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