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0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Regulator driver for PWM Regulators
0004  *
0005  * Copyright (C) 2014 - STMicroelectronics Inc.
0006  *
0007  * Author: Lee Jones <lee.jones@linaro.org>
0008  */
0009 
0010 #include <linux/module.h>
0011 #include <linux/init.h>
0012 #include <linux/err.h>
0013 #include <linux/regulator/driver.h>
0014 #include <linux/regulator/machine.h>
0015 #include <linux/regulator/of_regulator.h>
0016 #include <linux/of.h>
0017 #include <linux/of_device.h>
0018 #include <linux/pwm.h>
0019 #include <linux/gpio/consumer.h>
0020 
0021 struct pwm_continuous_reg_data {
0022     unsigned int min_uV_dutycycle;
0023     unsigned int max_uV_dutycycle;
0024     unsigned int dutycycle_unit;
0025 };
0026 
0027 struct pwm_regulator_data {
0028     /*  Shared */
0029     struct pwm_device *pwm;
0030 
0031     /* Voltage table */
0032     struct pwm_voltages *duty_cycle_table;
0033 
0034     /* Continuous mode info */
0035     struct pwm_continuous_reg_data continuous;
0036 
0037     /* regulator descriptor */
0038     struct regulator_desc desc;
0039 
0040     int state;
0041 
0042     /* Enable GPIO */
0043     struct gpio_desc *enb_gpio;
0044 };
0045 
0046 struct pwm_voltages {
0047     unsigned int uV;
0048     unsigned int dutycycle;
0049 };
0050 
0051 /*
0052  * Voltage table call-backs
0053  */
0054 static void pwm_regulator_init_state(struct regulator_dev *rdev)
0055 {
0056     struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
0057     struct pwm_state pwm_state;
0058     unsigned int dutycycle;
0059     int i;
0060 
0061     pwm_get_state(drvdata->pwm, &pwm_state);
0062     dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);
0063 
0064     for (i = 0; i < rdev->desc->n_voltages; i++) {
0065         if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
0066             drvdata->state = i;
0067             return;
0068         }
0069     }
0070 }
0071 
0072 static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
0073 {
0074     struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
0075 
0076     if (drvdata->state < 0)
0077         pwm_regulator_init_state(rdev);
0078 
0079     return drvdata->state;
0080 }
0081 
0082 static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
0083                      unsigned selector)
0084 {
0085     struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
0086     struct pwm_state pstate;
0087     int ret;
0088 
0089     pwm_init_state(drvdata->pwm, &pstate);
0090     pwm_set_relative_duty_cycle(&pstate,
0091             drvdata->duty_cycle_table[selector].dutycycle, 100);
0092 
0093     ret = pwm_apply_state(drvdata->pwm, &pstate);
0094     if (ret) {
0095         dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
0096         return ret;
0097     }
0098 
0099     drvdata->state = selector;
0100 
0101     return 0;
0102 }
0103 
0104 static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
0105                       unsigned selector)
0106 {
0107     struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
0108 
0109     if (selector >= rdev->desc->n_voltages)
0110         return -EINVAL;
0111 
0112     return drvdata->duty_cycle_table[selector].uV;
0113 }
0114 
0115 static int pwm_regulator_enable(struct regulator_dev *dev)
0116 {
0117     struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
0118 
0119     gpiod_set_value_cansleep(drvdata->enb_gpio, 1);
0120 
0121     return pwm_enable(drvdata->pwm);
0122 }
0123 
0124 static int pwm_regulator_disable(struct regulator_dev *dev)
0125 {
0126     struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
0127 
0128     pwm_disable(drvdata->pwm);
0129 
0130     gpiod_set_value_cansleep(drvdata->enb_gpio, 0);
0131 
0132     return 0;
0133 }
0134 
0135 static int pwm_regulator_is_enabled(struct regulator_dev *dev)
0136 {
0137     struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
0138 
0139     if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
0140         return false;
0141 
0142     return pwm_is_enabled(drvdata->pwm);
0143 }
0144 
0145 static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
0146 {
0147     struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
0148     unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
0149     unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
0150     unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
0151     int min_uV = rdev->constraints->min_uV;
0152     int max_uV = rdev->constraints->max_uV;
0153     int diff_uV = max_uV - min_uV;
0154     struct pwm_state pstate;
0155     unsigned int diff_duty;
0156     unsigned int voltage;
0157 
0158     pwm_get_state(drvdata->pwm, &pstate);
0159 
0160     voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
0161 
0162     /*
0163      * The dutycycle for min_uV might be greater than the one for max_uV.
0164      * This is happening when the user needs an inversed polarity, but the
0165      * PWM device does not support inversing it in hardware.
0166      */
0167     if (max_uV_duty < min_uV_duty) {
0168         voltage = min_uV_duty - voltage;
0169         diff_duty = min_uV_duty - max_uV_duty;
0170     } else {
0171         voltage = voltage - min_uV_duty;
0172         diff_duty = max_uV_duty - min_uV_duty;
0173     }
0174 
0175     voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
0176 
0177     return voltage + min_uV;
0178 }
0179 
0180 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
0181                      int req_min_uV, int req_max_uV,
0182                      unsigned int *selector)
0183 {
0184     struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
0185     unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
0186     unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
0187     unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
0188     int min_uV = rdev->constraints->min_uV;
0189     int max_uV = rdev->constraints->max_uV;
0190     int diff_uV = max_uV - min_uV;
0191     struct pwm_state pstate;
0192     unsigned int diff_duty;
0193     unsigned int dutycycle;
0194     int ret;
0195 
0196     pwm_init_state(drvdata->pwm, &pstate);
0197 
0198     /*
0199      * The dutycycle for min_uV might be greater than the one for max_uV.
0200      * This is happening when the user needs an inversed polarity, but the
0201      * PWM device does not support inversing it in hardware.
0202      */
0203     if (max_uV_duty < min_uV_duty)
0204         diff_duty = min_uV_duty - max_uV_duty;
0205     else
0206         diff_duty = max_uV_duty - min_uV_duty;
0207 
0208     dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
0209                       diff_duty,
0210                       diff_uV);
0211 
0212     if (max_uV_duty < min_uV_duty)
0213         dutycycle = min_uV_duty - dutycycle;
0214     else
0215         dutycycle = min_uV_duty + dutycycle;
0216 
0217     pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
0218 
0219     ret = pwm_apply_state(drvdata->pwm, &pstate);
0220     if (ret) {
0221         dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
0222         return ret;
0223     }
0224 
0225     return 0;
0226 }
0227 
0228 static const struct regulator_ops pwm_regulator_voltage_table_ops = {
0229     .set_voltage_sel = pwm_regulator_set_voltage_sel,
0230     .get_voltage_sel = pwm_regulator_get_voltage_sel,
0231     .list_voltage    = pwm_regulator_list_voltage,
0232     .map_voltage     = regulator_map_voltage_iterate,
0233     .enable          = pwm_regulator_enable,
0234     .disable         = pwm_regulator_disable,
0235     .is_enabled      = pwm_regulator_is_enabled,
0236 };
0237 
0238 static const struct regulator_ops pwm_regulator_voltage_continuous_ops = {
0239     .get_voltage = pwm_regulator_get_voltage,
0240     .set_voltage = pwm_regulator_set_voltage,
0241     .enable          = pwm_regulator_enable,
0242     .disable         = pwm_regulator_disable,
0243     .is_enabled      = pwm_regulator_is_enabled,
0244 };
0245 
0246 static const struct regulator_desc pwm_regulator_desc = {
0247     .name       = "pwm-regulator",
0248     .type       = REGULATOR_VOLTAGE,
0249     .owner      = THIS_MODULE,
0250     .supply_name    = "pwm",
0251 };
0252 
0253 static int pwm_regulator_init_table(struct platform_device *pdev,
0254                     struct pwm_regulator_data *drvdata)
0255 {
0256     struct device_node *np = pdev->dev.of_node;
0257     struct pwm_voltages *duty_cycle_table;
0258     unsigned int length = 0;
0259     int ret;
0260 
0261     of_find_property(np, "voltage-table", &length);
0262 
0263     if ((length < sizeof(*duty_cycle_table)) ||
0264         (length % sizeof(*duty_cycle_table))) {
0265         dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
0266             length);
0267         return -EINVAL;
0268     }
0269 
0270     duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
0271     if (!duty_cycle_table)
0272         return -ENOMEM;
0273 
0274     ret = of_property_read_u32_array(np, "voltage-table",
0275                      (u32 *)duty_cycle_table,
0276                      length / sizeof(u32));
0277     if (ret) {
0278         dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
0279         return ret;
0280     }
0281 
0282     drvdata->state          = -ENOTRECOVERABLE;
0283     drvdata->duty_cycle_table   = duty_cycle_table;
0284     drvdata->desc.ops = &pwm_regulator_voltage_table_ops;
0285     drvdata->desc.n_voltages    = length / sizeof(*duty_cycle_table);
0286 
0287     return 0;
0288 }
0289 
0290 static int pwm_regulator_init_continuous(struct platform_device *pdev,
0291                      struct pwm_regulator_data *drvdata)
0292 {
0293     u32 dutycycle_range[2] = { 0, 100 };
0294     u32 dutycycle_unit = 100;
0295 
0296     drvdata->desc.ops = &pwm_regulator_voltage_continuous_ops;
0297     drvdata->desc.continuous_voltage_range = true;
0298 
0299     of_property_read_u32_array(pdev->dev.of_node,
0300                    "pwm-dutycycle-range",
0301                    dutycycle_range, 2);
0302     of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
0303                  &dutycycle_unit);
0304 
0305     if (dutycycle_range[0] > dutycycle_unit ||
0306         dutycycle_range[1] > dutycycle_unit)
0307         return -EINVAL;
0308 
0309     drvdata->continuous.dutycycle_unit = dutycycle_unit;
0310     drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
0311     drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
0312 
0313     return 0;
0314 }
0315 
0316 static int pwm_regulator_probe(struct platform_device *pdev)
0317 {
0318     const struct regulator_init_data *init_data;
0319     struct pwm_regulator_data *drvdata;
0320     struct regulator_dev *regulator;
0321     struct regulator_config config = { };
0322     struct device_node *np = pdev->dev.of_node;
0323     enum gpiod_flags gpio_flags;
0324     int ret;
0325 
0326     if (!np) {
0327         dev_err(&pdev->dev, "Device Tree node missing\n");
0328         return -EINVAL;
0329     }
0330 
0331     drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
0332     if (!drvdata)
0333         return -ENOMEM;
0334 
0335     memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
0336 
0337     if (of_find_property(np, "voltage-table", NULL))
0338         ret = pwm_regulator_init_table(pdev, drvdata);
0339     else
0340         ret = pwm_regulator_init_continuous(pdev, drvdata);
0341     if (ret)
0342         return ret;
0343 
0344     init_data = of_get_regulator_init_data(&pdev->dev, np,
0345                            &drvdata->desc);
0346     if (!init_data)
0347         return -ENOMEM;
0348 
0349     config.of_node = np;
0350     config.dev = &pdev->dev;
0351     config.driver_data = drvdata;
0352     config.init_data = init_data;
0353 
0354     drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
0355     if (IS_ERR(drvdata->pwm))
0356         return dev_err_probe(&pdev->dev, PTR_ERR(drvdata->pwm),
0357                      "Failed to get PWM\n");
0358 
0359     if (init_data->constraints.boot_on || init_data->constraints.always_on)
0360         gpio_flags = GPIOD_OUT_HIGH;
0361     else
0362         gpio_flags = GPIOD_OUT_LOW;
0363     drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
0364                             gpio_flags);
0365     if (IS_ERR(drvdata->enb_gpio)) {
0366         ret = PTR_ERR(drvdata->enb_gpio);
0367         dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
0368         return ret;
0369     }
0370 
0371     ret = pwm_adjust_config(drvdata->pwm);
0372     if (ret)
0373         return ret;
0374 
0375     regulator = devm_regulator_register(&pdev->dev,
0376                         &drvdata->desc, &config);
0377     if (IS_ERR(regulator)) {
0378         ret = PTR_ERR(regulator);
0379         dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
0380             drvdata->desc.name, ret);
0381         return ret;
0382     }
0383 
0384     return 0;
0385 }
0386 
0387 static const struct of_device_id __maybe_unused pwm_of_match[] = {
0388     { .compatible = "pwm-regulator" },
0389     { },
0390 };
0391 MODULE_DEVICE_TABLE(of, pwm_of_match);
0392 
0393 static struct platform_driver pwm_regulator_driver = {
0394     .driver = {
0395         .name       = "pwm-regulator",
0396         .of_match_table = of_match_ptr(pwm_of_match),
0397     },
0398     .probe = pwm_regulator_probe,
0399 };
0400 
0401 module_platform_driver(pwm_regulator_driver);
0402 
0403 MODULE_LICENSE("GPL");
0404 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
0405 MODULE_DESCRIPTION("PWM Regulator Driver");
0406 MODULE_ALIAS("platform:pwm-regulator");
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