[go: nahoru, domu]
1/*
2 * Regulator driver for 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
23struct pwm_regulator_data {
24	struct regulator_desc desc;
25	struct pwm_voltages *duty_cycle_table;
26	struct pwm_device *pwm;
27	bool enabled;
28	int state;
29};
30
31struct pwm_voltages {
32	unsigned int uV;
33	unsigned int dutycycle;
34};
35
36static int pwm_regulator_get_voltage_sel(struct regulator_dev *dev)
37{
38	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
39
40	return drvdata->state;
41}
42
43static int pwm_regulator_set_voltage_sel(struct regulator_dev *dev,
44					 unsigned selector)
45{
46	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
47	unsigned int pwm_reg_period;
48	int dutycycle;
49	int ret;
50
51	pwm_reg_period = pwm_get_period(drvdata->pwm);
52
53	dutycycle = (pwm_reg_period *
54		    drvdata->duty_cycle_table[selector].dutycycle) / 100;
55
56	ret = pwm_config(drvdata->pwm, dutycycle, pwm_reg_period);
57	if (ret) {
58		dev_err(&dev->dev, "Failed to configure PWM\n");
59		return ret;
60	}
61
62	drvdata->state = selector;
63
64	if (!drvdata->enabled) {
65		ret = pwm_enable(drvdata->pwm);
66		if (ret) {
67			dev_err(&dev->dev, "Failed to enable PWM\n");
68			return ret;
69		}
70		drvdata->enabled = true;
71	}
72
73	return 0;
74}
75
76static int pwm_regulator_list_voltage(struct regulator_dev *dev,
77				      unsigned selector)
78{
79	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
80
81	if (selector >= drvdata->desc.n_voltages)
82		return -EINVAL;
83
84	return drvdata->duty_cycle_table[selector].uV;
85}
86
87static struct regulator_ops pwm_regulator_voltage_ops = {
88	.set_voltage_sel = pwm_regulator_set_voltage_sel,
89	.get_voltage_sel = pwm_regulator_get_voltage_sel,
90	.list_voltage    = pwm_regulator_list_voltage,
91	.map_voltage     = regulator_map_voltage_iterate,
92};
93
94static const struct regulator_desc pwm_regulator_desc = {
95	.name		= "pwm-regulator",
96	.ops		= &pwm_regulator_voltage_ops,
97	.type		= REGULATOR_VOLTAGE,
98	.owner		= THIS_MODULE,
99	.supply_name    = "pwm",
100};
101
102static int pwm_regulator_probe(struct platform_device *pdev)
103{
104	struct pwm_regulator_data *drvdata;
105	struct property *prop;
106	struct regulator_dev *regulator;
107	struct regulator_config config = { };
108	struct device_node *np = pdev->dev.of_node;
109	int length, ret;
110
111	if (!np) {
112		dev_err(&pdev->dev, "Device Tree node missing\n");
113		return -EINVAL;
114	}
115
116	drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
117	if (!drvdata)
118		return -ENOMEM;
119
120	memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(pwm_regulator_desc));
121
122	/* determine the number of voltage-table */
123	prop = of_find_property(np, "voltage-table", &length);
124	if (!prop) {
125		dev_err(&pdev->dev, "No voltage-table\n");
126		return -EINVAL;
127	}
128
129	if ((length < sizeof(*drvdata->duty_cycle_table)) ||
130	    (length % sizeof(*drvdata->duty_cycle_table))) {
131		dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
132			length);
133		return -EINVAL;
134	}
135
136	drvdata->desc.n_voltages = length / sizeof(*drvdata->duty_cycle_table);
137
138	drvdata->duty_cycle_table = devm_kzalloc(&pdev->dev,
139						 length, GFP_KERNEL);
140	if (!drvdata->duty_cycle_table)
141		return -ENOMEM;
142
143	/* read voltage table from DT property */
144	ret = of_property_read_u32_array(np, "voltage-table",
145					 (u32 *)drvdata->duty_cycle_table,
146					 length / sizeof(u32));
147	if (ret < 0) {
148		dev_err(&pdev->dev, "read voltage-table failed\n");
149		return ret;
150	}
151
152	config.init_data = of_get_regulator_init_data(&pdev->dev, np);
153	if (!config.init_data)
154		return -ENOMEM;
155
156	config.of_node = np;
157	config.dev = &pdev->dev;
158	config.driver_data = drvdata;
159
160	drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
161	if (IS_ERR(drvdata->pwm)) {
162		dev_err(&pdev->dev, "Failed to get PWM\n");
163		return PTR_ERR(drvdata->pwm);
164	}
165
166	regulator = devm_regulator_register(&pdev->dev,
167					    &drvdata->desc, &config);
168	if (IS_ERR(regulator)) {
169		dev_err(&pdev->dev, "Failed to register regulator %s\n",
170			drvdata->desc.name);
171		return PTR_ERR(regulator);
172	}
173
174	return 0;
175}
176
177static const struct of_device_id pwm_of_match[] = {
178	{ .compatible = "pwm-regulator" },
179	{ },
180};
181MODULE_DEVICE_TABLE(of, pwm_of_match);
182
183static struct platform_driver pwm_regulator_driver = {
184	.driver = {
185		.name		= "pwm-regulator",
186		.owner		= THIS_MODULE,
187		.of_match_table = of_match_ptr(pwm_of_match),
188	},
189	.probe = pwm_regulator_probe,
190};
191
192module_platform_driver(pwm_regulator_driver);
193
194MODULE_LICENSE("GPL");
195MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
196MODULE_DESCRIPTION("PWM Regulator Driver");
197MODULE_ALIAS("platform:pwm-regulator");
198