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_list_voltage(struct regulator_dev *rdev, 73 unsigned int selector) 74 { 75 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 76 77 if (rdev_get_id(rdev) != 0) 78 return -EINVAL; 79 80 return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000; 81 } 82 83 static int max8952_is_enabled(struct regulator_dev *rdev) 84 { 85 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 86 return max8952->en; 87 } 88 89 static int max8952_enable(struct regulator_dev *rdev) 90 { 91 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 92 93 /* If not valid, assume "ALWAYS_HIGH" */ 94 if (gpio_is_valid(max8952->pdata->gpio_en)) 95 gpio_set_value(max8952->pdata->gpio_en, 1); 96 97 max8952->en = true; 98 return 0; 99 } 100 101 static int max8952_disable(struct regulator_dev *rdev) 102 { 103 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 104 105 /* If not valid, assume "ALWAYS_HIGH" -> not permitted */ 106 if (gpio_is_valid(max8952->pdata->gpio_en)) 107 gpio_set_value(max8952->pdata->gpio_en, 0); 108 else 109 return -EPERM; 110 111 max8952->en = false; 112 return 0; 113 } 114 115 static int max8952_get_voltage_sel(struct regulator_dev *rdev) 116 { 117 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 118 u8 vid = 0; 119 120 if (max8952->vid0) 121 vid += 1; 122 if (max8952->vid1) 123 vid += 2; 124 125 return vid; 126 } 127 128 static int max8952_set_voltage_sel(struct regulator_dev *rdev, 129 unsigned selector) 130 { 131 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 132 133 if (!gpio_is_valid(max8952->pdata->gpio_vid0) || 134 !gpio_is_valid(max8952->pdata->gpio_vid1)) { 135 /* DVS not supported */ 136 return -EPERM; 137 } 138 139 max8952->vid0 = selector & 0x1; 140 max8952->vid1 = (selector >> 1) & 0x1; 141 gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0); 142 gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1); 143 144 return 0; 145 } 146 147 static struct regulator_ops max8952_ops = { 148 .list_voltage = max8952_list_voltage, 149 .is_enabled = max8952_is_enabled, 150 .enable = max8952_enable, 151 .disable = max8952_disable, 152 .get_voltage_sel = max8952_get_voltage_sel, 153 .set_voltage_sel = max8952_set_voltage_sel, 154 .set_suspend_disable = max8952_disable, 155 }; 156 157 static const struct regulator_desc regulator = { 158 .name = "MAX8952_VOUT", 159 .id = 0, 160 .n_voltages = MAX8952_NUM_DVS_MODE, 161 .ops = &max8952_ops, 162 .type = REGULATOR_VOLTAGE, 163 .owner = THIS_MODULE, 164 }; 165 166 static int __devinit max8952_pmic_probe(struct i2c_client *client, 167 const struct i2c_device_id *i2c_id) 168 { 169 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); 170 struct max8952_platform_data *pdata = client->dev.platform_data; 171 struct regulator_config config = { }; 172 struct max8952_data *max8952; 173 174 int ret = 0, err = 0; 175 176 if (!pdata) { 177 dev_err(&client->dev, "Require the platform data\n"); 178 return -EINVAL; 179 } 180 181 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) 182 return -EIO; 183 184 max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data), 185 GFP_KERNEL); 186 if (!max8952) 187 return -ENOMEM; 188 189 max8952->client = client; 190 max8952->dev = &client->dev; 191 max8952->pdata = pdata; 192 193 config.dev = max8952->dev; 194 config.init_data = &pdata->reg_data; 195 config.driver_data = max8952; 196 197 max8952->rdev = regulator_register(®ulator, &config); 198 199 if (IS_ERR(max8952->rdev)) { 200 ret = PTR_ERR(max8952->rdev); 201 dev_err(max8952->dev, "regulator init failed (%d)\n", ret); 202 return ret; 203 } 204 205 max8952->en = !!(pdata->reg_data.constraints.boot_on); 206 max8952->vid0 = pdata->default_mode & 0x1; 207 max8952->vid1 = (pdata->default_mode >> 1) & 0x1; 208 209 if (gpio_is_valid(pdata->gpio_en)) { 210 if (!gpio_request(pdata->gpio_en, "MAX8952 EN")) 211 gpio_direction_output(pdata->gpio_en, max8952->en); 212 else 213 err = 1; 214 } else 215 err = 2; 216 217 if (err) { 218 dev_info(max8952->dev, "EN gpio invalid: assume that EN" 219 "is always High\n"); 220 max8952->en = 1; 221 pdata->gpio_en = -1; /* Mark invalid */ 222 } 223 224 err = 0; 225 226 if (gpio_is_valid(pdata->gpio_vid0) && 227 gpio_is_valid(pdata->gpio_vid1)) { 228 if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0")) 229 gpio_direction_output(pdata->gpio_vid0, 230 (pdata->default_mode) & 0x1); 231 else 232 err = 1; 233 234 if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1")) 235 gpio_direction_output(pdata->gpio_vid1, 236 (pdata->default_mode >> 1) & 0x1); 237 else { 238 if (!err) 239 gpio_free(pdata->gpio_vid0); 240 err = 2; 241 } 242 243 } else 244 err = 3; 245 246 if (err) { 247 dev_warn(max8952->dev, "VID0/1 gpio invalid: " 248 "DVS not available.\n"); 249 max8952->vid0 = 0; 250 max8952->vid1 = 0; 251 /* Mark invalid */ 252 pdata->gpio_vid0 = -1; 253 pdata->gpio_vid1 = -1; 254 255 /* Disable Pulldown of EN only */ 256 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60); 257 258 dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1" 259 " do not have proper controls.\n"); 260 } else { 261 /* 262 * Disable Pulldown on EN, VID0, VID1 to reduce 263 * leakage current of MAX8952 assuming that MAX8952 264 * is turned on (EN==1). Note that without having VID0/1 265 * properly connected, turning pulldown off can be 266 * problematic. Thus, turn this off only when they are 267 * controllable by GPIO. 268 */ 269 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0); 270 } 271 272 max8952_write_reg(max8952, MAX8952_REG_MODE0, 273 (max8952_read_reg(max8952, 274 MAX8952_REG_MODE0) & 0xC0) | 275 (pdata->dvs_mode[0] & 0x3F)); 276 max8952_write_reg(max8952, MAX8952_REG_MODE1, 277 (max8952_read_reg(max8952, 278 MAX8952_REG_MODE1) & 0xC0) | 279 (pdata->dvs_mode[1] & 0x3F)); 280 max8952_write_reg(max8952, MAX8952_REG_MODE2, 281 (max8952_read_reg(max8952, 282 MAX8952_REG_MODE2) & 0xC0) | 283 (pdata->dvs_mode[2] & 0x3F)); 284 max8952_write_reg(max8952, MAX8952_REG_MODE3, 285 (max8952_read_reg(max8952, 286 MAX8952_REG_MODE3) & 0xC0) | 287 (pdata->dvs_mode[3] & 0x3F)); 288 289 max8952_write_reg(max8952, MAX8952_REG_SYNC, 290 (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) | 291 ((pdata->sync_freq & 0x3) << 6)); 292 max8952_write_reg(max8952, MAX8952_REG_RAMP, 293 (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) | 294 ((pdata->ramp_speed & 0x7) << 5)); 295 296 i2c_set_clientdata(client, max8952); 297 298 return 0; 299 } 300 301 static int __devexit max8952_pmic_remove(struct i2c_client *client) 302 { 303 struct max8952_data *max8952 = i2c_get_clientdata(client); 304 struct max8952_platform_data *pdata = max8952->pdata; 305 struct regulator_dev *rdev = max8952->rdev; 306 307 regulator_unregister(rdev); 308 309 gpio_free(pdata->gpio_vid0); 310 gpio_free(pdata->gpio_vid1); 311 gpio_free(pdata->gpio_en); 312 return 0; 313 } 314 315 static const struct i2c_device_id max8952_ids[] = { 316 { "max8952", 0 }, 317 { }, 318 }; 319 MODULE_DEVICE_TABLE(i2c, max8952_ids); 320 321 static struct i2c_driver max8952_pmic_driver = { 322 .probe = max8952_pmic_probe, 323 .remove = __devexit_p(max8952_pmic_remove), 324 .driver = { 325 .name = "max8952", 326 }, 327 .id_table = max8952_ids, 328 }; 329 330 static int __init max8952_pmic_init(void) 331 { 332 return i2c_add_driver(&max8952_pmic_driver); 333 } 334 subsys_initcall(max8952_pmic_init); 335 336 static void __exit max8952_pmic_exit(void) 337 { 338 i2c_del_driver(&max8952_pmic_driver); 339 } 340 module_exit(max8952_pmic_exit); 341 342 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver"); 343 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); 344 MODULE_LICENSE("GPL"); 345