Loading...
1/*
2 * Copyright (C) 2016 Google, Inc
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2, as published by
6 * the Free Software Foundation.
7 *
8 * Expose a PWM controlled by the ChromeOS EC to the host processor.
9 */
10
11#include <linux/module.h>
12#include <linux/mfd/cros_ec.h>
13#include <linux/mfd/cros_ec_commands.h>
14#include <linux/platform_device.h>
15#include <linux/pwm.h>
16#include <linux/slab.h>
17
18/**
19 * struct cros_ec_pwm_device - Driver data for EC PWM
20 *
21 * @dev: Device node
22 * @ec: Pointer to EC device
23 * @chip: PWM controller chip
24 */
25struct cros_ec_pwm_device {
26 struct device *dev;
27 struct cros_ec_device *ec;
28 struct pwm_chip chip;
29};
30
31static inline struct cros_ec_pwm_device *pwm_to_cros_ec_pwm(struct pwm_chip *c)
32{
33 return container_of(c, struct cros_ec_pwm_device, chip);
34}
35
36static int cros_ec_pwm_set_duty(struct cros_ec_device *ec, u8 index, u16 duty)
37{
38 struct {
39 struct cros_ec_command msg;
40 struct ec_params_pwm_set_duty params;
41 } __packed buf;
42 struct ec_params_pwm_set_duty *params = &buf.params;
43 struct cros_ec_command *msg = &buf.msg;
44
45 memset(&buf, 0, sizeof(buf));
46
47 msg->version = 0;
48 msg->command = EC_CMD_PWM_SET_DUTY;
49 msg->insize = 0;
50 msg->outsize = sizeof(*params);
51
52 params->duty = duty;
53 params->pwm_type = EC_PWM_TYPE_GENERIC;
54 params->index = index;
55
56 return cros_ec_cmd_xfer_status(ec, msg);
57}
58
59static int __cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index,
60 u32 *result)
61{
62 struct {
63 struct cros_ec_command msg;
64 union {
65 struct ec_params_pwm_get_duty params;
66 struct ec_response_pwm_get_duty resp;
67 };
68 } __packed buf;
69 struct ec_params_pwm_get_duty *params = &buf.params;
70 struct ec_response_pwm_get_duty *resp = &buf.resp;
71 struct cros_ec_command *msg = &buf.msg;
72 int ret;
73
74 memset(&buf, 0, sizeof(buf));
75
76 msg->version = 0;
77 msg->command = EC_CMD_PWM_GET_DUTY;
78 msg->insize = sizeof(*resp);
79 msg->outsize = sizeof(*params);
80
81 params->pwm_type = EC_PWM_TYPE_GENERIC;
82 params->index = index;
83
84 ret = cros_ec_cmd_xfer_status(ec, msg);
85 if (result)
86 *result = msg->result;
87 if (ret < 0)
88 return ret;
89
90 return resp->duty;
91}
92
93static int cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index)
94{
95 return __cros_ec_pwm_get_duty(ec, index, NULL);
96}
97
98static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
99 struct pwm_state *state)
100{
101 struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip);
102 int duty_cycle;
103
104 /* The EC won't let us change the period */
105 if (state->period != EC_PWM_MAX_DUTY)
106 return -EINVAL;
107
108 /*
109 * EC doesn't separate the concept of duty cycle and enabled, but
110 * kernel does. Translate.
111 */
112 duty_cycle = state->enabled ? state->duty_cycle : 0;
113
114 return cros_ec_pwm_set_duty(ec_pwm->ec, pwm->hwpwm, duty_cycle);
115}
116
117static void cros_ec_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
118 struct pwm_state *state)
119{
120 struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip);
121 int ret;
122
123 ret = cros_ec_pwm_get_duty(ec_pwm->ec, pwm->hwpwm);
124 if (ret < 0) {
125 dev_err(chip->dev, "error getting initial duty: %d\n", ret);
126 return;
127 }
128
129 state->enabled = (ret > 0);
130 state->period = EC_PWM_MAX_DUTY;
131
132 /* Note that "disabled" and "duty cycle == 0" are treated the same */
133 state->duty_cycle = ret;
134}
135
136static struct pwm_device *
137cros_ec_pwm_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
138{
139 struct pwm_device *pwm;
140
141 if (args->args[0] >= pc->npwm)
142 return ERR_PTR(-EINVAL);
143
144 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
145 if (IS_ERR(pwm))
146 return pwm;
147
148 /* The EC won't let us change the period */
149 pwm->args.period = EC_PWM_MAX_DUTY;
150
151 return pwm;
152}
153
154static const struct pwm_ops cros_ec_pwm_ops = {
155 .get_state = cros_ec_pwm_get_state,
156 .apply = cros_ec_pwm_apply,
157 .owner = THIS_MODULE,
158};
159
160static int cros_ec_num_pwms(struct cros_ec_device *ec)
161{
162 int i, ret;
163
164 /* The index field is only 8 bits */
165 for (i = 0; i <= U8_MAX; i++) {
166 u32 result = 0;
167
168 ret = __cros_ec_pwm_get_duty(ec, i, &result);
169 /* We want to parse EC protocol errors */
170 if (ret < 0 && !(ret == -EPROTO && result))
171 return ret;
172
173 /*
174 * We look for SUCCESS, INVALID_COMMAND, or INVALID_PARAM
175 * responses; everything else is treated as an error.
176 */
177 if (result == EC_RES_INVALID_COMMAND)
178 return -ENODEV;
179 else if (result == EC_RES_INVALID_PARAM)
180 return i;
181 else if (result)
182 return -EPROTO;
183 }
184
185 return U8_MAX;
186}
187
188static int cros_ec_pwm_probe(struct platform_device *pdev)
189{
190 struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
191 struct device *dev = &pdev->dev;
192 struct cros_ec_pwm_device *ec_pwm;
193 struct pwm_chip *chip;
194 int ret;
195
196 if (!ec) {
197 dev_err(dev, "no parent EC device\n");
198 return -EINVAL;
199 }
200
201 ec_pwm = devm_kzalloc(dev, sizeof(*ec_pwm), GFP_KERNEL);
202 if (!ec_pwm)
203 return -ENOMEM;
204 chip = &ec_pwm->chip;
205 ec_pwm->ec = ec;
206
207 /* PWM chip */
208 chip->dev = dev;
209 chip->ops = &cros_ec_pwm_ops;
210 chip->of_xlate = cros_ec_pwm_xlate;
211 chip->of_pwm_n_cells = 1;
212 chip->base = -1;
213 ret = cros_ec_num_pwms(ec);
214 if (ret < 0) {
215 dev_err(dev, "Couldn't find PWMs: %d\n", ret);
216 return ret;
217 }
218 chip->npwm = ret;
219 dev_dbg(dev, "Probed %u PWMs\n", chip->npwm);
220
221 ret = pwmchip_add(chip);
222 if (ret < 0) {
223 dev_err(dev, "cannot register PWM: %d\n", ret);
224 return ret;
225 }
226
227 platform_set_drvdata(pdev, ec_pwm);
228
229 return ret;
230}
231
232static int cros_ec_pwm_remove(struct platform_device *dev)
233{
234 struct cros_ec_pwm_device *ec_pwm = platform_get_drvdata(dev);
235 struct pwm_chip *chip = &ec_pwm->chip;
236
237 return pwmchip_remove(chip);
238}
239
240#ifdef CONFIG_OF
241static const struct of_device_id cros_ec_pwm_of_match[] = {
242 { .compatible = "google,cros-ec-pwm" },
243 {},
244};
245MODULE_DEVICE_TABLE(of, cros_ec_pwm_of_match);
246#endif
247
248static struct platform_driver cros_ec_pwm_driver = {
249 .probe = cros_ec_pwm_probe,
250 .remove = cros_ec_pwm_remove,
251 .driver = {
252 .name = "cros-ec-pwm",
253 .of_match_table = of_match_ptr(cros_ec_pwm_of_match),
254 },
255};
256module_platform_driver(cros_ec_pwm_driver);
257
258MODULE_ALIAS("platform:cros-ec-pwm");
259MODULE_DESCRIPTION("ChromeOS EC PWM driver");
260MODULE_LICENSE("GPL v2");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Expose a PWM controlled by the ChromeOS EC to the host processor.
4 *
5 * Copyright (C) 2016 Google, Inc.
6 */
7
8#include <linux/module.h>
9#include <linux/platform_data/cros_ec_commands.h>
10#include <linux/platform_data/cros_ec_proto.h>
11#include <linux/platform_device.h>
12#include <linux/pwm.h>
13#include <linux/slab.h>
14
15/**
16 * struct cros_ec_pwm_device - Driver data for EC PWM
17 *
18 * @dev: Device node
19 * @ec: Pointer to EC device
20 * @chip: PWM controller chip
21 */
22struct cros_ec_pwm_device {
23 struct device *dev;
24 struct cros_ec_device *ec;
25 struct pwm_chip chip;
26};
27
28static inline struct cros_ec_pwm_device *pwm_to_cros_ec_pwm(struct pwm_chip *c)
29{
30 return container_of(c, struct cros_ec_pwm_device, chip);
31}
32
33static int cros_ec_pwm_set_duty(struct cros_ec_device *ec, u8 index, u16 duty)
34{
35 struct {
36 struct cros_ec_command msg;
37 struct ec_params_pwm_set_duty params;
38 } __packed buf;
39 struct ec_params_pwm_set_duty *params = &buf.params;
40 struct cros_ec_command *msg = &buf.msg;
41
42 memset(&buf, 0, sizeof(buf));
43
44 msg->version = 0;
45 msg->command = EC_CMD_PWM_SET_DUTY;
46 msg->insize = 0;
47 msg->outsize = sizeof(*params);
48
49 params->duty = duty;
50 params->pwm_type = EC_PWM_TYPE_GENERIC;
51 params->index = index;
52
53 return cros_ec_cmd_xfer_status(ec, msg);
54}
55
56static int __cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index,
57 u32 *result)
58{
59 struct {
60 struct cros_ec_command msg;
61 union {
62 struct ec_params_pwm_get_duty params;
63 struct ec_response_pwm_get_duty resp;
64 };
65 } __packed buf;
66 struct ec_params_pwm_get_duty *params = &buf.params;
67 struct ec_response_pwm_get_duty *resp = &buf.resp;
68 struct cros_ec_command *msg = &buf.msg;
69 int ret;
70
71 memset(&buf, 0, sizeof(buf));
72
73 msg->version = 0;
74 msg->command = EC_CMD_PWM_GET_DUTY;
75 msg->insize = sizeof(*resp);
76 msg->outsize = sizeof(*params);
77
78 params->pwm_type = EC_PWM_TYPE_GENERIC;
79 params->index = index;
80
81 ret = cros_ec_cmd_xfer_status(ec, msg);
82 if (result)
83 *result = msg->result;
84 if (ret < 0)
85 return ret;
86
87 return resp->duty;
88}
89
90static int cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index)
91{
92 return __cros_ec_pwm_get_duty(ec, index, NULL);
93}
94
95static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
96 const struct pwm_state *state)
97{
98 struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip);
99 int duty_cycle;
100
101 /* The EC won't let us change the period */
102 if (state->period != EC_PWM_MAX_DUTY)
103 return -EINVAL;
104
105 /*
106 * EC doesn't separate the concept of duty cycle and enabled, but
107 * kernel does. Translate.
108 */
109 duty_cycle = state->enabled ? state->duty_cycle : 0;
110
111 return cros_ec_pwm_set_duty(ec_pwm->ec, pwm->hwpwm, duty_cycle);
112}
113
114static void cros_ec_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
115 struct pwm_state *state)
116{
117 struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip);
118 int ret;
119
120 ret = cros_ec_pwm_get_duty(ec_pwm->ec, pwm->hwpwm);
121 if (ret < 0) {
122 dev_err(chip->dev, "error getting initial duty: %d\n", ret);
123 return;
124 }
125
126 state->enabled = (ret > 0);
127 state->period = EC_PWM_MAX_DUTY;
128
129 /* Note that "disabled" and "duty cycle == 0" are treated the same */
130 state->duty_cycle = ret;
131}
132
133static struct pwm_device *
134cros_ec_pwm_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
135{
136 struct pwm_device *pwm;
137
138 if (args->args[0] >= pc->npwm)
139 return ERR_PTR(-EINVAL);
140
141 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
142 if (IS_ERR(pwm))
143 return pwm;
144
145 /* The EC won't let us change the period */
146 pwm->args.period = EC_PWM_MAX_DUTY;
147
148 return pwm;
149}
150
151static const struct pwm_ops cros_ec_pwm_ops = {
152 .get_state = cros_ec_pwm_get_state,
153 .apply = cros_ec_pwm_apply,
154 .owner = THIS_MODULE,
155};
156
157static int cros_ec_num_pwms(struct cros_ec_device *ec)
158{
159 int i, ret;
160
161 /* The index field is only 8 bits */
162 for (i = 0; i <= U8_MAX; i++) {
163 u32 result = 0;
164
165 ret = __cros_ec_pwm_get_duty(ec, i, &result);
166 /* We want to parse EC protocol errors */
167 if (ret < 0 && !(ret == -EPROTO && result))
168 return ret;
169
170 /*
171 * We look for SUCCESS, INVALID_COMMAND, or INVALID_PARAM
172 * responses; everything else is treated as an error.
173 */
174 if (result == EC_RES_INVALID_COMMAND)
175 return -ENODEV;
176 else if (result == EC_RES_INVALID_PARAM)
177 return i;
178 else if (result)
179 return -EPROTO;
180 }
181
182 return U8_MAX;
183}
184
185static int cros_ec_pwm_probe(struct platform_device *pdev)
186{
187 struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
188 struct device *dev = &pdev->dev;
189 struct cros_ec_pwm_device *ec_pwm;
190 struct pwm_chip *chip;
191 int ret;
192
193 if (!ec) {
194 dev_err(dev, "no parent EC device\n");
195 return -EINVAL;
196 }
197
198 ec_pwm = devm_kzalloc(dev, sizeof(*ec_pwm), GFP_KERNEL);
199 if (!ec_pwm)
200 return -ENOMEM;
201 chip = &ec_pwm->chip;
202 ec_pwm->ec = ec;
203
204 /* PWM chip */
205 chip->dev = dev;
206 chip->ops = &cros_ec_pwm_ops;
207 chip->of_xlate = cros_ec_pwm_xlate;
208 chip->of_pwm_n_cells = 1;
209 chip->base = -1;
210 ret = cros_ec_num_pwms(ec);
211 if (ret < 0) {
212 dev_err(dev, "Couldn't find PWMs: %d\n", ret);
213 return ret;
214 }
215 chip->npwm = ret;
216 dev_dbg(dev, "Probed %u PWMs\n", chip->npwm);
217
218 ret = pwmchip_add(chip);
219 if (ret < 0) {
220 dev_err(dev, "cannot register PWM: %d\n", ret);
221 return ret;
222 }
223
224 platform_set_drvdata(pdev, ec_pwm);
225
226 return ret;
227}
228
229static int cros_ec_pwm_remove(struct platform_device *dev)
230{
231 struct cros_ec_pwm_device *ec_pwm = platform_get_drvdata(dev);
232 struct pwm_chip *chip = &ec_pwm->chip;
233
234 return pwmchip_remove(chip);
235}
236
237#ifdef CONFIG_OF
238static const struct of_device_id cros_ec_pwm_of_match[] = {
239 { .compatible = "google,cros-ec-pwm" },
240 {},
241};
242MODULE_DEVICE_TABLE(of, cros_ec_pwm_of_match);
243#endif
244
245static struct platform_driver cros_ec_pwm_driver = {
246 .probe = cros_ec_pwm_probe,
247 .remove = cros_ec_pwm_remove,
248 .driver = {
249 .name = "cros-ec-pwm",
250 .of_match_table = of_match_ptr(cros_ec_pwm_of_match),
251 },
252};
253module_platform_driver(cros_ec_pwm_driver);
254
255MODULE_ALIAS("platform:cros-ec-pwm");
256MODULE_DESCRIPTION("ChromeOS EC PWM driver");
257MODULE_LICENSE("GPL v2");