drivers/regulator/max8660.c

   1 /*
   2  * max8660.c  --  Voltage regulation for the Maxim 8660/8661
   3  *
   4  * based on max1586.c and wm8400-regulator.c
   5  *
   6  * Copyright (C) 2009 Wolfram Sang, Pengutronix e.K.
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the Free
  10  * Software Foundation; version 2 of the License.
  11  *
  12  * This program is distributed in the hope that it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along with
  18  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  19  * Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  * Some info:
  22  *
  23  * Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX8660-MAX8661.pdf
  24  *
  25  * This chip is a bit nasty because it is a write-only device. Thus, the driver
  26  * uses shadow registers to keep track of its values. The main problem appears
  27  * to be the initialization: When Linux boots up, we cannot know if the chip is
  28  * in the default state or not, so we would have to pass such information in
  29  * platform_data. As this adds a bit of complexity to the driver, this is left
  30  * out for now until it is really needed.
  31  *
  32  * [A|S|M]DTV1 registers are currently not used, but [A|S|M]DTV2.
  33  *
  34  * If the driver is feature complete, it might be worth to check if one set of
  35  * functions for V3-V7 is sufficient. For maximum flexibility during
  36  * development, they are separated for now.
  37  *
  38  */
  39
  40 #include <linux/module.h>
  41 #include <linux/err.h>
  42 #include <linux/i2c.h>
  43 #include <linux/platform_device.h>
  44 #include <linux/regulator/driver.h>
  45 #include <linux/slab.h>
  46 #include <linux/regulator/max8660.h>
  47
  48 #define MAX8660_DCDC_MIN_UV      725000
  49 #define MAX8660_DCDC_MAX_UV     1800000
  50 #define MAX8660_DCDC_STEP         25000
  51 #define MAX8660_DCDC_MAX_SEL    0x2b
  52
  53 #define MAX8660_LDO5_MIN_UV     1700000
  54 #define MAX8660_LDO5_MAX_UV     2000000
  55 #define MAX8660_LDO5_STEP         25000
  56 #define MAX8660_LDO5_MAX_SEL    0x0c
  57
  58 #define MAX8660_LDO67_MIN_UV    1800000
  59 #define MAX8660_LDO67_MAX_UV    3300000
  60 #define MAX8660_LDO67_STEP       100000
  61 #define MAX8660_LDO67_MAX_SEL   0x0f
  62
  63 enum {
  64         MAX8660_OVER1,
  65         MAX8660_OVER2,
  66         MAX8660_VCC1,
  67         MAX8660_ADTV1,
  68         MAX8660_ADTV2,
  69         MAX8660_SDTV1,
  70         MAX8660_SDTV2,
  71         MAX8660_MDTV1,
  72         MAX8660_MDTV2,
  73         MAX8660_L12VCR,
  74         MAX8660_FPWM,
  75         MAX8660_N_REGS, /* not a real register */
  76 };
  77
  78 struct max8660 {
  79         struct i2c_client *client;
  80         u8 shadow_regs[MAX8660_N_REGS];         /* as chip is write only */
  81         struct regulator_dev *rdev[];
  82 };
  83
  84 static int max8660_write(struct max8660 *max8660, u8 reg, u8 mask, u8 val)
  85 {
  86         static const u8 max8660_addresses[MAX8660_N_REGS] =
  87           { 0x10, 0x12, 0x20, 0x23, 0x24, 0x29, 0x2a, 0x32, 0x33, 0x39, 0x80 };
  88
  89         int ret;
  90         u8 reg_val = (max8660->shadow_regs[reg] & mask) | val;
  91         dev_vdbg(&max8660->client->dev, "Writing reg %02x with %02x\n",
  92                         max8660_addresses[reg], reg_val);
  93
  94         ret = i2c_smbus_write_byte_data(max8660->client,
  95                         max8660_addresses[reg], reg_val);
  96         if (ret == 0)
  97                 max8660->shadow_regs[reg] = reg_val;
  98
  99         return ret;
 100 }
 101
 102
 103 /*
 104  * DCDC functions
 105  */
 106
 107 static int max8660_dcdc_is_enabled(struct regulator_dev *rdev)
 108 {
 109         struct max8660 *max8660 = rdev_get_drvdata(rdev);
 110         u8 val = max8660->shadow_regs[MAX8660_OVER1];
 111         u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
 112         return !!(val & mask);
 113 }
 114
 115 static int max8660_dcdc_enable(struct regulator_dev *rdev)
 116 {
 117         struct max8660 *max8660 = rdev_get_drvdata(rdev);
 118         u8 bit = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
 119         return max8660_write(max8660, MAX8660_OVER1, 0xff, bit);
 120 }
 121
 122 static int max8660_dcdc_disable(struct regulator_dev *rdev)
 123 {
 124         struct max8660 *max8660 = rdev_get_drvdata(rdev);
 125         u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? ~1 : ~4;
 126         return max8660_write(max8660, MAX8660_OVER1, mask, 0);
 127 }
 128
 129 static int max8660_dcdc_get_voltage_sel(struct regulator_dev *rdev)
 130 {
 131         struct max8660 *max8660 = rdev_get_drvdata(rdev);
 132
 133         u8 reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
 134         u8 selector = max8660->shadow_regs[reg];
 135         return selector;
 136 }
 137
 138 static int max8660_dcdc_set_voltage_sel(struct regulator_dev *rdev,
 139                                         unsigned int selector)
 140 {
 141         struct max8660 *max8660 = rdev_get_drvdata(rdev);
 142         u8 reg, bits;
 143         int ret;
 144
 145         reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
 146         ret = max8660_write(max8660, reg, 0, selector);
 147         if (ret)
 148                 return ret;
 149
 150         /* Select target voltage register and activate regulation */
 151         bits = (rdev_get_id(rdev) == MAX8660_V3) ? 0x03 : 0x30;
 152         return max8660_write(max8660, MAX8660_VCC1, 0xff, bits);
 153 }
 154
 155 static struct regulator_ops max8660_dcdc_ops = {
 156         .is_enabled = max8660_dcdc_is_enabled,
 157         .list_voltage = regulator_list_voltage_linear,
 158         .map_voltage = regulator_map_voltage_linear,
 159         .set_voltage_sel = max8660_dcdc_set_voltage_sel,
 160         .get_voltage_sel = max8660_dcdc_get_voltage_sel,
 161 };
 162
 163
 164 /*
 165  * LDO5 functions
 166  */
 167
 168 static int max8660_ldo5_get_voltage_sel(struct regulator_dev *rdev)
 169 {
 170         struct max8660 *max8660 = rdev_get_drvdata(rdev);
 171
 172         u8 selector = max8660->shadow_regs[MAX8660_MDTV2];
 173         return selector;
 174 }
 175
 176 static int max8660_ldo5_set_voltage_sel(struct regulator_dev *rdev,
 177                                         unsigned int selector)
 178 {
 179         struct max8660 *max8660 = rdev_get_drvdata(rdev);
 180         int ret;
 181
 182         ret = max8660_write(max8660, MAX8660_MDTV2, 0, selector);
 183         if (ret)
 184                 return ret;
 185
 186         /* Select target voltage register and activate regulation */
 187         return max8660_write(max8660, MAX8660_VCC1, 0xff, 0xc0);
 188 }
 189
 190 static struct regulator_ops max8660_ldo5_ops = {
 191         .list_voltage = regulator_list_voltage_linear,
 192         .map_voltage = regulator_map_voltage_linear,
 193         .set_voltage_sel = max8660_ldo5_set_voltage_sel,
 194         .get_voltage_sel = max8660_ldo5_get_voltage_sel,
 195 };
 196
 197
 198 /*
 199  * LDO67 functions
 200  */
 201
 202 static int max8660_ldo67_is_enabled(struct regulator_dev *rdev)
 203 {
 204         struct max8660 *max8660 = rdev_get_drvdata(rdev);
 205         u8 val = max8660->shadow_regs[MAX8660_OVER2];
 206         u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
 207         return !!(val & mask);
 208 }
 209
 210 static int max8660_ldo67_enable(struct regulator_dev *rdev)
 211 {
 212         struct max8660 *max8660 = rdev_get_drvdata(rdev);
 213         u8 bit = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
 214         return max8660_write(max8660, MAX8660_OVER2, 0xff, bit);
 215 }
 216
 217 static int max8660_ldo67_disable(struct regulator_dev *rdev)
 218 {
 219         struct max8660 *max8660 = rdev_get_drvdata(rdev);
 220         u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? ~2 : ~4;
 221         return max8660_write(max8660, MAX8660_OVER2, mask, 0);
 222 }
 223
 224 static int max8660_ldo67_get_voltage_sel(struct regulator_dev *rdev)
 225 {
 226         struct max8660 *max8660 = rdev_get_drvdata(rdev);
 227
 228         u8 shift = (rdev_get_id(rdev) == MAX8660_V6) ? 0 : 4;
 229         u8 selector = (max8660->shadow_regs[MAX8660_L12VCR] >> shift) & 0xf;
 230         return selector;
 231 }
 232
 233 static int max8660_ldo67_set_voltage_sel(struct regulator_dev *rdev,
 234                                          unsigned int selector)
 235 {
 236         struct max8660 *max8660 = rdev_get_drvdata(rdev);
 237
 238         if (rdev_get_id(rdev) == MAX8660_V6)
 239                 return max8660_write(max8660, MAX8660_L12VCR, 0xf0, selector);
 240         else
 241                 return max8660_write(max8660, MAX8660_L12VCR, 0x0f,
 242                                      selector << 4);
 243 }
 244
 245 static struct regulator_ops max8660_ldo67_ops = {
 246         .is_enabled = max8660_ldo67_is_enabled,
 247         .enable = max8660_ldo67_enable,
 248         .disable = max8660_ldo67_disable,
 249         .list_voltage = regulator_list_voltage_linear,
 250         .map_voltage = regulator_map_voltage_linear,
 251         .get_voltage_sel = max8660_ldo67_get_voltage_sel,
 252         .set_voltage_sel = max8660_ldo67_set_voltage_sel,
 253 };
 254
 255 static const struct regulator_desc max8660_reg[] = {
 256         {
 257                 .name = "V3(DCDC)",
 258                 .id = MAX8660_V3,
 259                 .ops = &max8660_dcdc_ops,
 260                 .type = REGULATOR_VOLTAGE,
 261                 .n_voltages = MAX8660_DCDC_MAX_SEL + 1,
 262                 .owner = THIS_MODULE,
 263                 .min_uV = MAX8660_DCDC_MIN_UV,
 264                 .uV_step = MAX8660_DCDC_STEP,
 265         },
 266         {
 267                 .name = "V4(DCDC)",
 268                 .id = MAX8660_V4,
 269                 .ops = &max8660_dcdc_ops,
 270                 .type = REGULATOR_VOLTAGE,
 271                 .n_voltages = MAX8660_DCDC_MAX_SEL + 1,
 272                 .owner = THIS_MODULE,
 273                 .min_uV = MAX8660_DCDC_MIN_UV,
 274                 .uV_step = MAX8660_DCDC_STEP,
 275         },
 276         {
 277                 .name = "V5(LDO)",
 278                 .id = MAX8660_V5,
 279                 .ops = &max8660_ldo5_ops,
 280                 .type = REGULATOR_VOLTAGE,
 281                 .n_voltages = MAX8660_LDO5_MAX_SEL + 1,
 282                 .owner = THIS_MODULE,
 283                 .min_uV = MAX8660_LDO5_MIN_UV,
 284                 .uV_step = MAX8660_LDO5_STEP,
 285         },
 286         {
 287                 .name = "V6(LDO)",
 288                 .id = MAX8660_V6,
 289                 .ops = &max8660_ldo67_ops,
 290                 .type = REGULATOR_VOLTAGE,
 291                 .n_voltages = MAX8660_LDO67_MAX_SEL + 1,
 292                 .owner = THIS_MODULE,
 293                 .min_uV = MAX8660_LDO67_MIN_UV,
 294                 .uV_step = MAX8660_LDO67_STEP,
 295         },
 296         {
 297                 .name = "V7(LDO)",
 298                 .id = MAX8660_V7,
 299                 .ops = &max8660_ldo67_ops,
 300                 .type = REGULATOR_VOLTAGE,
 301                 .n_voltages = MAX8660_LDO67_MAX_SEL + 1,
 302                 .owner = THIS_MODULE,
 303                 .min_uV = MAX8660_LDO67_MIN_UV,
 304                 .uV_step = MAX8660_LDO67_STEP,
 305         },
 306 };
 307
 308 static int max8660_probe(struct i2c_client *client,
 309                                    const struct i2c_device_id *i2c_id)
 310 {
 311         struct regulator_dev **rdev;
 312         struct max8660_platform_data *pdata = client->dev.platform_data;
 313         struct regulator_config config = { };
 314         struct max8660 *max8660;
 315         int boot_on, i, id, ret = -EINVAL;
 316
 317         if (pdata->num_subdevs > MAX8660_V_END) {
 318                 dev_err(&client->dev, "Too many regulators found!\n");
 319                 return -EINVAL;
 320         }
 321
 322         max8660 = devm_kzalloc(&client->dev, sizeof(struct max8660) +
 323                         sizeof(struct regulator_dev *) * MAX8660_V_END,
 324                         GFP_KERNEL);
 325         if (!max8660)
 326                 return -ENOMEM;
 327
 328         max8660->client = client;
 329         rdev = max8660->rdev;
 330
 331         if (pdata->en34_is_high) {
 332                 /* Simulate always on */
 333                 max8660->shadow_regs[MAX8660_OVER1] = 5;
 334         } else {
 335                 /* Otherwise devices can be toggled via software */
 336                 max8660_dcdc_ops.enable = max8660_dcdc_enable;
 337                 max8660_dcdc_ops.disable = max8660_dcdc_disable;
 338         }
 339
 340         /*
 341          * First, set up shadow registers to prevent glitches. As some
 342          * registers are shared between regulators, everything must be properly
 343          * set up for all regulators in advance.
 344          */
 345         max8660->shadow_regs[MAX8660_ADTV1] =
 346                 max8660->shadow_regs[MAX8660_ADTV2] =
 347                 max8660->shadow_regs[MAX8660_SDTV1] =
 348                 max8660->shadow_regs[MAX8660_SDTV2] = 0x1b;
 349         max8660->shadow_regs[MAX8660_MDTV1] =
 350                 max8660->shadow_regs[MAX8660_MDTV2] = 0x04;
 351
 352         for (i = 0; i < pdata->num_subdevs; i++) {
 353
 354                 if (!pdata->subdevs[i].platform_data)
 355                         goto err_out;
 356
 357                 boot_on = pdata->subdevs[i].platform_data->constraints.boot_on;
 358
 359                 switch (pdata->subdevs[i].id) {
 360                 case MAX8660_V3:
 361                         if (boot_on)
 362                                 max8660->shadow_regs[MAX8660_OVER1] |= 1;
 363                         break;
 364
 365                 case MAX8660_V4:
 366                         if (boot_on)
 367                                 max8660->shadow_regs[MAX8660_OVER1] |= 4;
 368                         break;
 369
 370                 case MAX8660_V5:
 371                         break;
 372
 373                 case MAX8660_V6:
 374                         if (boot_on)
 375                                 max8660->shadow_regs[MAX8660_OVER2] |= 2;
 376                         break;
 377
 378                 case MAX8660_V7:
 379                         if (!strcmp(i2c_id->name, "max8661")) {
 380                                 dev_err(&client->dev, "Regulator not on this chip!\n");
 381                                 goto err_out;
 382                         }
 383
 384                         if (boot_on)
 385                                 max8660->shadow_regs[MAX8660_OVER2] |= 4;
 386                         break;
 387
 388                 default:
 389                         dev_err(&client->dev, "invalid regulator %s\n",
 390                                  pdata->subdevs[i].name);
 391                         goto err_out;
 392                 }
 393         }
 394
 395         /* Finally register devices */
 396         for (i = 0; i < pdata->num_subdevs; i++) {
 397
 398                 id = pdata->subdevs[i].id;
 399
 400                 config.dev = &client->dev;
 401                 config.init_data = pdata->subdevs[i].platform_data;
 402                 config.driver_data = max8660;
 403
 404                 rdev[i] = regulator_register(&max8660_reg[id], &config);
 405                 if (IS_ERR(rdev[i])) {
 406                         ret = PTR_ERR(rdev[i]);
 407                         dev_err(&client->dev, "failed to register %s\n",
 408                                 max8660_reg[id].name);
 409                         goto err_unregister;
 410                 }
 411         }
 412
 413         i2c_set_clientdata(client, max8660);
 414         return 0;
 415
 416 err_unregister:
 417         while (--i >= 0)
 418                 regulator_unregister(rdev[i]);
 419 err_out:
 420         return ret;
 421 }
 422
 423 static int max8660_remove(struct i2c_client *client)
 424 {
 425         struct max8660 *max8660 = i2c_get_clientdata(client);
 426         int i;
 427
 428         for (i = 0; i < MAX8660_V_END; i++)
 429                 regulator_unregister(max8660->rdev[i]);
 430         return 0;
 431 }
 432
 433 static const struct i2c_device_id max8660_id[] = {
 434         { "max8660", 0 },
 435         { "max8661", 0 },
 436         { }
 437 };
 438 MODULE_DEVICE_TABLE(i2c, max8660_id);
 439
 440 static struct i2c_driver max8660_driver = {
 441         .probe = max8660_probe,
 442         .remove = max8660_remove,
 443         .driver         = {
 444                 .name   = "max8660",
 445                 .owner  = THIS_MODULE,
 446         },
 447         .id_table       = max8660_id,
 448 };
 449
 450 static int __init max8660_init(void)
 451 {
 452         return i2c_add_driver(&max8660_driver);
 453 }
 454 subsys_initcall(max8660_init);
 455
 456 static void __exit max8660_exit(void)
 457 {
 458         i2c_del_driver(&max8660_driver);
 459 }
 460 module_exit(max8660_exit);
 461
 462 /* Module information */
 463 MODULE_DESCRIPTION("MAXIM 8660/8661 voltage regulator driver");
 464 MODULE_AUTHOR("Wolfram Sang");
 465 MODULE_LICENSE("GPL v2");