 |= MAX8973_INDUCTOR_NOMINAL; 315 break; 316 317 case MAX8973_CONTROL_INDUCTOR_VALUE_MINUS_30_PER: 318 control2 |= MAX8973_INDUCTOR_MIN_30_PER; 319 break; 320 321 case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_30_PER: 322 control2 |= MAX8973_INDUCTOR_PLUS_30_PER; 323 break; 324 325 case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_60_PER: 326 control2 |= MAX8973_INDUCTOR_PLUS_60_PER; 327 break; 328 } 329 330 ret = regmap_write(max->regmap, MAX8973_CONTROL1, control1); 331 if (ret < 0) { 332 dev_err(max->dev, "register %d write failed, err = %d", 333 MAX8973_CONTROL1, ret); 334 return ret; 335 } 336 337 ret = regmap_write(max->regmap, MAX8973_CONTROL2, control2); 338 if (ret < 0) { 339 dev_err(max->dev, "register %d write failed, err = %d", 340 MAX8973_CONTROL2, ret); 341 return ret; 342 } 343 344 /* If external control is enabled then disable EN bit */ 345 if (max->enable_external_control) { 346 ret = regmap_update_bits(max->regmap, MAX8973_VOUT, 347 MAX8973_VOUT_ENABLE, 0); 348 if (ret < 0) 349 dev_err(max->dev, "register %d update failed, err = %d", 350 MAX8973_VOUT, ret); 351 } 352 return ret; 353 } 354 355 static const struct regmap_config max8973_regmap_config = { 356 .reg_bits = 8, 357 .val_bits = 8, 358 .max_register = MAX8973_CHIPID2, 359 .cache_type = REGCACHE_RBTREE, 360 }; 361 362 static int max8973_probe(struct i2c_client *client, 363 const struct i2c_device_id *id) 364 { 365 struct max8973_regulator_platform_data *pdata; 366 struct regulator_config config = { }; 367 struct regulator_dev *rdev; 368 struct max8973_chip *max; 369 int ret; 370 371 pdata = client->dev.platform_data; 372 if (!pdata) { 373 dev_err(&client->dev, "No Platform data"); 374 return -EIO; 375 } 376 377 max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL); 378 if (!max) { 379 dev_err(&client->dev, "Memory allocation for max failed\n"); 380 return -ENOMEM; 381 } 382 383 max->regmap = devm_regmap_init_i2c(client, &max8973_regmap_config); 384 if (IS_ERR(max->regmap)) { 385 ret = PTR_ERR(max->regmap); 386 dev_err(&client->dev, "regmap init failed, err %d\n", ret); 387 return ret; 388 } 389 390 i2c_set_clientdata(client, max); 391 max->dev = &client->dev; 392 max->desc.name = id->name; 393 max->desc.id = 0; 394 max->desc.ops = &max8973_dcdc_ops; 395 max->desc.type = REGULATOR_VOLTAGE; 396 max->desc.owner = THIS_MODULE; 397 max->desc.min_uV = MAX8973_MIN_VOLATGE; 398 max->desc.uV_step = MAX8973_VOLATGE_STEP; 399 max->desc.n_voltages = MAX8973_BUCK_N_VOLTAGE; 400 401 if (!pdata->enable_ext_control) { 402 max->desc.enable_reg = MAX8973_VOUT; 403 max->desc.enable_mask = MAX8973_VOUT_ENABLE; 404 max8973_dcdc_ops.enable = regulator_enable_regmap; 405 max8973_dcdc_ops.disable = regulator_disable_regmap; 406 max8973_dcdc_ops.is_enabled = regulator_is_enabled_regmap; 407 } 408 409 max->enable_external_control = pdata->enable_ext_control; 410 max->dvs_gpio = pdata->dvs_gpio; 411 max->curr_gpio_val = pdata->dvs_def_state; 412 max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state; 413 max->lru_index[0] = max->curr_vout_reg; 414 max->valid_dvs_gpio = false; 415 416 if (gpio_is_valid(max->dvs_gpio)) { 417 int gpio_flags; 418 int i; 419 420 gpio_flags = (pdata->dvs_def_state) ? 421 GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW; 422 ret = devm_gpio_request_one(&client->dev, max->dvs_gpio, 423 gpio_flags, "max8973-dvs"); 424 if (ret) { 425 dev_err(&client->dev, 426 "gpio_request for gpio %d failed, err = %d\n", 427 max->dvs_gpio, ret); 428 return ret; 429 } 430 max->valid_dvs_gpio = true; 431 432 /* 433 * Initialize the lru index with vout_reg id 434 * The index 0 will be most recently used and 435 * set with the max->curr_vout_reg */ 436 for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) 437 max->lru_index[i] = i; 438 max->lru_index[0] = max->curr_vout_reg; 439 max->lru_index[max->curr_vout_reg] = 0; 440 } 441 442 ret = max8973_init_dcdc(max, pdata); 443 if (ret < 0) { 444 dev_err(max->dev, "Max8973 Init failed, err = %d\n", ret); 445 return ret; 446 } 447 448 config.dev = &client->dev; 449 config.init_data = pdata->reg_init_data; 450 config.driver_data = max; 451 config.of_node = client->dev.of_node; 452 config.regmap = max->regmap; 453 454 /* Register the regulators */ 455 rdev = regulator_register(&max->desc, &config); 456 if (IS_ERR(rdev)) { 457 ret = PTR_ERR(rdev); 458 dev_err(max->dev, "regulator register failed, err %d\n", ret); 459 return ret; 460 } 461 462 max->rdev = rdev; 463 return 0; 464 } 465 466 static int max8973_remove(struct i2c_client *client) 467 { 468 struct max8973_chip *max = i2c_get_clientdata(client); 469 470 regulator_unregister(max->rdev); 471 return 0; 472 } 473 474 static const struct i2c_device_id max8973_id[] = { 475 {.name = "max8973",}, 476 {}, 477 }; 478 479 MODULE_DEVICE_TABLE(i2c, max8973_id); 480 481 static struct i2c_driver max8973_i2c_driver = { 482 .driver = { 483 .name = "max8973", 484 .owner = THIS_MODULE, 485 }, 486 .probe = max8973_probe, 487 .remove = max8973_remove, 488 .id_table = max8973_id, 489 }; 490 491 static int __init max8973_init(void) 492 { 493 return i2c_add_driver(&max8973_i2c_driver); 494 } 495 subsys_initcall(max8973_init); 496 497 static void __exit max8973_cleanup(void) 498 { 499 i2c_del_driver(&max8973_i2c_driver); 500 } 501 module_exit(max8973_cleanup); 502 503 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>"); 504 MODULE_DESCRIPTION("MAX8973 voltage regulator driver"); 505 MODULE_LICENSE("GPL v2"); 506