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/mutex.h> 30 #include <linux/gpio.h> 31 #include <linux/io.h> 32 #include <linux/slab.h> 33 34 /* Registers */ 35 enum { 36 MAX8952_REG_MODE0, 37 MAX8952_REG_MODE1, 38 MAX8952_REG_MODE2, 39 MAX8952_REG_MODE3, 40 MAX8952_REG_CONTROL, 41 MAX8952_REG_SYNC, 42 MAX8952_REG_RAMP, 43 MAX8952_REG_CHIP_ID1, 44 MAX8952_REG_CHIP_ID2, 45 }; 46 47 struct max8952_data { 48 struct i2c_client *client; 49 struct device *dev; 50 struct mutex mutex; 51 struct max8952_platform_data *pdata; 52 struct regulator_dev *rdev; 53 54 bool vid0; 55 bool vid1; 56 bool en; 57 }; 58 59 static 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 68 static 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 74 static int max8952_voltage(struct max8952_data *max8952, u8 mode) 75 { 76 return (max8952->pdata->dvs_mode[mode] * 10 + 770) * 1000; 77 } 78 79 static int max8952_list_voltage(struct regulator_dev *rdev, 80 unsigned int selector) 81 { 82 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 83 84 if (rdev_get_id(rdev) != 0) 85 return -EINVAL; 86 87 return max8952_voltage(max8952, selector); 88 } 89 90 static int max8952_is_enabled(struct regulator_dev *rdev) 91 { 92 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 93 return max8952->en; 94 } 95 96 static int max8952_enable(struct regulator_dev *rdev) 97 { 98 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 99 100 /* If not valid, assume "ALWAYS_HIGH" */ 101 if (gpio_is_valid(max8952->pdata->gpio_en)) 102 gpio_set_value(max8952->pdata->gpio_en, 1); 103 104 max8952->en = true; 105 return 0; 106 } 107 108 static int max8952_disable(struct regulator_dev *rdev) 109 { 110 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 111 112 /* If not valid, assume "ALWAYS_HIGH" -> not permitted */ 113 if (gpio_is_valid(max8952->pdata->gpio_en)) 114 gpio_set_value(max8952->pdata->gpio_en, 0); 115 else 116 return -EPERM; 117 118 max8952->en = false; 119 return 0; 120 } 121 122 static int max8952_get_voltage(struct regulator_dev *rdev) 123 { 124 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 125 u8 vid = 0; 126 127 if (max8952->vid0) 128 vid += 1; 129 if (max8952->vid1) 130 vid += 2; 131 132 return max8952_voltage(max8952, vid); 133 } 134 135 static int max8952_set_voltage(struct regulator_dev *rdev, 136 int min_uV, int max_uV) 137 { 138 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 139 s8 vid = -1, i; 140 141 if (!gpio_is_valid(max8952->pdata->gpio_vid0) || 142 !gpio_is_valid(max8952->pdata->gpio_vid0)) { 143 /* DVS not supported */ 144 return -EPERM; 145 } 146 147 for (i = 0; i < MAX8952_NUM_DVS_MODE; i++) { 148 int volt = max8952_voltage(max8952, i); 149 150 /* Set the voltage as low as possible within the range */ 151 if (volt <= max_uV && volt >= min_uV) 152 if (vid == -1 || max8952_voltage(max8952, vid) > volt) 153 vid = i; 154 } 155 156 if (vid >= 0 && vid < MAX8952_NUM_DVS_MODE) { 157 max8952->vid0 = (vid % 2 == 1); 158 max8952->vid1 = (((vid >> 1) % 2) == 1); 159 gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0); 160 gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1); 161 } else 162 return -EINVAL; 163 164 return 0; 165 } 166 167 static struct regulator_ops max8952_ops = { 168 .list_voltage = max8952_list_voltage, 169 .is_enabled = max8952_is_enabled, 170 .enable = max8952_enable, 171 .disable = max8952_disable, 172 .get_voltage = max8952_get_voltage, 173 .set_voltage = max8952_set_voltage, 174 .set_suspend_disable = max8952_disable, 175 }; 176 177 static struct regulator_desc regulator = { 178 .name = "MAX8952_VOUT", 179 .id = 0, 180 .n_voltages = MAX8952_NUM_DVS_MODE, 181 .ops = &max8952_ops, 182 .type = REGULATOR_VOLTAGE, 183 .owner = THIS_MODULE, 184 }; 185 186 static int __devinit max8952_pmic_probe(struct i2c_client *client, 187 const struct i2c_device_id *i2c_id) 188 { 189 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); 190 struct max8952_platform_data *pdata = client->dev.platform_data; 191 struct max8952_data *max8952; 192 193 int ret = 0, err = 0; 194 195 if (!pdata) { 196 dev_err(&client->dev, "Require the platform data\n"); 197 return -EINVAL; 198 } 199 200 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) 201 return -EIO; 202 203 max8952 = kzalloc(sizeof(struct max8952_data), GFP_KERNEL); 204 if (!max8952) 205 return -ENOMEM; 206 207 max8952->client = client; 208 max8952->dev = &client->dev; 209 max8952->pdata = pdata; 210 mutex_init(&max8952->mutex); 211 212 max8952->rdev = regulator_register(®ulator, max8952->dev, 213 &pdata->reg_data, max8952); 214 215 if (IS_ERR(max8952->rdev)) { 216 ret = PTR_ERR(max8952->rdev); 217 dev_err(max8952->dev, "regulator init failed (%d)\n", ret); 218 goto err_reg; 219 } 220 221 max8952->en = !!(pdata->reg_data.constraints.boot_on); 222 max8952->vid0 = (pdata->default_mode % 2) == 1; 223 max8952->vid1 = ((pdata->default_mode >> 1) % 2) == 1; 224 225 if (gpio_is_valid(pdata->gpio_en)) { 226 if (!gpio_request(pdata->gpio_en, "MAX8952 EN")) 227 gpio_direction_output(pdata->gpio_en, max8952->en); 228 else 229 err = 1; 230 } else 231 err = 2; 232 233 if (err) { 234 dev_info(max8952->dev, "EN gpio invalid: assume that EN" 235 "is always High\n"); 236 max8952->en = 1; 237 pdata->gpio_en = -1; /* Mark invalid */ 238 } 239 240 err = 0; 241 242 if (gpio_is_valid(pdata->gpio_vid0) && 243 gpio_is_valid(pdata->gpio_vid1)) { 244 if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0")) 245 gpio_direction_output(pdata->gpio_vid0, 246 (pdata->default_mode) % 2); 247 else 248 err = 1; 249 250 if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1")) 251 gpio_direction_output(pdata->gpio_vid1, 252 (pdata->default_mode >> 1) % 2); 253 else { 254 if (!err) 255 gpio_free(pdata->gpio_vid0); 256 err = 2; 257 } 258 259 } else 260 err = 3; 261 262 if (err) { 263 dev_warn(max8952->dev, "VID0/1 gpio invalid: " 264 "DVS not avilable.\n"); 265 max8952->vid0 = 0; 266 max8952->vid1 = 0; 267 /* Mark invalid */ 268 pdata->gpio_vid0 = -1; 269 pdata->gpio_vid1 = -1; 270 271 /* Disable Pulldown of EN only */ 272 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60); 273 274 dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1" 275 " do not have proper controls.\n"); 276 } else { 277 /* 278 * Disable Pulldown on EN, VID0, VID1 to reduce 279 * leakage current of MAX8952 assuming that MAX8952 280 * is turned on (EN==1). Note that without having VID0/1 281 * properly connected, turning pulldown off can be 282 * problematic. Thus, turn this off only when they are 283 * controllable by GPIO. 284 */ 285 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0); 286 } 287 288 max8952_write_reg(max8952, MAX8952_REG_MODE0, 289 (max8952_read_reg(max8952, 290 MAX8952_REG_MODE0) & 0xC0) | 291 (pdata->dvs_mode[0] & 0x3F)); 292 max8952_write_reg(max8952, MAX8952_REG_MODE1, 293 (max8952_read_reg(max8952, 294 MAX8952_REG_MODE1) & 0xC0) | 295 (pdata->dvs_mode[1] & 0x3F)); 296 max8952_write_reg(max8952, MAX8952_REG_MODE2, 297 (max8952_read_reg(max8952, 298 MAX8952_REG_MODE2) & 0xC0) | 299 (pdata->dvs_mode[2] & 0x3F)); 300 max8952_write_reg(max8952, MAX8952_REG_MODE3, 301 (max8952_read_reg(max8952, 302 MAX8952_REG_MODE3) & 0xC0) | 303 (pdata->dvs_mode[3] & 0x3F)); 304 305 max8952_write_reg(max8952, MAX8952_REG_SYNC, 306 (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) | 307 ((pdata->sync_freq & 0x3) << 6)); 308 max8952_write_reg(max8952, MAX8952_REG_RAMP, 309 (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) | 310 ((pdata->ramp_speed & 0x7) << 5)); 311 312 i2c_set_clientdata(client, max8952); 313 314 return 0; 315 316 err_reg: 317 kfree(max8952); 318 return ret; 319 } 320 321 static int __devexit max8952_pmic_remove(struct i2c_client *client) 322 { 323 struct max8952_data *max8952 = i2c_get_clientdata(client); 324 struct max8952_platform_data *pdata = max8952->pdata; 325 struct regulator_dev *rdev = max8952->rdev; 326 327 regulator_unregister(rdev); 328 329 gpio_free(pdata->gpio_vid0); 330 gpio_free(pdata->gpio_vid1); 331 gpio_free(pdata->gpio_en); 332 333 kfree(max8952); 334 return 0; 335 } 336 337 static const struct i2c_device_id max8952_ids[] = { 338 { "max8952", 0 }, 339 { }, 340 }; 341 MODULE_DEVICE_TABLE(i2c, max8952_ids); 342 343 static struct i2c_driver max8952_pmic_driver = { 344 .probe = max8952_pmic_probe, 345 .remove = __devexit_p(max8952_pmic_remove), 346 .driver = { 347 .name = "max8952", 348 }, 349 .id_table = max8952_ids, 350 }; 351 352 static int __init max8952_pmic_init(void) 353 { 354 return i2c_add_driver(&max8952_pmic_driver); 355 } 356 subsys_initcall(max8952_pmic_init); 357 358 static void __exit max8952_pmic_exit(void) 359 { 360 i2c_del_driver(&max8952_pmic_driver); 361 } 362 module_exit(max8952_pmic_exit); 363 364 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver"); 365 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); 366 MODULE_LICENSE("GPL"); 367