1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * max8952.c - Voltage and current regulation for the Maxim 8952 4 * 5 * Copyright (C) 2010 Samsung Electronics 6 * MyungJoo Ham <myungjoo.ham@samsung.com> 7 */ 8 9 #include <linux/module.h> 10 #include <linux/init.h> 11 #include <linux/i2c.h> 12 #include <linux/err.h> 13 #include <linux/platform_device.h> 14 #include <linux/regulator/driver.h> 15 #include <linux/regulator/max8952.h> 16 #include <linux/gpio/consumer.h> 17 #include <linux/io.h> 18 #include <linux/of.h> 19 #include <linux/regulator/of_regulator.h> 20 #include <linux/slab.h> 21 22 /* Registers */ 23 enum { 24 MAX8952_REG_MODE0, 25 MAX8952_REG_MODE1, 26 MAX8952_REG_MODE2, 27 MAX8952_REG_MODE3, 28 MAX8952_REG_CONTROL, 29 MAX8952_REG_SYNC, 30 MAX8952_REG_RAMP, 31 MAX8952_REG_CHIP_ID1, 32 MAX8952_REG_CHIP_ID2, 33 }; 34 35 struct max8952_data { 36 struct i2c_client *client; 37 struct max8952_platform_data *pdata; 38 struct gpio_desc *vid0_gpiod; 39 struct gpio_desc *vid1_gpiod; 40 bool vid0; 41 bool vid1; 42 }; 43 44 static int max8952_read_reg(struct max8952_data *max8952, u8 reg) 45 { 46 int ret = i2c_smbus_read_byte_data(max8952->client, reg); 47 48 if (ret > 0) 49 ret &= 0xff; 50 51 return ret; 52 } 53 54 static int max8952_write_reg(struct max8952_data *max8952, 55 u8 reg, u8 value) 56 { 57 return i2c_smbus_write_byte_data(max8952->client, reg, value); 58 } 59 60 static int max8952_list_voltage(struct regulator_dev *rdev, 61 unsigned int selector) 62 { 63 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 64 65 if (rdev_get_id(rdev) != 0) 66 return -EINVAL; 67 68 return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000; 69 } 70 71 static int max8952_get_voltage_sel(struct regulator_dev *rdev) 72 { 73 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 74 u8 vid = 0; 75 76 if (max8952->vid0) 77 vid += 1; 78 if (max8952->vid1) 79 vid += 2; 80 81 return vid; 82 } 83 84 static int max8952_set_voltage_sel(struct regulator_dev *rdev, 85 unsigned selector) 86 { 87 struct max8952_data *max8952 = rdev_get_drvdata(rdev); 88 89 if (!max8952->vid0_gpiod || !max8952->vid1_gpiod) { 90 /* DVS not supported */ 91 return -EPERM; 92 } 93 94 max8952->vid0 = selector & 0x1; 95 max8952->vid1 = (selector >> 1) & 0x1; 96 gpiod_set_value(max8952->vid0_gpiod, max8952->vid0); 97 gpiod_set_value(max8952->vid1_gpiod, max8952->vid1); 98 99 return 0; 100 } 101 102 static const struct regulator_ops max8952_ops = { 103 .list_voltage = max8952_list_voltage, 104 .get_voltage_sel = max8952_get_voltage_sel, 105 .set_voltage_sel = max8952_set_voltage_sel, 106 }; 107 108 static const struct regulator_desc regulator = { 109 .name = "MAX8952_VOUT", 110 .id = 0, 111 .n_voltages = MAX8952_NUM_DVS_MODE, 112 .ops = &max8952_ops, 113 .type = REGULATOR_VOLTAGE, 114 .owner = THIS_MODULE, 115 }; 116 117 #ifdef CONFIG_OF 118 static const struct of_device_id max8952_dt_match[] = { 119 { .compatible = "maxim,max8952" }, 120 {}, 121 }; 122 MODULE_DEVICE_TABLE(of, max8952_dt_match); 123 124 static struct max8952_platform_data *max8952_parse_dt(struct device *dev) 125 { 126 struct max8952_platform_data *pd; 127 struct device_node *np = dev->of_node; 128 int ret; 129 int i; 130 131 pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL); 132 if (!pd) 133 return NULL; 134 135 if (of_property_read_u32(np, "max8952,default-mode", &pd->default_mode)) 136 dev_warn(dev, "Default mode not specified, assuming 0\n"); 137 138 ret = of_property_read_u32_array(np, "max8952,dvs-mode-microvolt", 139 pd->dvs_mode, ARRAY_SIZE(pd->dvs_mode)); 140 if (ret) { 141 dev_err(dev, "max8952,dvs-mode-microvolt property not specified"); 142 return NULL; 143 } 144 145 for (i = 0; i < ARRAY_SIZE(pd->dvs_mode); ++i) { 146 if (pd->dvs_mode[i] < 770000 || pd->dvs_mode[i] > 1400000) { 147 dev_err(dev, "DVS voltage %d out of range\n", i); 148 return NULL; 149 } 150 pd->dvs_mode[i] = (pd->dvs_mode[i] - 770000) / 10000; 151 } 152 153 if (of_property_read_u32(np, "max8952,sync-freq", &pd->sync_freq)) 154 dev_warn(dev, "max8952,sync-freq property not specified, defaulting to 26MHz\n"); 155 156 if (of_property_read_u32(np, "max8952,ramp-speed", &pd->ramp_speed)) 157 dev_warn(dev, "max8952,ramp-speed property not specified, defaulting to 32mV/us\n"); 158 159 pd->reg_data = of_get_regulator_init_data(dev, np, ®ulator); 160 if (!pd->reg_data) { 161 dev_err(dev, "Failed to parse regulator init data\n"); 162 return NULL; 163 } 164 165 return pd; 166 } 167 #else 168 static struct max8952_platform_data *max8952_parse_dt(struct device *dev) 169 { 170 return NULL; 171 } 172 #endif 173 174 static int max8952_pmic_probe(struct i2c_client *client, 175 const struct i2c_device_id *i2c_id) 176 { 177 struct i2c_adapter *adapter = client->adapter; 178 struct max8952_platform_data *pdata = dev_get_platdata(&client->dev); 179 struct regulator_config config = { }; 180 struct max8952_data *max8952; 181 struct regulator_dev *rdev; 182 struct gpio_desc *gpiod; 183 enum gpiod_flags gflags; 184 185 int ret = 0; 186 187 if (client->dev.of_node) 188 pdata = max8952_parse_dt(&client->dev); 189 190 if (!pdata) { 191 dev_err(&client->dev, "Require the platform data\n"); 192 return -EINVAL; 193 } 194 195 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) 196 return -EIO; 197 198 max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data), 199 GFP_KERNEL); 200 if (!max8952) 201 return -ENOMEM; 202 203 max8952->client = client; 204 max8952->pdata = pdata; 205 206 config.dev = &client->dev; 207 config.init_data = pdata->reg_data; 208 config.driver_data = max8952; 209 config.of_node = client->dev.of_node; 210 211 if (pdata->reg_data->constraints.boot_on) 212 gflags = GPIOD_OUT_HIGH; 213 else 214 gflags = GPIOD_OUT_LOW; 215 gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE; 216 /* 217 * Do not use devm* here: the regulator core takes over the 218 * lifecycle management of the GPIO descriptor. 219 */ 220 gpiod = gpiod_get_optional(&client->dev, 221 "max8952,en", 222 gflags); 223 if (IS_ERR(gpiod)) 224 return PTR_ERR(gpiod); 225 if (gpiod) 226 config.ena_gpiod = gpiod; 227 228 rdev = devm_regulator_register(&client->dev, ®ulator, &config); 229 if (IS_ERR(rdev)) { 230 ret = PTR_ERR(rdev); 231 dev_err(&client->dev, "regulator init failed (%d)\n", ret); 232 return ret; 233 } 234 235 max8952->vid0 = pdata->default_mode & 0x1; 236 max8952->vid1 = (pdata->default_mode >> 1) & 0x1; 237 238 /* Fetch vid0 and vid1 GPIOs if available */ 239 gflags = max8952->vid0 ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW; 240 max8952->vid0_gpiod = devm_gpiod_get_index_optional(&client->dev, 241 "max8952,vid", 242 0, gflags); 243 if (IS_ERR(max8952->vid0_gpiod)) 244 return PTR_ERR(max8952->vid0_gpiod); 245 gflags = max8952->vid1 ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW; 246 max8952->vid1_gpiod = devm_gpiod_get_index_optional(&client->dev, 247 "max8952,vid", 248 1, gflags); 249 if (IS_ERR(max8952->vid1_gpiod)) 250 return PTR_ERR(max8952->vid1_gpiod); 251 252 /* If either VID GPIO is missing just disable this */ 253 if (!max8952->vid0_gpiod || !max8952->vid1_gpiod) { 254 dev_warn(&client->dev, "VID0/1 gpio invalid: " 255 "DVS not available.\n"); 256 max8952->vid0 = 0; 257 max8952->vid1 = 0; 258 /* Make sure if we have any descriptors they get set to low */ 259 if (max8952->vid0_gpiod) 260 gpiod_set_value(max8952->vid0_gpiod, 0); 261 if (max8952->vid1_gpiod) 262 gpiod_set_value(max8952->vid1_gpiod, 0); 263 264 /* Disable Pulldown of EN only */ 265 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60); 266 267 dev_err(&client->dev, "DVS modes disabled because VID0 and VID1" 268 " do not have proper controls.\n"); 269 } else { 270 /* 271 * Disable Pulldown on EN, VID0, VID1 to reduce 272 * leakage current of MAX8952 assuming that MAX8952 273 * is turned on (EN==1). Note that without having VID0/1 274 * properly connected, turning pulldown off can be 275 * problematic. Thus, turn this off only when they are 276 * controllable by GPIO. 277 */ 278 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0); 279 } 280 281 max8952_write_reg(max8952, MAX8952_REG_MODE0, 282 (max8952_read_reg(max8952, 283 MAX8952_REG_MODE0) & 0xC0) | 284 (pdata->dvs_mode[0] & 0x3F)); 285 max8952_write_reg(max8952, MAX8952_REG_MODE1, 286 (max8952_read_reg(max8952, 287 MAX8952_REG_MODE1) & 0xC0) | 288 (pdata->dvs_mode[1] & 0x3F)); 289 max8952_write_reg(max8952, MAX8952_REG_MODE2, 290 (max8952_read_reg(max8952, 291 MAX8952_REG_MODE2) & 0xC0) | 292 (pdata->dvs_mode[2] & 0x3F)); 293 max8952_write_reg(max8952, MAX8952_REG_MODE3, 294 (max8952_read_reg(max8952, 295 MAX8952_REG_MODE3) & 0xC0) | 296 (pdata->dvs_mode[3] & 0x3F)); 297 298 max8952_write_reg(max8952, MAX8952_REG_SYNC, 299 (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) | 300 ((pdata->sync_freq & 0x3) << 6)); 301 max8952_write_reg(max8952, MAX8952_REG_RAMP, 302 (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) | 303 ((pdata->ramp_speed & 0x7) << 5)); 304 305 i2c_set_clientdata(client, max8952); 306 307 return 0; 308 } 309 310 static const struct i2c_device_id max8952_ids[] = { 311 { "max8952", 0 }, 312 { }, 313 }; 314 MODULE_DEVICE_TABLE(i2c, max8952_ids); 315 316 static struct i2c_driver max8952_pmic_driver = { 317 .probe = max8952_pmic_probe, 318 .driver = { 319 .name = "max8952", 320 .of_match_table = of_match_ptr(max8952_dt_match), 321 }, 322 .id_table = max8952_ids, 323 }; 324 325 static int __init max8952_pmic_init(void) 326 { 327 return i2c_add_driver(&max8952_pmic_driver); 328 } 329 subsys_initcall(max8952_pmic_init); 330 331 static void __exit max8952_pmic_exit(void) 332 { 333 i2c_del_driver(&max8952_pmic_driver); 334 } 335 module_exit(max8952_pmic_exit); 336 337 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver"); 338 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); 339 MODULE_LICENSE("GPL"); 340