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
;
31 /* regulator descriptor */
32 struct regulator_desc desc
;
35 struct regulator_ops ops
;
39 /* Continuous voltage */
45 unsigned int dutycycle
;
49 * Voltage table call-backs
51 static int pwm_regulator_get_voltage_sel(struct regulator_dev
*rdev
)
53 struct pwm_regulator_data
*drvdata
= rdev_get_drvdata(rdev
);
55 return drvdata
->state
;
58 static int pwm_regulator_set_voltage_sel(struct regulator_dev
*rdev
,
61 struct pwm_regulator_data
*drvdata
= rdev_get_drvdata(rdev
);
62 struct pwm_args pargs
;
66 pwm_get_args(drvdata
->pwm
, &pargs
);
68 dutycycle
= (pargs
.period
*
69 drvdata
->duty_cycle_table
[selector
].dutycycle
) / 100;
71 ret
= pwm_config(drvdata
->pwm
, dutycycle
, pargs
.period
);
73 dev_err(&rdev
->dev
, "Failed to configure PWM: %d\n", ret
);
77 drvdata
->state
= selector
;
82 static int pwm_regulator_list_voltage(struct regulator_dev
*rdev
,
85 struct pwm_regulator_data
*drvdata
= rdev_get_drvdata(rdev
);
87 if (selector
>= rdev
->desc
->n_voltages
)
90 return drvdata
->duty_cycle_table
[selector
].uV
;
93 static int pwm_regulator_enable(struct regulator_dev
*dev
)
95 struct pwm_regulator_data
*drvdata
= rdev_get_drvdata(dev
);
97 return pwm_enable(drvdata
->pwm
);
100 static int pwm_regulator_disable(struct regulator_dev
*dev
)
102 struct pwm_regulator_data
*drvdata
= rdev_get_drvdata(dev
);
104 pwm_disable(drvdata
->pwm
);
109 static int pwm_regulator_is_enabled(struct regulator_dev
*dev
)
111 struct pwm_regulator_data
*drvdata
= rdev_get_drvdata(dev
);
113 return pwm_is_enabled(drvdata
->pwm
);
116 static int pwm_regulator_get_voltage(struct regulator_dev
*rdev
)
118 struct pwm_regulator_data
*drvdata
= rdev_get_drvdata(rdev
);
120 return drvdata
->volt_uV
;
123 static int pwm_regulator_set_voltage(struct regulator_dev
*rdev
,
124 int min_uV
, int max_uV
,
127 struct pwm_regulator_data
*drvdata
= rdev_get_drvdata(rdev
);
128 unsigned int ramp_delay
= rdev
->constraints
->ramp_delay
;
129 struct pwm_args pargs
;
130 unsigned int req_diff
= min_uV
- rdev
->constraints
->min_uV
;
132 unsigned int duty_pulse
;
137 pwm_get_args(drvdata
->pwm
, &pargs
);
138 diff
= rdev
->constraints
->max_uV
- rdev
->constraints
->min_uV
;
140 /* First try to find out if we get the iduty cycle time which is
141 * factor of PWM period time. If (request_diff_to_min * pwm_period)
142 * is perfect divided by voltage_range_diff then it is possible to
143 * get duty cycle time which is factor of PWM period. This will help
144 * to get output voltage nearer to requested value as there is no
147 req_period
= req_diff
* pargs
.period
;
148 div_u64_rem(req_period
, diff
, &rem
);
150 do_div(req_period
, diff
);
151 duty_pulse
= (unsigned int)req_period
;
153 duty_pulse
= (pargs
.period
/ 100) * ((req_diff
* 100) / diff
);
156 ret
= pwm_config(drvdata
->pwm
, duty_pulse
, pargs
.period
);
158 dev_err(&rdev
->dev
, "Failed to configure PWM: %d\n", ret
);
162 ret
= pwm_enable(drvdata
->pwm
);
164 dev_err(&rdev
->dev
, "Failed to enable PWM: %d\n", ret
);
167 drvdata
->volt_uV
= min_uV
;
169 /* Delay required by PWM regulator to settle to the new voltage */
170 usleep_range(ramp_delay
, ramp_delay
+ 1000);
175 static struct regulator_ops pwm_regulator_voltage_table_ops
= {
176 .set_voltage_sel
= pwm_regulator_set_voltage_sel
,
177 .get_voltage_sel
= pwm_regulator_get_voltage_sel
,
178 .list_voltage
= pwm_regulator_list_voltage
,
179 .map_voltage
= regulator_map_voltage_iterate
,
180 .enable
= pwm_regulator_enable
,
181 .disable
= pwm_regulator_disable
,
182 .is_enabled
= pwm_regulator_is_enabled
,
185 static struct regulator_ops pwm_regulator_voltage_continuous_ops
= {
186 .get_voltage
= pwm_regulator_get_voltage
,
187 .set_voltage
= pwm_regulator_set_voltage
,
188 .enable
= pwm_regulator_enable
,
189 .disable
= pwm_regulator_disable
,
190 .is_enabled
= pwm_regulator_is_enabled
,
193 static struct regulator_desc pwm_regulator_desc
= {
194 .name
= "pwm-regulator",
195 .type
= REGULATOR_VOLTAGE
,
196 .owner
= THIS_MODULE
,
197 .supply_name
= "pwm",
200 static int pwm_regulator_init_table(struct platform_device
*pdev
,
201 struct pwm_regulator_data
*drvdata
)
203 struct device_node
*np
= pdev
->dev
.of_node
;
204 struct pwm_voltages
*duty_cycle_table
;
205 unsigned int length
= 0;
208 of_find_property(np
, "voltage-table", &length
);
210 if ((length
< sizeof(*duty_cycle_table
)) ||
211 (length
% sizeof(*duty_cycle_table
))) {
212 dev_err(&pdev
->dev
, "voltage-table length(%d) is invalid\n",
217 duty_cycle_table
= devm_kzalloc(&pdev
->dev
, length
, GFP_KERNEL
);
218 if (!duty_cycle_table
)
221 ret
= of_property_read_u32_array(np
, "voltage-table",
222 (u32
*)duty_cycle_table
,
223 length
/ sizeof(u32
));
225 dev_err(&pdev
->dev
, "Failed to read voltage-table: %d\n", ret
);
229 drvdata
->duty_cycle_table
= duty_cycle_table
;
230 memcpy(&drvdata
->ops
, &pwm_regulator_voltage_table_ops
,
231 sizeof(drvdata
->ops
));
232 drvdata
->desc
.ops
= &drvdata
->ops
;
233 drvdata
->desc
.n_voltages
= length
/ sizeof(*duty_cycle_table
);
238 static int pwm_regulator_init_continuous(struct platform_device
*pdev
,
239 struct pwm_regulator_data
*drvdata
)
241 memcpy(&drvdata
->ops
, &pwm_regulator_voltage_continuous_ops
,
242 sizeof(drvdata
->ops
));
243 drvdata
->desc
.ops
= &drvdata
->ops
;
244 drvdata
->desc
.continuous_voltage_range
= true;
249 static int pwm_regulator_probe(struct platform_device
*pdev
)
251 const struct regulator_init_data
*init_data
;
252 struct pwm_regulator_data
*drvdata
;
253 struct regulator_dev
*regulator
;
254 struct regulator_config config
= { };
255 struct device_node
*np
= pdev
->dev
.of_node
;
259 dev_err(&pdev
->dev
, "Device Tree node missing\n");
263 drvdata
= devm_kzalloc(&pdev
->dev
, sizeof(*drvdata
), GFP_KERNEL
);
267 memcpy(&drvdata
->desc
, &pwm_regulator_desc
, sizeof(drvdata
->desc
));
269 if (of_find_property(np
, "voltage-table", NULL
))
270 ret
= pwm_regulator_init_table(pdev
, drvdata
);
272 ret
= pwm_regulator_init_continuous(pdev
, drvdata
);
276 init_data
= of_get_regulator_init_data(&pdev
->dev
, np
,
282 config
.dev
= &pdev
->dev
;
283 config
.driver_data
= drvdata
;
284 config
.init_data
= init_data
;
286 drvdata
->pwm
= devm_pwm_get(&pdev
->dev
, NULL
);
287 if (IS_ERR(drvdata
->pwm
)) {
288 ret
= PTR_ERR(drvdata
->pwm
);
289 dev_err(&pdev
->dev
, "Failed to get PWM: %d\n", ret
);
294 * FIXME: pwm_apply_args() should be removed when switching to the
297 pwm_apply_args(drvdata
->pwm
);
299 regulator
= devm_regulator_register(&pdev
->dev
,
300 &drvdata
->desc
, &config
);
301 if (IS_ERR(regulator
)) {
302 ret
= PTR_ERR(regulator
);
303 dev_err(&pdev
->dev
, "Failed to register regulator %s: %d\n",
304 drvdata
->desc
.name
, ret
);
311 static const struct of_device_id pwm_of_match
[] = {
312 { .compatible
= "pwm-regulator" },
315 MODULE_DEVICE_TABLE(of
, pwm_of_match
);
317 static struct platform_driver pwm_regulator_driver
= {
319 .name
= "pwm-regulator",
320 .of_match_table
= of_match_ptr(pwm_of_match
),
322 .probe
= pwm_regulator_probe
,
325 module_platform_driver(pwm_regulator_driver
);
327 MODULE_LICENSE("GPL");
328 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
329 MODULE_DESCRIPTION("PWM Regulator Driver");
330 MODULE_ALIAS("platform:pwm-regulator");