drivers/regulator/ltc3676.c

   1 /*
   2  * Copyright (C) 2016 Gateworks Corporation, Inc. All Rights Reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14 #include <linux/i2c.h>
  15 #include <linux/init.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/module.h>
  18 #include <linux/kernel.h>
  19 #include <linux/of.h>
  20 #include <linux/regmap.h>
  21 #include <linux/regulator/driver.h>
  22 #include <linux/regulator/machine.h>
  23 #include <linux/regulator/of_regulator.h>
  24
  25 #define DRIVER_NAME             "ltc3676"
  26
  27 /* LTC3676 Registers */
  28 #define LTC3676_BUCK1     0x01
  29 #define LTC3676_BUCK2     0x02
  30 #define LTC3676_BUCK3     0x03
  31 #define LTC3676_BUCK4     0x04
  32 #define LTC3676_LDOA      0x05
  33 #define LTC3676_LDOB      0x06
  34 #define LTC3676_SQD1      0x07
  35 #define LTC3676_SQD2      0x08
  36 #define LTC3676_CNTRL     0x09
  37 #define LTC3676_DVB1A     0x0A
  38 #define LTC3676_DVB1B     0x0B
  39 #define LTC3676_DVB2A     0x0C
  40 #define LTC3676_DVB2B     0x0D
  41 #define LTC3676_DVB3A     0x0E
  42 #define LTC3676_DVB3B     0x0F
  43 #define LTC3676_DVB4A     0x10
  44 #define LTC3676_DVB4B     0x11
  45 #define LTC3676_MSKIRQ    0x12
  46 #define LTC3676_MSKPG     0x13
  47 #define LTC3676_USER      0x14
  48 #define LTC3676_IRQSTAT   0x15
  49 #define LTC3676_PGSTATL   0x16
  50 #define LTC3676_PGSTATRT  0x17
  51 #define LTC3676_HRST      0x1E
  52 #define LTC3676_CLIRQ     0x1F
  53
  54 #define LTC3676_DVBxA_REF_SELECT        BIT(5)
  55
  56 #define LTC3676_IRQSTAT_PGOOD_TIMEOUT   BIT(3)
  57 #define LTC3676_IRQSTAT_UNDERVOLT_WARN  BIT(4)
  58 #define LTC3676_IRQSTAT_UNDERVOLT_FAULT BIT(5)
  59 #define LTC3676_IRQSTAT_THERMAL_WARN    BIT(6)
  60 #define LTC3676_IRQSTAT_THERMAL_FAULT   BIT(7)
  61
  62 enum ltc3676_reg {
  63         LTC3676_SW1,
  64         LTC3676_SW2,
  65         LTC3676_SW3,
  66         LTC3676_SW4,
  67         LTC3676_LDO1,
  68         LTC3676_LDO2,
  69         LTC3676_LDO3,
  70         LTC3676_LDO4,
  71         LTC3676_NUM_REGULATORS,
  72 };
  73
  74 struct ltc3676 {
  75         struct regmap *regmap;
  76         struct device *dev;
  77         struct regulator_desc regulator_descs[LTC3676_NUM_REGULATORS];
  78         struct regulator_dev *regulators[LTC3676_NUM_REGULATORS];
  79 };
  80
  81 static int ltc3676_set_suspend_voltage(struct regulator_dev *rdev, int uV)
  82 {
  83         struct ltc3676 *ltc3676 = rdev_get_drvdata(rdev);
  84         struct device *dev = ltc3676->dev;
  85         int dcdc = rdev_get_id(rdev);
  86         int sel;
  87
  88         dev_dbg(dev, "%s id=%d uV=%d\n", __func__, dcdc, uV);
  89         sel = regulator_map_voltage_linear(rdev, uV, uV);
  90         if (sel < 0)
  91                 return sel;
  92
  93         /* DVBB register follows right after the corresponding DVBA register */
  94         return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg + 1,
  95                                   rdev->desc->vsel_mask, sel);
  96 }
  97
  98 static int ltc3676_set_suspend_mode(struct regulator_dev *rdev,
  99                                     unsigned int mode)
 100 {
 101         struct ltc3676 *ltc3676= rdev_get_drvdata(rdev);
 102         struct device *dev = ltc3676->dev;
 103         int mask, val;
 104         int dcdc = rdev_get_id(rdev);
 105
 106         dev_dbg(dev, "%s id=%d mode=%d\n", __func__, dcdc, mode);
 107
 108         mask = LTC3676_DVBxA_REF_SELECT;
 109         switch (mode) {
 110         case REGULATOR_MODE_STANDBY:
 111                 val = 0; /* select DVBxA */
 112                 break;
 113         case REGULATOR_MODE_NORMAL:
 114                 val = LTC3676_DVBxA_REF_SELECT; /* select DVBxB */
 115                 break;
 116         default:
 117                 dev_warn(&rdev->dev, "%s: regulator mode: 0x%x not supported\n",
 118                          rdev->desc->name, mode);
 119                 return -EINVAL;
 120         }
 121
 122         return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg,
 123                                   mask, val);
 124 }
 125
 126 static inline unsigned int ltc3676_scale(unsigned int uV, u32 r1, u32 r2)
 127 {
 128         uint64_t tmp;
 129         if (uV == 0)
 130                 return 0;
 131         tmp = (uint64_t)uV * r1;
 132         do_div(tmp, r2);
 133         return uV + (unsigned int)tmp;
 134 }
 135
 136 static int ltc3676_of_parse_cb(struct device_node *np,
 137                                const struct regulator_desc *desc,
 138                                struct regulator_config *config)
 139 {
 140         struct ltc3676 *ltc3676 = config->driver_data;
 141         struct regulator_desc *rdesc = &ltc3676->regulator_descs[desc->id];
 142         u32 r[2];
 143         int ret;
 144
 145         /* LDO3 has a fixed output */
 146         if (desc->id == LTC3676_LDO3)
 147                 return 0;
 148
 149         ret = of_property_read_u32_array(np, "lltc,fb-voltage-divider", r, 2);
 150         if (ret) {
 151                 dev_err(ltc3676->dev, "Failed to parse voltage divider: %d\n",
 152                         ret);
 153                 return ret;
 154         }
 155
 156         rdesc->min_uV = ltc3676_scale(desc->min_uV, r[0], r[1]);
 157         rdesc->uV_step = ltc3676_scale(desc->uV_step, r[0], r[1]);
 158         rdesc->fixed_uV = ltc3676_scale(desc->fixed_uV, r[0], r[1]);
 159
 160         return 0;
 161 }
 162
 163 /* SW1, SW2, SW3, SW4 linear 0.8V-3.3V with scalar via R1/R2 feeback res */
 164 static struct regulator_ops ltc3676_linear_regulator_ops = {
 165         .enable = regulator_enable_regmap,
 166         .disable = regulator_disable_regmap,
 167         .is_enabled = regulator_is_enabled_regmap,
 168         .list_voltage = regulator_list_voltage_linear,
 169         .set_voltage_sel = regulator_set_voltage_sel_regmap,
 170         .get_voltage_sel = regulator_get_voltage_sel_regmap,
 171         .set_suspend_voltage = ltc3676_set_suspend_voltage,
 172         .set_suspend_mode = ltc3676_set_suspend_mode,
 173 };
 174
 175 /* LDO1 always on fixed 0.8V-3.3V via scalar via R1/R2 feeback res */
 176 static struct regulator_ops ltc3676_fixed_standby_regulator_ops = {
 177 };
 178
 179 /* LDO2, LDO3 fixed (LDO2 has external scalar via R1/R2 feedback res) */
 180 static struct regulator_ops ltc3676_fixed_regulator_ops = {
 181         .enable = regulator_enable_regmap,
 182         .disable = regulator_disable_regmap,
 183         .is_enabled = regulator_is_enabled_regmap,
 184 };
 185
 186 #define LTC3676_REG(_id, _name, _ops, en_reg, en_bit, dvba_reg, dvb_mask)   \
 187         [LTC3676_ ## _id] = {                                        \
 188                 .name = #_name,                                \
 189                 .of_match = of_match_ptr(#_name),              \
 190                 .regulators_node = of_match_ptr("regulators"), \
 191                 .of_parse_cb = ltc3676_of_parse_cb,            \
 192                 .n_voltages = (dvb_mask) + 1,                  \
 193                 .min_uV = (dvba_reg) ? 412500 : 0,             \
 194                 .uV_step = (dvba_reg) ? 12500 : 0,             \
 195                 .ramp_delay = (dvba_reg) ? 800 : 0,            \
 196                 .fixed_uV = (dvb_mask) ? 0 : 725000,           \
 197                 .ops = &ltc3676_ ## _ops ## _regulator_ops,    \
 198                 .type = REGULATOR_VOLTAGE,                     \
 199                 .id = LTC3676_ ## _id,                         \
 200                 .owner = THIS_MODULE,                          \
 201                 .vsel_reg = (dvba_reg),                        \
 202                 .vsel_mask = (dvb_mask),                       \
 203                 .enable_reg = (en_reg),                        \
 204                 .enable_mask = (1 << en_bit),                  \
 205         }
 206
 207 #define LTC3676_LINEAR_REG(_id, _name, _en, _dvba)                     \
 208         LTC3676_REG(_id, _name, linear,                                \
 209                     LTC3676_ ## _en, 7,                                \
 210                     LTC3676_ ## _dvba, 0x1f)
 211
 212 #define LTC3676_FIXED_REG(_id, _name, _en_reg, _en_bit)                \
 213         LTC3676_REG(_id, _name, fixed, LTC3676_ ## _en_reg, _en_bit, 0, 0)
 214
 215 static struct regulator_desc ltc3676_regulators[LTC3676_NUM_REGULATORS] = {
 216         LTC3676_LINEAR_REG(SW1, sw1, BUCK1, DVB1A),
 217         LTC3676_LINEAR_REG(SW2, sw2, BUCK2, DVB2A),
 218         LTC3676_LINEAR_REG(SW3, sw3, BUCK3, DVB3A),
 219         LTC3676_LINEAR_REG(SW4, sw4, BUCK4, DVB4A),
 220         LTC3676_REG(LDO1, ldo1, fixed_standby, 0, 0, 0, 0),
 221         LTC3676_FIXED_REG(LDO2, ldo2, LDOA, 2),
 222         LTC3676_FIXED_REG(LDO3, ldo3, LDOA, 5),
 223         LTC3676_FIXED_REG(LDO4, ldo4, LDOB, 2),
 224 };
 225
 226 static bool ltc3676_writeable_reg(struct device *dev, unsigned int reg)
 227 {
 228         switch (reg) {
 229         case LTC3676_IRQSTAT:
 230         case LTC3676_BUCK1:
 231         case LTC3676_BUCK2:
 232         case LTC3676_BUCK3:
 233         case LTC3676_BUCK4:
 234         case LTC3676_LDOA:
 235         case LTC3676_LDOB:
 236         case LTC3676_SQD1:
 237         case LTC3676_SQD2:
 238         case LTC3676_CNTRL:
 239         case LTC3676_DVB1A:
 240         case LTC3676_DVB1B:
 241         case LTC3676_DVB2A:
 242         case LTC3676_DVB2B:
 243         case LTC3676_DVB3A:
 244         case LTC3676_DVB3B:
 245         case LTC3676_DVB4A:
 246         case LTC3676_DVB4B:
 247         case LTC3676_MSKIRQ:
 248         case LTC3676_MSKPG:
 249         case LTC3676_USER:
 250         case LTC3676_HRST:
 251         case LTC3676_CLIRQ:
 252                 return true;
 253         }
 254         return false;
 255 }
 256
 257 static bool ltc3676_readable_reg(struct device *dev, unsigned int reg)
 258 {
 259         switch (reg) {
 260         case LTC3676_IRQSTAT:
 261         case LTC3676_BUCK1:
 262         case LTC3676_BUCK2:
 263         case LTC3676_BUCK3:
 264         case LTC3676_BUCK4:
 265         case LTC3676_LDOA:
 266         case LTC3676_LDOB:
 267         case LTC3676_SQD1:
 268         case LTC3676_SQD2:
 269         case LTC3676_CNTRL:
 270         case LTC3676_DVB1A:
 271         case LTC3676_DVB1B:
 272         case LTC3676_DVB2A:
 273         case LTC3676_DVB2B:
 274         case LTC3676_DVB3A:
 275         case LTC3676_DVB3B:
 276         case LTC3676_DVB4A:
 277         case LTC3676_DVB4B:
 278         case LTC3676_MSKIRQ:
 279         case LTC3676_MSKPG:
 280         case LTC3676_USER:
 281         case LTC3676_HRST:
 282         case LTC3676_CLIRQ:
 283                 return true;
 284         }
 285         return false;
 286 }
 287
 288 static bool ltc3676_volatile_reg(struct device *dev, unsigned int reg)
 289 {
 290         switch (reg) {
 291         case LTC3676_IRQSTAT:
 292         case LTC3676_PGSTATL:
 293         case LTC3676_PGSTATRT:
 294                 return true;
 295         }
 296         return false;
 297 }
 298
 299 static const struct regmap_config ltc3676_regmap_config = {
 300         .reg_bits = 8,
 301         .val_bits = 8,
 302         .writeable_reg = ltc3676_writeable_reg,
 303         .readable_reg = ltc3676_readable_reg,
 304         .volatile_reg = ltc3676_volatile_reg,
 305         .max_register = LTC3676_CLIRQ,
 306         .use_single_rw = true,
 307         .cache_type = REGCACHE_RBTREE,
 308 };
 309
 310 static irqreturn_t ltc3676_isr(int irq, void *dev_id)
 311 {
 312         struct ltc3676 *ltc3676 = dev_id;
 313         struct device *dev = ltc3676->dev;
 314         unsigned int i, irqstat, event;
 315
 316         regmap_read(ltc3676->regmap, LTC3676_IRQSTAT, &irqstat);
 317
 318         dev_dbg(dev, "irq%d irqstat=0x%02x\n", irq, irqstat);
 319         if (irqstat & LTC3676_IRQSTAT_THERMAL_WARN) {
 320                 dev_warn(dev, "Over-temperature Warning\n");
 321                 event = REGULATOR_EVENT_OVER_TEMP;
 322                 for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
 323                         regulator_notifier_call_chain(ltc3676->regulators[i],
 324                                                       event, NULL);
 325         }
 326
 327         if (irqstat & LTC3676_IRQSTAT_UNDERVOLT_WARN) {
 328                 dev_info(dev, "Undervoltage Warning\n");
 329                 event = REGULATOR_EVENT_UNDER_VOLTAGE;
 330                 for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
 331                         regulator_notifier_call_chain(ltc3676->regulators[i],
 332                                                       event, NULL);
 333         }
 334
 335         /* Clear warning condition */
 336         regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
 337
 338         return IRQ_HANDLED;
 339 }
 340
 341 static int ltc3676_regulator_probe(struct i2c_client *client,
 342                                     const struct i2c_device_id *id)
 343 {
 344         struct device *dev = &client->dev;
 345         struct regulator_init_data *init_data = dev_get_platdata(dev);
 346         struct regulator_desc *descs;
 347         struct ltc3676 *ltc3676;
 348         int i, ret;
 349
 350         ltc3676 = devm_kzalloc(dev, sizeof(*ltc3676), GFP_KERNEL);
 351         if (!ltc3676)
 352                 return -ENOMEM;
 353
 354         i2c_set_clientdata(client, ltc3676);
 355         ltc3676->dev = dev;
 356
 357         descs = ltc3676->regulator_descs;
 358         memcpy(descs, ltc3676_regulators, sizeof(ltc3676_regulators));
 359         descs[LTC3676_LDO3].fixed_uV = 1800000; /* LDO3 is fixed 1.8V */
 360
 361         ltc3676->regmap = devm_regmap_init_i2c(client, &ltc3676_regmap_config);
 362         if (IS_ERR(ltc3676->regmap)) {
 363                 ret = PTR_ERR(ltc3676->regmap);
 364                 dev_err(dev, "failed to initialize regmap: %d\n", ret);
 365                 return ret;
 366         }
 367
 368         for (i = 0; i < LTC3676_NUM_REGULATORS; i++) {
 369                 struct regulator_desc *desc = &ltc3676->regulator_descs[i];
 370                 struct regulator_config config = { };
 371
 372                 if (init_data)
 373                         config.init_data = &init_data[i];
 374
 375                 config.dev = dev;
 376                 config.driver_data = ltc3676;
 377
 378                 ltc3676->regulators[i] = devm_regulator_register(dev, desc,
 379                                                                  &config);
 380                 if (IS_ERR(ltc3676->regulators[i])) {
 381                         ret = PTR_ERR(ltc3676->regulators[i]);
 382                         dev_err(dev, "failed to register regulator %s: %d\n",
 383                                 desc->name, ret);
 384                         return ret;
 385                 }
 386         }
 387
 388         regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
 389         if (client->irq) {
 390                 ret = devm_request_threaded_irq(dev, client->irq, NULL,
 391                                                 ltc3676_isr,
 392                                                 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 393                                                 client->name, ltc3676);
 394                 if (ret) {
 395                         dev_err(dev, "Failed to request IRQ: %d\n", ret);
 396                         return ret;
 397                 }
 398         }
 399
 400         return 0;
 401 }
 402
 403 static const struct i2c_device_id ltc3676_i2c_id[] = {
 404         { "ltc3676" },
 405         { }
 406 };
 407 MODULE_DEVICE_TABLE(i2c, ltc3676_i2c_id);
 408
 409 static struct i2c_driver ltc3676_driver = {
 410         .driver = {
 411                 .name = DRIVER_NAME,
 412         },
 413         .probe = ltc3676_regulator_probe,
 414         .id_table = ltc3676_i2c_id,
 415 };
 416 module_i2c_driver(ltc3676_driver);
 417
 418 MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
 419 MODULE_DESCRIPTION("Regulator driver for Linear Technology LTC1376");
 420 MODULE_LICENSE("GPL v2");