linux/drivers/regulator/max8952.c
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   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 */
  34enum {
  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
  46struct 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
  56static 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
  65static 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
  71static 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
  82static 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
  95static 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
 114static 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
 120static 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
 129static int 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
 250static int 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
 263static const struct i2c_device_id max8952_ids[] = {
 264        { "max8952", 0 },
 265        { },
 266};
 267MODULE_DEVICE_TABLE(i2c, max8952_ids);
 268
 269static struct i2c_driver max8952_pmic_driver = {
 270        .probe          = max8952_pmic_probe,
 271        .remove         = max8952_pmic_remove,
 272        .driver         = {
 273                .name   = "max8952",
 274        },
 275        .id_table       = max8952_ids,
 276};
 277
 278static int __init max8952_pmic_init(void)
 279{
 280        return i2c_add_driver(&max8952_pmic_driver);
 281}
 282subsys_initcall(max8952_pmic_init);
 283
 284static void __exit max8952_pmic_exit(void)
 285{
 286        i2c_del_driver(&max8952_pmic_driver);
 287}
 288module_exit(max8952_pmic_exit);
 289
 290MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
 291MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 292MODULE_LICENSE("GPL");
 293
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