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 #define LTC3676_DVBxB_PGOOD_MASK        BIT(5)
  56
  57 #define LTC3676_IRQSTAT_PGOOD_TIMEOUT   BIT(3)
  58 #define LTC3676_IRQSTAT_UNDERVOLT_WARN  BIT(4)
  59 #define LTC3676_IRQSTAT_UNDERVOLT_FAULT BIT(5)
  60 #define LTC3676_IRQSTAT_THERMAL_WARN    BIT(6)
  61 #define LTC3676_IRQSTAT_THERMAL_FAULT   BIT(7)
  62
  63 enum ltc3676_reg {
  64         LTC3676_SW1,
  65         LTC3676_SW2,
  66         LTC3676_SW3,
  67         LTC3676_SW4,
  68         LTC3676_LDO1,
  69         LTC3676_LDO2,
  70         LTC3676_LDO3,
  71         LTC3676_LDO4,
  72         LTC3676_NUM_REGULATORS,
  73 };
  74
  75 struct ltc3676 {
  76         struct regmap *regmap;
  77         struct device *dev;
  78         struct regulator_desc regulator_descs[LTC3676_NUM_REGULATORS];
  79         struct regulator_dev *regulators[LTC3676_NUM_REGULATORS];
  80 };
  81
  82 static int ltc3676_set_suspend_voltage(struct regulator_dev *rdev, int uV)
  83 {
  84         struct ltc3676 *ltc3676 = rdev_get_drvdata(rdev);
  85         struct device *dev = ltc3676->dev;
  86         int dcdc = rdev_get_id(rdev);
  87         int sel;
  88
  89         dev_dbg(dev, "%s id=%d uV=%d\n", __func__, dcdc, uV);
  90         sel = regulator_map_voltage_linear(rdev, uV, uV);
  91         if (sel < 0)
  92                 return sel;
  93
  94         /* DVBB register follows right after the corresponding DVBA register */
  95         return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg + 1,
  96                                   rdev->desc->vsel_mask, sel);
  97 }
  98
  99 static int ltc3676_set_suspend_mode(struct regulator_dev *rdev,
 100                                     unsigned int mode)
 101 {
 102         struct ltc3676 *ltc3676= rdev_get_drvdata(rdev);
 103         struct device *dev = ltc3676->dev;
 104         int mask, val;
 105         int dcdc = rdev_get_id(rdev);
 106
 107         dev_dbg(dev, "%s id=%d mode=%d\n", __func__, dcdc, mode);
 108
 109         mask = LTC3676_DVBxA_REF_SELECT;
 110         switch (mode) {
 111         case REGULATOR_MODE_STANDBY:
 112                 val = 0; /* select DVBxA */
 113                 break;
 114         case REGULATOR_MODE_NORMAL:
 115                 val = LTC3676_DVBxA_REF_SELECT; /* select DVBxB */
 116                 break;
 117         default:
 118                 dev_warn(&rdev->dev, "%s: regulator mode: 0x%x not supported\n",
 119                          rdev->desc->name, mode);
 120                 return -EINVAL;
 121         }
 122
 123         return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg,
 124                                   mask, val);
 125 }
 126
 127 static int ltc3676_set_voltage_sel(struct regulator_dev *rdev, unsigned selector)
 128 {
 129         struct ltc3676 *ltc3676 = rdev_get_drvdata(rdev);
 130         struct device *dev = ltc3676->dev;
 131         int ret, dcdc = rdev_get_id(rdev);
 132
 133         dev_dbg(dev, "%s id=%d selector=%d\n", __func__, dcdc, selector);
 134
 135         ret = regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg + 1,
 136                                  LTC3676_DVBxB_PGOOD_MASK,
 137                                  LTC3676_DVBxB_PGOOD_MASK);
 138         if (ret)
 139                 return ret;
 140
 141         return regulator_set_voltage_sel_regmap(rdev, selector);
 142 }
 143
 144 static inline unsigned int ltc3676_scale(unsigned int uV, u32 r1, u32 r2)
 145 {
 146         uint64_t tmp;
 147         if (uV == 0)
 148                 return 0;
 149         tmp = (uint64_t)uV * r1;
 150         do_div(tmp, r2);
 151         return uV + (unsigned int)tmp;
 152 }
 153
 154 static int ltc3676_of_parse_cb(struct device_node *np,
 155                                const struct regulator_desc *desc,
 156                                struct regulator_config *config)
 157 {
 158         struct ltc3676 *ltc3676 = config->driver_data;
 159         struct regulator_desc *rdesc = &ltc3676->regulator_descs[desc->id];
 160         u32 r[2];
 161         int ret;
 162
 163         /* LDO3 has a fixed output */
 164         if (desc->id == LTC3676_LDO3)
 165                 return 0;
 166
 167         ret = of_property_read_u32_array(np, "lltc,fb-voltage-divider", r, 2);
 168         if (ret) {
 169                 dev_err(ltc3676->dev, "Failed to parse voltage divider: %d\n",
 170                         ret);
 171                 return ret;
 172         }
 173
 174         rdesc->min_uV = ltc3676_scale(desc->min_uV, r[0], r[1]);
 175         rdesc->uV_step = ltc3676_scale(desc->uV_step, r[0], r[1]);
 176         rdesc->fixed_uV = ltc3676_scale(desc->fixed_uV, r[0], r[1]);
 177
 178         return 0;
 179 }
 180
 181 /* SW1, SW2, SW3, SW4 linear 0.8V-3.3V with scalar via R1/R2 feeback res */
 182 static const struct regulator_ops ltc3676_linear_regulator_ops = {
 183         .enable = regulator_enable_regmap,
 184         .disable = regulator_disable_regmap,
 185         .is_enabled = regulator_is_enabled_regmap,
 186         .list_voltage = regulator_list_voltage_linear,
 187         .set_voltage_sel = ltc3676_set_voltage_sel,
 188         .get_voltage_sel = regulator_get_voltage_sel_regmap,
 189         .set_suspend_voltage = ltc3676_set_suspend_voltage,
 190         .set_suspend_mode = ltc3676_set_suspend_mode,
 191 };
 192
 193 /* LDO1 always on fixed 0.8V-3.3V via scalar via R1/R2 feeback res */
 194 static const struct regulator_ops ltc3676_fixed_standby_regulator_ops = {
 195 };
 196
 197 /* LDO2, LDO3 fixed (LDO2 has external scalar via R1/R2 feedback res) */
 198 static const struct regulator_ops ltc3676_fixed_regulator_ops = {
 199         .enable = regulator_enable_regmap,
 200         .disable = regulator_disable_regmap,
 201         .is_enabled = regulator_is_enabled_regmap,
 202 };
 203
 204 #define LTC3676_REG(_id, _name, _ops, en_reg, en_bit, dvba_reg, dvb_mask)   \
 205         [LTC3676_ ## _id] = {                                        \
 206                 .name = #_name,                                \
 207                 .of_match = of_match_ptr(#_name),              \
 208                 .regulators_node = of_match_ptr("regulators"), \
 209                 .of_parse_cb = ltc3676_of_parse_cb,            \
 210                 .n_voltages = (dvb_mask) + 1,                  \
 211                 .min_uV = (dvba_reg) ? 412500 : 0,             \
 212                 .uV_step = (dvba_reg) ? 12500 : 0,             \
 213                 .ramp_delay = (dvba_reg) ? 800 : 0,            \
 214                 .fixed_uV = (dvb_mask) ? 0 : 725000,           \
 215                 .ops = &ltc3676_ ## _ops ## _regulator_ops,    \
 216                 .type = REGULATOR_VOLTAGE,                     \
 217                 .id = LTC3676_ ## _id,                         \
 218                 .owner = THIS_MODULE,                          \
 219                 .vsel_reg = (dvba_reg),                        \
 220                 .vsel_mask = (dvb_mask),                       \
 221                 .enable_reg = (en_reg),                        \
 222                 .enable_mask = (1 << en_bit),                  \
 223         }
 224
 225 #define LTC3676_LINEAR_REG(_id, _name, _en, _dvba)                     \
 226         LTC3676_REG(_id, _name, linear,                                \
 227                     LTC3676_ ## _en, 7,                                \
 228                     LTC3676_ ## _dvba, 0x1f)
 229
 230 #define LTC3676_FIXED_REG(_id, _name, _en_reg, _en_bit)                \
 231         LTC3676_REG(_id, _name, fixed, LTC3676_ ## _en_reg, _en_bit, 0, 0)
 232
 233 static struct regulator_desc ltc3676_regulators[LTC3676_NUM_REGULATORS] = {
 234         LTC3676_LINEAR_REG(SW1, sw1, BUCK1, DVB1A),
 235         LTC3676_LINEAR_REG(SW2, sw2, BUCK2, DVB2A),
 236         LTC3676_LINEAR_REG(SW3, sw3, BUCK3, DVB3A),
 237         LTC3676_LINEAR_REG(SW4, sw4, BUCK4, DVB4A),
 238         LTC3676_REG(LDO1, ldo1, fixed_standby, 0, 0, 0, 0),
 239         LTC3676_FIXED_REG(LDO2, ldo2, LDOA, 2),
 240         LTC3676_FIXED_REG(LDO3, ldo3, LDOA, 5),
 241         LTC3676_FIXED_REG(LDO4, ldo4, LDOB, 2),
 242 };
 243
 244 static bool ltc3676_readable_writeable_reg(struct device *dev, unsigned int reg)
 245 {
 246         switch (reg) {
 247         case LTC3676_BUCK1 ... LTC3676_IRQSTAT:
 248         case LTC3676_HRST:
 249         case LTC3676_CLIRQ:
 250                 return true;
 251         }
 252         return false;
 253 }
 254
 255 static bool ltc3676_volatile_reg(struct device *dev, unsigned int reg)
 256 {
 257         switch (reg) {
 258         case LTC3676_IRQSTAT ... LTC3676_PGSTATRT:
 259                 return true;
 260         }
 261         return false;
 262 }
 263
 264 static const struct regmap_config ltc3676_regmap_config = {
 265         .reg_bits = 8,
 266         .val_bits = 8,
 267         .writeable_reg = ltc3676_readable_writeable_reg,
 268         .readable_reg = ltc3676_readable_writeable_reg,
 269         .volatile_reg = ltc3676_volatile_reg,
 270         .max_register = LTC3676_CLIRQ,
 271         .use_single_read = true,
 272         .use_single_write = true,
 273         .cache_type = REGCACHE_RBTREE,
 274 };
 275
 276 static irqreturn_t ltc3676_isr(int irq, void *dev_id)
 277 {
 278         struct ltc3676 *ltc3676 = dev_id;
 279         struct device *dev = ltc3676->dev;
 280         unsigned int i, irqstat, event;
 281
 282         regmap_read(ltc3676->regmap, LTC3676_IRQSTAT, &irqstat);
 283
 284         dev_dbg(dev, "irq%d irqstat=0x%02x\n", irq, irqstat);
 285         if (irqstat & LTC3676_IRQSTAT_THERMAL_WARN) {
 286                 dev_warn(dev, "Over-temperature Warning\n");
 287                 event = REGULATOR_EVENT_OVER_TEMP;
 288                 for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
 289                         regulator_notifier_call_chain(ltc3676->regulators[i],
 290                                                       event, NULL);
 291         }
 292
 293         if (irqstat & LTC3676_IRQSTAT_UNDERVOLT_WARN) {
 294                 dev_info(dev, "Undervoltage Warning\n");
 295                 event = REGULATOR_EVENT_UNDER_VOLTAGE;
 296                 for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
 297                         regulator_notifier_call_chain(ltc3676->regulators[i],
 298                                                       event, NULL);
 299         }
 300
 301         /* Clear warning condition */
 302         regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
 303
 304         return IRQ_HANDLED;
 305 }
 306
 307 static int ltc3676_regulator_probe(struct i2c_client *client,
 308                                     const struct i2c_device_id *id)
 309 {
 310         struct device *dev = &client->dev;
 311         struct regulator_init_data *init_data = dev_get_platdata(dev);
 312         struct regulator_desc *descs;
 313         struct ltc3676 *ltc3676;
 314         int i, ret;
 315
 316         ltc3676 = devm_kzalloc(dev, sizeof(*ltc3676), GFP_KERNEL);
 317         if (!ltc3676)
 318                 return -ENOMEM;
 319
 320         i2c_set_clientdata(client, ltc3676);
 321         ltc3676->dev = dev;
 322
 323         descs = ltc3676->regulator_descs;
 324         memcpy(descs, ltc3676_regulators, sizeof(ltc3676_regulators));
 325         descs[LTC3676_LDO3].fixed_uV = 1800000; /* LDO3 is fixed 1.8V */
 326
 327         ltc3676->regmap = devm_regmap_init_i2c(client, &ltc3676_regmap_config);
 328         if (IS_ERR(ltc3676->regmap)) {
 329                 ret = PTR_ERR(ltc3676->regmap);
 330                 dev_err(dev, "failed to initialize regmap: %d\n", ret);
 331                 return ret;
 332         }
 333
 334         for (i = 0; i < LTC3676_NUM_REGULATORS; i++) {
 335                 struct regulator_desc *desc = &ltc3676->regulator_descs[i];
 336                 struct regulator_config config = { };
 337
 338                 if (init_data)
 339                         config.init_data = &init_data[i];
 340
 341                 config.dev = dev;
 342                 config.driver_data = ltc3676;
 343
 344                 ltc3676->regulators[i] = devm_regulator_register(dev, desc,
 345                                                                  &config);
 346                 if (IS_ERR(ltc3676->regulators[i])) {
 347                         ret = PTR_ERR(ltc3676->regulators[i]);
 348                         dev_err(dev, "failed to register regulator %s: %d\n",
 349                                 desc->name, ret);
 350                         return ret;
 351                 }
 352         }
 353
 354         regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
 355         if (client->irq) {
 356                 ret = devm_request_threaded_irq(dev, client->irq, NULL,
 357                                                 ltc3676_isr,
 358                                                 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 359                                                 client->name, ltc3676);
 360                 if (ret) {
 361                         dev_err(dev, "Failed to request IRQ: %d\n", ret);
 362                         return ret;
 363                 }
 364         }
 365
 366         return 0;
 367 }
 368
 369 static const struct i2c_device_id ltc3676_i2c_id[] = {
 370         { "ltc3676" },
 371         { }
 372 };
 373 MODULE_DEVICE_TABLE(i2c, ltc3676_i2c_id);
 374
 375 static const struct of_device_id ltc3676_of_match[] = {
 376         { .compatible = "lltc,ltc3676" },
 377         { },
 378 };
 379 MODULE_DEVICE_TABLE(of, ltc3676_of_match);
 380
 381 static struct i2c_driver ltc3676_driver = {
 382         .driver = {
 383                 .name = DRIVER_NAME,
 384                 .of_match_table = of_match_ptr(ltc3676_of_match),
 385         },
 386         .probe = ltc3676_regulator_probe,
 387         .id_table = ltc3676_i2c_id,
 388 };
 389 module_i2c_driver(ltc3676_driver);
 390
 391 MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
 392 MODULE_DESCRIPTION("Regulator driver for Linear Technology LTC3676");
 393 MODULE_LICENSE("GPL v2");