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/of.h> 30 #include <linux/platform_device.h> 31 #include <linux/regulator/driver.h> 32 #include <linux/regulator/machine.h> 33 #include <linux/regulator/max8973-regulator.h> 34 #include <linux/regulator/of_regulator.h> 35 #include <linux/gpio.h> 36 #include <linux/i2c.h> 37 #include <linux/slab.h> 38 #include <linux/regmap.h> 39 40 /* Register definitions */ 41 #define MAX8973_VOUT 0x0 42 #define MAX8973_VOUT_DVS 0x1 43 #define MAX8973_CONTROL1 0x2 44 #define MAX8973_CONTROL2 0x3 45 #define MAX8973_CHIPID1 0x4 46 #define MAX8973_CHIPID2 0x5 47 48 #define MAX8973_MAX_VOUT_REG 2 49 50 /* MAX8973_VOUT */ 51 #define MAX8973_VOUT_ENABLE BIT(7) 52 #define MAX8973_VOUT_MASK 0x7F 53 54 /* MAX8973_VOUT_DVS */ 55 #define MAX8973_DVS_VOUT_MASK 0x7F 56 57 /* MAX8973_CONTROL1 */ 58 #define MAX8973_SNS_ENABLE BIT(7) 59 #define MAX8973_FPWM_EN_M BIT(6) 60 #define MAX8973_NFSR_ENABLE BIT(5) 61 #define MAX8973_AD_ENABLE BIT(4) 62 #define MAX8973_BIAS_ENABLE BIT(3) 63 #define MAX8973_FREQSHIFT_9PER BIT(2) 64 65 #define MAX8973_RAMP_12mV_PER_US 0x0 66 #define MAX8973_RAMP_25mV_PER_US 0x1 67 #define MAX8973_RAMP_50mV_PER_US 0x2 68 #define MAX8973_RAMP_200mV_PER_US 0x3 69 70 /* MAX8973_CONTROL2 */ 71 #define MAX8973_WDTMR_ENABLE BIT(6) 72 #define MAX8973_DISCH_ENBABLE BIT(5) 73 #define MAX8973_FT_ENABLE BIT(4) 74 75 #define MAX8973_CKKADV_TRIP_DISABLE 0xC 76 #define MAX8973_CKKADV_TRIP_75mV_PER_US 0x0 77 #define MAX8973_CKKADV_TRIP_150mV_PER_US 0x4 78 #define MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS 0x8 79 #define MAX8973_CONTROL_CLKADV_TRIP_MASK 0x00030000 80 81 #define MAX8973_INDUCTOR_MIN_30_PER 0x0 82 #define MAX8973_INDUCTOR_NOMINAL 0x1 83 #define MAX8973_INDUCTOR_PLUS_30_PER 0x2 84 #define MAX8973_INDUCTOR_PLUS_60_PER 0x3 85 #define MAX8973_CONTROL_INDUCTOR_VALUE_MASK 0x00300000 86 87 #define MAX8973_MIN_VOLATGE 606250 88 #define MAX8973_MAX_VOLATGE 1400000 89 #define MAX8973_VOLATGE_STEP 6250 90 #define MAX8973_BUCK_N_VOLTAGE 0x80 91 92 /* Maxim 8973 chip information */ 93 struct max8973_chip { 94 struct device *dev; 95 struct regulator_desc desc; 96 struct regmap *regmap; 97 bool enable_external_control; 98 int dvs_gpio; 99 int lru_index[MAX8973_MAX_VOUT_REG]; 100 int curr_vout_val[MAX8973_MAX_VOUT_REG]; 101 int curr_vout_reg; 102 int curr_gpio_val; 103 bool valid_dvs_gpio; 104 struct regulator_ops ops; 105 }; 106 107 /* 108 * find_voltage_set_register: Find new voltage configuration register (VOUT). 109 * The finding of the new VOUT register will be based on the LRU mechanism. 110 * Each VOUT register will have different voltage configured . This 111 * Function will look if any of the VOUT register have requested voltage set 112 * or not. 113 * - If it is already there then it will make that register as most 114 * recently used and return as found so that caller need not to set 115 * the VOUT register but need to set the proper gpios to select this 116 * VOUT register. 117 * - If requested voltage is not found then it will use the least 118 * recently mechanism to get new VOUT register for new configuration 119 * and will return not_found so that caller need to set new VOUT 120 * register and then gpios (both). 121 */ 122 static bool find_voltage_set_register(struct max8973_chip *tps, 123 int req_vsel, int *vout_reg, int *gpio_val) 124 { 125 int i; 126 bool found = false; 127 int new_vout_reg = tps->lru_index[MAX8973_MAX_VOUT_REG - 1]; 128 int found_index = MAX8973_MAX_VOUT_REG - 1; 129 130 for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) { 131 if (tps->curr_vout_val[tps->lru_index[i]] == req_vsel) { 132 new_vout_reg = tps->lru_index[i]; 133 found_index = i; 134 found = true; 135 goto update_lru_index; 136 } 137 } 138 139 update_lru_index: 140 for (i = found_index; i > 0; i--) 141 tps->lru_index[i] = tps->lru_index[i - 1]; 142 143 tps->lru_index[0] = new_vout_reg; 144 *gpio_val = new_vout_reg; 145 *vout_reg = MAX8973_VOUT + new_vout_reg; 146 return found; 147 } 148 149 static int max8973_dcdc_get_voltage_sel(struct regulator_dev *rdev) 150 { 151 struct max8973_chip *max = rdev_get_drvdata(rdev); 152 unsigned int data; 153 int ret; 154 155 ret = regmap_read(max->regmap, max->curr_vout_reg, &data); 156 if (ret < 0) { 157 dev_err(max->dev, "register %d read failed, err = %d\n", 158 max->curr_vout_reg, ret); 159 return ret; 160 } 161 return data & MAX8973_VOUT_MASK; 162 } 163 164 static int max8973_dcdc_set_voltage_sel(struct regulator_dev *rdev, 165 unsigned vsel) 166 { 167 struct max8973_chip *max = rdev_get_drvdata(rdev); 168 int ret; 169 bool found = false; 170 int vout_reg = max->curr_vout_reg; 171 int gpio_val = max->curr_gpio_val; 172 173 /* 174 * If gpios are available to select the VOUT register then least 175 * recently used register for new configuration. 176 */ 177 if (max->valid_dvs_gpio) 178 found = find_voltage_set_register(max, vsel, 179 &vout_reg, &gpio_val); 180 181 if (!found) { 182 ret = regmap_update_bits(max->regmap, vout_reg, 183 MAX8973_VOUT_MASK, vsel); 184 if (ret < 0) { 185 dev_err(max->dev, "register %d update failed, err %d\n", 186 vout_reg, ret); 187 return ret; 188 } 189 max->curr_vout_reg = vout_reg; 190 max->curr_vout_val[gpio_val] = vsel; 191 } 192 193 /* Select proper VOUT register vio gpios */ 194 if (max->valid_dvs_gpio) { 195 gpio_set_value_cansleep(max->dvs_gpio, gpio_val & 0x1); 196 max->curr_gpio_val = gpio_val; 197 } 198 return 0; 199 } 200 201 static int max8973_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode) 202 { 203 struct max8973_chip *max = rdev_get_drvdata(rdev); 204 int ret; 205 int pwm; 206 207 /* Enable force PWM mode in FAST mode only. */ 208 switch (mode) { 209 case REGULATOR_MODE_FAST: 210 pwm = MAX8973_FPWM_EN_M; 211 break; 212 213 case REGULATOR_MODE_NORMAL: 214 pwm = 0; 215 break; 216 217 default: 218 return -EINVAL; 219 } 220 221 ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1, 222 MAX8973_FPWM_EN_M, pwm); 223 if (ret < 0) 224 dev_err(max->dev, "register %d update failed, err %d\n", 225 MAX8973_CONTROL1, ret); 226 return ret; 227 } 228 229 static unsigned int max8973_dcdc_get_mode(struct regulator_dev *rdev) 230 { 231 struct max8973_chip *max = rdev_get_drvdata(rdev); 232 unsigned int data; 233 int ret; 234 235 ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data); 236 if (ret < 0) { 237 dev_err(max->dev, "register %d read failed, err %d\n", 238 MAX8973_CONTROL1, ret); 239 return ret; 240 } 241 return (data & MAX8973_FPWM_EN_M) ? 242 REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL; 243 } 244 245 static const struct regulator_ops max8973_dcdc_ops = { 246 .get_voltage_sel = max8973_dcdc_get_voltage_sel, 247 .set_voltage_sel = max8973_dcdc_set_voltage_sel, 248 .list_voltage = regulator_list_voltage_linear, 249 .set_mode = max8973_dcdc_set_mode, 250 .get_mode = max8973_dcdc_get_mode, 251 }; 252 253 static int max8973_init_dcdc(struct max8973_chip *max, 254 struct max8973_regulator_platform_data *pdata) 255 { 256 int ret; 257 uint8_t control1 = 0; 258 uint8_t control2 = 0; 259 260 if (pdata->control_flags & MAX8973_CONTROL_REMOTE_SENSE_ENABLE) 261 control1 |= MAX8973_SNS_ENABLE; 262 263 if (!(pdata->control_flags & MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE)) 264 control1 |= MAX8973_NFSR_ENABLE; 265 266 if (pdata->control_flags & MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE) 267 control1 |= MAX8973_AD_ENABLE; 268 269 if (pdata->control_flags & MAX8973_CONTROL_BIAS_ENABLE) 270 control1 |= MAX8973_BIAS_ENABLE; 271 272 if (pdata->control_flags & MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE) 273 control1 |= MAX8973_FREQSHIFT_9PER; 274 275 /* Set ramp delay */ 276 if (pdata->reg_init_data && 277 pdata->reg_init_data->constraints.ramp_delay) { 278 if (pdata->reg_init_data->constraints.ramp_delay < 25000) 279 control1 |= MAX8973_RAMP_12mV_PER_US; 280 else if (pdata->reg_init_data->constraints.ramp_delay < 50000) 281 control1 |= MAX8973_RAMP_25mV_PER_US; 282 else if (pdata->reg_init_data->constraints.ramp_delay < 200000) 283 control1 |= MAX8973_RAMP_50mV_PER_US; 284 else 285 control1 |= MAX8973_RAMP_200mV_PER_US; 286 } else { 287 control1 |= MAX8973_RAMP_12mV_PER_US; 288 max->desc.ramp_delay = 12500; 289 } 290 291 if (!(pdata->control_flags & MAX8973_CONTROL_PULL_DOWN_ENABLE)) 292 control2 |= MAX8973_DISCH_ENBABLE; 293 294 /* Clock advance trip configuration */ 295 switch (pdata->control_flags & MAX8973_CONTROL_CLKADV_TRIP_MASK) { 296 case MAX8973_CONTROL_CLKADV_TRIP_DISABLED: 297 control2 |= MAX8973_CKKADV_TRIP_DISABLE; 298 break; 299 300 case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US: 301 control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US; 302 break; 303 304 case MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US: 305 control2 |= MAX8973_CKKADV_TRIP_150mV_PER_US; 306 break; 307 308 case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US_HIST_DIS: 309 control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS; 310 break; 311 } 312 313 /* Configure inductor value */ 314 switch (pdata->control_flags & MAX8973_CONTROL_INDUCTOR_VALUE_MASK) { 315 case MAX8973_CONTROL_INDUCTOR_VALUE_NOMINAL: 316 control2 |= MAX8973_INDUCTOR_NOMINAL; 317 break; 318 319 case MAX8973_CONTROL_INDUCTOR_VALUE_MINUS_30_PER: 320 control2 |= MAX8973_INDUCTOR_MIN_30_PER; 321 break; 322 323 case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_30_PER: 324 control2 |= MAX8973_INDUCTOR_PLUS_30_PER; 325 break; 326 327 case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_60_PER: 328 control2 |= MAX8973_INDUCTOR_PLUS_60_PER; 329 break; 330 } 331 332 ret = regmap_write(max->regmap, MAX8973_CONTROL1, control1); 333 if (ret < 0) { 334 dev_err(max->dev, "register %d write failed, err = %d", 335 MAX8973_CONTROL1, ret); 336 return ret; 337 } 338 339 ret = regmap_write(max->regmap, MAX8973_CONTROL2, control2); 340 if (ret < 0) { 341 dev_err(max->dev, "register %d write failed, err = %d", 342 MAX8973_CONTROL2, ret); 343 return ret; 344 } 345 346 /* If external control is enabled then disable EN bit */ 347 if (max->enable_external_control) { 348 ret = regmap_update_bits(max->regmap, MAX8973_VOUT, 349 MAX8973_VOUT_ENABLE, 0); 350 if (ret < 0) 351 dev_err(max->dev, "register %d update failed, err = %d", 352 MAX8973_VOUT, ret); 353 } 354 return ret; 355 } 356 357 static const struct regmap_config max8973_regmap_config = { 358 .reg_bits = 8, 359 .val_bits = 8, 360 .max_register = MAX8973_CHIPID2, 361 .cache_type = REGCACHE_RBTREE, 362 }; 363 364 static int max8973_probe(struct i2c_client *client, 365 const struct i2c_device_id *id) 366 { 367 struct max8973_regulator_platform_data *pdata; 368 struct regulator_config config = { }; 369 struct regulator_dev *rdev; 370 struct max8973_chip *max; 371 int ret; 372 373 pdata = dev_get_platdata(&client->dev); 374 375 if (!pdata && !client->dev.of_node) { 376 dev_err(&client->dev, "No Platform data"); 377 return -EIO; 378 } 379 380 max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL); 381 if (!max) 382 return -ENOMEM; 383 384 max->regmap = devm_regmap_init_i2c(client, &max8973_regmap_config); 385 if (IS_ERR(max->regmap)) { 386 ret = PTR_ERR(max->regmap); 387 dev_err(&client->dev, "regmap init failed, err %d\n", ret); 388 return ret; 389 } 390 391 i2c_set_clientdata(client, max); 392 max->ops = max8973_dcdc_ops; 393 max->dev = &client->dev; 394 max->desc.name = id->name; 395 max->desc.id = 0; 396 max->desc.ops = &max->ops; 397 max->desc.type = REGULATOR_VOLTAGE; 398 max->desc.owner = THIS_MODULE; 399 max->desc.min_uV = MAX8973_MIN_VOLATGE; 400 max->desc.uV_step = MAX8973_VOLATGE_STEP; 401 max->desc.n_voltages = MAX8973_BUCK_N_VOLTAGE; 402 403 if (!pdata || !pdata->enable_ext_control) { 404 max->desc.enable_reg = MAX8973_VOUT; 405 max->desc.enable_mask = MAX8973_VOUT_ENABLE; 406 max->ops.enable = regulator_enable_regmap; 407 max->ops.disable = regulator_disable_regmap; 408 max->ops.is_enabled = regulator_is_enabled_regmap; 409 } 410 411 if (pdata) { 412 max->dvs_gpio = pdata->dvs_gpio; 413 max->enable_external_control = pdata->enable_ext_control; 414 max->curr_gpio_val = pdata->dvs_def_state; 415 max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state; 416 } else { 417 max->dvs_gpio = -EINVAL; 418 max->curr_vout_reg = MAX8973_VOUT; 419 } 420 421 max->lru_index[0] = max->curr_vout_reg; 422 423 if (gpio_is_valid(max->dvs_gpio)) { 424 int gpio_flags; 425 int i; 426 427 gpio_flags = (pdata->dvs_def_state) ? 428 GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW; 429 ret = devm_gpio_request_one(&client->dev, max->dvs_gpio, 430 gpio_flags, "max8973-dvs"); 431 if (ret) { 432 dev_err(&client->dev, 433 "gpio_request for gpio %d failed, err = %d\n", 434 max->dvs_gpio, ret); 435 return ret; 436 } 437 max->valid_dvs_gpio = true; 438 439 /* 440 * Initialize the lru index with vout_reg id 441 * The index 0 will be most recently used and 442 * set with the max->curr_vout_reg */ 443 for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) 444 max->lru_index[i] = i; 445 max->lru_index[0] = max->curr_vout_reg; 446 max->lru_index[max->curr_vout_reg] = 0; 447 } else { 448 max->valid_dvs_gpio = false; 449 } 450 451 if (pdata) { 452 ret = max8973_init_dcdc(max, pdata); 453 if (ret < 0) { 454 dev_err(max->dev, "Max8973 Init failed, err = %d\n", ret); 455 return ret; 456 } 457 } 458 459 config.dev = &client->dev; 460 config.init_data = pdata ? pdata->reg_init_data : 461 of_get_regulator_init_data(&client->dev, client->dev.of_node, 462 &max->desc); 463 config.driver_data = max; 464 config.of_node = client->dev.of_node; 465 config.regmap = max->regmap; 466 467 /* Register the regulators */ 468 rdev = devm_regulator_register(&client->dev, &max->desc, &config); 469 if (IS_ERR(rdev)) { 470 ret = PTR_ERR(rdev); 471 dev_err(max->dev, "regulator register failed, err %d\n", ret); 472 return ret; 473 } 474 475 return 0; 476 } 477 478 static const struct i2c_device_id max8973_id[] = { 479 {.name = "max8973",}, 480 {}, 481 }; 482 483 MODULE_DEVICE_TABLE(i2c, max8973_id); 484 485 static struct i2c_driver max8973_i2c_driver = { 486 .driver = { 487 .name = "max8973", 488 .owner = THIS_MODULE, 489 }, 490 .probe = max8973_probe, 491 .id_table = max8973_id, 492 }; 493 494 static int __init max8973_init(void) 495 { 496 return i2c_add_driver(&max8973_i2c_driver); 497 } 498 subsys_initcall(max8973_init); 499 500 static void __exit max8973_cleanup(void) 501 { 502 i2c_del_driver(&max8973_i2c_driver); 503 } 504 module_exit(max8973_cleanup); 505 506 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>"); 507 MODULE_DESCRIPTION("MAX8973 voltage regulator driver"); 508 MODULE_LICENSE("GPL v2"); 509