drivers/regulator/max8952.c

   1 /*
   2  * max8952.c - Voltage and current regulation for the Maxim 8952
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  * MyungJoo Ham <myungjoo.ham@samsung.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/i2c.h>
  25 #include <linux/err.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/regulator/driver.h>
  28 #include <linux/regulator/max8952.h>
  29 #include <linux/gpio.h>
  30 #include <linux/io.h>
  31 #include <linux/slab.h>
  32
  33 /* Registers */
  34 enum {
  35         MAX8952_REG_MODE0,
  36         MAX8952_REG_MODE1,
  37         MAX8952_REG_MODE2,
  38         MAX8952_REG_MODE3,
  39         MAX8952_REG_CONTROL,
  40         MAX8952_REG_SYNC,
  41         MAX8952_REG_RAMP,
  42         MAX8952_REG_CHIP_ID1,
  43         MAX8952_REG_CHIP_ID2,
  44 };
  45
  46 struct max8952_data {
  47         struct i2c_client       *client;
  48         struct device           *dev;
  49         struct max8952_platform_data *pdata;
  50         struct regulator_dev    *rdev;
  51
  52         bool vid0;
  53         bool vid1;
  54         bool en;
  55 };
  56
  57 static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
  58 {
  59         int ret = i2c_smbus_read_byte_data(max8952->client, reg);
  60         if (ret > 0)
  61                 ret &= 0xff;
  62
  63         return ret;
  64 }
  65
  66 static int max8952_write_reg(struct max8952_data *max8952,
  67                 u8 reg, u8 value)
  68 {
  69         return i2c_smbus_write_byte_data(max8952->client, reg, value);
  70 }
  71
  72 static int max8952_voltage(struct max8952_data *max8952, u8 mode)
  73 {
  74         return (max8952->pdata->dvs_mode[mode] * 10 + 770) * 1000;
  75 }
  76
  77 static int max8952_list_voltage(struct regulator_dev *rdev,
  78                 unsigned int selector)
  79 {
  80         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  81
  82         if (rdev_get_id(rdev) != 0)
  83                 return -EINVAL;
  84
  85         return max8952_voltage(max8952, selector);
  86 }
  87
  88 static int max8952_is_enabled(struct regulator_dev *rdev)
  89 {
  90         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  91         return max8952->en;
  92 }
  93
  94 static int max8952_enable(struct regulator_dev *rdev)
  95 {
  96         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  97
  98         /* If not valid, assume "ALWAYS_HIGH" */
  99         if (gpio_is_valid(max8952->pdata->gpio_en))
 100                 gpio_set_value(max8952->pdata->gpio_en, 1);
 101
 102         max8952->en = true;
 103         return 0;
 104 }
 105
 106 static int max8952_disable(struct regulator_dev *rdev)
 107 {
 108         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
 109
 110         /* If not valid, assume "ALWAYS_HIGH" -> not permitted */
 111         if (gpio_is_valid(max8952->pdata->gpio_en))
 112                 gpio_set_value(max8952->pdata->gpio_en, 0);
 113         else
 114                 return -EPERM;
 115
 116         max8952->en = false;
 117         return 0;
 118 }
 119
 120 static int max8952_get_voltage(struct regulator_dev *rdev)
 121 {
 122         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
 123         u8 vid = 0;
 124
 125         if (max8952->vid0)
 126                 vid += 1;
 127         if (max8952->vid1)
 128                 vid += 2;
 129
 130         return max8952_voltage(max8952, vid);
 131 }
 132
 133 static int max8952_set_voltage(struct regulator_dev *rdev,
 134                                int min_uV, int max_uV, unsigned *selector)
 135 {
 136         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
 137         s8 vid = -1, i;
 138
 139         if (!gpio_is_valid(max8952->pdata->gpio_vid0) ||
 140                         !gpio_is_valid(max8952->pdata->gpio_vid1)) {
 141                 /* DVS not supported */
 142                 return -EPERM;
 143         }
 144
 145         for (i = 0; i < MAX8952_NUM_DVS_MODE; i++) {
 146                 int volt = max8952_voltage(max8952, i);
 147
 148                 /* Set the voltage as low as possible within the range */
 149                 if (volt <= max_uV && volt >= min_uV)
 150                         if (vid == -1 || max8952_voltage(max8952, vid) > volt)
 151                                 vid = i;
 152         }
 153
 154         if (vid >= 0 && vid < MAX8952_NUM_DVS_MODE) {
 155                 max8952->vid0 = (vid % 2 == 1);
 156                 max8952->vid1 = (((vid >> 1) % 2) == 1);
 157                 *selector = vid;
 158                 gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0);
 159                 gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1);
 160         } else
 161                 return -EINVAL;
 162
 163         return 0;
 164 }
 165
 166 static struct regulator_ops max8952_ops = {
 167         .list_voltage           = max8952_list_voltage,
 168         .is_enabled             = max8952_is_enabled,
 169         .enable                 = max8952_enable,
 170         .disable                = max8952_disable,
 171         .get_voltage            = max8952_get_voltage,
 172         .set_voltage            = max8952_set_voltage,
 173         .set_suspend_disable    = max8952_disable,
 174 };
 175
 176 static struct regulator_desc regulator = {
 177         .name           = "MAX8952_VOUT",
 178         .id             = 0,
 179         .n_voltages     = MAX8952_NUM_DVS_MODE,
 180         .ops            = &max8952_ops,
 181         .type           = REGULATOR_VOLTAGE,
 182         .owner          = THIS_MODULE,
 183 };
 184
 185 static int __devinit max8952_pmic_probe(struct i2c_client *client,
 186                 const struct i2c_device_id *i2c_id)
 187 {
 188         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 189         struct max8952_platform_data *pdata = client->dev.platform_data;
 190         struct max8952_data *max8952;
 191
 192         int ret = 0, err = 0;
 193
 194         if (!pdata) {
 195                 dev_err(&client->dev, "Require the platform data\n");
 196                 return -EINVAL;
 197         }
 198
 199         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
 200                 return -EIO;
 201
 202         max8952 = kzalloc(sizeof(struct max8952_data), GFP_KERNEL);
 203         if (!max8952)
 204                 return -ENOMEM;
 205
 206         max8952->client = client;
 207         max8952->dev = &client->dev;
 208         max8952->pdata = pdata;
 209
 210         max8952->rdev = regulator_register(&regulator, max8952->dev,
 211                         &pdata->reg_data, max8952);
 212
 213         if (IS_ERR(max8952->rdev)) {
 214                 ret = PTR_ERR(max8952->rdev);
 215                 dev_err(max8952->dev, "regulator init failed (%d)\n", ret);
 216                 goto err_reg;
 217         }
 218
 219         max8952->en = !!(pdata->reg_data.constraints.boot_on);
 220         max8952->vid0 = (pdata->default_mode % 2) == 1;
 221         max8952->vid1 = ((pdata->default_mode >> 1) % 2) == 1;
 222
 223         if (gpio_is_valid(pdata->gpio_en)) {
 224                 if (!gpio_request(pdata->gpio_en, "MAX8952 EN"))
 225                         gpio_direction_output(pdata->gpio_en, max8952->en);
 226                 else
 227                         err = 1;
 228         } else
 229                 err = 2;
 230
 231         if (err) {
 232                 dev_info(max8952->dev, "EN gpio invalid: assume that EN"
 233                                 "is always High\n");
 234                 max8952->en = 1;
 235                 pdata->gpio_en = -1; /* Mark invalid */
 236         }
 237
 238         err = 0;
 239
 240         if (gpio_is_valid(pdata->gpio_vid0) &&
 241                         gpio_is_valid(pdata->gpio_vid1)) {
 242                 if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0"))
 243                         gpio_direction_output(pdata->gpio_vid0,
 244                                         (pdata->default_mode) % 2);
 245                 else
 246                         err = 1;
 247
 248                 if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1"))
 249                         gpio_direction_output(pdata->gpio_vid1,
 250                                 (pdata->default_mode >> 1) % 2);
 251                 else {
 252                         if (!err)
 253                                 gpio_free(pdata->gpio_vid0);
 254                         err = 2;
 255                 }
 256
 257         } else
 258                 err = 3;
 259
 260         if (err) {
 261                 dev_warn(max8952->dev, "VID0/1 gpio invalid: "
 262                                 "DVS not available.\n");
 263                 max8952->vid0 = 0;
 264                 max8952->vid1 = 0;
 265                 /* Mark invalid */
 266                 pdata->gpio_vid0 = -1;
 267                 pdata->gpio_vid1 = -1;
 268
 269                 /* Disable Pulldown of EN only */
 270                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
 271
 272                 dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1"
 273                                 " do not have proper controls.\n");
 274         } else {
 275                 /*
 276                  * Disable Pulldown on EN, VID0, VID1 to reduce
 277                  * leakage current of MAX8952 assuming that MAX8952
 278                  * is turned on (EN==1). Note that without having VID0/1
 279                  * properly connected, turning pulldown off can be
 280                  * problematic. Thus, turn this off only when they are
 281                  * controllable by GPIO.
 282                  */
 283                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
 284         }
 285
 286         max8952_write_reg(max8952, MAX8952_REG_MODE0,
 287                         (max8952_read_reg(max8952,
 288                                           MAX8952_REG_MODE0) & 0xC0) |
 289                         (pdata->dvs_mode[0] & 0x3F));
 290         max8952_write_reg(max8952, MAX8952_REG_MODE1,
 291                         (max8952_read_reg(max8952,
 292                                           MAX8952_REG_MODE1) & 0xC0) |
 293                         (pdata->dvs_mode[1] & 0x3F));
 294         max8952_write_reg(max8952, MAX8952_REG_MODE2,
 295                         (max8952_read_reg(max8952,
 296                                           MAX8952_REG_MODE2) & 0xC0) |
 297                         (pdata->dvs_mode[2] & 0x3F));
 298         max8952_write_reg(max8952, MAX8952_REG_MODE3,
 299                         (max8952_read_reg(max8952,
 300                                           MAX8952_REG_MODE3) & 0xC0) |
 301                         (pdata->dvs_mode[3] & 0x3F));
 302
 303         max8952_write_reg(max8952, MAX8952_REG_SYNC,
 304                         (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
 305                         ((pdata->sync_freq & 0x3) << 6));
 306         max8952_write_reg(max8952, MAX8952_REG_RAMP,
 307                         (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
 308                         ((pdata->ramp_speed & 0x7) << 5));
 309
 310         i2c_set_clientdata(client, max8952);
 311
 312         return 0;
 313
 314 err_reg:
 315         kfree(max8952);
 316         return ret;
 317 }
 318
 319 static int __devexit max8952_pmic_remove(struct i2c_client *client)
 320 {
 321         struct max8952_data *max8952 = i2c_get_clientdata(client);
 322         struct max8952_platform_data *pdata = max8952->pdata;
 323         struct regulator_dev *rdev = max8952->rdev;
 324
 325         regulator_unregister(rdev);
 326
 327         gpio_free(pdata->gpio_vid0);
 328         gpio_free(pdata->gpio_vid1);
 329         gpio_free(pdata->gpio_en);
 330
 331         kfree(max8952);
 332         return 0;
 333 }
 334
 335 static const struct i2c_device_id max8952_ids[] = {
 336         { "max8952", 0 },
 337         { },
 338 };
 339 MODULE_DEVICE_TABLE(i2c, max8952_ids);
 340
 341 static struct i2c_driver max8952_pmic_driver = {
 342         .probe          = max8952_pmic_probe,
 343         .remove         = __devexit_p(max8952_pmic_remove),
 344         .driver         = {
 345                 .name   = "max8952",
 346         },
 347         .id_table       = max8952_ids,
 348 };
 349
 350 static int __init max8952_pmic_init(void)
 351 {
 352         return i2c_add_driver(&max8952_pmic_driver);
 353 }
 354 subsys_initcall(max8952_pmic_init);
 355
 356 static void __exit max8952_pmic_exit(void)
 357 {
 358         i2c_del_driver(&max8952_pmic_driver);
 359 }
 360 module_exit(max8952_pmic_exit);
 361
 362 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
 363 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 364 MODULE_LICENSE("GPL");