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/of.h>
  32 #include <linux/of_gpio.h>
  33 #include <linux/regulator/of_regulator.h>
  34 #include <linux/slab.h>
  35
  36 /* Registers */
  37 enum {
  38         MAX8952_REG_MODE0,
  39         MAX8952_REG_MODE1,
  40         MAX8952_REG_MODE2,
  41         MAX8952_REG_MODE3,
  42         MAX8952_REG_CONTROL,
  43         MAX8952_REG_SYNC,
  44         MAX8952_REG_RAMP,
  45         MAX8952_REG_CHIP_ID1,
  46         MAX8952_REG_CHIP_ID2,
  47 };
  48
  49 struct max8952_data {
  50         struct i2c_client       *client;
  51         struct device           *dev;
  52         struct max8952_platform_data *pdata;
  53         struct regulator_dev    *rdev;
  54
  55         bool vid0;
  56         bool vid1;
  57 };
  58
  59 static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
  60 {
  61         int ret = i2c_smbus_read_byte_data(max8952->client, reg);
  62         if (ret > 0)
  63                 ret &= 0xff;
  64
  65         return ret;
  66 }
  67
  68 static int max8952_write_reg(struct max8952_data *max8952,
  69                 u8 reg, u8 value)
  70 {
  71         return i2c_smbus_write_byte_data(max8952->client, reg, value);
  72 }
  73
  74 static int max8952_list_voltage(struct regulator_dev *rdev,
  75                 unsigned int selector)
  76 {
  77         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  78
  79         if (rdev_get_id(rdev) != 0)
  80                 return -EINVAL;
  81
  82         return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000;
  83 }
  84
  85 static int max8952_get_voltage_sel(struct regulator_dev *rdev)
  86 {
  87         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  88         u8 vid = 0;
  89
  90         if (max8952->vid0)
  91                 vid += 1;
  92         if (max8952->vid1)
  93                 vid += 2;
  94
  95         return vid;
  96 }
  97
  98 static int max8952_set_voltage_sel(struct regulator_dev *rdev,
  99                                    unsigned selector)
 100 {
 101         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
 102
 103         if (!gpio_is_valid(max8952->pdata->gpio_vid0) ||
 104                         !gpio_is_valid(max8952->pdata->gpio_vid1)) {
 105                 /* DVS not supported */
 106                 return -EPERM;
 107         }
 108
 109         max8952->vid0 = selector & 0x1;
 110         max8952->vid1 = (selector >> 1) & 0x1;
 111         gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0);
 112         gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1);
 113
 114         return 0;
 115 }
 116
 117 static struct regulator_ops max8952_ops = {
 118         .list_voltage           = max8952_list_voltage,
 119         .get_voltage_sel        = max8952_get_voltage_sel,
 120         .set_voltage_sel        = max8952_set_voltage_sel,
 121 };
 122
 123 static const struct regulator_desc regulator = {
 124         .name           = "MAX8952_VOUT",
 125         .id             = 0,
 126         .n_voltages     = MAX8952_NUM_DVS_MODE,
 127         .ops            = &max8952_ops,
 128         .type           = REGULATOR_VOLTAGE,
 129         .owner          = THIS_MODULE,
 130 };
 131
 132 #ifdef CONFIG_OF
 133 static struct of_device_id max8952_dt_match[] = {
 134         { .compatible = "maxim,max8952" },
 135         {},
 136 };
 137 MODULE_DEVICE_TABLE(of, max8952_dt_match);
 138
 139 static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
 140 {
 141         struct max8952_platform_data *pd;
 142         struct device_node *np = dev->of_node;
 143         int ret;
 144         int i;
 145
 146         pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
 147         if (!pd) {
 148                 dev_err(dev, "Failed to allocate platform data\n");
 149                 return NULL;
 150         }
 151
 152         pd->gpio_vid0 = of_get_named_gpio(np, "max8952,vid-gpios", 0);
 153         pd->gpio_vid1 = of_get_named_gpio(np, "max8952,vid-gpios", 1);
 154         pd->gpio_en = of_get_named_gpio(np, "max8952,en-gpio", 0);
 155
 156         if (of_property_read_u32(np, "max8952,default-mode", &pd->default_mode))
 157                 dev_warn(dev, "Default mode not specified, assuming 0\n");
 158
 159         ret = of_property_read_u32_array(np, "max8952,dvs-mode-microvolt",
 160                                         pd->dvs_mode, ARRAY_SIZE(pd->dvs_mode));
 161         if (ret) {
 162                 dev_err(dev, "max8952,dvs-mode-microvolt property not specified");
 163                 return NULL;
 164         }
 165
 166         for (i = 0; i < ARRAY_SIZE(pd->dvs_mode); ++i) {
 167                 if (pd->dvs_mode[i] < 770000 || pd->dvs_mode[i] > 1400000) {
 168                         dev_err(dev, "DVS voltage %d out of range\n", i);
 169                         return NULL;
 170                 }
 171                 pd->dvs_mode[i] = (pd->dvs_mode[i] - 770000) / 10000;
 172         }
 173
 174         if (of_property_read_u32(np, "max8952,sync-freq", &pd->sync_freq))
 175                 dev_warn(dev, "max8952,sync-freq property not specified, defaulting to 26MHz\n");
 176
 177         if (of_property_read_u32(np, "max8952,ramp-speed", &pd->ramp_speed))
 178                 dev_warn(dev, "max8952,ramp-speed property not specified, defaulting to 32mV/us\n");
 179
 180         pd->reg_data = of_get_regulator_init_data(dev, np);
 181         if (!pd->reg_data) {
 182                 dev_err(dev, "Failed to parse regulator init data\n");
 183                 return NULL;
 184         }
 185
 186         return pd;
 187 }
 188 #else
 189 static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
 190 {
 191         return NULL;
 192 }
 193 #endif
 194
 195 static int max8952_pmic_probe(struct i2c_client *client,
 196                 const struct i2c_device_id *i2c_id)
 197 {
 198         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 199         struct max8952_platform_data *pdata = client->dev.platform_data;
 200         struct regulator_config config = { };
 201         struct max8952_data *max8952;
 202
 203         int ret = 0, err = 0;
 204
 205         if (client->dev.of_node)
 206                 pdata = max8952_parse_dt(&client->dev);
 207
 208         if (!pdata) {
 209                 dev_err(&client->dev, "Require the platform data\n");
 210                 return -EINVAL;
 211         }
 212
 213         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
 214                 return -EIO;
 215
 216         max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data),
 217                                GFP_KERNEL);
 218         if (!max8952)
 219                 return -ENOMEM;
 220
 221         max8952->client = client;
 222         max8952->dev = &client->dev;
 223         max8952->pdata = pdata;
 224
 225         config.dev = max8952->dev;
 226         config.init_data = pdata->reg_data;
 227         config.driver_data = max8952;
 228         config.of_node = client->dev.of_node;
 229
 230         config.ena_gpio = pdata->gpio_en;
 231         if (pdata->reg_data->constraints.boot_on)
 232                 config.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 233
 234         max8952->rdev = regulator_register(&regulator, &config);
 235
 236         if (IS_ERR(max8952->rdev)) {
 237                 ret = PTR_ERR(max8952->rdev);
 238                 dev_err(max8952->dev, "regulator init failed (%d)\n", ret);
 239                 return ret;
 240         }
 241
 242         max8952->vid0 = pdata->default_mode & 0x1;
 243         max8952->vid1 = (pdata->default_mode >> 1) & 0x1;
 244
 245         if (gpio_is_valid(pdata->gpio_vid0) &&
 246                         gpio_is_valid(pdata->gpio_vid1)) {
 247                 if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0"))
 248                         gpio_direction_output(pdata->gpio_vid0,
 249                                         (pdata->default_mode) & 0x1);
 250                 else
 251                         err = 1;
 252
 253                 if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1"))
 254                         gpio_direction_output(pdata->gpio_vid1,
 255                                 (pdata->default_mode >> 1) & 0x1);
 256                 else {
 257                         if (!err)
 258                                 gpio_free(pdata->gpio_vid0);
 259                         err = 2;
 260                 }
 261
 262         } else
 263                 err = 3;
 264
 265         if (err) {
 266                 dev_warn(max8952->dev, "VID0/1 gpio invalid: "
 267                                 "DVS not available.\n");
 268                 max8952->vid0 = 0;
 269                 max8952->vid1 = 0;
 270                 /* Mark invalid */
 271                 pdata->gpio_vid0 = -1;
 272                 pdata->gpio_vid1 = -1;
 273
 274                 /* Disable Pulldown of EN only */
 275                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
 276
 277                 dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1"
 278                                 " do not have proper controls.\n");
 279         } else {
 280                 /*
 281                  * Disable Pulldown on EN, VID0, VID1 to reduce
 282                  * leakage current of MAX8952 assuming that MAX8952
 283                  * is turned on (EN==1). Note that without having VID0/1
 284                  * properly connected, turning pulldown off can be
 285                  * problematic. Thus, turn this off only when they are
 286                  * controllable by GPIO.
 287                  */
 288                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
 289         }
 290
 291         max8952_write_reg(max8952, MAX8952_REG_MODE0,
 292                         (max8952_read_reg(max8952,
 293                                           MAX8952_REG_MODE0) & 0xC0) |
 294                         (pdata->dvs_mode[0] & 0x3F));
 295         max8952_write_reg(max8952, MAX8952_REG_MODE1,
 296                         (max8952_read_reg(max8952,
 297                                           MAX8952_REG_MODE1) & 0xC0) |
 298                         (pdata->dvs_mode[1] & 0x3F));
 299         max8952_write_reg(max8952, MAX8952_REG_MODE2,
 300                         (max8952_read_reg(max8952,
 301                                           MAX8952_REG_MODE2) & 0xC0) |
 302                         (pdata->dvs_mode[2] & 0x3F));
 303         max8952_write_reg(max8952, MAX8952_REG_MODE3,
 304                         (max8952_read_reg(max8952,
 305                                           MAX8952_REG_MODE3) & 0xC0) |
 306                         (pdata->dvs_mode[3] & 0x3F));
 307
 308         max8952_write_reg(max8952, MAX8952_REG_SYNC,
 309                         (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
 310                         ((pdata->sync_freq & 0x3) << 6));
 311         max8952_write_reg(max8952, MAX8952_REG_RAMP,
 312                         (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
 313                         ((pdata->ramp_speed & 0x7) << 5));
 314
 315         i2c_set_clientdata(client, max8952);
 316
 317         return 0;
 318 }
 319
 320 static int max8952_pmic_remove(struct i2c_client *client)
 321 {
 322         struct max8952_data *max8952 = i2c_get_clientdata(client);
 323         struct max8952_platform_data *pdata = max8952->pdata;
 324         struct regulator_dev *rdev = max8952->rdev;
 325
 326         regulator_unregister(rdev);
 327
 328         gpio_free(pdata->gpio_vid0);
 329         gpio_free(pdata->gpio_vid1);
 330         return 0;
 331 }
 332
 333 static const struct i2c_device_id max8952_ids[] = {
 334         { "max8952", 0 },
 335         { },
 336 };
 337 MODULE_DEVICE_TABLE(i2c, max8952_ids);
 338
 339 static struct i2c_driver max8952_pmic_driver = {
 340         .probe          = max8952_pmic_probe,
 341         .remove         = max8952_pmic_remove,
 342         .driver         = {
 343                 .name   = "max8952",
 344                 .of_match_table = of_match_ptr(max8952_dt_match),
 345         },
 346         .id_table       = max8952_ids,
 347 };
 348
 349 static int __init max8952_pmic_init(void)
 350 {
 351         return i2c_add_driver(&max8952_pmic_driver);
 352 }
 353 subsys_initcall(max8952_pmic_init);
 354
 355 static void __exit max8952_pmic_exit(void)
 356 {
 357         i2c_del_driver(&max8952_pmic_driver);
 358 }
 359 module_exit(max8952_pmic_exit);
 360
 361 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
 362 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 363 MODULE_LICENSE("GPL");