1aa66cc66SChris Zhong /* 2aa66cc66SChris Zhong * Regulator driver for PWM Regulators 3aa66cc66SChris Zhong * 4aa66cc66SChris Zhong * Copyright (C) 2014 - STMicroelectronics Inc. 5aa66cc66SChris Zhong * 6aa66cc66SChris Zhong * Author: Lee Jones <lee.jones@linaro.org> 7aa66cc66SChris Zhong * 8aa66cc66SChris Zhong * This program is free software; you can redistribute it and/or modify 9aa66cc66SChris Zhong * it under the terms of the GNU General Public License version 2 as 10aa66cc66SChris Zhong * published by the Free Software Foundation. 11aa66cc66SChris Zhong */ 12aa66cc66SChris Zhong 134773be18SLee Jones #include <linux/delay.h> 14aa66cc66SChris Zhong #include <linux/module.h> 15aa66cc66SChris Zhong #include <linux/init.h> 16aa66cc66SChris Zhong #include <linux/err.h> 17aa66cc66SChris Zhong #include <linux/regulator/driver.h> 18aa66cc66SChris Zhong #include <linux/regulator/machine.h> 19aa66cc66SChris Zhong #include <linux/regulator/of_regulator.h> 20aa66cc66SChris Zhong #include <linux/of.h> 21aa66cc66SChris Zhong #include <linux/of_device.h> 22aa66cc66SChris Zhong #include <linux/pwm.h> 23aa66cc66SChris Zhong 24aa66cc66SChris Zhong struct pwm_regulator_data { 254773be18SLee Jones /* Shared */ 26aa66cc66SChris Zhong struct pwm_device *pwm; 274773be18SLee Jones 284773be18SLee Jones /* Voltage table */ 294773be18SLee Jones struct pwm_voltages *duty_cycle_table; 30aa66cc66SChris Zhong int state; 314773be18SLee Jones 324773be18SLee Jones /* Continuous voltage */ 334773be18SLee Jones int volt_uV; 34aa66cc66SChris Zhong }; 35aa66cc66SChris Zhong 36aa66cc66SChris Zhong struct pwm_voltages { 37aa66cc66SChris Zhong unsigned int uV; 38aa66cc66SChris Zhong unsigned int dutycycle; 39aa66cc66SChris Zhong }; 40aa66cc66SChris Zhong 414773be18SLee Jones /** 424773be18SLee Jones * Voltage table call-backs 434773be18SLee Jones */ 44ab101e35SLee Jones static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev) 45aa66cc66SChris Zhong { 46ab101e35SLee Jones struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); 47aa66cc66SChris Zhong 48aa66cc66SChris Zhong return drvdata->state; 49aa66cc66SChris Zhong } 50aa66cc66SChris Zhong 51ab101e35SLee Jones static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev, 52aa66cc66SChris Zhong unsigned selector) 53aa66cc66SChris Zhong { 54ab101e35SLee Jones struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); 55aa66cc66SChris Zhong unsigned int pwm_reg_period; 56aa66cc66SChris Zhong int dutycycle; 57aa66cc66SChris Zhong int ret; 58aa66cc66SChris Zhong 59aa66cc66SChris Zhong pwm_reg_period = pwm_get_period(drvdata->pwm); 60aa66cc66SChris Zhong 61aa66cc66SChris Zhong dutycycle = (pwm_reg_period * 62aa66cc66SChris Zhong drvdata->duty_cycle_table[selector].dutycycle) / 100; 63aa66cc66SChris Zhong 64aa66cc66SChris Zhong ret = pwm_config(drvdata->pwm, dutycycle, pwm_reg_period); 65aa66cc66SChris Zhong if (ret) { 66ab101e35SLee Jones dev_err(&rdev->dev, "Failed to configure PWM\n"); 67aa66cc66SChris Zhong return ret; 68aa66cc66SChris Zhong } 69aa66cc66SChris Zhong 70aa66cc66SChris Zhong drvdata->state = selector; 71aa66cc66SChris Zhong 72aa66cc66SChris Zhong return 0; 73aa66cc66SChris Zhong } 74aa66cc66SChris Zhong 75ab101e35SLee Jones static int pwm_regulator_list_voltage(struct regulator_dev *rdev, 76aa66cc66SChris Zhong unsigned selector) 77aa66cc66SChris Zhong { 78ab101e35SLee Jones struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); 79aa66cc66SChris Zhong 80ab101e35SLee Jones if (selector >= rdev->desc->n_voltages) 81aa66cc66SChris Zhong return -EINVAL; 82aa66cc66SChris Zhong 83aa66cc66SChris Zhong return drvdata->duty_cycle_table[selector].uV; 84aa66cc66SChris Zhong } 854773be18SLee Jones 86*1de7d802SBoris Brezillon static int pwm_regulator_enable(struct regulator_dev *dev) 87*1de7d802SBoris Brezillon { 88*1de7d802SBoris Brezillon struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); 89*1de7d802SBoris Brezillon 90*1de7d802SBoris Brezillon return pwm_enable(drvdata->pwm); 91*1de7d802SBoris Brezillon } 92*1de7d802SBoris Brezillon 93*1de7d802SBoris Brezillon static int pwm_regulator_disable(struct regulator_dev *dev) 94*1de7d802SBoris Brezillon { 95*1de7d802SBoris Brezillon struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); 96*1de7d802SBoris Brezillon 97*1de7d802SBoris Brezillon pwm_disable(drvdata->pwm); 98*1de7d802SBoris Brezillon 99*1de7d802SBoris Brezillon return 0; 100*1de7d802SBoris Brezillon } 101*1de7d802SBoris Brezillon 102*1de7d802SBoris Brezillon static int pwm_regulator_is_enabled(struct regulator_dev *dev) 103*1de7d802SBoris Brezillon { 104*1de7d802SBoris Brezillon struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); 105*1de7d802SBoris Brezillon 106*1de7d802SBoris Brezillon return pwm_is_enabled(drvdata->pwm); 107*1de7d802SBoris Brezillon } 108*1de7d802SBoris Brezillon 1094773be18SLee Jones /** 1104773be18SLee Jones * Continuous voltage call-backs 1114773be18SLee Jones */ 112f3f6439dSLee Jones static int pwm_voltage_to_duty_cycle_percentage(struct regulator_dev *rdev, int req_uV) 1134773be18SLee Jones { 114cae897deSLee Jones int min_uV = rdev->constraints->min_uV; 115cae897deSLee Jones int max_uV = rdev->constraints->max_uV; 116cae897deSLee Jones int diff = max_uV - min_uV; 1174773be18SLee Jones 118f3f6439dSLee Jones return 100 - (((req_uV * 100) - (min_uV * 100)) / diff); 1194773be18SLee Jones } 1204773be18SLee Jones 1214773be18SLee Jones static int pwm_regulator_get_voltage(struct regulator_dev *rdev) 1224773be18SLee Jones { 1234773be18SLee Jones struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); 1244773be18SLee Jones 1254773be18SLee Jones return drvdata->volt_uV; 1264773be18SLee Jones } 1274773be18SLee Jones 1284773be18SLee Jones static int pwm_regulator_set_voltage(struct regulator_dev *rdev, 1294773be18SLee Jones int min_uV, int max_uV, 1304773be18SLee Jones unsigned *selector) 1314773be18SLee Jones { 1324773be18SLee Jones struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); 1334773be18SLee Jones unsigned int ramp_delay = rdev->constraints->ramp_delay; 134f3f6439dSLee Jones unsigned int period = pwm_get_period(drvdata->pwm); 1354773be18SLee Jones int duty_cycle; 1364773be18SLee Jones int ret; 1374773be18SLee Jones 138f3f6439dSLee Jones duty_cycle = pwm_voltage_to_duty_cycle_percentage(rdev, min_uV); 1394773be18SLee Jones 140f3f6439dSLee Jones ret = pwm_config(drvdata->pwm, (period / 100) * duty_cycle, period); 1414773be18SLee Jones if (ret) { 1424773be18SLee Jones dev_err(&rdev->dev, "Failed to configure PWM\n"); 1434773be18SLee Jones return ret; 1444773be18SLee Jones } 1454773be18SLee Jones 1464773be18SLee Jones ret = pwm_enable(drvdata->pwm); 1474773be18SLee Jones if (ret) { 1484773be18SLee Jones dev_err(&rdev->dev, "Failed to enable PWM\n"); 1494773be18SLee Jones return ret; 1504773be18SLee Jones } 1514773be18SLee Jones drvdata->volt_uV = min_uV; 1524773be18SLee Jones 1534773be18SLee Jones /* Delay required by PWM regulator to settle to the new voltage */ 1544773be18SLee Jones usleep_range(ramp_delay, ramp_delay + 1000); 1554773be18SLee Jones 1564773be18SLee Jones return 0; 1574773be18SLee Jones } 1584773be18SLee Jones 159f9178dadSLee Jones static struct regulator_ops pwm_regulator_voltage_table_ops = { 160aa66cc66SChris Zhong .set_voltage_sel = pwm_regulator_set_voltage_sel, 161aa66cc66SChris Zhong .get_voltage_sel = pwm_regulator_get_voltage_sel, 162aa66cc66SChris Zhong .list_voltage = pwm_regulator_list_voltage, 163aa66cc66SChris Zhong .map_voltage = regulator_map_voltage_iterate, 164*1de7d802SBoris Brezillon .enable = pwm_regulator_enable, 165*1de7d802SBoris Brezillon .disable = pwm_regulator_disable, 166*1de7d802SBoris Brezillon .is_enabled = pwm_regulator_is_enabled, 167aa66cc66SChris Zhong }; 168aa66cc66SChris Zhong 1694773be18SLee Jones static struct regulator_ops pwm_regulator_voltage_continuous_ops = { 1704773be18SLee Jones .get_voltage = pwm_regulator_get_voltage, 1714773be18SLee Jones .set_voltage = pwm_regulator_set_voltage, 172*1de7d802SBoris Brezillon .enable = pwm_regulator_enable, 173*1de7d802SBoris Brezillon .disable = pwm_regulator_disable, 174*1de7d802SBoris Brezillon .is_enabled = pwm_regulator_is_enabled, 1754773be18SLee Jones }; 1764773be18SLee Jones 177b6f55e74SLee Jones static struct regulator_desc pwm_regulator_desc = { 178aa66cc66SChris Zhong .name = "pwm-regulator", 179aa66cc66SChris Zhong .type = REGULATOR_VOLTAGE, 180aa66cc66SChris Zhong .owner = THIS_MODULE, 181aa66cc66SChris Zhong .supply_name = "pwm", 182aa66cc66SChris Zhong }; 183aa66cc66SChris Zhong 184f9178dadSLee Jones static int pwm_regulator_init_table(struct platform_device *pdev, 185f9178dadSLee Jones struct pwm_regulator_data *drvdata) 186f9178dadSLee Jones { 187f9178dadSLee Jones struct device_node *np = pdev->dev.of_node; 188f9178dadSLee Jones struct pwm_voltages *duty_cycle_table; 18960cb65ebSLee Jones unsigned int length = 0; 190f9178dadSLee Jones int ret; 191f9178dadSLee Jones 192f9178dadSLee Jones of_find_property(np, "voltage-table", &length); 193f9178dadSLee Jones 194f9178dadSLee Jones if ((length < sizeof(*duty_cycle_table)) || 195f9178dadSLee Jones (length % sizeof(*duty_cycle_table))) { 196f9178dadSLee Jones dev_err(&pdev->dev, 197f9178dadSLee Jones "voltage-table length(%d) is invalid\n", 198f9178dadSLee Jones length); 199f9178dadSLee Jones return -EINVAL; 200f9178dadSLee Jones } 201f9178dadSLee Jones 202f9178dadSLee Jones duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL); 203f9178dadSLee Jones if (!duty_cycle_table) 204f9178dadSLee Jones return -ENOMEM; 205f9178dadSLee Jones 206f9178dadSLee Jones ret = of_property_read_u32_array(np, "voltage-table", 207f9178dadSLee Jones (u32 *)duty_cycle_table, 208f9178dadSLee Jones length / sizeof(u32)); 209f9178dadSLee Jones if (ret) { 210f9178dadSLee Jones dev_err(&pdev->dev, "Failed to read voltage-table\n"); 211f9178dadSLee Jones return ret; 212f9178dadSLee Jones } 213f9178dadSLee Jones 214f9178dadSLee Jones drvdata->duty_cycle_table = duty_cycle_table; 215f9178dadSLee Jones pwm_regulator_desc.ops = &pwm_regulator_voltage_table_ops; 216f9178dadSLee Jones pwm_regulator_desc.n_voltages = length / sizeof(*duty_cycle_table); 217f9178dadSLee Jones 218f9178dadSLee Jones return 0; 219f9178dadSLee Jones } 220f9178dadSLee Jones 2214773be18SLee Jones static int pwm_regulator_init_continuous(struct platform_device *pdev, 2224773be18SLee Jones struct pwm_regulator_data *drvdata) 2234773be18SLee Jones { 2244773be18SLee Jones pwm_regulator_desc.ops = &pwm_regulator_voltage_continuous_ops; 2254773be18SLee Jones pwm_regulator_desc.continuous_voltage_range = true; 2264773be18SLee Jones 2274773be18SLee Jones return 0; 2284773be18SLee Jones } 2294773be18SLee Jones 230aa66cc66SChris Zhong static int pwm_regulator_probe(struct platform_device *pdev) 231aa66cc66SChris Zhong { 2325ad2cb14SLee Jones const struct regulator_init_data *init_data; 233aa66cc66SChris Zhong struct pwm_regulator_data *drvdata; 234aa66cc66SChris Zhong struct regulator_dev *regulator; 235aa66cc66SChris Zhong struct regulator_config config = { }; 236aa66cc66SChris Zhong struct device_node *np = pdev->dev.of_node; 237f9178dadSLee Jones int ret; 238aa66cc66SChris Zhong 239aa66cc66SChris Zhong if (!np) { 240aa66cc66SChris Zhong dev_err(&pdev->dev, "Device Tree node missing\n"); 241aa66cc66SChris Zhong return -EINVAL; 242aa66cc66SChris Zhong } 243aa66cc66SChris Zhong 244aa66cc66SChris Zhong drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL); 245aa66cc66SChris Zhong if (!drvdata) 246aa66cc66SChris Zhong return -ENOMEM; 247aa66cc66SChris Zhong 2484773be18SLee Jones if (of_find_property(np, "voltage-table", NULL)) 249f9178dadSLee Jones ret = pwm_regulator_init_table(pdev, drvdata); 2504773be18SLee Jones else 2514773be18SLee Jones ret = pwm_regulator_init_continuous(pdev, drvdata); 252f9178dadSLee Jones if (ret) 253aa66cc66SChris Zhong return ret; 254aa66cc66SChris Zhong 2555ad2cb14SLee Jones init_data = of_get_regulator_init_data(&pdev->dev, np, 256b6f55e74SLee Jones &pwm_regulator_desc); 2575ad2cb14SLee Jones if (!init_data) 258aa66cc66SChris Zhong return -ENOMEM; 259aa66cc66SChris Zhong 260aa66cc66SChris Zhong config.of_node = np; 261aa66cc66SChris Zhong config.dev = &pdev->dev; 262aa66cc66SChris Zhong config.driver_data = drvdata; 2635ad2cb14SLee Jones config.init_data = init_data; 264aa66cc66SChris Zhong 265aa66cc66SChris Zhong drvdata->pwm = devm_pwm_get(&pdev->dev, NULL); 266aa66cc66SChris Zhong if (IS_ERR(drvdata->pwm)) { 267aa66cc66SChris Zhong dev_err(&pdev->dev, "Failed to get PWM\n"); 268aa66cc66SChris Zhong return PTR_ERR(drvdata->pwm); 269aa66cc66SChris Zhong } 270aa66cc66SChris Zhong 271aa66cc66SChris Zhong regulator = devm_regulator_register(&pdev->dev, 272b6f55e74SLee Jones &pwm_regulator_desc, &config); 273aa66cc66SChris Zhong if (IS_ERR(regulator)) { 274aa66cc66SChris Zhong dev_err(&pdev->dev, "Failed to register regulator %s\n", 275b6f55e74SLee Jones pwm_regulator_desc.name); 276aa66cc66SChris Zhong return PTR_ERR(regulator); 277aa66cc66SChris Zhong } 278aa66cc66SChris Zhong 279aa66cc66SChris Zhong return 0; 280aa66cc66SChris Zhong } 281aa66cc66SChris Zhong 282aa66cc66SChris Zhong static const struct of_device_id pwm_of_match[] = { 283aa66cc66SChris Zhong { .compatible = "pwm-regulator" }, 284aa66cc66SChris Zhong { }, 285aa66cc66SChris Zhong }; 286aa66cc66SChris Zhong MODULE_DEVICE_TABLE(of, pwm_of_match); 287aa66cc66SChris Zhong 288aa66cc66SChris Zhong static struct platform_driver pwm_regulator_driver = { 289aa66cc66SChris Zhong .driver = { 290aa66cc66SChris Zhong .name = "pwm-regulator", 291aa66cc66SChris Zhong .of_match_table = of_match_ptr(pwm_of_match), 292aa66cc66SChris Zhong }, 293aa66cc66SChris Zhong .probe = pwm_regulator_probe, 294aa66cc66SChris Zhong }; 295aa66cc66SChris Zhong 296aa66cc66SChris Zhong module_platform_driver(pwm_regulator_driver); 297aa66cc66SChris Zhong 298aa66cc66SChris Zhong MODULE_LICENSE("GPL"); 299aa66cc66SChris Zhong MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>"); 300aa66cc66SChris Zhong MODULE_DESCRIPTION("PWM Regulator Driver"); 301aa66cc66SChris Zhong MODULE_ALIAS("platform:pwm-regulator"); 302