2 * Regulator driver for PWM Regulators
4 * Copyright (C) 2014 - STMicroelectronics Inc.
6 * Author: Lee Jones <lee.jones@linaro.org>
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.
13 #include <linux/delay.h>
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/err.h>
17 #include <linux/regulator/driver.h>
18 #include <linux/regulator/machine.h>
19 #include <linux/regulator/of_regulator.h>
21 #include <linux/of_device.h>
22 #include <linux/pwm.h>
24 struct pwm_regulator_data
{
26 struct pwm_device
*pwm
;
29 struct pwm_voltages
*duty_cycle_table
;
32 /* Continuous voltage */
38 unsigned int dutycycle
;
42 * Voltage table call-backs
44 static int pwm_regulator_get_voltage_sel(struct regulator_dev
*rdev
)
46 struct pwm_regulator_data
*drvdata
= rdev_get_drvdata(rdev
);
48 return drvdata
->state
;
51 static int pwm_regulator_set_voltage_sel(struct regulator_dev
*rdev
,
54 struct pwm_regulator_data
*drvdata
= rdev_get_drvdata(rdev
);
55 unsigned int pwm_reg_period
;
59 pwm_reg_period
= pwm_get_period(drvdata
->pwm
);
61 dutycycle
= (pwm_reg_period
*
62 drvdata
->duty_cycle_table
[selector
].dutycycle
) / 100;
64 ret
= pwm_config(drvdata
->pwm
, dutycycle
, pwm_reg_period
);
66 dev_err(&rdev
->dev
, "Failed to configure PWM\n");
70 drvdata
->state
= selector
;
72 ret
= pwm_enable(drvdata
->pwm
);
74 dev_err(&rdev
->dev
, "Failed to enable PWM\n");
81 static int pwm_regulator_list_voltage(struct regulator_dev
*rdev
,
84 struct pwm_regulator_data
*drvdata
= rdev_get_drvdata(rdev
);
86 if (selector
>= rdev
->desc
->n_voltages
)
89 return drvdata
->duty_cycle_table
[selector
].uV
;
93 * Continuous voltage call-backs
95 static int pwm_voltage_to_duty_cycle_percentage(struct regulator_dev
*rdev
, int req_uV
)
97 int min_uV
= rdev
->constraints
->min_uV
;
98 int max_uV
= rdev
->constraints
->max_uV
;
99 int diff
= max_uV
- min_uV
;
101 return 100 - (((req_uV
* 100) - (min_uV
* 100)) / diff
);
104 static int pwm_regulator_get_voltage(struct regulator_dev
*rdev
)
106 struct pwm_regulator_data
*drvdata
= rdev_get_drvdata(rdev
);
108 return drvdata
->volt_uV
;
111 static int pwm_regulator_set_voltage(struct regulator_dev
*rdev
,
112 int min_uV
, int max_uV
,
115 struct pwm_regulator_data
*drvdata
= rdev_get_drvdata(rdev
);
116 unsigned int ramp_delay
= rdev
->constraints
->ramp_delay
;
117 unsigned int period
= pwm_get_period(drvdata
->pwm
);
121 duty_cycle
= pwm_voltage_to_duty_cycle_percentage(rdev
, min_uV
);
123 ret
= pwm_config(drvdata
->pwm
, (period
/ 100) * duty_cycle
, period
);
125 dev_err(&rdev
->dev
, "Failed to configure PWM\n");
129 ret
= pwm_enable(drvdata
->pwm
);
131 dev_err(&rdev
->dev
, "Failed to enable PWM\n");
134 drvdata
->volt_uV
= min_uV
;
136 /* Delay required by PWM regulator to settle to the new voltage */
137 usleep_range(ramp_delay
, ramp_delay
+ 1000);
142 static struct regulator_ops pwm_regulator_voltage_table_ops
= {
143 .set_voltage_sel
= pwm_regulator_set_voltage_sel
,
144 .get_voltage_sel
= pwm_regulator_get_voltage_sel
,
145 .list_voltage
= pwm_regulator_list_voltage
,
146 .map_voltage
= regulator_map_voltage_iterate
,
149 static struct regulator_ops pwm_regulator_voltage_continuous_ops
= {
150 .get_voltage
= pwm_regulator_get_voltage
,
151 .set_voltage
= pwm_regulator_set_voltage
,
154 static struct regulator_desc pwm_regulator_desc
= {
155 .name
= "pwm-regulator",
156 .type
= REGULATOR_VOLTAGE
,
157 .owner
= THIS_MODULE
,
158 .supply_name
= "pwm",
161 static int pwm_regulator_init_table(struct platform_device
*pdev
,
162 struct pwm_regulator_data
*drvdata
)
164 struct device_node
*np
= pdev
->dev
.of_node
;
165 struct pwm_voltages
*duty_cycle_table
;
166 unsigned int length
= 0;
169 of_find_property(np
, "voltage-table", &length
);
171 if ((length
< sizeof(*duty_cycle_table
)) ||
172 (length
% sizeof(*duty_cycle_table
))) {
174 "voltage-table length(%d) is invalid\n",
179 duty_cycle_table
= devm_kzalloc(&pdev
->dev
, length
, GFP_KERNEL
);
180 if (!duty_cycle_table
)
183 ret
= of_property_read_u32_array(np
, "voltage-table",
184 (u32
*)duty_cycle_table
,
185 length
/ sizeof(u32
));
187 dev_err(&pdev
->dev
, "Failed to read voltage-table\n");
191 drvdata
->duty_cycle_table
= duty_cycle_table
;
192 pwm_regulator_desc
.ops
= &pwm_regulator_voltage_table_ops
;
193 pwm_regulator_desc
.n_voltages
= length
/ sizeof(*duty_cycle_table
);
198 static int pwm_regulator_init_continuous(struct platform_device
*pdev
,
199 struct pwm_regulator_data
*drvdata
)
201 pwm_regulator_desc
.ops
= &pwm_regulator_voltage_continuous_ops
;
202 pwm_regulator_desc
.continuous_voltage_range
= true;
207 static int pwm_regulator_probe(struct platform_device
*pdev
)
209 const struct regulator_init_data
*init_data
;
210 struct pwm_regulator_data
*drvdata
;
211 struct regulator_dev
*regulator
;
212 struct regulator_config config
= { };
213 struct device_node
*np
= pdev
->dev
.of_node
;
217 dev_err(&pdev
->dev
, "Device Tree node missing\n");
221 drvdata
= devm_kzalloc(&pdev
->dev
, sizeof(*drvdata
), GFP_KERNEL
);
225 if (of_find_property(np
, "voltage-table", NULL
))
226 ret
= pwm_regulator_init_table(pdev
, drvdata
);
228 ret
= pwm_regulator_init_continuous(pdev
, drvdata
);
232 init_data
= of_get_regulator_init_data(&pdev
->dev
, np
,
233 &pwm_regulator_desc
);
238 config
.dev
= &pdev
->dev
;
239 config
.driver_data
= drvdata
;
240 config
.init_data
= init_data
;
242 drvdata
->pwm
= devm_pwm_get(&pdev
->dev
, NULL
);
243 if (IS_ERR(drvdata
->pwm
)) {
244 dev_err(&pdev
->dev
, "Failed to get PWM\n");
245 return PTR_ERR(drvdata
->pwm
);
248 regulator
= devm_regulator_register(&pdev
->dev
,
249 &pwm_regulator_desc
, &config
);
250 if (IS_ERR(regulator
)) {
251 dev_err(&pdev
->dev
, "Failed to register regulator %s\n",
252 pwm_regulator_desc
.name
);
253 return PTR_ERR(regulator
);
259 static const struct of_device_id pwm_of_match
[] = {
260 { .compatible
= "pwm-regulator" },
263 MODULE_DEVICE_TABLE(of
, pwm_of_match
);
265 static struct platform_driver pwm_regulator_driver
= {
267 .name
= "pwm-regulator",
268 .of_match_table
= of_match_ptr(pwm_of_match
),
270 .probe
= pwm_regulator_probe
,
273 module_platform_driver(pwm_regulator_driver
);
275 MODULE_LICENSE("GPL");
276 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
277 MODULE_DESCRIPTION("PWM Regulator Driver");
278 MODULE_ALIAS("platform:pwm-regulator");