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Linux/drivers/regulator/st-pwm.c

  1 /*
  2  * Regulator driver for ST's 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 
 23 #define ST_PWM_REG_PERIOD 8448
 24 
 25 struct st_pwm_regulator_pdata {
 26         const struct regulator_desc *desc;
 27         struct st_pwm_voltages *duty_cycle_table;
 28 };
 29 
 30 struct st_pwm_regulator_data {
 31         const struct st_pwm_regulator_pdata *pdata;
 32         struct pwm_device *pwm;
 33         bool enabled;
 34         int state;
 35 };
 36 
 37 struct st_pwm_voltages {
 38         unsigned int uV;
 39         unsigned int dutycycle;
 40 };
 41 
 42 static int st_pwm_regulator_get_voltage_sel(struct regulator_dev *dev)
 43 {
 44         struct st_pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 45 
 46         return drvdata->state;
 47 }
 48 
 49 static int st_pwm_regulator_set_voltage_sel(struct regulator_dev *dev,
 50                                             unsigned selector)
 51 {
 52         struct st_pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 53         int dutycycle;
 54         int ret;
 55 
 56         dutycycle = (ST_PWM_REG_PERIOD / 100) *
 57                 drvdata->pdata->duty_cycle_table[selector].dutycycle;
 58 
 59         ret = pwm_config(drvdata->pwm, dutycycle, ST_PWM_REG_PERIOD);
 60         if (ret) {
 61                 dev_err(&dev->dev, "Failed to configure PWM\n");
 62                 return ret;
 63         }
 64 
 65         drvdata->state = selector;
 66 
 67         if (!drvdata->enabled) {
 68                 ret = pwm_enable(drvdata->pwm);
 69                 if (ret) {
 70                         dev_err(&dev->dev, "Failed to enable PWM\n");
 71                         return ret;
 72                 }
 73                 drvdata->enabled = true;
 74         }
 75 
 76         return 0;
 77 }
 78 
 79 static int st_pwm_regulator_list_voltage(struct regulator_dev *dev,
 80                                          unsigned selector)
 81 {
 82         struct st_pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 83 
 84         if (selector >= dev->desc->n_voltages)
 85                 return -EINVAL;
 86 
 87         return drvdata->pdata->duty_cycle_table[selector].uV;
 88 }
 89 
 90 static struct regulator_ops st_pwm_regulator_voltage_ops = {
 91         .set_voltage_sel = st_pwm_regulator_set_voltage_sel,
 92         .get_voltage_sel = st_pwm_regulator_get_voltage_sel,
 93         .list_voltage    = st_pwm_regulator_list_voltage,
 94         .map_voltage     = regulator_map_voltage_iterate,
 95 };
 96 
 97 static struct st_pwm_voltages b2105_duty_cycle_table[] = {
 98         { .uV = 1114000, .dutycycle = 0,  },
 99         { .uV = 1095000, .dutycycle = 10, },
100         { .uV = 1076000, .dutycycle = 20, },
101         { .uV = 1056000, .dutycycle = 30, },
102         { .uV = 1036000, .dutycycle = 40, },
103         { .uV = 1016000, .dutycycle = 50, },
104         /* WARNING: Values above 50% duty-cycle cause boot failures. */
105 };
106 
107 static const struct regulator_desc b2105_desc = {
108         .name           = "b2105-pwm-regulator",
109         .ops            = &st_pwm_regulator_voltage_ops,
110         .type           = REGULATOR_VOLTAGE,
111         .owner          = THIS_MODULE,
112         .n_voltages     = ARRAY_SIZE(b2105_duty_cycle_table),
113         .supply_name    = "pwm",
114 };
115 
116 static const struct st_pwm_regulator_pdata b2105_info = {
117         .desc             = &b2105_desc,
118         .duty_cycle_table = b2105_duty_cycle_table,
119 };
120 
121 static struct of_device_id st_pwm_of_match[] = {
122         { .compatible = "st,b2105-pwm-regulator", .data = &b2105_info, },
123         { },
124 };
125 MODULE_DEVICE_TABLE(of, st_pwm_of_match);
126 
127 static int st_pwm_regulator_probe(struct platform_device *pdev)
128 {
129         struct st_pwm_regulator_data *drvdata;
130         struct regulator_dev *regulator;
131         struct regulator_config config = { };
132         struct device_node *np = pdev->dev.of_node;
133         const struct of_device_id *of_match;
134 
135         if (!np) {
136                 dev_err(&pdev->dev, "Device Tree node missing\n");
137                 return -EINVAL;
138         }
139 
140         drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
141         if (!drvdata)
142                 return -ENOMEM;
143 
144         of_match = of_match_device(st_pwm_of_match, &pdev->dev);
145         if (!of_match) {
146                 dev_err(&pdev->dev, "failed to match of device\n");
147                 return -ENODEV;
148         }
149         drvdata->pdata = of_match->data;
150 
151         config.init_data = of_get_regulator_init_data(&pdev->dev, np);
152         if (!config.init_data)
153                 return -ENOMEM;
154 
155         config.of_node = np;
156         config.dev = &pdev->dev;
157         config.driver_data = drvdata;
158 
159         drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
160         if (IS_ERR(drvdata->pwm)) {
161                 dev_err(&pdev->dev, "Failed to get PWM\n");
162                 return PTR_ERR(drvdata->pwm);
163         }
164 
165         regulator = devm_regulator_register(&pdev->dev,
166                                             drvdata->pdata->desc, &config);
167         if (IS_ERR(regulator)) {
168                 dev_err(&pdev->dev, "Failed to register regulator %s\n",
169                         drvdata->pdata->desc->name);
170                 return PTR_ERR(regulator);
171         }
172 
173         return 0;
174 }
175 
176 static struct platform_driver st_pwm_regulator_driver = {
177         .driver = {
178                 .name           = "st-pwm-regulator",
179                 .owner          = THIS_MODULE,
180                 .of_match_table = of_match_ptr(st_pwm_of_match),
181         },
182         .probe = st_pwm_regulator_probe,
183 };
184 
185 module_platform_driver(st_pwm_regulator_driver);
186 
187 MODULE_LICENSE("GPL");
188 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
189 MODULE_DESCRIPTION("ST PWM Regulator Driver");
190 MODULE_ALIAS("platform:st_pwm-regulator");
191 

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