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 device           *dev;
  52        struct max8952_platform_data *pdata;
  53        struct regulator_dev    *rdev;
  54
  55        bool vid0;
  56        bool vid1;
  57};
  58
  59static 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
  68static 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
  74static 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
  85static 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
  98static 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
 117static 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
 123static 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
 133static struct of_device_id max8952_dt_match[] = {
 134        { .compatible = "maxim,max8952" },
 135        {},
 136};
 137MODULE_DEVICE_TABLE(of, max8952_dt_match);
 138
 139static 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
 189static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
 190{
 191        return NULL;
 192}
 193#endif
 194
 195static 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
 320static 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
 333static const struct i2c_device_id max8952_ids[] = {
 334        { "max8952", 0 },
 335        { },
 336};
 337MODULE_DEVICE_TABLE(i2c, max8952_ids);
 338
 339static 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
 349static int __init max8952_pmic_init(void)
 350{
 351        return i2c_add_driver(&max8952_pmic_driver);
 352}
 353subsys_initcall(max8952_pmic_init);
 354
 355static void __exit max8952_pmic_exit(void)
 356{
 357        i2c_del_driver(&max8952_pmic_driver);
 358}
 359module_exit(max8952_pmic_exit);
 360
 361MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
 362MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 363MODULE_LICENSE("GPL");
 364
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