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/of.h> 32 #include <linux/of_gpio.h> 33 #include <linux/regulator/of_regulator.h> 34 #include <linux/slab.h> 35 36 /* Registers */ 37 enum { 38 MAX8952_REG_MODE0, 39 MAX8952_REG_MODE1, 40 MAX8952_REG_MODE2, 41 MAX8952_REG_MODE3, 42 MAX8952_REG_CONTROL, 43 MAX8952_REG_SYNC, 44 MAX8952_REG_RAMP, 45 MAX8952_REG_CHIP_ID1, 46 MAX8952_REG_CHIP_ID2, 47 }; 48 49 struct max8952_data { 50 struct i2c_client *client; 51 struct device *dev; 52 struct max8952_platform_data *pdata; 53 struct regulator_dev *rdev; 54 55 bool vid0; 56 bool vid1; 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_list_voltage(struct regulator_dev *rdev, 75 unsigned int selector) 76 { 77 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 78 79 if (rdev_get_id(rdev) != 0) 80 return -EINVAL; 81 82 return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000; 83 } 84 85 static int max8952_get_voltage_sel(struct regulator_dev *rdev) 86 { 87 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 88 u8 vid = 0; 89 90 if (max8952->vid0) 91 vid += 1; 92 if (max8952->vid1) 93 vid += 2; 94 95 return vid; 96 } 97 98 static int max8952_set_voltage_sel(struct regulator_dev *rdev, 99 unsigned selector) 100 { 101 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 102 103 if (!gpio_is_valid(max8952->pdata->gpio_vid0) || 104 !gpio_is_valid(max8952->pdata->gpio_vid1)) { 105 /* DVS not supported */ 106 return -EPERM; 107 } 108 109 max8952->vid0 = selector & 0x1; 110 max8952->vid1 = (selector >> 1) & 0x1; 111 gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0); 112 gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1); 113 114 return 0; 115 } 116 117 static struct regulator_ops max8952_ops = { 118 .list_voltage = max8952_list_voltage, 119 .get_voltage_sel = max8952_get_voltage_sel, 120 .set_voltage_sel = max8952_set_voltage_sel, 121 }; 122 123 static const struct regulator_desc regulator = { 124 .name = "MAX8952_VOUT", 125 .id = 0, 126 .n_voltages = MAX8952_NUM_DVS_MODE, 127 .ops = &max8952_ops, 128 .type = REGULATOR_VOLTAGE, 129 .owner = THIS_MODULE, 130 }; 131 132 #ifdef CONFIG_OF 133 static struct of_device_id max8952_dt_match[] = { 134 { .compatible = "maxim,max8952" }, 135 {}, 136 }; 137 MODULE_DEVICE_TABLE(of, max8952_dt_match); 138 139 static struct max8952_platform_data *max8952_parse_dt(struct device *dev) 140 { 141 struct max8952_platform_data *pd; 142 struct device_node *np = dev->of_node; 143 int ret; 144 int i; 145 146 pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL); 147 if (!pd) { 148 dev_err(dev, "Failed to allocate platform data\n"); 149 return NULL; 150 } 151 152 pd->gpio_vid0 = of_get_named_gpio(np, "max8952,vid-gpios", 0); 153 pd->gpio_vid1 = of_get_named_gpio(np, "max8952,vid-gpios", 1); 154 pd->gpio_en = of_get_named_gpio(np, "max8952,en-gpio", 0); 155 156 if (of_property_read_u32(np, "max8952,default-mode", &pd->default_mode)) 157 dev_warn(dev, "Default mode not specified, assuming 0\n"); 158 159 ret = of_property_read_u32_array(np, "max8952,dvs-mode-microvolt", 160 pd->dvs_mode, ARRAY_SIZE(pd->dvs_mode)); 161 if (ret) { 162 dev_err(dev, "max8952,dvs-mode-microvolt property not specified"); 163 return NULL; 164 } 165 166 for (i = 0; i < ARRAY_SIZE(pd->dvs_mode); ++i) { 167 if (pd->dvs_mode[i] < 770000 || pd->dvs_mode[i] > 1400000) { 168 dev_err(dev, "DVS voltage %d out of range\n", i); 169 return NULL; 170 } 171 pd->dvs_mode[i] = (pd->dvs_mode[i] - 770000) / 10000; 172 } 173 174 if (of_property_read_u32(np, "max8952,sync-freq", &pd->sync_freq)) 175 dev_warn(dev, "max8952,sync-freq property not specified, defaulting to 26MHz\n"); 176 177 if (of_property_read_u32(np, "max8952,ramp-speed", &pd->ramp_speed)) 178 dev_warn(dev, "max8952,ramp-speed property not specified, defaulting to 32mV/us\n"); 179 180 pd->reg_data = of_get_regulator_init_data(dev, np); 181 if (!pd->reg_data) { 182 dev_err(dev, "Failed to parse regulator init data\n"); 183 return NULL; 184 } 185 186 return pd; 187 } 188 #else 189 static struct max8952_platform_data *max8952_parse_dt(struct device *dev) 190 { 191 return NULL; 192 } 193 #endif 194 195 static int max8952_pmic_probe(struct i2c_client *client, 196 const struct i2c_device_id *i2c_id) 197 { 198 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); 199 struct max8952_platform_data *pdata = dev_get_platdata(&client->dev); 200 struct regulator_config config = { }; 201 struct max8952_data *max8952; 202 203 int ret = 0, err = 0; 204 205 if (client->dev.of_node) 206 pdata = max8952_parse_dt(&client->dev); 207 208 if (!pdata) { 209 dev_err(&client->dev, "Require the platform data\n"); 210 return -EINVAL; 211 } 212 213 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) 214 return -EIO; 215 216 max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data), 217 GFP_KERNEL); 218 if (!max8952) 219 return -ENOMEM; 220 221 max8952->client = client; 222 max8952->dev = &client->dev; 223 max8952->pdata = pdata; 224 225 config.dev = max8952->dev; 226 config.init_data = pdata->reg_data; 227 config.driver_data = max8952; 228 config.of_node = client->dev.of_node; 229 230 config.ena_gpio = pdata->gpio_en; 231 if (pdata->reg_data->constraints.boot_on) 232 config.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH; 233 234 max8952->rdev = regulator_register(®ulator, &config); 235 236 if (IS_ERR(max8952->rdev)) { 237 ret = PTR_ERR(max8952->rdev); 238 dev_err(max8952->dev, "regulator init failed (%d)\n", ret); 239 return ret; 240 } 241 242 max8952->vid0 = pdata->default_mode & 0x1; 243 max8952->vid1 = (pdata->default_mode >> 1) & 0x1; 244 245 if (gpio_is_valid(pdata->gpio_vid0) && 246 gpio_is_valid(pdata->gpio_vid1)) { 247 if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0")) 248 gpio_direction_output(pdata->gpio_vid0, 249 (pdata->default_mode) & 0x1); 250 else 251 err = 1; 252 253 if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1")) 254 gpio_direction_output(pdata->gpio_vid1, 255 (pdata->default_mode >> 1) & 0x1); 256 else { 257 if (!err) 258 gpio_free(pdata->gpio_vid0); 259 err = 2; 260 } 261 262 } else 263 err = 3; 264 265 if (err) { 266 dev_warn(max8952->dev, "VID0/1 gpio invalid: " 267 "DVS not available.\n"); 268 max8952->vid0 = 0; 269 max8952->vid1 = 0; 270 /* Mark invalid */ 271 pdata->gpio_vid0 = -1; 272 pdata->gpio_vid1 = -1; 273 274 /* Disable Pulldown of EN only */ 275 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60); 276 277 dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1" 278 " do not have proper controls.\n"); 279 } else { 280 /* 281 * Disable Pulldown on EN, VID0, VID1 to reduce 282 * leakage current of MAX8952 assuming that MAX8952 283 * is turned on (EN==1). Note that without having VID0/1 284 * properly connected, turning pulldown off can be 285 * problematic. Thus, turn this off only when they are 286 * controllable by GPIO. 287 */ 288 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0); 289 } 290 291 max8952_write_reg(max8952, MAX8952_REG_MODE0, 292 (max8952_read_reg(max8952, 293 MAX8952_REG_MODE0) & 0xC0) | 294 (pdata->dvs_mode[0] & 0x3F)); 295 max8952_write_reg(max8952, MAX8952_REG_MODE1, 296 (max8952_read_reg(max8952, 297 MAX8952_REG_MODE1) & 0xC0) | 298 (pdata->dvs_mode[1] & 0x3F)); 299 max8952_write_reg(max8952, MAX8952_REG_MODE2, 300 (max8952_read_reg(max8952, 301 MAX8952_REG_MODE2) & 0xC0) | 302 (pdata->dvs_mode[2] & 0x3F)); 303 max8952_write_reg(max8952, MAX8952_REG_MODE3, 304 (max8952_read_reg(max8952, 305 MAX8952_REG_MODE3) & 0xC0) | 306 (pdata->dvs_mode[3] & 0x3F)); 307 308 max8952_write_reg(max8952, MAX8952_REG_SYNC, 309 (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) | 310 ((pdata->sync_freq & 0x3) << 6)); 311 max8952_write_reg(max8952, MAX8952_REG_RAMP, 312 (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) | 313 ((pdata->ramp_speed & 0x7) << 5)); 314 315 i2c_set_clientdata(client, max8952); 316 317 return 0; 318 } 319 320 static int max8952_pmic_remove(struct i2c_client *client) 321 { 322 struct max8952_data *max8952 = i2c_get_clientdata(client); 323 struct max8952_platform_data *pdata = max8952->pdata; 324 struct regulator_dev *rdev = max8952->rdev; 325 326 regulator_unregister(rdev); 327 328 gpio_free(pdata->gpio_vid0); 329 gpio_free(pdata->gpio_vid1); 330 return 0; 331 } 332 333 static const struct i2c_device_id max8952_ids[] = { 334 { "max8952", 0 }, 335 { }, 336 }; 337 MODULE_DEVICE_TABLE(i2c, max8952_ids); 338 339 static struct i2c_driver max8952_pmic_driver = { 340 .probe = max8952_pmic_probe, 341 .remove = max8952_pmic_remove, 342 .driver = { 343 .name = "max8952", 344 .of_match_table = of_match_ptr(max8952_dt_match), 345 }, 346 .id_table = max8952_ids, 347 }; 348 349 static int __init max8952_pmic_init(void) 350 { 351 return i2c_add_driver(&max8952_pmic_driver); 352 } 353 subsys_initcall(max8952_pmic_init); 354 355 static void __exit max8952_pmic_exit(void) 356 { 357 i2c_del_driver(&max8952_pmic_driver); 358 } 359 module_exit(max8952_pmic_exit); 360 361 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver"); 362 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); 363 MODULE_LICENSE("GPL"); 364