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/of.h>
  32#include <linux/of_gpio.h>
  33#include <linux/regulator/of_regulator.h>
  34#include <linux/slab.h>
  35
  36/* Registers */
  37enum {
  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
  49struct max8952_data {
  50        struct i2c_client       *client;
  51        struct max8952_platform_data *pdata;
  52
  53        bool vid0;
  54        bool vid1;
  55};
  56
  57static 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
  67static 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
  73static 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
  84static 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
  97static 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
 116static 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
 122static 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
 132static const struct of_device_id max8952_dt_match[] = {
 133        { .compatible = "maxim,max8952" },
 134        {},
 135};
 136MODULE_DEVICE_TABLE(of, max8952_dt_match);
 137
 138static 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, &regulator);
 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
 186static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
 187{
 188        return NULL;
 189}
 190#endif
 191
 192static 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 (client->dev.of_node)
 229                config.ena_gpio_initialized = true;
 230        if (pdata->reg_data->constraints.boot_on)
 231                config.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 232
 233        rdev = devm_regulator_register(&client->dev, &regulator, &config);
 234        if (IS_ERR(rdev)) {
 235                ret = PTR_ERR(rdev);
 236                dev_err(&client->dev, "regulator init failed (%d)\n", ret);
 237                return ret;
 238        }
 239
 240        max8952->vid0 = pdata->default_mode & 0x1;
 241        max8952->vid1 = (pdata->default_mode >> 1) & 0x1;
 242
 243        if (gpio_is_valid(pdata->gpio_vid0) &&
 244                        gpio_is_valid(pdata->gpio_vid1)) {
 245                unsigned long gpio_flags;
 246
 247                gpio_flags = max8952->vid0 ?
 248                             GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
 249                if (devm_gpio_request_one(&client->dev, pdata->gpio_vid0,
 250                                          gpio_flags, "MAX8952 VID0"))
 251                        err = 1;
 252
 253                gpio_flags = max8952->vid1 ?
 254                             GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
 255                if (devm_gpio_request_one(&client->dev, pdata->gpio_vid1,
 256                                          gpio_flags, "MAX8952 VID1"))
 257                        err = 2;
 258        } else
 259                err = 3;
 260
 261        if (err) {
 262                dev_warn(&client->dev, "VID0/1 gpio invalid: "
 263                                "DVS not available.\n");
 264                max8952->vid0 = 0;
 265                max8952->vid1 = 0;
 266                /* Mark invalid */
 267                pdata->gpio_vid0 = -1;
 268                pdata->gpio_vid1 = -1;
 269
 270                /* Disable Pulldown of EN only */
 271                max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
 272
 273                dev_err(&client->dev, "DVS modes disabled because VID0 and VID1"
 274                                " do not have proper controls.\n");
 275        } else {
 276                /*
 277                 * Disable Pulldown on EN, VID0, VID1 to reduce
 278                 * leakage current of MAX8952 assuming that MAX8952
 279                 * is turned on (EN==1). Note that without having VID0/1
 280                 * properly connected, turning pulldown off can be
 281                 * problematic. Thus, turn this off only when they are
 282                 * controllable by GPIO.
 283                 */
 284                max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
 285        }
 286
 287        max8952_write_reg(max8952, MAX8952_REG_MODE0,
 288                        (max8952_read_reg(max8952,
 289                                          MAX8952_REG_MODE0) & 0xC0) |
 290                        (pdata->dvs_mode[0] & 0x3F));
 291        max8952_write_reg(max8952, MAX8952_REG_MODE1,
 292                        (max8952_read_reg(max8952,
 293                                          MAX8952_REG_MODE1) & 0xC0) |
 294                        (pdata->dvs_mode[1] & 0x3F));
 295        max8952_write_reg(max8952, MAX8952_REG_MODE2,
 296                        (max8952_read_reg(max8952,
 297                                          MAX8952_REG_MODE2) & 0xC0) |
 298                        (pdata->dvs_mode[2] & 0x3F));
 299        max8952_write_reg(max8952, MAX8952_REG_MODE3,
 300                        (max8952_read_reg(max8952,
 301                                          MAX8952_REG_MODE3) & 0xC0) |
 302                        (pdata->dvs_mode[3] & 0x3F));
 303
 304        max8952_write_reg(max8952, MAX8952_REG_SYNC,
 305                        (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
 306                        ((pdata->sync_freq & 0x3) << 6));
 307        max8952_write_reg(max8952, MAX8952_REG_RAMP,
 308                        (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
 309                        ((pdata->ramp_speed & 0x7) << 5));
 310
 311        i2c_set_clientdata(client, max8952);
 312
 313        return 0;
 314}
 315
 316static const struct i2c_device_id max8952_ids[] = {
 317        { "max8952", 0 },
 318        { },
 319};
 320MODULE_DEVICE_TABLE(i2c, max8952_ids);
 321
 322static struct i2c_driver max8952_pmic_driver = {
 323        .probe          = max8952_pmic_probe,
 324        .driver         = {
 325                .name   = "max8952",
 326                .of_match_table = of_match_ptr(max8952_dt_match),
 327        },
 328        .id_table       = max8952_ids,
 329};
 330
 331static int __init max8952_pmic_init(void)
 332{
 333        return i2c_add_driver(&max8952_pmic_driver);
 334}
 335subsys_initcall(max8952_pmic_init);
 336
 337static void __exit max8952_pmic_exit(void)
 338{
 339        i2c_del_driver(&max8952_pmic_driver);
 340}
 341module_exit(max8952_pmic_exit);
 342
 343MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
 344MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 345MODULE_LICENSE("GPL");
 346