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, unsigned *selector) 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_vid1)) { 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 *selector = vid; 160 gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0); 161 gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1); 162 } else 163 return -EINVAL; 164 165 return 0; 166 } 167 168 static struct regulator_ops max8952_ops = { 169 .list_voltage = max8952_list_voltage, 170 .is_enabled = max8952_is_enabled, 171 .enable = max8952_enable, 172 .disable = max8952_disable, 173 .get_voltage = max8952_get_voltage, 174 .set_voltage = max8952_set_voltage, 175 .set_suspend_disable = max8952_disable, 176 }; 177 178 static struct regulator_desc regulator = { 179 .name = "MAX8952_VOUT", 180 .id = 0, 181 .n_voltages = MAX8952_NUM_DVS_MODE, 182 .ops = &max8952_ops, 183 .type = REGULATOR_VOLTAGE, 184 .owner = THIS_MODULE, 185 }; 186 187 static int __devinit max8952_pmic_probe(struct i2c_client *client, 188 const struct i2c_device_id *i2c_id) 189 { 190 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); 191 struct max8952_platform_data *pdata = client->dev.platform_data; 192 struct max8952_data *max8952; 193 194 int ret = 0, err = 0; 195 196 if (!pdata) { 197 dev_err(&client->dev, "Require the platform data\n"); 198 return -EINVAL; 199 } 200 201 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) 202 return -EIO; 203 204 max8952 = kzalloc(sizeof(struct max8952_data), GFP_KERNEL); 205 if (!max8952) 206 return -ENOMEM; 207 208 max8952->client = client; 209 max8952->dev = &client->dev; 210 max8952->pdata = pdata; 211 mutex_init(&max8952->mutex); 212 213 max8952->rdev = regulator_register(®ulator, max8952->dev, 214 &pdata->reg_data, max8952); 215 216 if (IS_ERR(max8952->rdev)) { 217 ret = PTR_ERR(max8952->rdev); 218 dev_err(max8952->dev, "regulator init failed (%d)\n", ret); 219 goto err_reg; 220 } 221 222 max8952->en = !!(pdata->reg_data.constraints.boot_on); 223 max8952->vid0 = (pdata->default_mode % 2) == 1; 224 max8952->vid1 = ((pdata->default_mode >> 1) % 2) == 1; 225 226 if (gpio_is_valid(pdata->gpio_en)) { 227 if (!gpio_request(pdata->gpio_en, "MAX8952 EN")) 228 gpio_direction_output(pdata->gpio_en, max8952->en); 229 else 230 err = 1; 231 } else 232 err = 2; 233 234 if (err) { 235 dev_info(max8952->dev, "EN gpio invalid: assume that EN" 236 "is always High\n"); 237 max8952->en = 1; 238 pdata->gpio_en = -1; /* Mark invalid */ 239 } 240 241 err = 0; 242 243 if (gpio_is_valid(pdata->gpio_vid0) && 244 gpio_is_valid(pdata->gpio_vid1)) { 245 if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0")) 246 gpio_direction_output(pdata->gpio_vid0, 247 (pdata->default_mode) % 2); 248 else 249 err = 1; 250 251 if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1")) 252 gpio_direction_output(pdata->gpio_vid1, 253 (pdata->default_mode >> 1) % 2); 254 else { 255 if (!err) 256 gpio_free(pdata->gpio_vid0); 257 err = 2; 258 } 259 260 } else 261 err = 3; 262 263 if (err) { 264 dev_warn(max8952->dev, "VID0/1 gpio invalid: " 265 "DVS not available.\n"); 266 max8952->vid0 = 0; 267 max8952->vid1 = 0; 268 /* Mark invalid */ 269 pdata->gpio_vid0 = -1; 270 pdata->gpio_vid1 = -1; 271 272 /* Disable Pulldown of EN only */ 273 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60); 274 275 dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1" 276 " do not have proper controls.\n"); 277 } else { 278 /* 279 * Disable Pulldown on EN, VID0, VID1 to reduce 280 * leakage current of MAX8952 assuming that MAX8952 281 * is turned on (EN==1). Note that without having VID0/1 282 * properly connected, turning pulldown off can be 283 * problematic. Thus, turn this off only when they are 284 * controllable by GPIO. 285 */ 286 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0); 287 } 288 289 max8952_write_reg(max8952, MAX8952_REG_MODE0, 290 (max8952_read_reg(max8952, 291 MAX8952_REG_MODE0) & 0xC0) | 292 (pdata->dvs_mode[0] & 0x3F)); 293 max8952_write_reg(max8952, MAX8952_REG_MODE1, 294 (max8952_read_reg(max8952, 295 MAX8952_REG_MODE1) & 0xC0) | 296 (pdata->dvs_mode[1] & 0x3F)); 297 max8952_write_reg(max8952, MAX8952_REG_MODE2, 298 (max8952_read_reg(max8952, 299 MAX8952_REG_MODE2) & 0xC0) | 300 (pdata->dvs_mode[2] & 0x3F)); 301 max8952_write_reg(max8952, MAX8952_REG_MODE3, 302 (max8952_read_reg(max8952, 303 MAX8952_REG_MODE3) & 0xC0) | 304 (pdata->dvs_mode[3] & 0x3F)); 305 306 max8952_write_reg(max8952, MAX8952_REG_SYNC, 307 (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) | 308 ((pdata->sync_freq & 0x3) << 6)); 309 max8952_write_reg(max8952, MAX8952_REG_RAMP, 310 (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) | 311 ((pdata->ramp_speed & 0x7) << 5)); 312 313 i2c_set_clientdata(client, max8952); 314 315 return 0; 316 317 err_reg: 318 kfree(max8952); 319 return ret; 320 } 321 322 static int __devexit max8952_pmic_remove(struct i2c_client *client) 323 { 324 struct max8952_data *max8952 = i2c_get_clientdata(client); 325 struct max8952_platform_data *pdata = max8952->pdata; 326 struct regulator_dev *rdev = max8952->rdev; 327 328 regulator_unregister(rdev); 329 330 gpio_free(pdata->gpio_vid0); 331 gpio_free(pdata->gpio_vid1); 332 gpio_free(pdata->gpio_en); 333 334 kfree(max8952); 335 return 0; 336 } 337 338 static const struct i2c_device_id max8952_ids[] = { 339 { "max8952", 0 }, 340 { }, 341 }; 342 MODULE_DEVICE_TABLE(i2c, max8952_ids); 343 344 static struct i2c_driver max8952_pmic_driver = { 345 .probe = max8952_pmic_probe, 346 .remove = __devexit_p(max8952_pmic_remove), 347 .driver = { 348 .name = "max8952", 349 }, 350 .id_table = max8952_ids, 351 }; 352 353 static int __init max8952_pmic_init(void) 354 { 355 return i2c_add_driver(&max8952_pmic_driver); 356 } 357 subsys_initcall(max8952_pmic_init); 358 359 static void __exit max8952_pmic_exit(void) 360 { 361 i2c_del_driver(&max8952_pmic_driver); 362 } 363 module_exit(max8952_pmic_exit); 364 365 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver"); 366 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); 367 MODULE_LICENSE("GPL"); 368