| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* |
| 3 | * Regulator driver for PWM Regulators |
| 4 | * |
| 5 | * Copyright (C) 2014 - STMicroelectronics Inc. |
| 6 | * |
| 7 | * Author: Lee Jones <lee.jones@linaro.org> |
| 8 | */ |
| 9 | |
| 10 | #include <linux/module.h> |
| 11 | #include <linux/init.h> |
| 12 | #include <linux/err.h> |
| 13 | #include <linux/platform_device.h> |
| 14 | #include <linux/regulator/driver.h> |
| 15 | #include <linux/regulator/machine.h> |
| 16 | #include <linux/regulator/of_regulator.h> |
| 17 | #include <linux/of.h> |
| 18 | #include <linux/pwm.h> |
| 19 | #include <linux/gpio/consumer.h> |
| 20 | |
| 21 | struct pwm_continuous_reg_data { |
| 22 | unsigned int min_uV_dutycycle; |
| 23 | unsigned int max_uV_dutycycle; |
| 24 | unsigned int dutycycle_unit; |
| 25 | }; |
| 26 | |
| 27 | struct pwm_regulator_data { |
| 28 | /* Shared */ |
| 29 | struct pwm_device *pwm; |
| 30 | |
| 31 | /* Voltage table */ |
| 32 | struct pwm_voltages *duty_cycle_table; |
| 33 | |
| 34 | /* Continuous mode info */ |
| 35 | struct pwm_continuous_reg_data continuous; |
| 36 | |
| 37 | /* regulator descriptor */ |
| 38 | struct regulator_desc desc; |
| 39 | |
| 40 | int state; |
| 41 | |
| 42 | /* Enable GPIO */ |
| 43 | struct gpio_desc *enb_gpio; |
| 44 | }; |
| 45 | |
| 46 | struct pwm_voltages { |
| 47 | unsigned int uV; |
| 48 | unsigned int dutycycle; |
| 49 | }; |
| 50 | |
| 51 | /* |
| 52 | * Voltage table call-backs |
| 53 | */ |
| 54 | static void pwm_regulator_init_state(struct regulator_dev *rdev) |
| 55 | { |
| 56 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); |
| 57 | struct pwm_state pwm_state; |
| 58 | unsigned int dutycycle; |
| 59 | int i; |
| 60 | |
| 61 | pwm_get_state(drvdata->pwm, &pwm_state); |
| 62 | dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100); |
| 63 | |
| 64 | for (i = 0; i < rdev->desc->n_voltages; i++) { |
| 65 | if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) { |
| 66 | drvdata->state = i; |
| 67 | return; |
| 68 | } |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev) |
| 73 | { |
| 74 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); |
| 75 | |
| 76 | if (drvdata->state < 0) |
| 77 | pwm_regulator_init_state(rdev); |
| 78 | |
| 79 | return drvdata->state; |
| 80 | } |
| 81 | |
| 82 | static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev, |
| 83 | unsigned selector) |
| 84 | { |
| 85 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); |
| 86 | struct pwm_state pstate; |
| 87 | int ret; |
| 88 | |
| 89 | pwm_init_state(drvdata->pwm, &pstate); |
| 90 | pwm_set_relative_duty_cycle(&pstate, |
| 91 | drvdata->duty_cycle_table[selector].dutycycle, 100); |
| 92 | |
| 93 | ret = pwm_apply_might_sleep(drvdata->pwm, &pstate); |
| 94 | if (ret) { |
| 95 | dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret); |
| 96 | return ret; |
| 97 | } |
| 98 | |
| 99 | drvdata->state = selector; |
| 100 | |
| 101 | return 0; |
| 102 | } |
| 103 | |
| 104 | static int pwm_regulator_list_voltage(struct regulator_dev *rdev, |
| 105 | unsigned selector) |
| 106 | { |
| 107 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); |
| 108 | |
| 109 | if (selector >= rdev->desc->n_voltages) |
| 110 | return -EINVAL; |
| 111 | |
| 112 | return drvdata->duty_cycle_table[selector].uV; |
| 113 | } |
| 114 | |
| 115 | static int pwm_regulator_enable(struct regulator_dev *dev) |
| 116 | { |
| 117 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); |
| 118 | |
| 119 | gpiod_set_value_cansleep(drvdata->enb_gpio, 1); |
| 120 | |
| 121 | return pwm_enable(drvdata->pwm); |
| 122 | } |
| 123 | |
| 124 | static int pwm_regulator_disable(struct regulator_dev *dev) |
| 125 | { |
| 126 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); |
| 127 | |
| 128 | pwm_disable(drvdata->pwm); |
| 129 | |
| 130 | gpiod_set_value_cansleep(drvdata->enb_gpio, 0); |
| 131 | |
| 132 | return 0; |
| 133 | } |
| 134 | |
| 135 | static int pwm_regulator_is_enabled(struct regulator_dev *dev) |
| 136 | { |
| 137 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); |
| 138 | |
| 139 | if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio)) |
| 140 | return false; |
| 141 | |
| 142 | return pwm_is_enabled(drvdata->pwm); |
| 143 | } |
| 144 | |
| 145 | static int pwm_regulator_get_voltage(struct regulator_dev *rdev) |
| 146 | { |
| 147 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); |
| 148 | unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle; |
| 149 | unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle; |
| 150 | unsigned int duty_unit = drvdata->continuous.dutycycle_unit; |
| 151 | int min_uV = rdev->constraints->min_uV; |
| 152 | int max_uV = rdev->constraints->max_uV; |
| 153 | int diff_uV = max_uV - min_uV; |
| 154 | struct pwm_state pstate; |
| 155 | unsigned int diff_duty; |
| 156 | unsigned int voltage; |
| 157 | |
| 158 | pwm_get_state(drvdata->pwm, &pstate); |
| 159 | |
| 160 | if (!pstate.enabled) { |
| 161 | if (pstate.polarity == PWM_POLARITY_INVERSED) |
| 162 | pstate.duty_cycle = pstate.period; |
| 163 | else |
| 164 | pstate.duty_cycle = 0; |
| 165 | } |
| 166 | |
| 167 | voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit); |
| 168 | if (voltage < min(max_uV_duty, min_uV_duty) || |
| 169 | voltage > max(max_uV_duty, min_uV_duty)) |
| 170 | return -ENOTRECOVERABLE; |
| 171 | |
| 172 | /* |
| 173 | * The dutycycle for min_uV might be greater than the one for max_uV. |
| 174 | * This is happening when the user needs an inversed polarity, but the |
| 175 | * PWM device does not support inversing it in hardware. |
| 176 | */ |
| 177 | if (max_uV_duty < min_uV_duty) { |
| 178 | voltage = min_uV_duty - voltage; |
| 179 | diff_duty = min_uV_duty - max_uV_duty; |
| 180 | } else { |
| 181 | voltage = voltage - min_uV_duty; |
| 182 | diff_duty = max_uV_duty - min_uV_duty; |
| 183 | } |
| 184 | |
| 185 | voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty); |
| 186 | |
| 187 | return voltage + min_uV; |
| 188 | } |
| 189 | |
| 190 | static int pwm_regulator_set_voltage(struct regulator_dev *rdev, |
| 191 | int req_min_uV, int req_max_uV, |
| 192 | unsigned int *selector) |
| 193 | { |
| 194 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); |
| 195 | unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle; |
| 196 | unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle; |
| 197 | unsigned int duty_unit = drvdata->continuous.dutycycle_unit; |
| 198 | int min_uV = rdev->constraints->min_uV; |
| 199 | int max_uV = rdev->constraints->max_uV; |
| 200 | int diff_uV = max_uV - min_uV; |
| 201 | struct pwm_state pstate; |
| 202 | unsigned int diff_duty; |
| 203 | unsigned int dutycycle; |
| 204 | int ret; |
| 205 | |
| 206 | pwm_init_state(drvdata->pwm, &pstate); |
| 207 | |
| 208 | /* |
| 209 | * The dutycycle for min_uV might be greater than the one for max_uV. |
| 210 | * This is happening when the user needs an inversed polarity, but the |
| 211 | * PWM device does not support inversing it in hardware. |
| 212 | */ |
| 213 | if (max_uV_duty < min_uV_duty) |
| 214 | diff_duty = min_uV_duty - max_uV_duty; |
| 215 | else |
| 216 | diff_duty = max_uV_duty - min_uV_duty; |
| 217 | |
| 218 | dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) * |
| 219 | diff_duty, |
| 220 | diff_uV); |
| 221 | |
| 222 | if (max_uV_duty < min_uV_duty) |
| 223 | dutycycle = min_uV_duty - dutycycle; |
| 224 | else |
| 225 | dutycycle = min_uV_duty + dutycycle; |
| 226 | |
| 227 | pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit); |
| 228 | |
| 229 | ret = pwm_apply_might_sleep(drvdata->pwm, &pstate); |
| 230 | if (ret) { |
| 231 | dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret); |
| 232 | return ret; |
| 233 | } |
| 234 | |
| 235 | return 0; |
| 236 | } |
| 237 | |
| 238 | static const struct regulator_ops pwm_regulator_voltage_table_ops = { |
| 239 | .set_voltage_sel = pwm_regulator_set_voltage_sel, |
| 240 | .get_voltage_sel = pwm_regulator_get_voltage_sel, |
| 241 | .list_voltage = pwm_regulator_list_voltage, |
| 242 | .map_voltage = regulator_map_voltage_iterate, |
| 243 | .enable = pwm_regulator_enable, |
| 244 | .disable = pwm_regulator_disable, |
| 245 | .is_enabled = pwm_regulator_is_enabled, |
| 246 | }; |
| 247 | |
| 248 | static const struct regulator_ops pwm_regulator_voltage_continuous_ops = { |
| 249 | .get_voltage = pwm_regulator_get_voltage, |
| 250 | .set_voltage = pwm_regulator_set_voltage, |
| 251 | .enable = pwm_regulator_enable, |
| 252 | .disable = pwm_regulator_disable, |
| 253 | .is_enabled = pwm_regulator_is_enabled, |
| 254 | }; |
| 255 | |
| 256 | static const struct regulator_desc pwm_regulator_desc = { |
| 257 | .name = "pwm-regulator", |
| 258 | .type = REGULATOR_VOLTAGE, |
| 259 | .owner = THIS_MODULE, |
| 260 | .supply_name = "pwm", |
| 261 | }; |
| 262 | |
| 263 | static int pwm_regulator_init_table(struct platform_device *pdev, |
| 264 | struct pwm_regulator_data *drvdata) |
| 265 | { |
| 266 | struct device_node *np = pdev->dev.of_node; |
| 267 | struct pwm_voltages *duty_cycle_table; |
| 268 | unsigned int length = 0; |
| 269 | int ret; |
| 270 | |
| 271 | of_find_property(np, "voltage-table", &length); |
| 272 | |
| 273 | if ((length < sizeof(*duty_cycle_table)) || |
| 274 | (length % sizeof(*duty_cycle_table))) { |
| 275 | dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n", |
| 276 | length); |
| 277 | return -EINVAL; |
| 278 | } |
| 279 | |
| 280 | duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL); |
| 281 | if (!duty_cycle_table) |
| 282 | return -ENOMEM; |
| 283 | |
| 284 | ret = of_property_read_u32_array(np, "voltage-table", |
| 285 | (u32 *)duty_cycle_table, |
| 286 | length / sizeof(u32)); |
| 287 | if (ret) { |
| 288 | dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret); |
| 289 | return ret; |
| 290 | } |
| 291 | |
| 292 | drvdata->state = -ENOTRECOVERABLE; |
| 293 | drvdata->duty_cycle_table = duty_cycle_table; |
| 294 | drvdata->desc.ops = &pwm_regulator_voltage_table_ops; |
| 295 | drvdata->desc.n_voltages = length / sizeof(*duty_cycle_table); |
| 296 | |
| 297 | return 0; |
| 298 | } |
| 299 | |
| 300 | static int pwm_regulator_init_continuous(struct platform_device *pdev, |
| 301 | struct pwm_regulator_data *drvdata) |
| 302 | { |
| 303 | u32 dutycycle_range[2] = { 0, 100 }; |
| 304 | u32 dutycycle_unit = 100; |
| 305 | |
| 306 | drvdata->desc.ops = &pwm_regulator_voltage_continuous_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_init_boot_on(struct platform_device *pdev, |
| 327 | struct pwm_regulator_data *drvdata, |
| 328 | const struct regulator_init_data *init_data) |
| 329 | { |
| 330 | struct pwm_state pstate; |
| 331 | |
| 332 | if (!init_data->constraints.boot_on || drvdata->enb_gpio) |
| 333 | return 0; |
| 334 | |
| 335 | pwm_get_state(drvdata->pwm, &pstate); |
| 336 | if (pstate.enabled) |
| 337 | return 0; |
| 338 | |
| 339 | /* |
| 340 | * Update the duty cycle so the output does not change |
| 341 | * when the regulator core enables the regulator (and |
| 342 | * thus the PWM channel). |
| 343 | */ |
| 344 | if (pstate.polarity == PWM_POLARITY_INVERSED) |
| 345 | pstate.duty_cycle = pstate.period; |
| 346 | else |
| 347 | pstate.duty_cycle = 0; |
| 348 | |
| 349 | return pwm_apply_might_sleep(drvdata->pwm, &pstate); |
| 350 | } |
| 351 | |
| 352 | static int pwm_regulator_probe(struct platform_device *pdev) |
| 353 | { |
| 354 | const struct regulator_init_data *init_data; |
| 355 | struct pwm_regulator_data *drvdata; |
| 356 | struct regulator_dev *regulator; |
| 357 | struct regulator_config config = { }; |
| 358 | struct device_node *np = pdev->dev.of_node; |
| 359 | enum gpiod_flags gpio_flags; |
| 360 | int ret; |
| 361 | |
| 362 | if (!np) { |
| 363 | dev_err(&pdev->dev, "Device Tree node missing\n"); |
| 364 | return -EINVAL; |
| 365 | } |
| 366 | |
| 367 | drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL); |
| 368 | if (!drvdata) |
| 369 | return -ENOMEM; |
| 370 | |
| 371 | memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc)); |
| 372 | |
| 373 | if (of_property_present(np, "voltage-table")) |
| 374 | ret = pwm_regulator_init_table(pdev, drvdata); |
| 375 | else |
| 376 | ret = pwm_regulator_init_continuous(pdev, drvdata); |
| 377 | if (ret) |
| 378 | return ret; |
| 379 | |
| 380 | init_data = of_get_regulator_init_data(&pdev->dev, np, |
| 381 | &drvdata->desc); |
| 382 | if (!init_data) |
| 383 | return -ENOMEM; |
| 384 | |
| 385 | config.of_node = np; |
| 386 | config.dev = &pdev->dev; |
| 387 | config.driver_data = drvdata; |
| 388 | config.init_data = init_data; |
| 389 | |
| 390 | drvdata->pwm = devm_pwm_get(&pdev->dev, NULL); |
| 391 | if (IS_ERR(drvdata->pwm)) |
| 392 | return dev_err_probe(&pdev->dev, PTR_ERR(drvdata->pwm), |
| 393 | "Failed to get PWM\n"); |
| 394 | |
| 395 | if (init_data->constraints.boot_on || init_data->constraints.always_on) |
| 396 | gpio_flags = GPIOD_OUT_HIGH; |
| 397 | else |
| 398 | gpio_flags = GPIOD_OUT_LOW; |
| 399 | drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable", |
| 400 | gpio_flags); |
| 401 | if (IS_ERR(drvdata->enb_gpio)) { |
| 402 | ret = PTR_ERR(drvdata->enb_gpio); |
| 403 | dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret); |
| 404 | return ret; |
| 405 | } |
| 406 | |
| 407 | ret = pwm_adjust_config(drvdata->pwm); |
| 408 | if (ret) |
| 409 | return ret; |
| 410 | |
| 411 | ret = pwm_regulator_init_boot_on(pdev, drvdata, init_data); |
| 412 | if (ret) { |
| 413 | dev_err(&pdev->dev, "Failed to apply boot_on settings: %d\n", |
| 414 | ret); |
| 415 | return ret; |
| 416 | } |
| 417 | |
| 418 | regulator = devm_regulator_register(&pdev->dev, |
| 419 | &drvdata->desc, &config); |
| 420 | if (IS_ERR(regulator)) { |
| 421 | ret = PTR_ERR(regulator); |
| 422 | dev_err(&pdev->dev, "Failed to register regulator %s: %d\n", |
| 423 | drvdata->desc.name, ret); |
| 424 | return ret; |
| 425 | } |
| 426 | |
| 427 | return 0; |
| 428 | } |
| 429 | |
| 430 | static const struct of_device_id __maybe_unused pwm_of_match[] = { |
| 431 | { .compatible = "pwm-regulator" }, |
| 432 | { }, |
| 433 | }; |
| 434 | MODULE_DEVICE_TABLE(of, pwm_of_match); |
| 435 | |
| 436 | static struct platform_driver pwm_regulator_driver = { |
| 437 | .driver = { |
| 438 | .name = "pwm-regulator", |
| 439 | .probe_type = PROBE_PREFER_ASYNCHRONOUS, |
| 440 | .of_match_table = of_match_ptr(pwm_of_match), |
| 441 | }, |
| 442 | .probe = pwm_regulator_probe, |
| 443 | }; |
| 444 | |
| 445 | module_platform_driver(pwm_regulator_driver); |
| 446 | |
| 447 | MODULE_LICENSE("GPL"); |
| 448 | MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>"); |
| 449 | MODULE_DESCRIPTION("PWM Regulator Driver"); |
| 450 | MODULE_ALIAS("platform:pwm-regulator"); |