drivers/regulator/max8952.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * max8952.c - Voltage and current regulation for the Maxim 8952
   4  *
   5  * Copyright (C) 2010 Samsung Electronics
   6  * MyungJoo Ham <myungjoo.ham@samsung.com>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/init.h>
  11 #include <linux/i2c.h>
  12 #include <linux/err.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/regulator/driver.h>
  15 #include <linux/regulator/max8952.h>
  16 #include <linux/gpio/consumer.h>
  17 #include <linux/io.h>
  18 #include <linux/of.h>
  19 #include <linux/regulator/of_regulator.h>
  20 #include <linux/slab.h>
  21
  22 /* Registers */
  23 enum {
  24         MAX8952_REG_MODE0,
  25         MAX8952_REG_MODE1,
  26         MAX8952_REG_MODE2,
  27         MAX8952_REG_MODE3,
  28         MAX8952_REG_CONTROL,
  29         MAX8952_REG_SYNC,
  30         MAX8952_REG_RAMP,
  31         MAX8952_REG_CHIP_ID1,
  32         MAX8952_REG_CHIP_ID2,
  33 };
  34
  35 struct max8952_data {
  36         struct i2c_client       *client;
  37         struct max8952_platform_data *pdata;
  38         struct gpio_desc *vid0_gpiod;
  39         struct gpio_desc *vid1_gpiod;
  40         bool vid0;
  41         bool vid1;
  42 };
  43
  44 static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
  45 {
  46         int ret = i2c_smbus_read_byte_data(max8952->client, reg);
  47
  48         if (ret > 0)
  49                 ret &= 0xff;
  50
  51         return ret;
  52 }
  53
  54 static int max8952_write_reg(struct max8952_data *max8952,
  55                 u8 reg, u8 value)
  56 {
  57         return i2c_smbus_write_byte_data(max8952->client, reg, value);
  58 }
  59
  60 static int max8952_list_voltage(struct regulator_dev *rdev,
  61                 unsigned int selector)
  62 {
  63         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  64
  65         if (rdev_get_id(rdev) != 0)
  66                 return -EINVAL;
  67
  68         return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000;
  69 }
  70
  71 static int max8952_get_voltage_sel(struct regulator_dev *rdev)
  72 {
  73         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  74         u8 vid = 0;
  75
  76         if (max8952->vid0)
  77                 vid += 1;
  78         if (max8952->vid1)
  79                 vid += 2;
  80
  81         return vid;
  82 }
  83
  84 static int max8952_set_voltage_sel(struct regulator_dev *rdev,
  85                                    unsigned selector)
  86 {
  87         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  88
  89         if (!max8952->vid0_gpiod || !max8952->vid1_gpiod) {
  90                 /* DVS not supported */
  91                 return -EPERM;
  92         }
  93
  94         max8952->vid0 = selector & 0x1;
  95         max8952->vid1 = (selector >> 1) & 0x1;
  96         gpiod_set_value(max8952->vid0_gpiod, max8952->vid0);
  97         gpiod_set_value(max8952->vid1_gpiod, max8952->vid1);
  98
  99         return 0;
 100 }
 101
 102 static const struct regulator_ops max8952_ops = {
 103         .list_voltage           = max8952_list_voltage,
 104         .get_voltage_sel        = max8952_get_voltage_sel,
 105         .set_voltage_sel        = max8952_set_voltage_sel,
 106 };
 107
 108 static const struct regulator_desc regulator = {
 109         .name           = "MAX8952_VOUT",
 110         .id             = 0,
 111         .n_voltages     = MAX8952_NUM_DVS_MODE,
 112         .ops            = &max8952_ops,
 113         .type           = REGULATOR_VOLTAGE,
 114         .owner          = THIS_MODULE,
 115 };
 116
 117 #ifdef CONFIG_OF
 118 static const struct of_device_id max8952_dt_match[] = {
 119         { .compatible = "maxim,max8952" },
 120         {},
 121 };
 122 MODULE_DEVICE_TABLE(of, max8952_dt_match);
 123
 124 static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
 125 {
 126         struct max8952_platform_data *pd;
 127         struct device_node *np = dev->of_node;
 128         int ret;
 129         int i;
 130
 131         pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
 132         if (!pd)
 133                 return NULL;
 134
 135         if (of_property_read_u32(np, "max8952,default-mode", &pd->default_mode))
 136                 dev_warn(dev, "Default mode not specified, assuming 0\n");
 137
 138         ret = of_property_read_u32_array(np, "max8952,dvs-mode-microvolt",
 139                                         pd->dvs_mode, ARRAY_SIZE(pd->dvs_mode));
 140         if (ret) {
 141                 dev_err(dev, "max8952,dvs-mode-microvolt property not specified");
 142                 return NULL;
 143         }
 144
 145         for (i = 0; i < ARRAY_SIZE(pd->dvs_mode); ++i) {
 146                 if (pd->dvs_mode[i] < 770000 || pd->dvs_mode[i] > 1400000) {
 147                         dev_err(dev, "DVS voltage %d out of range\n", i);
 148                         return NULL;
 149                 }
 150                 pd->dvs_mode[i] = (pd->dvs_mode[i] - 770000) / 10000;
 151         }
 152
 153         if (of_property_read_u32(np, "max8952,sync-freq", &pd->sync_freq))
 154                 dev_warn(dev, "max8952,sync-freq property not specified, defaulting to 26MHz\n");
 155
 156         if (of_property_read_u32(np, "max8952,ramp-speed", &pd->ramp_speed))
 157                 dev_warn(dev, "max8952,ramp-speed property not specified, defaulting to 32mV/us\n");
 158
 159         pd->reg_data = of_get_regulator_init_data(dev, np, &regulator);
 160         if (!pd->reg_data) {
 161                 dev_err(dev, "Failed to parse regulator init data\n");
 162                 return NULL;
 163         }
 164
 165         return pd;
 166 }
 167 #else
 168 static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
 169 {
 170         return NULL;
 171 }
 172 #endif
 173
 174 static int max8952_pmic_probe(struct i2c_client *client)
 175 {
 176         struct i2c_adapter *adapter = client->adapter;
 177         struct max8952_platform_data *pdata = dev_get_platdata(&client->dev);
 178         struct regulator_config config = { };
 179         struct max8952_data *max8952;
 180         struct regulator_dev *rdev;
 181         struct gpio_desc *gpiod;
 182         enum gpiod_flags gflags;
 183
 184         int ret = 0;
 185
 186         if (client->dev.of_node)
 187                 pdata = max8952_parse_dt(&client->dev);
 188
 189         if (!pdata) {
 190                 dev_err(&client->dev, "Require the platform data\n");
 191                 return -EINVAL;
 192         }
 193
 194         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
 195                 return -EIO;
 196
 197         max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data),
 198                                GFP_KERNEL);
 199         if (!max8952)
 200                 return -ENOMEM;
 201
 202         max8952->client = client;
 203         max8952->pdata = pdata;
 204
 205         config.dev = &client->dev;
 206         config.init_data = pdata->reg_data;
 207         config.driver_data = max8952;
 208         config.of_node = client->dev.of_node;
 209
 210         if (pdata->reg_data->constraints.boot_on)
 211                 gflags = GPIOD_OUT_HIGH;
 212         else
 213                 gflags = GPIOD_OUT_LOW;
 214         gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
 215         /*
 216          * Do not use devm* here: the regulator core takes over the
 217          * lifecycle management of the GPIO descriptor.
 218          */
 219         gpiod = gpiod_get_optional(&client->dev,
 220                                    "max8952,en",
 221                                    gflags);
 222         if (IS_ERR(gpiod))
 223                 return PTR_ERR(gpiod);
 224         if (gpiod)
 225                 config.ena_gpiod = gpiod;
 226
 227         rdev = devm_regulator_register(&client->dev, &regulator, &config);
 228         if (IS_ERR(rdev)) {
 229                 ret = PTR_ERR(rdev);
 230                 dev_err(&client->dev, "regulator init failed (%d)\n", ret);
 231                 return ret;
 232         }
 233
 234         max8952->vid0 = pdata->default_mode & 0x1;
 235         max8952->vid1 = (pdata->default_mode >> 1) & 0x1;
 236
 237         /* Fetch vid0 and vid1 GPIOs if available */
 238         gflags = max8952->vid0 ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
 239         max8952->vid0_gpiod = devm_gpiod_get_index_optional(&client->dev,
 240                                                             "max8952,vid",
 241                                                             0, gflags);
 242         if (IS_ERR(max8952->vid0_gpiod))
 243                 return PTR_ERR(max8952->vid0_gpiod);
 244         gflags = max8952->vid1 ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
 245         max8952->vid1_gpiod = devm_gpiod_get_index_optional(&client->dev,
 246                                                             "max8952,vid",
 247                                                             1, gflags);
 248         if (IS_ERR(max8952->vid1_gpiod))
 249                 return PTR_ERR(max8952->vid1_gpiod);
 250
 251         /* If either VID GPIO is missing just disable this */
 252         if (!max8952->vid0_gpiod || !max8952->vid1_gpiod) {
 253                 dev_warn(&client->dev, "VID0/1 gpio invalid: "
 254                          "DVS not available.\n");
 255                 max8952->vid0 = 0;
 256                 max8952->vid1 = 0;
 257                 /* Make sure if we have any descriptors they get set to low */
 258                 if (max8952->vid0_gpiod)
 259                         gpiod_set_value(max8952->vid0_gpiod, 0);
 260                 if (max8952->vid1_gpiod)
 261                         gpiod_set_value(max8952->vid1_gpiod, 0);
 262
 263                 /* Disable Pulldown of EN only */
 264                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
 265
 266                 dev_err(&client->dev, "DVS modes disabled because VID0 and VID1"
 267                                 " do not have proper controls.\n");
 268         } else {
 269                 /*
 270                  * Disable Pulldown on EN, VID0, VID1 to reduce
 271                  * leakage current of MAX8952 assuming that MAX8952
 272                  * is turned on (EN==1). Note that without having VID0/1
 273                  * properly connected, turning pulldown off can be
 274                  * problematic. Thus, turn this off only when they are
 275                  * controllable by GPIO.
 276                  */
 277                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
 278         }
 279
 280         max8952_write_reg(max8952, MAX8952_REG_MODE0,
 281                         (max8952_read_reg(max8952,
 282                                           MAX8952_REG_MODE0) & 0xC0) |
 283                         (pdata->dvs_mode[0] & 0x3F));
 284         max8952_write_reg(max8952, MAX8952_REG_MODE1,
 285                         (max8952_read_reg(max8952,
 286                                           MAX8952_REG_MODE1) & 0xC0) |
 287                         (pdata->dvs_mode[1] & 0x3F));
 288         max8952_write_reg(max8952, MAX8952_REG_MODE2,
 289                         (max8952_read_reg(max8952,
 290                                           MAX8952_REG_MODE2) & 0xC0) |
 291                         (pdata->dvs_mode[2] & 0x3F));
 292         max8952_write_reg(max8952, MAX8952_REG_MODE3,
 293                         (max8952_read_reg(max8952,
 294                                           MAX8952_REG_MODE3) & 0xC0) |
 295                         (pdata->dvs_mode[3] & 0x3F));
 296
 297         max8952_write_reg(max8952, MAX8952_REG_SYNC,
 298                         (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
 299                         ((pdata->sync_freq & 0x3) << 6));
 300         max8952_write_reg(max8952, MAX8952_REG_RAMP,
 301                         (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
 302                         ((pdata->ramp_speed & 0x7) << 5));
 303
 304         i2c_set_clientdata(client, max8952);
 305
 306         return 0;
 307 }
 308
 309 static const struct i2c_device_id max8952_ids[] = {
 310         { "max8952" },
 311         { }
 312 };
 313 MODULE_DEVICE_TABLE(i2c, max8952_ids);
 314
 315 static struct i2c_driver max8952_pmic_driver = {
 316         .probe          = max8952_pmic_probe,
 317         .driver         = {
 318                 .name   = "max8952",
 319                 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
 320                 .of_match_table = of_match_ptr(max8952_dt_match),
 321         },
 322         .id_table       = max8952_ids,
 323 };
 324
 325 static int __init max8952_pmic_init(void)
 326 {
 327         return i2c_add_driver(&max8952_pmic_driver);
 328 }
 329 subsys_initcall(max8952_pmic_init);
 330
 331 static void __exit max8952_pmic_exit(void)
 332 {
 333         i2c_del_driver(&max8952_pmic_driver);
 334 }
 335 module_exit(max8952_pmic_exit);
 336
 337 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
 338 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 339 MODULE_LICENSE("GPL");