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 };
  55
  56 static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
  57 {
  58         int ret = i2c_smbus_read_byte_data(max8952->client, reg);
  59         if (ret > 0)
  60                 ret &= 0xff;
  61
  62         return ret;
  63 }
  64
  65 static int max8952_write_reg(struct max8952_data *max8952,
  66                 u8 reg, u8 value)
  67 {
  68         return i2c_smbus_write_byte_data(max8952->client, reg, value);
  69 }
  70
  71 static int max8952_list_voltage(struct regulator_dev *rdev,
  72                 unsigned int selector)
  73 {
  74         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  75
  76         if (rdev_get_id(rdev) != 0)
  77                 return -EINVAL;
  78
  79         return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000;
  80 }
  81
  82 static int max8952_get_voltage_sel(struct regulator_dev *rdev)
  83 {
  84         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  85         u8 vid = 0;
  86
  87         if (max8952->vid0)
  88                 vid += 1;
  89         if (max8952->vid1)
  90                 vid += 2;
  91
  92         return vid;
  93 }
  94
  95 static int max8952_set_voltage_sel(struct regulator_dev *rdev,
  96                                    unsigned selector)
  97 {
  98         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  99
 100         if (!gpio_is_valid(max8952->pdata->gpio_vid0) ||
 101                         !gpio_is_valid(max8952->pdata->gpio_vid1)) {
 102                 /* DVS not supported */
 103                 return -EPERM;
 104         }
 105
 106         max8952->vid0 = selector & 0x1;
 107         max8952->vid1 = (selector >> 1) & 0x1;
 108         gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0);
 109         gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1);
 110
 111         return 0;
 112 }
 113
 114 static struct regulator_ops max8952_ops = {
 115         .list_voltage           = max8952_list_voltage,
 116         .get_voltage_sel        = max8952_get_voltage_sel,
 117         .set_voltage_sel        = max8952_set_voltage_sel,
 118 };
 119
 120 static const struct regulator_desc regulator = {
 121         .name           = "MAX8952_VOUT",
 122         .id             = 0,
 123         .n_voltages     = MAX8952_NUM_DVS_MODE,
 124         .ops            = &max8952_ops,
 125         .type           = REGULATOR_VOLTAGE,
 126         .owner          = THIS_MODULE,
 127 };
 128
 129 static int __devinit max8952_pmic_probe(struct i2c_client *client,
 130                 const struct i2c_device_id *i2c_id)
 131 {
 132         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 133         struct max8952_platform_data *pdata = client->dev.platform_data;
 134         struct regulator_config config = { };
 135         struct max8952_data *max8952;
 136
 137         int ret = 0, err = 0;
 138
 139         if (!pdata) {
 140                 dev_err(&client->dev, "Require the platform data\n");
 141                 return -EINVAL;
 142         }
 143
 144         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
 145                 return -EIO;
 146
 147         max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data),
 148                                GFP_KERNEL);
 149         if (!max8952)
 150                 return -ENOMEM;
 151
 152         max8952->client = client;
 153         max8952->dev = &client->dev;
 154         max8952->pdata = pdata;
 155
 156         config.dev = max8952->dev;
 157         config.init_data = &pdata->reg_data;
 158         config.driver_data = max8952;
 159
 160         config.ena_gpio = pdata->gpio_en;
 161         if (pdata->reg_data.constraints.boot_on)
 162                 config.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 163
 164         max8952->rdev = regulator_register(&regulator, &config);
 165
 166         if (IS_ERR(max8952->rdev)) {
 167                 ret = PTR_ERR(max8952->rdev);
 168                 dev_err(max8952->dev, "regulator init failed (%d)\n", ret);
 169                 return ret;
 170         }
 171
 172         max8952->vid0 = pdata->default_mode & 0x1;
 173         max8952->vid1 = (pdata->default_mode >> 1) & 0x1;
 174
 175         if (gpio_is_valid(pdata->gpio_vid0) &&
 176                         gpio_is_valid(pdata->gpio_vid1)) {
 177                 if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0"))
 178                         gpio_direction_output(pdata->gpio_vid0,
 179                                         (pdata->default_mode) & 0x1);
 180                 else
 181                         err = 1;
 182
 183                 if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1"))
 184                         gpio_direction_output(pdata->gpio_vid1,
 185                                 (pdata->default_mode >> 1) & 0x1);
 186                 else {
 187                         if (!err)
 188                                 gpio_free(pdata->gpio_vid0);
 189                         err = 2;
 190                 }
 191
 192         } else
 193                 err = 3;
 194
 195         if (err) {
 196                 dev_warn(max8952->dev, "VID0/1 gpio invalid: "
 197                                 "DVS not available.\n");
 198                 max8952->vid0 = 0;
 199                 max8952->vid1 = 0;
 200                 /* Mark invalid */
 201                 pdata->gpio_vid0 = -1;
 202                 pdata->gpio_vid1 = -1;
 203
 204                 /* Disable Pulldown of EN only */
 205                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
 206
 207                 dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1"
 208                                 " do not have proper controls.\n");
 209         } else {
 210                 /*
 211                  * Disable Pulldown on EN, VID0, VID1 to reduce
 212                  * leakage current of MAX8952 assuming that MAX8952
 213                  * is turned on (EN==1). Note that without having VID0/1
 214                  * properly connected, turning pulldown off can be
 215                  * problematic. Thus, turn this off only when they are
 216                  * controllable by GPIO.
 217                  */
 218                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
 219         }
 220
 221         max8952_write_reg(max8952, MAX8952_REG_MODE0,
 222                         (max8952_read_reg(max8952,
 223                                           MAX8952_REG_MODE0) & 0xC0) |
 224                         (pdata->dvs_mode[0] & 0x3F));
 225         max8952_write_reg(max8952, MAX8952_REG_MODE1,
 226                         (max8952_read_reg(max8952,
 227                                           MAX8952_REG_MODE1) & 0xC0) |
 228                         (pdata->dvs_mode[1] & 0x3F));
 229         max8952_write_reg(max8952, MAX8952_REG_MODE2,
 230                         (max8952_read_reg(max8952,
 231                                           MAX8952_REG_MODE2) & 0xC0) |
 232                         (pdata->dvs_mode[2] & 0x3F));
 233         max8952_write_reg(max8952, MAX8952_REG_MODE3,
 234                         (max8952_read_reg(max8952,
 235                                           MAX8952_REG_MODE3) & 0xC0) |
 236                         (pdata->dvs_mode[3] & 0x3F));
 237
 238         max8952_write_reg(max8952, MAX8952_REG_SYNC,
 239                         (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
 240                         ((pdata->sync_freq & 0x3) << 6));
 241         max8952_write_reg(max8952, MAX8952_REG_RAMP,
 242                         (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
 243                         ((pdata->ramp_speed & 0x7) << 5));
 244
 245         i2c_set_clientdata(client, max8952);
 246
 247         return 0;
 248 }
 249
 250 static int __devexit max8952_pmic_remove(struct i2c_client *client)
 251 {
 252         struct max8952_data *max8952 = i2c_get_clientdata(client);
 253         struct max8952_platform_data *pdata = max8952->pdata;
 254         struct regulator_dev *rdev = max8952->rdev;
 255
 256         regulator_unregister(rdev);
 257
 258         gpio_free(pdata->gpio_vid0);
 259         gpio_free(pdata->gpio_vid1);
 260         return 0;
 261 }
 262
 263 static const struct i2c_device_id max8952_ids[] = {
 264         { "max8952", 0 },
 265         { },
 266 };
 267 MODULE_DEVICE_TABLE(i2c, max8952_ids);
 268
 269 static struct i2c_driver max8952_pmic_driver = {
 270         .probe          = max8952_pmic_probe,
 271         .remove         = __devexit_p(max8952_pmic_remove),
 272         .driver         = {
 273                 .name   = "max8952",
 274         },
 275         .id_table       = max8952_ids,
 276 };
 277
 278 static int __init max8952_pmic_init(void)
 279 {
 280         return i2c_add_driver(&max8952_pmic_driver);
 281 }
 282 subsys_initcall(max8952_pmic_init);
 283
 284 static void __exit max8952_pmic_exit(void)
 285 {
 286         i2c_del_driver(&max8952_pmic_driver);
 287 }
 288 module_exit(max8952_pmic_exit);
 289
 290 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
 291 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 292 MODULE_LICENSE("GPL");