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/gpio/consumer.h> 31 #include <linux/io.h> 32 #include <linux/of.h> 33 #include <linux/of_gpio.h> 34 #include <linux/regulator/of_regulator.h> 35 #include <linux/slab.h> 36 37 /* Registers */ 38 enum { 39 MAX8952_REG_MODE0, 40 MAX8952_REG_MODE1, 41 MAX8952_REG_MODE2, 42 MAX8952_REG_MODE3, 43 MAX8952_REG_CONTROL, 44 MAX8952_REG_SYNC, 45 MAX8952_REG_RAMP, 46 MAX8952_REG_CHIP_ID1, 47 MAX8952_REG_CHIP_ID2, 48 }; 49 50 struct max8952_data { 51 struct i2c_client *client; 52 struct max8952_platform_data *pdata; 53 54 bool vid0; 55 bool vid1; 56 }; 57 58 static int max8952_read_reg(struct max8952_data *max8952, u8 reg) 59 { 60 int ret = i2c_smbus_read_byte_data(max8952->client, reg); 61 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 const 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 const 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 return NULL; 149 150 pd->gpio_vid0 = of_get_named_gpio(np, "max8952,vid-gpios", 0); 151 pd->gpio_vid1 = of_get_named_gpio(np, "max8952,vid-gpios", 1); 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, ®ulator); 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 struct gpio_desc *gpiod; 201 enum gpiod_flags gflags; 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->pdata = pdata; 223 224 config.dev = &client->dev; 225 config.init_data = pdata->reg_data; 226 config.driver_data = max8952; 227 config.of_node = client->dev.of_node; 228 229 if (pdata->reg_data->constraints.boot_on) 230 gflags = GPIOD_OUT_HIGH; 231 else 232 gflags = GPIOD_OUT_LOW; 233 gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE; 234 /* 235 * Do not use devm* here: the regulator core takes over the 236 * lifecycle management of the GPIO descriptor. 237 */ 238 gpiod = gpiod_get_optional(&client->dev, 239 "max8952,en", 240 gflags); 241 if (IS_ERR(gpiod)) 242 return PTR_ERR(gpiod); 243 if (gpiod) 244 config.ena_gpiod = gpiod; 245 246 rdev = devm_regulator_register(&client->dev, ®ulator, &config); 247 if (IS_ERR(rdev)) { 248 ret = PTR_ERR(rdev); 249 dev_err(&client->dev, "regulator init failed (%d)\n", ret); 250 return ret; 251 } 252 253 max8952->vid0 = pdata->default_mode & 0x1; 254 max8952->vid1 = (pdata->default_mode >> 1) & 0x1; 255 256 if (gpio_is_valid(pdata->gpio_vid0) && 257 gpio_is_valid(pdata->gpio_vid1)) { 258 unsigned long gpio_flags; 259 260 gpio_flags = max8952->vid0 ? 261 GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW; 262 if (devm_gpio_request_one(&client->dev, pdata->gpio_vid0, 263 gpio_flags, "MAX8952 VID0")) 264 err = 1; 265 266 gpio_flags = max8952->vid1 ? 267 GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW; 268 if (devm_gpio_request_one(&client->dev, pdata->gpio_vid1, 269 gpio_flags, "MAX8952 VID1")) 270 err = 2; 271 } else 272 err = 3; 273 274 if (err) { 275 dev_warn(&client->dev, "VID0/1 gpio invalid: " 276 "DVS not available.\n"); 277 max8952->vid0 = 0; 278 max8952->vid1 = 0; 279 /* Mark invalid */ 280 pdata->gpio_vid0 = -1; 281 pdata->gpio_vid1 = -1; 282 283 /* Disable Pulldown of EN only */ 284 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60); 285 286 dev_err(&client->dev, "DVS modes disabled because VID0 and VID1" 287 " do not have proper controls.\n"); 288 } else { 289 /* 290 * Disable Pulldown on EN, VID0, VID1 to reduce 291 * leakage current of MAX8952 assuming that MAX8952 292 * is turned on (EN==1). Note that without having VID0/1 293 * properly connected, turning pulldown off can be 294 * problematic. Thus, turn this off only when they are 295 * controllable by GPIO. 296 */ 297 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0); 298 } 299 300 max8952_write_reg(max8952, MAX8952_REG_MODE0, 301 (max8952_read_reg(max8952, 302 MAX8952_REG_MODE0) & 0xC0) | 303 (pdata->dvs_mode[0] & 0x3F)); 304 max8952_write_reg(max8952, MAX8952_REG_MODE1, 305 (max8952_read_reg(max8952, 306 MAX8952_REG_MODE1) & 0xC0) | 307 (pdata->dvs_mode[1] & 0x3F)); 308 max8952_write_reg(max8952, MAX8952_REG_MODE2, 309 (max8952_read_reg(max8952, 310 MAX8952_REG_MODE2) & 0xC0) | 311 (pdata->dvs_mode[2] & 0x3F)); 312 max8952_write_reg(max8952, MAX8952_REG_MODE3, 313 (max8952_read_reg(max8952, 314 MAX8952_REG_MODE3) & 0xC0) | 315 (pdata->dvs_mode[3] & 0x3F)); 316 317 max8952_write_reg(max8952, MAX8952_REG_SYNC, 318 (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) | 319 ((pdata->sync_freq & 0x3) << 6)); 320 max8952_write_reg(max8952, MAX8952_REG_RAMP, 321 (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) | 322 ((pdata->ramp_speed & 0x7) << 5)); 323 324 i2c_set_clientdata(client, max8952); 325 326 return 0; 327 } 328 329 static const struct i2c_device_id max8952_ids[] = { 330 { "max8952", 0 }, 331 { }, 332 }; 333 MODULE_DEVICE_TABLE(i2c, max8952_ids); 334 335 static struct i2c_driver max8952_pmic_driver = { 336 .probe = max8952_pmic_probe, 337 .driver = { 338 .name = "max8952", 339 .of_match_table = of_match_ptr(max8952_dt_match), 340 }, 341 .id_table = max8952_ids, 342 }; 343 344 static int __init max8952_pmic_init(void) 345 { 346 return i2c_add_driver(&max8952_pmic_driver); 347 } 348 subsys_initcall(max8952_pmic_init); 349 350 static void __exit max8952_pmic_exit(void) 351 { 352 i2c_del_driver(&max8952_pmic_driver); 353 } 354 module_exit(max8952_pmic_exit); 355 356 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver"); 357 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); 358 MODULE_LICENSE("GPL"); 359