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aa66cc66 CZ |
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 | ||
4773be18 | 13 | #include <linux/delay.h> |
aa66cc66 CZ |
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> | |
20 | #include <linux/of.h> | |
21 | #include <linux/of_device.h> | |
22 | #include <linux/pwm.h> | |
23 | ||
24 | struct pwm_regulator_data { | |
4773be18 | 25 | /* Shared */ |
aa66cc66 | 26 | struct pwm_device *pwm; |
4773be18 LJ |
27 | |
28 | /* Voltage table */ | |
29 | struct pwm_voltages *duty_cycle_table; | |
aa66cc66 | 30 | int state; |
4773be18 LJ |
31 | |
32 | /* Continuous voltage */ | |
4773be18 | 33 | int volt_uV; |
aa66cc66 CZ |
34 | }; |
35 | ||
36 | struct pwm_voltages { | |
37 | unsigned int uV; | |
38 | unsigned int dutycycle; | |
39 | }; | |
40 | ||
4773be18 LJ |
41 | /** |
42 | * Voltage table call-backs | |
43 | */ | |
ab101e35 | 44 | static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev) |
aa66cc66 | 45 | { |
ab101e35 | 46 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); |
aa66cc66 CZ |
47 | |
48 | return drvdata->state; | |
49 | } | |
50 | ||
ab101e35 | 51 | static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev, |
aa66cc66 CZ |
52 | unsigned selector) |
53 | { | |
ab101e35 | 54 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); |
aa66cc66 CZ |
55 | unsigned int pwm_reg_period; |
56 | int dutycycle; | |
57 | int ret; | |
58 | ||
59 | pwm_reg_period = pwm_get_period(drvdata->pwm); | |
60 | ||
61 | dutycycle = (pwm_reg_period * | |
62 | drvdata->duty_cycle_table[selector].dutycycle) / 100; | |
63 | ||
64 | ret = pwm_config(drvdata->pwm, dutycycle, pwm_reg_period); | |
65 | if (ret) { | |
ab101e35 | 66 | dev_err(&rdev->dev, "Failed to configure PWM\n"); |
aa66cc66 CZ |
67 | return ret; |
68 | } | |
69 | ||
70 | drvdata->state = selector; | |
71 | ||
c779cebb LJ |
72 | ret = pwm_enable(drvdata->pwm); |
73 | if (ret) { | |
ab101e35 | 74 | dev_err(&rdev->dev, "Failed to enable PWM\n"); |
c779cebb | 75 | return ret; |
aa66cc66 CZ |
76 | } |
77 | ||
78 | return 0; | |
79 | } | |
80 | ||
ab101e35 | 81 | static int pwm_regulator_list_voltage(struct regulator_dev *rdev, |
aa66cc66 CZ |
82 | unsigned selector) |
83 | { | |
ab101e35 | 84 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); |
aa66cc66 | 85 | |
ab101e35 | 86 | if (selector >= rdev->desc->n_voltages) |
aa66cc66 CZ |
87 | return -EINVAL; |
88 | ||
89 | return drvdata->duty_cycle_table[selector].uV; | |
90 | } | |
4773be18 LJ |
91 | |
92 | /** | |
93 | * Continuous voltage call-backs | |
94 | */ | |
f3f6439d | 95 | static int pwm_voltage_to_duty_cycle_percentage(struct regulator_dev *rdev, int req_uV) |
4773be18 | 96 | { |
cae897de LJ |
97 | int min_uV = rdev->constraints->min_uV; |
98 | int max_uV = rdev->constraints->max_uV; | |
99 | int diff = max_uV - min_uV; | |
100 | ||
f3f6439d | 101 | return 100 - (((req_uV * 100) - (min_uV * 100)) / diff); |
4773be18 LJ |
102 | } |
103 | ||
104 | static int pwm_regulator_get_voltage(struct regulator_dev *rdev) | |
105 | { | |
106 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); | |
107 | ||
108 | return drvdata->volt_uV; | |
109 | } | |
110 | ||
111 | static int pwm_regulator_set_voltage(struct regulator_dev *rdev, | |
112 | int min_uV, int max_uV, | |
113 | unsigned *selector) | |
114 | { | |
115 | struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); | |
116 | unsigned int ramp_delay = rdev->constraints->ramp_delay; | |
f3f6439d | 117 | unsigned int period = pwm_get_period(drvdata->pwm); |
4773be18 LJ |
118 | int duty_cycle; |
119 | int ret; | |
120 | ||
f3f6439d | 121 | duty_cycle = pwm_voltage_to_duty_cycle_percentage(rdev, min_uV); |
4773be18 | 122 | |
f3f6439d | 123 | ret = pwm_config(drvdata->pwm, (period / 100) * duty_cycle, period); |
4773be18 LJ |
124 | if (ret) { |
125 | dev_err(&rdev->dev, "Failed to configure PWM\n"); | |
126 | return ret; | |
127 | } | |
128 | ||
129 | ret = pwm_enable(drvdata->pwm); | |
130 | if (ret) { | |
131 | dev_err(&rdev->dev, "Failed to enable PWM\n"); | |
132 | return ret; | |
133 | } | |
134 | drvdata->volt_uV = min_uV; | |
135 | ||
136 | /* Delay required by PWM regulator to settle to the new voltage */ | |
137 | usleep_range(ramp_delay, ramp_delay + 1000); | |
138 | ||
139 | return 0; | |
140 | } | |
141 | ||
f9178dad | 142 | static struct regulator_ops pwm_regulator_voltage_table_ops = { |
aa66cc66 CZ |
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, | |
147 | }; | |
148 | ||
4773be18 LJ |
149 | static struct regulator_ops pwm_regulator_voltage_continuous_ops = { |
150 | .get_voltage = pwm_regulator_get_voltage, | |
151 | .set_voltage = pwm_regulator_set_voltage, | |
152 | }; | |
153 | ||
b6f55e74 | 154 | static struct regulator_desc pwm_regulator_desc = { |
aa66cc66 | 155 | .name = "pwm-regulator", |
aa66cc66 CZ |
156 | .type = REGULATOR_VOLTAGE, |
157 | .owner = THIS_MODULE, | |
158 | .supply_name = "pwm", | |
159 | }; | |
160 | ||
f9178dad LJ |
161 | static int pwm_regulator_init_table(struct platform_device *pdev, |
162 | struct pwm_regulator_data *drvdata) | |
163 | { | |
164 | struct device_node *np = pdev->dev.of_node; | |
165 | struct pwm_voltages *duty_cycle_table; | |
60cb65eb | 166 | unsigned int length = 0; |
f9178dad LJ |
167 | int ret; |
168 | ||
169 | of_find_property(np, "voltage-table", &length); | |
170 | ||
171 | if ((length < sizeof(*duty_cycle_table)) || | |
172 | (length % sizeof(*duty_cycle_table))) { | |
173 | dev_err(&pdev->dev, | |
174 | "voltage-table length(%d) is invalid\n", | |
175 | length); | |
176 | return -EINVAL; | |
177 | } | |
178 | ||
179 | duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL); | |
180 | if (!duty_cycle_table) | |
181 | return -ENOMEM; | |
182 | ||
183 | ret = of_property_read_u32_array(np, "voltage-table", | |
184 | (u32 *)duty_cycle_table, | |
185 | length / sizeof(u32)); | |
186 | if (ret) { | |
187 | dev_err(&pdev->dev, "Failed to read voltage-table\n"); | |
188 | return ret; | |
189 | } | |
190 | ||
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); | |
194 | ||
195 | return 0; | |
196 | } | |
197 | ||
4773be18 LJ |
198 | static int pwm_regulator_init_continuous(struct platform_device *pdev, |
199 | struct pwm_regulator_data *drvdata) | |
200 | { | |
4773be18 LJ |
201 | pwm_regulator_desc.ops = &pwm_regulator_voltage_continuous_ops; |
202 | pwm_regulator_desc.continuous_voltage_range = true; | |
203 | ||
204 | return 0; | |
205 | } | |
206 | ||
aa66cc66 CZ |
207 | static int pwm_regulator_probe(struct platform_device *pdev) |
208 | { | |
5ad2cb14 | 209 | const struct regulator_init_data *init_data; |
aa66cc66 | 210 | struct pwm_regulator_data *drvdata; |
aa66cc66 CZ |
211 | struct regulator_dev *regulator; |
212 | struct regulator_config config = { }; | |
213 | struct device_node *np = pdev->dev.of_node; | |
f9178dad | 214 | int ret; |
aa66cc66 CZ |
215 | |
216 | if (!np) { | |
217 | dev_err(&pdev->dev, "Device Tree node missing\n"); | |
218 | return -EINVAL; | |
219 | } | |
220 | ||
221 | drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL); | |
222 | if (!drvdata) | |
223 | return -ENOMEM; | |
224 | ||
4773be18 | 225 | if (of_find_property(np, "voltage-table", NULL)) |
f9178dad | 226 | ret = pwm_regulator_init_table(pdev, drvdata); |
4773be18 LJ |
227 | else |
228 | ret = pwm_regulator_init_continuous(pdev, drvdata); | |
229 | if (ret) | |
230 | return ret; | |
aa66cc66 | 231 | |
5ad2cb14 LJ |
232 | init_data = of_get_regulator_init_data(&pdev->dev, np, |
233 | &pwm_regulator_desc); | |
234 | if (!init_data) | |
aa66cc66 CZ |
235 | return -ENOMEM; |
236 | ||
237 | config.of_node = np; | |
238 | config.dev = &pdev->dev; | |
239 | config.driver_data = drvdata; | |
5ad2cb14 | 240 | config.init_data = init_data; |
aa66cc66 CZ |
241 | |
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); | |
246 | } | |
247 | ||
248 | regulator = devm_regulator_register(&pdev->dev, | |
b6f55e74 | 249 | &pwm_regulator_desc, &config); |
aa66cc66 CZ |
250 | if (IS_ERR(regulator)) { |
251 | dev_err(&pdev->dev, "Failed to register regulator %s\n", | |
b6f55e74 | 252 | pwm_regulator_desc.name); |
aa66cc66 CZ |
253 | return PTR_ERR(regulator); |
254 | } | |
255 | ||
256 | return 0; | |
257 | } | |
258 | ||
259 | static const struct of_device_id pwm_of_match[] = { | |
260 | { .compatible = "pwm-regulator" }, | |
261 | { }, | |
262 | }; | |
263 | MODULE_DEVICE_TABLE(of, pwm_of_match); | |
264 | ||
265 | static struct platform_driver pwm_regulator_driver = { | |
266 | .driver = { | |
267 | .name = "pwm-regulator", | |
aa66cc66 CZ |
268 | .of_match_table = of_match_ptr(pwm_of_match), |
269 | }, | |
270 | .probe = pwm_regulator_probe, | |
271 | }; | |
272 | ||
273 | module_platform_driver(pwm_regulator_driver); | |
274 | ||
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"); |