1 /* 2 * Regulator driver for PWM Regulators 3 * 4 * Copyright (C) 2014 - STMicroelectronics Inc. 5 * 6 * Author: Lee Jones <lee.jones@linaro.org> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13 #include <linux/module.h> 14 #include <linux/init.h> 15 #include <linux/err.h> 16 #include <linux/regulator/driver.h> 17 #include <linux/regulator/machine.h> 18 #include <linux/regulator/of_regulator.h> 19 #include <linux/of.h> 20 #include <linux/of_device.h> 21 #include <linux/pwm.h> 22 #include <linux/gpio/consumer.h> 23 24 struct pwm_continuous_reg_data { 25 unsigned int min_uV_dutycycle; 26 unsigned int max_uV_dutycycle; 27 unsigned int dutycycle_unit; 28 }; 29 30 struct pwm_regulator_data { 31 /* Shared */ 32 struct pwm_device *pwm; 33 34 /* Voltage table */ 35 struct pwm_voltages *duty_cycle_table; 36 37 /* Continuous mode info */ 38 struct pwm_continuous_reg_data continuous; 39 40 /* regulator descriptor */ 41 struct regulator_desc desc; 42 43 /* Regulator ops */ 44 struct regulator_ops ops; 45 46 int state; 47 48 /* Enable GPIO */ 49 struct gpio_desc *enb_gpio; 50 }; 51 52 struct pwm_voltages { 53 unsigned int uV; 54 unsigned int dutycycle; 55 }; 56 57 /** 58 * Voltage table call-backs 59 */ 60 static void pwm_regulator_init_state(struct regulator_dev *rdev) 61 { 62 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); 63 struct pwm_state pwm_state; 64 unsigned int dutycycle; 65 int i; 66 67 pwm_get_state(drvdata->pwm, &pwm_state); 68 dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100); 69 70 for (i = 0; i < rdev->desc->n_voltages; i++) { 71 if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) { 72 drvdata->state = i; 73 return; 74 } 75 } 76 } 77 78 static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev) 79 { 80 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); 81 82 if (drvdata->state < 0) 83 pwm_regulator_init_state(rdev); 84 85 return drvdata->state; 86 } 87 88 static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev, 89 unsigned selector) 90 { 91 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); 92 struct pwm_state pstate; 93 int ret; 94 95 pwm_init_state(drvdata->pwm, &pstate); 96 pwm_set_relative_duty_cycle(&pstate, 97 drvdata->duty_cycle_table[selector].dutycycle, 100); 98 99 ret = pwm_apply_state(drvdata->pwm, &pstate); 100 if (ret) { 101 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret); 102 return ret; 103 } 104 105 drvdata->state = selector; 106 107 return 0; 108 } 109 110 static int pwm_regulator_list_voltage(struct regulator_dev *rdev, 111 unsigned selector) 112 { 113 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); 114 115 if (selector >= rdev->desc->n_voltages) 116 return -EINVAL; 117 118 return drvdata->duty_cycle_table[selector].uV; 119 } 120 121 static int pwm_regulator_enable(struct regulator_dev *dev) 122 { 123 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); 124 125 gpiod_set_value_cansleep(drvdata->enb_gpio, 1); 126 127 return pwm_enable(drvdata->pwm); 128 } 129 130 static int pwm_regulator_disable(struct regulator_dev *dev) 131 { 132 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); 133 134 pwm_disable(drvdata->pwm); 135 136 gpiod_set_value_cansleep(drvdata->enb_gpio, 0); 137 138 return 0; 139 } 140 141 static int pwm_regulator_is_enabled(struct regulator_dev *dev) 142 { 143 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); 144 145 if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio)) 146 return false; 147 148 return pwm_is_enabled(drvdata->pwm); 149 } 150 151 static int pwm_regulator_get_voltage(struct regulator_dev *rdev) 152 { 153 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); 154 unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle; 155 unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle; 156 unsigned int duty_unit = drvdata->continuous.dutycycle_unit; 157 int min_uV = rdev->constraints->min_uV; 158 int max_uV = rdev->constraints->max_uV; 159 int diff_uV = max_uV - min_uV; 160 struct pwm_state pstate; 161 unsigned int diff_duty; 162 unsigned int voltage; 163 164 pwm_get_state(drvdata->pwm, &pstate); 165 166 voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit); 167 168 /* 169 * The dutycycle for min_uV might be greater than the one for max_uV. 170 * This is happening when the user needs an inversed polarity, but the 171 * PWM device does not support inversing it in hardware. 172 */ 173 if (max_uV_duty < min_uV_duty) { 174 voltage = min_uV_duty - voltage; 175 diff_duty = min_uV_duty - max_uV_duty; 176 } else { 177 voltage = voltage - min_uV_duty; 178 diff_duty = max_uV_duty - min_uV_duty; 179 } 180 181 voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty); 182 183 return voltage + min_uV; 184 } 185 186 static int pwm_regulator_set_voltage(struct regulator_dev *rdev, 187 int req_min_uV, int req_max_uV, 188 unsigned int *selector) 189 { 190 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); 191 unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle; 192 unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle; 193 unsigned int duty_unit = drvdata->continuous.dutycycle_unit; 194 int min_uV = rdev->constraints->min_uV; 195 int max_uV = rdev->constraints->max_uV; 196 int diff_uV = max_uV - min_uV; 197 struct pwm_state pstate; 198 unsigned int diff_duty; 199 unsigned int dutycycle; 200 int ret; 201 202 pwm_init_state(drvdata->pwm, &pstate); 203 204 /* 205 * The dutycycle for min_uV might be greater than the one for max_uV. 206 * This is happening when the user needs an inversed polarity, but the 207 * PWM device does not support inversing it in hardware. 208 */ 209 if (max_uV_duty < min_uV_duty) 210 diff_duty = min_uV_duty - max_uV_duty; 211 else 212 diff_duty = max_uV_duty - min_uV_duty; 213 214 dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) * 215 diff_duty, 216 diff_uV); 217 218 if (max_uV_duty < min_uV_duty) 219 dutycycle = min_uV_duty - dutycycle; 220 else 221 dutycycle = min_uV_duty + dutycycle; 222 223 pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit); 224 225 ret = pwm_apply_state(drvdata->pwm, &pstate); 226 if (ret) { 227 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret); 228 return ret; 229 } 230 231 return 0; 232 } 233 234 static struct regulator_ops pwm_regulator_voltage_table_ops = { 235 .set_voltage_sel = pwm_regulator_set_voltage_sel, 236 .get_voltage_sel = pwm_regulator_get_voltage_sel, 237 .list_voltage = pwm_regulator_list_voltage, 238 .map_voltage = regulator_map_voltage_iterate, 239 .enable = pwm_regulator_enable, 240 .disable = pwm_regulator_disable, 241 .is_enabled = pwm_regulator_is_enabled, 242 }; 243 244 static struct regulator_ops pwm_regulator_voltage_continuous_ops = { 245 .get_voltage = pwm_regulator_get_voltage, 246 .set_voltage = pwm_regulator_set_voltage, 247 .enable = pwm_regulator_enable, 248 .disable = pwm_regulator_disable, 249 .is_enabled = pwm_regulator_is_enabled, 250 }; 251 252 static struct regulator_desc pwm_regulator_desc = { 253 .name = "pwm-regulator", 254 .type = REGULATOR_VOLTAGE, 255 .owner = THIS_MODULE, 256 .supply_name = "pwm", 257 }; 258 259 static int pwm_regulator_init_table(struct platform_device *pdev, 260 struct pwm_regulator_data *drvdata) 261 { 262 struct device_node *np = pdev->dev.of_node; 263 struct pwm_voltages *duty_cycle_table; 264 unsigned int length = 0; 265 int ret; 266 267 of_find_property(np, "voltage-table", &length); 268 269 if ((length < sizeof(*duty_cycle_table)) || 270 (length % sizeof(*duty_cycle_table))) { 271 dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n", 272 length); 273 return -EINVAL; 274 } 275 276 duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL); 277 if (!duty_cycle_table) 278 return -ENOMEM; 279 280 ret = of_property_read_u32_array(np, "voltage-table", 281 (u32 *)duty_cycle_table, 282 length / sizeof(u32)); 283 if (ret) { 284 dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret); 285 return ret; 286 } 287 288 drvdata->state = -EINVAL; 289 drvdata->duty_cycle_table = duty_cycle_table; 290 memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops, 291 sizeof(drvdata->ops)); 292 drvdata->desc.ops = &drvdata->ops; 293 drvdata->desc.n_voltages = length / sizeof(*duty_cycle_table); 294 295 return 0; 296 } 297 298 static int pwm_regulator_init_continuous(struct platform_device *pdev, 299 struct pwm_regulator_data *drvdata) 300 { 301 u32 dutycycle_range[2] = { 0, 100 }; 302 u32 dutycycle_unit = 100; 303 304 memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops, 305 sizeof(drvdata->ops)); 306 drvdata->desc.ops = &drvdata->ops; 307 drvdata->desc.continuous_voltage_range = true; 308 309 of_property_read_u32_array(pdev->dev.of_node, 310 "pwm-dutycycle-range", 311 dutycycle_range, 2); 312 of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit", 313 &dutycycle_unit); 314 315 if (dutycycle_range[0] > dutycycle_unit || 316 dutycycle_range[1] > dutycycle_unit) 317 return -EINVAL; 318 319 drvdata->continuous.dutycycle_unit = dutycycle_unit; 320 drvdata->continuous.min_uV_dutycycle = dutycycle_range[0]; 321 drvdata->continuous.max_uV_dutycycle = dutycycle_range[1]; 322 323 return 0; 324 } 325 326 static int pwm_regulator_probe(struct platform_device *pdev) 327 { 328 const struct regulator_init_data *init_data; 329 struct pwm_regulator_data *drvdata; 330 struct regulator_dev *regulator; 331 struct regulator_config config = { }; 332 struct device_node *np = pdev->dev.of_node; 333 enum gpiod_flags gpio_flags; 334 int ret; 335 336 if (!np) { 337 dev_err(&pdev->dev, "Device Tree node missing\n"); 338 return -EINVAL; 339 } 340 341 drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL); 342 if (!drvdata) 343 return -ENOMEM; 344 345 memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc)); 346 347 if (of_find_property(np, "voltage-table", NULL)) 348 ret = pwm_regulator_init_table(pdev, drvdata); 349 else 350 ret = pwm_regulator_init_continuous(pdev, drvdata); 351 if (ret) 352 return ret; 353 354 init_data = of_get_regulator_init_data(&pdev->dev, np, 355 &drvdata->desc); 356 if (!init_data) 357 return -ENOMEM; 358 359 config.of_node = np; 360 config.dev = &pdev->dev; 361 config.driver_data = drvdata; 362 config.init_data = init_data; 363 364 drvdata->pwm = devm_pwm_get(&pdev->dev, NULL); 365 if (IS_ERR(drvdata->pwm)) { 366 ret = PTR_ERR(drvdata->pwm); 367 dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret); 368 return ret; 369 } 370 371 if (init_data->constraints.boot_on || init_data->constraints.always_on) 372 gpio_flags = GPIOD_OUT_HIGH; 373 else 374 gpio_flags = GPIOD_OUT_LOW; 375 drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable", 376 gpio_flags); 377 if (IS_ERR(drvdata->enb_gpio)) { 378 ret = PTR_ERR(drvdata->enb_gpio); 379 dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret); 380 return ret; 381 } 382 383 ret = pwm_adjust_config(drvdata->pwm); 384 if (ret) 385 return ret; 386 387 regulator = devm_regulator_register(&pdev->dev, 388 &drvdata->desc, &config); 389 if (IS_ERR(regulator)) { 390 ret = PTR_ERR(regulator); 391 dev_err(&pdev->dev, "Failed to register regulator %s: %d\n", 392 drvdata->desc.name, ret); 393 return ret; 394 } 395 396 return 0; 397 } 398 399 static const struct of_device_id pwm_of_match[] = { 400 { .compatible = "pwm-regulator" }, 401 { }, 402 }; 403 MODULE_DEVICE_TABLE(of, pwm_of_match); 404 405 static struct platform_driver pwm_regulator_driver = { 406 .driver = { 407 .name = "pwm-regulator", 408 .of_match_table = of_match_ptr(pwm_of_match), 409 }, 410 .probe = pwm_regulator_probe, 411 }; 412 413 module_platform_driver(pwm_regulator_driver); 414 415 MODULE_LICENSE("GPL"); 416 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>"); 417 MODULE_DESCRIPTION("PWM Regulator Driver"); 418 MODULE_ALIAS("platform:pwm-regulator"); 419