drivers/regulator/max1586.c

   1 /*
   2  * max1586.c  --  Voltage and current regulation for the Maxim 1586
   3  *
   4  * Copyright (C) 2008 Robert Jarzmik
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #include <linux/module.h>
  21 #include <linux/err.h>
  22 #include <linux/i2c.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/regulator/driver.h>
  25 #include <linux/slab.h>
  26 #include <linux/regulator/max1586.h>
  27 #include <linux/of_device.h>
  28 #include <linux/regulator/of_regulator.h>
  29
  30 #define MAX1586_V3_MAX_VSEL 31
  31 #define MAX1586_V6_MAX_VSEL 3
  32
  33 #define MAX1586_V3_MIN_UV   700000
  34 #define MAX1586_V3_MAX_UV  1475000
  35
  36 #define MAX1586_V6_MIN_UV        0
  37 #define MAX1586_V6_MAX_UV  3000000
  38
  39 #define I2C_V3_SELECT (0 << 5)
  40 #define I2C_V6_SELECT (1 << 5)
  41
  42 struct max1586_data {
  43         struct i2c_client *client;
  44
  45         /* min/max V3 voltage */
  46         unsigned int min_uV;
  47         unsigned int max_uV;
  48
  49         unsigned int v3_curr_sel;
  50         unsigned int v6_curr_sel;
  51 };
  52
  53 /*
  54  * V6 voltage
  55  * On I2C bus, sending a "x" byte to the max1586 means :
  56  *   set V6 to either 0V, 1.8V, 2.5V, 3V depending on (x & 0x3)
  57  * As regulator framework doesn't accept voltages to be 0V, we use 1uV.
  58  */
  59 static const unsigned int v6_voltages_uv[] = { 1, 1800000, 2500000, 3000000 };
  60
  61 /*
  62  * V3 voltage
  63  * On I2C bus, sending a "x" byte to the max1586 means :
  64  *   set V3 to 0.700V + (x & 0x1f) * 0.025V
  65  * This voltage can be increased by external resistors
  66  * R24 and R25=100kOhm as described in the data sheet.
  67  * The gain is approximately: 1 + R24/R25 + R24/185.5kOhm
  68  */
  69 static int max1586_v3_get_voltage_sel(struct regulator_dev *rdev)
  70 {
  71         struct max1586_data *max1586 = rdev_get_drvdata(rdev);
  72
  73         return max1586->v3_curr_sel;
  74 }
  75
  76 static int max1586_v3_set_voltage_sel(struct regulator_dev *rdev,
  77                                       unsigned selector)
  78 {
  79         struct max1586_data *max1586 = rdev_get_drvdata(rdev);
  80         struct i2c_client *client = max1586->client;
  81         int ret;
  82         u8 v3_prog;
  83
  84         dev_dbg(&client->dev, "changing voltage v3 to %dmv\n",
  85                 regulator_list_voltage_linear(rdev, selector) / 1000);
  86
  87         v3_prog = I2C_V3_SELECT | (u8) selector;
  88         ret = i2c_smbus_write_byte(client, v3_prog);
  89         if (ret)
  90                 return ret;
  91
  92         max1586->v3_curr_sel = selector;
  93
  94         return 0;
  95 }
  96
  97 static int max1586_v6_get_voltage_sel(struct regulator_dev *rdev)
  98 {
  99         struct max1586_data *max1586 = rdev_get_drvdata(rdev);
 100
 101         return max1586->v6_curr_sel;
 102 }
 103
 104 static int max1586_v6_set_voltage_sel(struct regulator_dev *rdev,
 105                                       unsigned int selector)
 106 {
 107         struct max1586_data *max1586 = rdev_get_drvdata(rdev);
 108         struct i2c_client *client = max1586->client;
 109         u8 v6_prog;
 110         int ret;
 111
 112         dev_dbg(&client->dev, "changing voltage v6 to %dmv\n",
 113                 rdev->desc->volt_table[selector] / 1000);
 114
 115         v6_prog = I2C_V6_SELECT | (u8) selector;
 116         ret = i2c_smbus_write_byte(client, v6_prog);
 117         if (ret)
 118                 return ret;
 119
 120         max1586->v6_curr_sel = selector;
 121
 122         return 0;
 123 }
 124
 125 /*
 126  * The Maxim 1586 controls V3 and V6 voltages, but offers no way of reading back
 127  * the set up value.
 128  */
 129 static const struct regulator_ops max1586_v3_ops = {
 130         .get_voltage_sel = max1586_v3_get_voltage_sel,
 131         .set_voltage_sel = max1586_v3_set_voltage_sel,
 132         .list_voltage = regulator_list_voltage_linear,
 133         .map_voltage = regulator_map_voltage_linear,
 134 };
 135
 136 static const struct regulator_ops max1586_v6_ops = {
 137         .get_voltage_sel = max1586_v6_get_voltage_sel,
 138         .set_voltage_sel = max1586_v6_set_voltage_sel,
 139         .list_voltage = regulator_list_voltage_table,
 140 };
 141
 142 static struct regulator_desc max1586_reg[] = {
 143         {
 144                 .name = "Output_V3",
 145                 .id = MAX1586_V3,
 146                 .ops = &max1586_v3_ops,
 147                 .type = REGULATOR_VOLTAGE,
 148                 .n_voltages = MAX1586_V3_MAX_VSEL + 1,
 149                 .owner = THIS_MODULE,
 150         },
 151         {
 152                 .name = "Output_V6",
 153                 .id = MAX1586_V6,
 154                 .ops = &max1586_v6_ops,
 155                 .type = REGULATOR_VOLTAGE,
 156                 .n_voltages = MAX1586_V6_MAX_VSEL + 1,
 157                 .volt_table = v6_voltages_uv,
 158                 .owner = THIS_MODULE,
 159         },
 160 };
 161
 162 static int of_get_max1586_platform_data(struct device *dev,
 163                                  struct max1586_platform_data *pdata)
 164 {
 165         struct max1586_subdev_data *sub;
 166         struct of_regulator_match rmatch[ARRAY_SIZE(max1586_reg)] = { };
 167         struct device_node *np = dev->of_node;
 168         int i, matched;
 169
 170         if (of_property_read_u32(np, "v3-gain",
 171                                  &pdata->v3_gain) < 0) {
 172                 dev_err(dev, "%pOF has no 'v3-gain' property\n", np);
 173                 return -EINVAL;
 174         }
 175
 176         np = of_get_child_by_name(np, "regulators");
 177         if (!np) {
 178                 dev_err(dev, "missing 'regulators' subnode in DT\n");
 179                 return -EINVAL;
 180         }
 181
 182         for (i = 0; i < ARRAY_SIZE(rmatch); i++)
 183                 rmatch[i].name = max1586_reg[i].name;
 184
 185         matched = of_regulator_match(dev, np, rmatch, ARRAY_SIZE(rmatch));
 186         of_node_put(np);
 187         /*
 188          * If matched is 0, ie. neither Output_V3 nor Output_V6 have been found,
 189          * return 0, which signals the normal situation where no subregulator is
 190          * available. This is normal because the max1586 doesn't provide any
 191          * readback support, so the subregulators can't report any status
 192          * anyway.  If matched < 0, return the error.
 193          */
 194         if (matched <= 0)
 195                 return matched;
 196
 197         pdata->subdevs = devm_kzalloc(dev, sizeof(struct max1586_subdev_data) *
 198                                                 matched, GFP_KERNEL);
 199         if (!pdata->subdevs)
 200                 return -ENOMEM;
 201
 202         pdata->num_subdevs = matched;
 203         sub = pdata->subdevs;
 204
 205         for (i = 0; i < matched; i++) {
 206                 sub->id = i;
 207                 sub->name = rmatch[i].of_node->name;
 208                 sub->platform_data = rmatch[i].init_data;
 209                 sub++;
 210         }
 211
 212         return 0;
 213 }
 214
 215 static const struct of_device_id max1586_of_match[] = {
 216         { .compatible = "maxim,max1586", },
 217         {},
 218 };
 219 MODULE_DEVICE_TABLE(of, max1586_of_match);
 220
 221 static int max1586_pmic_probe(struct i2c_client *client,
 222                                         const struct i2c_device_id *i2c_id)
 223 {
 224         struct max1586_platform_data *pdata, pdata_of;
 225         struct regulator_config config = { };
 226         struct max1586_data *max1586;
 227         int i, id, ret;
 228         const struct of_device_id *match;
 229
 230         pdata = dev_get_platdata(&client->dev);
 231         if (client->dev.of_node && !pdata) {
 232                 match = of_match_device(of_match_ptr(max1586_of_match),
 233                                         &client->dev);
 234                 if (!match) {
 235                         dev_err(&client->dev, "Error: No device match found\n");
 236                         return -ENODEV;
 237                 }
 238                 ret = of_get_max1586_platform_data(&client->dev, &pdata_of);
 239                 if (ret < 0)
 240                         return ret;
 241                 pdata = &pdata_of;
 242         }
 243
 244         max1586 = devm_kzalloc(&client->dev, sizeof(struct max1586_data),
 245                         GFP_KERNEL);
 246         if (!max1586)
 247                 return -ENOMEM;
 248
 249         max1586->client = client;
 250
 251         if (!pdata->v3_gain)
 252                 return -EINVAL;
 253
 254         max1586->min_uV = MAX1586_V3_MIN_UV / 1000 * pdata->v3_gain / 1000;
 255         max1586->max_uV = MAX1586_V3_MAX_UV / 1000 * pdata->v3_gain / 1000;
 256
 257         /* Set curr_sel to default voltage on power-up */
 258         max1586->v3_curr_sel = 24; /* 1.3V */
 259         max1586->v6_curr_sel = 0;
 260
 261         for (i = 0; i < pdata->num_subdevs && i <= MAX1586_V6; i++) {
 262                 struct regulator_dev *rdev;
 263
 264                 id = pdata->subdevs[i].id;
 265                 if (!pdata->subdevs[i].platform_data)
 266                         continue;
 267                 if (id < MAX1586_V3 || id > MAX1586_V6) {
 268                         dev_err(&client->dev, "invalid regulator id %d\n", id);
 269                         return -EINVAL;
 270                 }
 271
 272                 if (id == MAX1586_V3) {
 273                         max1586_reg[id].min_uV = max1586->min_uV;
 274                         max1586_reg[id].uV_step =
 275                                         (max1586->max_uV - max1586->min_uV) /
 276                                         MAX1586_V3_MAX_VSEL;
 277                 }
 278
 279                 config.dev = &client->dev;
 280                 config.init_data = pdata->subdevs[i].platform_data;
 281                 config.driver_data = max1586;
 282
 283                 rdev = devm_regulator_register(&client->dev,
 284                                                   &max1586_reg[id], &config);
 285                 if (IS_ERR(rdev)) {
 286                         dev_err(&client->dev, "failed to register %s\n",
 287                                 max1586_reg[id].name);
 288                         return PTR_ERR(rdev);
 289                 }
 290         }
 291
 292         i2c_set_clientdata(client, max1586);
 293         dev_info(&client->dev, "Maxim 1586 regulator driver loaded\n");
 294         return 0;
 295 }
 296
 297 static const struct i2c_device_id max1586_id[] = {
 298         { "max1586", 0 },
 299         { }
 300 };
 301 MODULE_DEVICE_TABLE(i2c, max1586_id);
 302
 303 static struct i2c_driver max1586_pmic_driver = {
 304         .probe = max1586_pmic_probe,
 305         .driver         = {
 306                 .name   = "max1586",
 307                 .of_match_table = of_match_ptr(max1586_of_match),
 308         },
 309         .id_table       = max1586_id,
 310 };
 311
 312 static int __init max1586_pmic_init(void)
 313 {
 314         return i2c_add_driver(&max1586_pmic_driver);
 315 }
 316 subsys_initcall(max1586_pmic_init);
 317
 318 static void __exit max1586_pmic_exit(void)
 319 {
 320         i2c_del_driver(&max1586_pmic_driver);
 321 }
 322 module_exit(max1586_pmic_exit);
 323
 324 /* Module information */
 325 MODULE_DESCRIPTION("MAXIM 1586 voltage regulator driver");
 326 MODULE_AUTHOR("Robert Jarzmik");
 327 MODULE_LICENSE("GPL");