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/slab.h> 32 33 /* Registers */ 34 enum { 35 MAX8952_REG_MODE0, 36 MAX8952_REG_MODE1, 37 MAX8952_REG_MODE2, 38 MAX8952_REG_MODE3, 39 MAX8952_REG_CONTROL, 40 MAX8952_REG_SYNC, 41 MAX8952_REG_RAMP, 42 MAX8952_REG_CHIP_ID1, 43 MAX8952_REG_CHIP_ID2, 44 }; 45 46 struct max8952_data { 47 struct i2c_client *client; 48 struct device *dev; 49 struct max8952_platform_data *pdata; 50 struct regulator_dev *rdev; 51 52 bool vid0; 53 bool vid1; 54 bool en; 55 }; 56 57 static int max8952_read_reg(struct max8952_data *max8952, u8 reg) 58 { 59 int ret = i2c_smbus_read_byte_data(max8952->client, reg); 60 if (ret > 0) 61 ret &= 0xff; 62 63 return ret; 64 } 65 66 static int max8952_write_reg(struct max8952_data *max8952, 67 u8 reg, u8 value) 68 { 69 return i2c_smbus_write_byte_data(max8952->client, reg, value); 70 } 71 72 static int max8952_voltage(struct max8952_data *max8952, u8 mode) 73 { 74 return (max8952->pdata->dvs_mode[mode] * 10 + 770) * 1000; 75 } 76 77 static int max8952_list_voltage(struct regulator_dev *rdev, 78 unsigned int selector) 79 { 80 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 81 82 if (rdev_get_id(rdev) != 0) 83 return -EINVAL; 84 85 return max8952_voltage(max8952, selector); 86 } 87 88 static int max8952_is_enabled(struct regulator_dev *rdev) 89 { 90 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 91 return max8952->en; 92 } 93 94 static int max8952_enable(struct regulator_dev *rdev) 95 { 96 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 97 98 /* If not valid, assume "ALWAYS_HIGH" */ 99 if (gpio_is_valid(max8952->pdata->gpio_en)) 100 gpio_set_value(max8952->pdata->gpio_en, 1); 101 102 max8952->en = true; 103 return 0; 104 } 105 106 static int max8952_disable(struct regulator_dev *rdev) 107 { 108 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 109 110 /* If not valid, assume "ALWAYS_HIGH" -> not permitted */ 111 if (gpio_is_valid(max8952->pdata->gpio_en)) 112 gpio_set_value(max8952->pdata->gpio_en, 0); 113 else 114 return -EPERM; 115 116 max8952->en = false; 117 return 0; 118 } 119 120 static int max8952_get_voltage(struct regulator_dev *rdev) 121 { 122 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 123 u8 vid = 0; 124 125 if (max8952->vid0) 126 vid += 1; 127 if (max8952->vid1) 128 vid += 2; 129 130 return max8952_voltage(max8952, vid); 131 } 132 133 static int max8952_set_voltage(struct regulator_dev *rdev, 134 int min_uV, int max_uV, unsigned *selector) 135 { 136 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 137 s8 vid = -1, i; 138 139 if (!gpio_is_valid(max8952->pdata->gpio_vid0) || 140 !gpio_is_valid(max8952->pdata->gpio_vid1)) { 141 /* DVS not supported */ 142 return -EPERM; 143 } 144 145 for (i = 0; i < MAX8952_NUM_DVS_MODE; i++) { 146 int volt = max8952_voltage(max8952, i); 147 148 /* Set the voltage as low as possible within the range */ 149 if (volt <= max_uV && volt >= min_uV) 150 if (vid == -1 || max8952_voltage(max8952, vid) > volt) 151 vid = i; 152 } 153 154 if (vid >= 0 && vid < MAX8952_NUM_DVS_MODE) { 155 max8952->vid0 = vid & 0x1; 156 max8952->vid1 = (vid >> 1) & 0x1; 157 *selector = vid; 158 gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0); 159 gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1); 160 } else 161 return -EINVAL; 162 163 return 0; 164 } 165 166 static struct regulator_ops max8952_ops = { 167 .list_voltage = max8952_list_voltage, 168 .is_enabled = max8952_is_enabled, 169 .enable = max8952_enable, 170 .disable = max8952_disable, 171 .get_voltage = max8952_get_voltage, 172 .set_voltage = max8952_set_voltage, 173 .set_suspend_disable = max8952_disable, 174 }; 175 176 static struct regulator_desc regulator = { 177 .name = "MAX8952_VOUT", 178 .id = 0, 179 .n_voltages = MAX8952_NUM_DVS_MODE, 180 .ops = &max8952_ops, 181 .type = REGULATOR_VOLTAGE, 182 .owner = THIS_MODULE, 183 }; 184 185 static int __devinit max8952_pmic_probe(struct i2c_client *client, 186 const struct i2c_device_id *i2c_id) 187 { 188 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); 189 struct max8952_platform_data *pdata = client->dev.platform_data; 190 struct max8952_data *max8952; 191 192 int ret = 0, err = 0; 193 194 if (!pdata) { 195 dev_err(&client->dev, "Require the platform data\n"); 196 return -EINVAL; 197 } 198 199 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) 200 return -EIO; 201 202 max8952 = kzalloc(sizeof(struct max8952_data), GFP_KERNEL); 203 if (!max8952) 204 return -ENOMEM; 205 206 max8952->client = client; 207 max8952->dev = &client->dev; 208 max8952->pdata = pdata; 209 210 max8952->rdev = regulator_register(®ulator, max8952->dev, 211 &pdata->reg_data, max8952, NULL); 212 213 if (IS_ERR(max8952->rdev)) { 214 ret = PTR_ERR(max8952->rdev); 215 dev_err(max8952->dev, "regulator init failed (%d)\n", ret); 216 goto err_reg; 217 } 218 219 max8952->en = !!(pdata->reg_data.constraints.boot_on); 220 max8952->vid0 = pdata->default_mode & 0x1; 221 max8952->vid1 = (pdata->default_mode >> 1) & 0x1; 222 223 if (gpio_is_valid(pdata->gpio_en)) { 224 if (!gpio_request(pdata->gpio_en, "MAX8952 EN")) 225 gpio_direction_output(pdata->gpio_en, max8952->en); 226 else 227 err = 1; 228 } else 229 err = 2; 230 231 if (err) { 232 dev_info(max8952->dev, "EN gpio invalid: assume that EN" 233 "is always High\n"); 234 max8952->en = 1; 235 pdata->gpio_en = -1; /* Mark invalid */ 236 } 237 238 err = 0; 239 240 if (gpio_is_valid(pdata->gpio_vid0) && 241 gpio_is_valid(pdata->gpio_vid1)) { 242 if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0")) 243 gpio_direction_output(pdata->gpio_vid0, 244 (pdata->default_mode) & 0x1); 245 else 246 err = 1; 247 248 if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1")) 249 gpio_direction_output(pdata->gpio_vid1, 250 (pdata->default_mode >> 1) & 0x1); 251 else { 252 if (!err) 253 gpio_free(pdata->gpio_vid0); 254 err = 2; 255 } 256 257 } else 258 err = 3; 259 260 if (err) { 261 dev_warn(max8952->dev, "VID0/1 gpio invalid: " 262 "DVS not available.\n"); 263 max8952->vid0 = 0; 264 max8952->vid1 = 0; 265 /* Mark invalid */ 266 pdata->gpio_vid0 = -1; 267 pdata->gpio_vid1 = -1; 268 269 /* Disable Pulldown of EN only */ 270 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60); 271 272 dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1" 273 " do not have proper controls.\n"); 274 } else { 275 /* 276 * Disable Pulldown on EN, VID0, VID1 to reduce 277 * leakage current of MAX8952 assuming that MAX8952 278 * is turned on (EN==1). Note that without having VID0/1 279 * properly connected, turning pulldown off can be 280 * problematic. Thus, turn this off only when they are 281 * controllable by GPIO. 282 */ 283 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0); 284 } 285 286 max8952_write_reg(max8952, MAX8952_REG_MODE0, 287 (max8952_read_reg(max8952, 288 MAX8952_REG_MODE0) & 0xC0) | 289 (pdata->dvs_mode[0] & 0x3F)); 290 max8952_write_reg(max8952, MAX8952_REG_MODE1, 291 (max8952_read_reg(max8952, 292 MAX8952_REG_MODE1) & 0xC0) | 293 (pdata->dvs_mode[1] & 0x3F)); 294 max8952_write_reg(max8952, MAX8952_REG_MODE2, 295 (max8952_read_reg(max8952, 296 MAX8952_REG_MODE2) & 0xC0) | 297 (pdata->dvs_mode[2] & 0x3F)); 298 max8952_write_reg(max8952, MAX8952_REG_MODE3, 299 (max8952_read_reg(max8952, 300 MAX8952_REG_MODE3) & 0xC0) | 301 (pdata->dvs_mode[3] & 0x3F)); 302 303 max8952_write_reg(max8952, MAX8952_REG_SYNC, 304 (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) | 305 ((pdata->sync_freq & 0x3) << 6)); 306 max8952_write_reg(max8952, MAX8952_REG_RAMP, 307 (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) | 308 ((pdata->ramp_speed & 0x7) << 5)); 309 310 i2c_set_clientdata(client, max8952); 311 312 return 0; 313 314 err_reg: 315 kfree(max8952); 316 return ret; 317 } 318 319 static int __devexit max8952_pmic_remove(struct i2c_client *client) 320 { 321 struct max8952_data *max8952 = i2c_get_clientdata(client); 322 struct max8952_platform_data *pdata = max8952->pdata; 323 struct regulator_dev *rdev = max8952->rdev; 324 325 regulator_unregister(rdev); 326 327 gpio_free(pdata->gpio_vid0); 328 gpio_free(pdata->gpio_vid1); 329 gpio_free(pdata->gpio_en); 330 331 kfree(max8952); 332 return 0; 333 } 334 335 static const struct i2c_device_id max8952_ids[] = { 336 { "max8952", 0 }, 337 { }, 338 }; 339 MODULE_DEVICE_TABLE(i2c, max8952_ids); 340 341 static struct i2c_driver max8952_pmic_driver = { 342 .probe = max8952_pmic_probe, 343 .remove = __devexit_p(max8952_pmic_remove), 344 .driver = { 345 .name = "max8952", 346 }, 347 .id_table = max8952_ids, 348 }; 349 350 static int __init max8952_pmic_init(void) 351 { 352 return i2c_add_driver(&max8952_pmic_driver); 353 } 354 subsys_initcall(max8952_pmic_init); 355 356 static void __exit max8952_pmic_exit(void) 357 { 358 i2c_del_driver(&max8952_pmic_driver); 359 } 360 module_exit(max8952_pmic_exit); 361 362 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver"); 363 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); 364 MODULE_LICENSE("GPL"); 365