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 { 176 struct i2c_adapter *adapter = client->adapter; 177 struct max8952_platform_data *pdata = dev_get_platdata(&client->dev); 178 struct regulator_config config = { }; 179 struct max8952_data *max8952; 180 struct regulator_dev *rdev; 181 struct gpio_desc *gpiod; 182 enum gpiod_flags gflags; 183 184 int ret = 0; 185 186 if (client->dev.of_node) 187 pdata = max8952_parse_dt(&client->dev); 188 189 if (!pdata) { 190 dev_err(&client->dev, "Require the platform data\n"); 191 return -EINVAL; 192 } 193 194 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) 195 return -EIO; 196 197 max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data), 198 GFP_KERNEL); 199 if (!max8952) 200 return -ENOMEM; 201 202 max8952->client = client; 203 max8952->pdata = pdata; 204 205 config.dev = &client->dev; 206 config.init_data = pdata->reg_data; 207 config.driver_data = max8952; 208 config.of_node = client->dev.of_node; 209 210 if (pdata->reg_data->constraints.boot_on) 211 gflags = GPIOD_OUT_HIGH; 212 else 213 gflags = GPIOD_OUT_LOW; 214 gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE; 215 /* 216 * Do not use devm* here: the regulator core takes over the 217 * lifecycle management of the GPIO descriptor. 218 */ 219 gpiod = gpiod_get_optional(&client->dev, 220 "max8952,en", 221 gflags); 222 if (IS_ERR(gpiod)) 223 return PTR_ERR(gpiod); 224 if (gpiod) 225 config.ena_gpiod = gpiod; 226 227 rdev = devm_regulator_register(&client->dev, ®ulator, &config); 228 if (IS_ERR(rdev)) { 229 ret = PTR_ERR(rdev); 230 dev_err(&client->dev, "regulator init failed (%d)\n", ret); 231 return ret; 232 } 233 234 max8952->vid0 = pdata->default_mode & 0x1; 235 max8952->vid1 = (pdata->default_mode >> 1) & 0x1; 236 237 /* Fetch vid0 and vid1 GPIOs if available */ 238 gflags = max8952->vid0 ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW; 239 max8952->vid0_gpiod = devm_gpiod_get_index_optional(&client->dev, 240 "max8952,vid", 241 0, gflags); 242 if (IS_ERR(max8952->vid0_gpiod)) 243 return PTR_ERR(max8952->vid0_gpiod); 244 gflags = max8952->vid1 ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW; 245 max8952->vid1_gpiod = devm_gpiod_get_index_optional(&client->dev, 246 "max8952,vid", 247 1, gflags); 248 if (IS_ERR(max8952->vid1_gpiod)) 249 return PTR_ERR(max8952->vid1_gpiod); 250 251 /* If either VID GPIO is missing just disable this */ 252 if (!max8952->vid0_gpiod || !max8952->vid1_gpiod) { 253 dev_warn(&client->dev, "VID0/1 gpio invalid: " 254 "DVS not available.\n"); 255 max8952->vid0 = 0; 256 max8952->vid1 = 0; 257 /* Make sure if we have any descriptors they get set to low */ 258 if (max8952->vid0_gpiod) 259 gpiod_set_value(max8952->vid0_gpiod, 0); 260 if (max8952->vid1_gpiod) 261 gpiod_set_value(max8952->vid1_gpiod, 0); 262 263 /* Disable Pulldown of EN only */ 264 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60); 265 266 dev_err(&client->dev, "DVS modes disabled because VID0 and VID1" 267 " do not have proper controls.\n"); 268 } else { 269 /* 270 * Disable Pulldown on EN, VID0, VID1 to reduce 271 * leakage current of MAX8952 assuming that MAX8952 272 * is turned on (EN==1). Note that without having VID0/1 273 * properly connected, turning pulldown off can be 274 * problematic. Thus, turn this off only when they are 275 * controllable by GPIO. 276 */ 277 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0); 278 } 279 280 max8952_write_reg(max8952, MAX8952_REG_MODE0, 281 (max8952_read_reg(max8952, 282 MAX8952_REG_MODE0) & 0xC0) | 283 (pdata->dvs_mode[0] & 0x3F)); 284 max8952_write_reg(max8952, MAX8952_REG_MODE1, 285 (max8952_read_reg(max8952, 286 MAX8952_REG_MODE1) & 0xC0) | 287 (pdata->dvs_mode[1] & 0x3F)); 288 max8952_write_reg(max8952, MAX8952_REG_MODE2, 289 (max8952_read_reg(max8952, 290 MAX8952_REG_MODE2) & 0xC0) | 291 (pdata->dvs_mode[2] & 0x3F)); 292 max8952_write_reg(max8952, MAX8952_REG_MODE3, 293 (max8952_read_reg(max8952, 294 MAX8952_REG_MODE3) & 0xC0) | 295 (pdata->dvs_mode[3] & 0x3F)); 296 297 max8952_write_reg(max8952, MAX8952_REG_SYNC, 298 (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) | 299 ((pdata->sync_freq & 0x3) << 6)); 300 max8952_write_reg(max8952, MAX8952_REG_RAMP, 301 (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) | 302 ((pdata->ramp_speed & 0x7) << 5)); 303 304 i2c_set_clientdata(client, max8952); 305 306 return 0; 307 } 308 309 static const struct i2c_device_id max8952_ids[] = { 310 { "max8952", 0 }, 311 { }, 312 }; 313 MODULE_DEVICE_TABLE(i2c, max8952_ids); 314 315 static struct i2c_driver max8952_pmic_driver = { 316 .probe_new = max8952_pmic_probe, 317 .driver = { 318 .name = "max8952", 319 .of_match_table = of_match_ptr(max8952_dt_match), 320 }, 321 .id_table = max8952_ids, 322 }; 323 324 static int __init max8952_pmic_init(void) 325 { 326 return i2c_add_driver(&max8952_pmic_driver); 327 } 328 subsys_initcall(max8952_pmic_init); 329 330 static void __exit max8952_pmic_exit(void) 331 { 332 i2c_del_driver(&max8952_pmic_driver); 333 } 334 module_exit(max8952_pmic_exit); 335 336 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver"); 337 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); 338 MODULE_LICENSE("GPL"); 339