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_list_voltage(struct regulator_dev *rdev,
  73                 unsigned int selector)
  74 {
  75         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  76
  77         if (rdev_get_id(rdev) != 0)
  78                 return -EINVAL;
  79
  80         return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000;
  81 }
  82
  83 static int max8952_is_enabled(struct regulator_dev *rdev)
  84 {
  85         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  86         return max8952->en;
  87 }
  88
  89 static int max8952_enable(struct regulator_dev *rdev)
  90 {
  91         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  92
  93         /* If not valid, assume "ALWAYS_HIGH" */
  94         if (gpio_is_valid(max8952->pdata->gpio_en))
  95                 gpio_set_value(max8952->pdata->gpio_en, 1);
  96
  97         max8952->en = true;
  98         return 0;
  99 }
 100
 101 static int max8952_disable(struct regulator_dev *rdev)
 102 {
 103         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
 104
 105         /* If not valid, assume "ALWAYS_HIGH" -> not permitted */
 106         if (gpio_is_valid(max8952->pdata->gpio_en))
 107                 gpio_set_value(max8952->pdata->gpio_en, 0);
 108         else
 109                 return -EPERM;
 110
 111         max8952->en = false;
 112         return 0;
 113 }
 114
 115 static int max8952_get_voltage_sel(struct regulator_dev *rdev)
 116 {
 117         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
 118         u8 vid = 0;
 119
 120         if (max8952->vid0)
 121                 vid += 1;
 122         if (max8952->vid1)
 123                 vid += 2;
 124
 125         return vid;
 126 }
 127
 128 static int max8952_set_voltage_sel(struct regulator_dev *rdev,
 129                                    unsigned selector)
 130 {
 131         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
 132
 133         if (!gpio_is_valid(max8952->pdata->gpio_vid0) ||
 134                         !gpio_is_valid(max8952->pdata->gpio_vid1)) {
 135                 /* DVS not supported */
 136                 return -EPERM;
 137         }
 138
 139         max8952->vid0 = selector & 0x1;
 140         max8952->vid1 = (selector >> 1) & 0x1;
 141         gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0);
 142         gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1);
 143
 144         return 0;
 145 }
 146
 147 static struct regulator_ops max8952_ops = {
 148         .list_voltage           = max8952_list_voltage,
 149         .is_enabled             = max8952_is_enabled,
 150         .enable                 = max8952_enable,
 151         .disable                = max8952_disable,
 152         .get_voltage_sel        = max8952_get_voltage_sel,
 153         .set_voltage_sel        = max8952_set_voltage_sel,
 154         .set_suspend_disable    = max8952_disable,
 155 };
 156
 157 static const struct regulator_desc regulator = {
 158         .name           = "MAX8952_VOUT",
 159         .id             = 0,
 160         .n_voltages     = MAX8952_NUM_DVS_MODE,
 161         .ops            = &max8952_ops,
 162         .type           = REGULATOR_VOLTAGE,
 163         .owner          = THIS_MODULE,
 164 };
 165
 166 static int __devinit max8952_pmic_probe(struct i2c_client *client,
 167                 const struct i2c_device_id *i2c_id)
 168 {
 169         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 170         struct max8952_platform_data *pdata = client->dev.platform_data;
 171         struct regulator_config config = { };
 172         struct max8952_data *max8952;
 173
 174         int ret = 0, err = 0;
 175
 176         if (!pdata) {
 177                 dev_err(&client->dev, "Require the platform data\n");
 178                 return -EINVAL;
 179         }
 180
 181         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
 182                 return -EIO;
 183
 184         max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data),
 185                                GFP_KERNEL);
 186         if (!max8952)
 187                 return -ENOMEM;
 188
 189         max8952->client = client;
 190         max8952->dev = &client->dev;
 191         max8952->pdata = pdata;
 192
 193         config.dev = max8952->dev;
 194         config.init_data = &pdata->reg_data;
 195         config.driver_data = max8952;
 196
 197         max8952->rdev = regulator_register(&regulator, &config);
 198
 199         if (IS_ERR(max8952->rdev)) {
 200                 ret = PTR_ERR(max8952->rdev);
 201                 dev_err(max8952->dev, "regulator init failed (%d)\n", ret);
 202                 return ret;
 203         }
 204
 205         max8952->en = !!(pdata->reg_data.constraints.boot_on);
 206         max8952->vid0 = pdata->default_mode & 0x1;
 207         max8952->vid1 = (pdata->default_mode >> 1) & 0x1;
 208
 209         if (gpio_is_valid(pdata->gpio_en)) {
 210                 if (!gpio_request(pdata->gpio_en, "MAX8952 EN"))
 211                         gpio_direction_output(pdata->gpio_en, max8952->en);
 212                 else
 213                         err = 1;
 214         } else
 215                 err = 2;
 216
 217         if (err) {
 218                 dev_info(max8952->dev, "EN gpio invalid: assume that EN"
 219                                 "is always High\n");
 220                 max8952->en = 1;
 221                 pdata->gpio_en = -1; /* Mark invalid */
 222         }
 223
 224         err = 0;
 225
 226         if (gpio_is_valid(pdata->gpio_vid0) &&
 227                         gpio_is_valid(pdata->gpio_vid1)) {
 228                 if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0"))
 229                         gpio_direction_output(pdata->gpio_vid0,
 230                                         (pdata->default_mode) & 0x1);
 231                 else
 232                         err = 1;
 233
 234                 if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1"))
 235                         gpio_direction_output(pdata->gpio_vid1,
 236                                 (pdata->default_mode >> 1) & 0x1);
 237                 else {
 238                         if (!err)
 239                                 gpio_free(pdata->gpio_vid0);
 240                         err = 2;
 241                 }
 242
 243         } else
 244                 err = 3;
 245
 246         if (err) {
 247                 dev_warn(max8952->dev, "VID0/1 gpio invalid: "
 248                                 "DVS not available.\n");
 249                 max8952->vid0 = 0;
 250                 max8952->vid1 = 0;
 251                 /* Mark invalid */
 252                 pdata->gpio_vid0 = -1;
 253                 pdata->gpio_vid1 = -1;
 254
 255                 /* Disable Pulldown of EN only */
 256                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
 257
 258                 dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1"
 259                                 " do not have proper controls.\n");
 260         } else {
 261                 /*
 262                  * Disable Pulldown on EN, VID0, VID1 to reduce
 263                  * leakage current of MAX8952 assuming that MAX8952
 264                  * is turned on (EN==1). Note that without having VID0/1
 265                  * properly connected, turning pulldown off can be
 266                  * problematic. Thus, turn this off only when they are
 267                  * controllable by GPIO.
 268                  */
 269                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
 270         }
 271
 272         max8952_write_reg(max8952, MAX8952_REG_MODE0,
 273                         (max8952_read_reg(max8952,
 274                                           MAX8952_REG_MODE0) & 0xC0) |
 275                         (pdata->dvs_mode[0] & 0x3F));
 276         max8952_write_reg(max8952, MAX8952_REG_MODE1,
 277                         (max8952_read_reg(max8952,
 278                                           MAX8952_REG_MODE1) & 0xC0) |
 279                         (pdata->dvs_mode[1] & 0x3F));
 280         max8952_write_reg(max8952, MAX8952_REG_MODE2,
 281                         (max8952_read_reg(max8952,
 282                                           MAX8952_REG_MODE2) & 0xC0) |
 283                         (pdata->dvs_mode[2] & 0x3F));
 284         max8952_write_reg(max8952, MAX8952_REG_MODE3,
 285                         (max8952_read_reg(max8952,
 286                                           MAX8952_REG_MODE3) & 0xC0) |
 287                         (pdata->dvs_mode[3] & 0x3F));
 288
 289         max8952_write_reg(max8952, MAX8952_REG_SYNC,
 290                         (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
 291                         ((pdata->sync_freq & 0x3) << 6));
 292         max8952_write_reg(max8952, MAX8952_REG_RAMP,
 293                         (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
 294                         ((pdata->ramp_speed & 0x7) << 5));
 295
 296         i2c_set_clientdata(client, max8952);
 297
 298         return 0;
 299 }
 300
 301 static int __devexit max8952_pmic_remove(struct i2c_client *client)
 302 {
 303         struct max8952_data *max8952 = i2c_get_clientdata(client);
 304         struct max8952_platform_data *pdata = max8952->pdata;
 305         struct regulator_dev *rdev = max8952->rdev;
 306
 307         regulator_unregister(rdev);
 308
 309         gpio_free(pdata->gpio_vid0);
 310         gpio_free(pdata->gpio_vid1);
 311         gpio_free(pdata->gpio_en);
 312         return 0;
 313 }
 314
 315 static const struct i2c_device_id max8952_ids[] = {
 316         { "max8952", 0 },
 317         { },
 318 };
 319 MODULE_DEVICE_TABLE(i2c, max8952_ids);
 320
 321 static struct i2c_driver max8952_pmic_driver = {
 322         .probe          = max8952_pmic_probe,
 323         .remove         = __devexit_p(max8952_pmic_remove),
 324         .driver         = {
 325                 .name   = "max8952",
 326         },
 327         .id_table       = max8952_ids,
 328 };
 329
 330 static int __init max8952_pmic_init(void)
 331 {
 332         return i2c_add_driver(&max8952_pmic_driver);
 333 }
 334 subsys_initcall(max8952_pmic_init);
 335
 336 static void __exit max8952_pmic_exit(void)
 337 {
 338         i2c_del_driver(&max8952_pmic_driver);
 339 }
 340 module_exit(max8952_pmic_exit);
 341
 342 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
 343 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 344 MODULE_LICENSE("GPL");