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 max8952_platform_data *pdata; 52 53 bool vid0; 54 bool vid1; 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 61 if (ret > 0) 62 ret &= 0xff; 63 64 return ret; 65 } 66 67 static int max8952_write_reg(struct max8952_data *max8952, 68 u8 reg, u8 value) 69 { 70 return i2c_smbus_write_byte_data(max8952->client, reg, value); 71 } 72 73 static int max8952_list_voltage(struct regulator_dev *rdev, 74 unsigned int selector) 75 { 76 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 77 78 if (rdev_get_id(rdev) != 0) 79 return -EINVAL; 80 81 return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000; 82 } 83 84 static int max8952_get_voltage_sel(struct regulator_dev *rdev) 85 { 86 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 87 u8 vid = 0; 88 89 if (max8952->vid0) 90 vid += 1; 91 if (max8952->vid1) 92 vid += 2; 93 94 return vid; 95 } 96 97 static int max8952_set_voltage_sel(struct regulator_dev *rdev, 98 unsigned selector) 99 { 100 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 101 102 if (!gpio_is_valid(max8952->pdata->gpio_vid0) || 103 !gpio_is_valid(max8952->pdata->gpio_vid1)) { 104 /* DVS not supported */ 105 return -EPERM; 106 } 107 108 max8952->vid0 = selector & 0x1; 109 max8952->vid1 = (selector >> 1) & 0x1; 110 gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0); 111 gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1); 112 113 return 0; 114 } 115 116 static struct regulator_ops max8952_ops = { 117 .list_voltage = max8952_list_voltage, 118 .get_voltage_sel = max8952_get_voltage_sel, 119 .set_voltage_sel = max8952_set_voltage_sel, 120 }; 121 122 static const struct regulator_desc regulator = { 123 .name = "MAX8952_VOUT", 124 .id = 0, 125 .n_voltages = MAX8952_NUM_DVS_MODE, 126 .ops = &max8952_ops, 127 .type = REGULATOR_VOLTAGE, 128 .owner = THIS_MODULE, 129 }; 130 131 #ifdef CONFIG_OF 132 static struct of_device_id max8952_dt_match[] = { 133 { .compatible = "maxim,max8952" }, 134 {}, 135 }; 136 MODULE_DEVICE_TABLE(of, max8952_dt_match); 137 138 static struct max8952_platform_data *max8952_parse_dt(struct device *dev) 139 { 140 struct max8952_platform_data *pd; 141 struct device_node *np = dev->of_node; 142 int ret; 143 int i; 144 145 pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL); 146 if (!pd) 147 return NULL; 148 149 pd->gpio_vid0 = of_get_named_gpio(np, "max8952,vid-gpios", 0); 150 pd->gpio_vid1 = of_get_named_gpio(np, "max8952,vid-gpios", 1); 151 pd->gpio_en = of_get_named_gpio(np, "max8952,en-gpio", 0); 152 153 if (of_property_read_u32(np, "max8952,default-mode", &pd->default_mode)) 154 dev_warn(dev, "Default mode not specified, assuming 0\n"); 155 156 ret = of_property_read_u32_array(np, "max8952,dvs-mode-microvolt", 157 pd->dvs_mode, ARRAY_SIZE(pd->dvs_mode)); 158 if (ret) { 159 dev_err(dev, "max8952,dvs-mode-microvolt property not specified"); 160 return NULL; 161 } 162 163 for (i = 0; i < ARRAY_SIZE(pd->dvs_mode); ++i) { 164 if (pd->dvs_mode[i] < 770000 || pd->dvs_mode[i] > 1400000) { 165 dev_err(dev, "DVS voltage %d out of range\n", i); 166 return NULL; 167 } 168 pd->dvs_mode[i] = (pd->dvs_mode[i] - 770000) / 10000; 169 } 170 171 if (of_property_read_u32(np, "max8952,sync-freq", &pd->sync_freq)) 172 dev_warn(dev, "max8952,sync-freq property not specified, defaulting to 26MHz\n"); 173 174 if (of_property_read_u32(np, "max8952,ramp-speed", &pd->ramp_speed)) 175 dev_warn(dev, "max8952,ramp-speed property not specified, defaulting to 32mV/us\n"); 176 177 pd->reg_data = of_get_regulator_init_data(dev, np); 178 if (!pd->reg_data) { 179 dev_err(dev, "Failed to parse regulator init data\n"); 180 return NULL; 181 } 182 183 return pd; 184 } 185 #else 186 static struct max8952_platform_data *max8952_parse_dt(struct device *dev) 187 { 188 return NULL; 189 } 190 #endif 191 192 static int max8952_pmic_probe(struct i2c_client *client, 193 const struct i2c_device_id *i2c_id) 194 { 195 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); 196 struct max8952_platform_data *pdata = dev_get_platdata(&client->dev); 197 struct regulator_config config = { }; 198 struct max8952_data *max8952; 199 struct regulator_dev *rdev; 200 201 int ret = 0, err = 0; 202 203 if (client->dev.of_node) 204 pdata = max8952_parse_dt(&client->dev); 205 206 if (!pdata) { 207 dev_err(&client->dev, "Require the platform data\n"); 208 return -EINVAL; 209 } 210 211 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) 212 return -EIO; 213 214 max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data), 215 GFP_KERNEL); 216 if (!max8952) 217 return -ENOMEM; 218 219 max8952->client = client; 220 max8952->pdata = pdata; 221 222 config.dev = &client->dev; 223 config.init_data = pdata->reg_data; 224 config.driver_data = max8952; 225 config.of_node = client->dev.of_node; 226 227 config.ena_gpio = pdata->gpio_en; 228 if (pdata->reg_data->constraints.boot_on) 229 config.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH; 230 231 rdev = devm_regulator_register(&client->dev, ®ulator, &config); 232 233 if (IS_ERR(rdev)) { 234 ret = PTR_ERR(rdev); 235 dev_err(&client->dev, "regulator init failed (%d)\n", ret); 236 return ret; 237 } 238 239 max8952->vid0 = pdata->default_mode & 0x1; 240 max8952->vid1 = (pdata->default_mode >> 1) & 0x1; 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) & 0x1); 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) & 0x1); 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(&client->dev, "VID0/1 gpio invalid: " 264 "DVS not available.\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(&client->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 } 316 317 static int max8952_pmic_remove(struct i2c_client *client) 318 { 319 struct max8952_data *max8952 = i2c_get_clientdata(client); 320 struct max8952_platform_data *pdata = max8952->pdata; 321 322 gpio_free(pdata->gpio_vid0); 323 gpio_free(pdata->gpio_vid1); 324 return 0; 325 } 326 327 static const struct i2c_device_id max8952_ids[] = { 328 { "max8952", 0 }, 329 { }, 330 }; 331 MODULE_DEVICE_TABLE(i2c, max8952_ids); 332 333 static struct i2c_driver max8952_pmic_driver = { 334 .probe = max8952_pmic_probe, 335 .remove = max8952_pmic_remove, 336 .driver = { 337 .name = "max8952", 338 .of_match_table = of_match_ptr(max8952_dt_match), 339 }, 340 .id_table = max8952_ids, 341 }; 342 343 static int __init max8952_pmic_init(void) 344 { 345 return i2c_add_driver(&max8952_pmic_driver); 346 } 347 subsys_initcall(max8952_pmic_init); 348 349 static void __exit max8952_pmic_exit(void) 350 { 351 i2c_del_driver(&max8952_pmic_driver); 352 } 353 module_exit(max8952_pmic_exit); 354 355 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver"); 356 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); 357 MODULE_LICENSE("GPL"); 358