linux/drivers/regulator/pwm-regulator.c
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   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/regulator/driver.h>
  14#include <linux/regulator/machine.h>
  15#include <linux/regulator/of_regulator.h>
  16#include <linux/of.h>
  17#include <linux/of_device.h>
  18#include <linux/pwm.h>
  19#include <linux/gpio/consumer.h>
  20
  21struct pwm_continuous_reg_data {
  22        unsigned int min_uV_dutycycle;
  23        unsigned int max_uV_dutycycle;
  24        unsigned int dutycycle_unit;
  25};
  26
  27struct 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
  46struct pwm_voltages {
  47        unsigned int uV;
  48        unsigned int dutycycle;
  49};
  50
  51/**
  52 * Voltage table call-backs
  53 */
  54static 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
  72static 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
  82static 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_state(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
 104static 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
 115static 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
 124static 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
 135static 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
 145static 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        voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
 161
 162        /*
 163         * The dutycycle for min_uV might be greater than the one for max_uV.
 164         * This is happening when the user needs an inversed polarity, but the
 165         * PWM device does not support inversing it in hardware.
 166         */
 167        if (max_uV_duty < min_uV_duty) {
 168                voltage = min_uV_duty - voltage;
 169                diff_duty = min_uV_duty - max_uV_duty;
 170        } else {
 171                voltage = voltage - min_uV_duty;
 172                diff_duty = max_uV_duty - min_uV_duty;
 173        }
 174
 175        voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
 176
 177        return voltage + min_uV;
 178}
 179
 180static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
 181                                     int req_min_uV, int req_max_uV,
 182                                     unsigned int *selector)
 183{
 184        struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 185        unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 186        unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 187        unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 188        int min_uV = rdev->constraints->min_uV;
 189        int max_uV = rdev->constraints->max_uV;
 190        int diff_uV = max_uV - min_uV;
 191        struct pwm_state pstate;
 192        unsigned int diff_duty;
 193        unsigned int dutycycle;
 194        int ret;
 195
 196        pwm_init_state(drvdata->pwm, &pstate);
 197
 198        /*
 199         * The dutycycle for min_uV might be greater than the one for max_uV.
 200         * This is happening when the user needs an inversed polarity, but the
 201         * PWM device does not support inversing it in hardware.
 202         */
 203        if (max_uV_duty < min_uV_duty)
 204                diff_duty = min_uV_duty - max_uV_duty;
 205        else
 206                diff_duty = max_uV_duty - min_uV_duty;
 207
 208        dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
 209                                          diff_duty,
 210                                          diff_uV);
 211
 212        if (max_uV_duty < min_uV_duty)
 213                dutycycle = min_uV_duty - dutycycle;
 214        else
 215                dutycycle = min_uV_duty + dutycycle;
 216
 217        pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
 218
 219        ret = pwm_apply_state(drvdata->pwm, &pstate);
 220        if (ret) {
 221                dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 222                return ret;
 223        }
 224
 225        return 0;
 226}
 227
 228static const struct regulator_ops pwm_regulator_voltage_table_ops = {
 229        .set_voltage_sel = pwm_regulator_set_voltage_sel,
 230        .get_voltage_sel = pwm_regulator_get_voltage_sel,
 231        .list_voltage    = pwm_regulator_list_voltage,
 232        .map_voltage     = regulator_map_voltage_iterate,
 233        .enable          = pwm_regulator_enable,
 234        .disable         = pwm_regulator_disable,
 235        .is_enabled      = pwm_regulator_is_enabled,
 236};
 237
 238static const struct regulator_ops pwm_regulator_voltage_continuous_ops = {
 239        .get_voltage = pwm_regulator_get_voltage,
 240        .set_voltage = pwm_regulator_set_voltage,
 241        .enable          = pwm_regulator_enable,
 242        .disable         = pwm_regulator_disable,
 243        .is_enabled      = pwm_regulator_is_enabled,
 244};
 245
 246static const struct regulator_desc pwm_regulator_desc = {
 247        .name           = "pwm-regulator",
 248        .type           = REGULATOR_VOLTAGE,
 249        .owner          = THIS_MODULE,
 250        .supply_name    = "pwm",
 251};
 252
 253static int pwm_regulator_init_table(struct platform_device *pdev,
 254                                    struct pwm_regulator_data *drvdata)
 255{
 256        struct device_node *np = pdev->dev.of_node;
 257        struct pwm_voltages *duty_cycle_table;
 258        unsigned int length = 0;
 259        int ret;
 260
 261        of_find_property(np, "voltage-table", &length);
 262
 263        if ((length < sizeof(*duty_cycle_table)) ||
 264            (length % sizeof(*duty_cycle_table))) {
 265                dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
 266                        length);
 267                return -EINVAL;
 268        }
 269
 270        duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
 271        if (!duty_cycle_table)
 272                return -ENOMEM;
 273
 274        ret = of_property_read_u32_array(np, "voltage-table",
 275                                         (u32 *)duty_cycle_table,
 276                                         length / sizeof(u32));
 277        if (ret) {
 278                dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
 279                return ret;
 280        }
 281
 282        drvdata->state                  = -EINVAL;
 283        drvdata->duty_cycle_table       = duty_cycle_table;
 284        drvdata->desc.ops = &pwm_regulator_voltage_table_ops;
 285        drvdata->desc.n_voltages        = length / sizeof(*duty_cycle_table);
 286
 287        return 0;
 288}
 289
 290static int pwm_regulator_init_continuous(struct platform_device *pdev,
 291                                         struct pwm_regulator_data *drvdata)
 292{
 293        u32 dutycycle_range[2] = { 0, 100 };
 294        u32 dutycycle_unit = 100;
 295
 296        drvdata->desc.ops = &pwm_regulator_voltage_continuous_ops;
 297        drvdata->desc.continuous_voltage_range = true;
 298
 299        of_property_read_u32_array(pdev->dev.of_node,
 300                                   "pwm-dutycycle-range",
 301                                   dutycycle_range, 2);
 302        of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
 303                             &dutycycle_unit);
 304
 305        if (dutycycle_range[0] > dutycycle_unit ||
 306            dutycycle_range[1] > dutycycle_unit)
 307                return -EINVAL;
 308
 309        drvdata->continuous.dutycycle_unit = dutycycle_unit;
 310        drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
 311        drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
 312
 313        return 0;
 314}
 315
 316static int pwm_regulator_probe(struct platform_device *pdev)
 317{
 318        const struct regulator_init_data *init_data;
 319        struct pwm_regulator_data *drvdata;
 320        struct regulator_dev *regulator;
 321        struct regulator_config config = { };
 322        struct device_node *np = pdev->dev.of_node;
 323        enum gpiod_flags gpio_flags;
 324        int ret;
 325
 326        if (!np) {
 327                dev_err(&pdev->dev, "Device Tree node missing\n");
 328                return -EINVAL;
 329        }
 330
 331        drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
 332        if (!drvdata)
 333                return -ENOMEM;
 334
 335        memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
 336
 337        if (of_find_property(np, "voltage-table", NULL))
 338                ret = pwm_regulator_init_table(pdev, drvdata);
 339        else
 340                ret = pwm_regulator_init_continuous(pdev, drvdata);
 341        if (ret)
 342                return ret;
 343
 344        init_data = of_get_regulator_init_data(&pdev->dev, np,
 345                                               &drvdata->desc);
 346        if (!init_data)
 347                return -ENOMEM;
 348
 349        config.of_node = np;
 350        config.dev = &pdev->dev;
 351        config.driver_data = drvdata;
 352        config.init_data = init_data;
 353
 354        drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
 355        if (IS_ERR(drvdata->pwm)) {
 356                ret = PTR_ERR(drvdata->pwm);
 357                dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
 358                return ret;
 359        }
 360
 361        if (init_data->constraints.boot_on || init_data->constraints.always_on)
 362                gpio_flags = GPIOD_OUT_HIGH;
 363        else
 364                gpio_flags = GPIOD_OUT_LOW;
 365        drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
 366                                                    gpio_flags);
 367        if (IS_ERR(drvdata->enb_gpio)) {
 368                ret = PTR_ERR(drvdata->enb_gpio);
 369                dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
 370                return ret;
 371        }
 372
 373        ret = pwm_adjust_config(drvdata->pwm);
 374        if (ret)
 375                return ret;
 376
 377        regulator = devm_regulator_register(&pdev->dev,
 378                                            &drvdata->desc, &config);
 379        if (IS_ERR(regulator)) {
 380                ret = PTR_ERR(regulator);
 381                dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
 382                        drvdata->desc.name, ret);
 383                return ret;
 384        }
 385
 386        return 0;
 387}
 388
 389static const struct of_device_id pwm_of_match[] = {
 390        { .compatible = "pwm-regulator" },
 391        { },
 392};
 393MODULE_DEVICE_TABLE(of, pwm_of_match);
 394
 395static struct platform_driver pwm_regulator_driver = {
 396        .driver = {
 397                .name           = "pwm-regulator",
 398                .of_match_table = of_match_ptr(pwm_of_match),
 399        },
 400        .probe = pwm_regulator_probe,
 401};
 402
 403module_platform_driver(pwm_regulator_driver);
 404
 405MODULE_LICENSE("GPL");
 406MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
 407MODULE_DESCRIPTION("PWM Regulator Driver");
 408MODULE_ALIAS("platform:pwm-regulator");
 409