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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * ChromeOS EC LED Driver
4 *
5 * Copyright (C) 2024 Thomas Weißschuh <linux@weissschuh.net>
6 */
7
8#include <linux/device.h>
9#include <linux/leds.h>
10#include <linux/led-class-multicolor.h>
11#include <linux/mod_devicetable.h>
12#include <linux/module.h>
13#include <linux/platform_device.h>
14#include <linux/platform_data/cros_ec_commands.h>
15#include <linux/platform_data/cros_ec_proto.h>
16
17static const char * const cros_ec_led_functions[] = {
18 [EC_LED_ID_BATTERY_LED] = LED_FUNCTION_CHARGING,
19 [EC_LED_ID_POWER_LED] = LED_FUNCTION_POWER,
20 [EC_LED_ID_ADAPTER_LED] = "adapter",
21 [EC_LED_ID_LEFT_LED] = "left",
22 [EC_LED_ID_RIGHT_LED] = "right",
23 [EC_LED_ID_RECOVERY_HW_REINIT_LED] = "recovery-hw-reinit",
24 [EC_LED_ID_SYSRQ_DEBUG_LED] = "sysrq-debug",
25};
26
27static_assert(ARRAY_SIZE(cros_ec_led_functions) == EC_LED_ID_COUNT);
28
29static const int cros_ec_led_to_linux_id[] = {
30 [EC_LED_COLOR_RED] = LED_COLOR_ID_RED,
31 [EC_LED_COLOR_GREEN] = LED_COLOR_ID_GREEN,
32 [EC_LED_COLOR_BLUE] = LED_COLOR_ID_BLUE,
33 [EC_LED_COLOR_YELLOW] = LED_COLOR_ID_YELLOW,
34 [EC_LED_COLOR_WHITE] = LED_COLOR_ID_WHITE,
35 [EC_LED_COLOR_AMBER] = LED_COLOR_ID_AMBER,
36};
37
38static_assert(ARRAY_SIZE(cros_ec_led_to_linux_id) == EC_LED_COLOR_COUNT);
39
40static const int cros_ec_linux_to_ec_id[] = {
41 [LED_COLOR_ID_RED] = EC_LED_COLOR_RED,
42 [LED_COLOR_ID_GREEN] = EC_LED_COLOR_GREEN,
43 [LED_COLOR_ID_BLUE] = EC_LED_COLOR_BLUE,
44 [LED_COLOR_ID_YELLOW] = EC_LED_COLOR_YELLOW,
45 [LED_COLOR_ID_WHITE] = EC_LED_COLOR_WHITE,
46 [LED_COLOR_ID_AMBER] = EC_LED_COLOR_AMBER,
47};
48
49struct cros_ec_led_priv {
50 struct led_classdev_mc led_mc_cdev;
51 struct cros_ec_device *cros_ec;
52 enum ec_led_id led_id;
53};
54
55static inline struct cros_ec_led_priv *cros_ec_led_cdev_to_priv(struct led_classdev *led_cdev)
56{
57 return container_of(lcdev_to_mccdev(led_cdev), struct cros_ec_led_priv, led_mc_cdev);
58}
59
60union cros_ec_led_cmd_data {
61 struct ec_params_led_control req;
62 struct ec_response_led_control resp;
63} __packed;
64
65static int cros_ec_led_send_cmd(struct cros_ec_device *cros_ec,
66 union cros_ec_led_cmd_data *arg)
67{
68 int ret;
69 struct {
70 struct cros_ec_command msg;
71 union cros_ec_led_cmd_data data;
72 } __packed buf = {
73 .msg = {
74 .version = 1,
75 .command = EC_CMD_LED_CONTROL,
76 .insize = sizeof(arg->resp),
77 .outsize = sizeof(arg->req),
78 },
79 .data.req = arg->req
80 };
81
82 ret = cros_ec_cmd_xfer_status(cros_ec, &buf.msg);
83 if (ret < 0)
84 return ret;
85
86 arg->resp = buf.data.resp;
87
88 return 0;
89}
90
91static int cros_ec_led_trigger_activate(struct led_classdev *led_cdev)
92{
93 struct cros_ec_led_priv *priv = cros_ec_led_cdev_to_priv(led_cdev);
94 union cros_ec_led_cmd_data arg = {};
95
96 arg.req.led_id = priv->led_id;
97 arg.req.flags = EC_LED_FLAGS_AUTO;
98
99 return cros_ec_led_send_cmd(priv->cros_ec, &arg);
100}
101
102static struct led_hw_trigger_type cros_ec_led_trigger_type;
103
104static struct led_trigger cros_ec_led_trigger = {
105 .name = "chromeos-auto",
106 .trigger_type = &cros_ec_led_trigger_type,
107 .activate = cros_ec_led_trigger_activate,
108};
109
110static int cros_ec_led_brightness_set_blocking(struct led_classdev *led_cdev,
111 enum led_brightness brightness)
112{
113 struct cros_ec_led_priv *priv = cros_ec_led_cdev_to_priv(led_cdev);
114 union cros_ec_led_cmd_data arg = {};
115 enum ec_led_colors led_color;
116 struct mc_subled *subled;
117 size_t i;
118
119 led_mc_calc_color_components(&priv->led_mc_cdev, brightness);
120
121 arg.req.led_id = priv->led_id;
122
123 for (i = 0; i < priv->led_mc_cdev.num_colors; i++) {
124 subled = &priv->led_mc_cdev.subled_info[i];
125 led_color = cros_ec_linux_to_ec_id[subled->color_index];
126 arg.req.brightness[led_color] = subled->brightness;
127 }
128
129 return cros_ec_led_send_cmd(priv->cros_ec, &arg);
130}
131
132static int cros_ec_led_count_subleds(struct device *dev,
133 struct ec_response_led_control *resp,
134 unsigned int *max_brightness)
135{
136 unsigned int range, common_range = 0;
137 int num_subleds = 0;
138 size_t i;
139
140 for (i = 0; i < EC_LED_COLOR_COUNT; i++) {
141 range = resp->brightness_range[i];
142
143 if (!range)
144 continue;
145
146 num_subleds++;
147
148 if (!common_range)
149 common_range = range;
150
151 if (common_range != range) {
152 /* The multicolor LED API expects a uniform max_brightness */
153 dev_err(dev, "Inconsistent LED brightness values\n");
154 return -EINVAL;
155 }
156 }
157
158 if (!num_subleds)
159 return -EINVAL;
160
161 *max_brightness = common_range;
162 return num_subleds;
163}
164
165static const char *cros_ec_led_get_color_name(struct led_classdev_mc *led_mc_cdev)
166{
167 int color;
168
169 if (led_mc_cdev->num_colors == 1)
170 color = led_mc_cdev->subled_info[0].color_index;
171 else
172 color = LED_COLOR_ID_MULTI;
173
174 return led_get_color_name(color);
175}
176
177static int cros_ec_led_probe_one(struct device *dev, struct cros_ec_device *cros_ec,
178 enum ec_led_id id)
179{
180 union cros_ec_led_cmd_data arg = {};
181 struct cros_ec_led_priv *priv;
182 struct led_classdev *led_cdev;
183 struct mc_subled *subleds;
184 int i, ret, num_subleds;
185 size_t subled;
186
187 arg.req.led_id = id;
188 arg.req.flags = EC_LED_FLAGS_QUERY;
189 ret = cros_ec_led_send_cmd(cros_ec, &arg);
190 if (ret == -EINVAL)
191 return 0; /* Unknown LED, skip */
192 if (ret == -EOPNOTSUPP)
193 return -ENODEV;
194 if (ret < 0)
195 return ret;
196
197 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
198 if (!priv)
199 return -ENOMEM;
200
201 num_subleds = cros_ec_led_count_subleds(dev, &arg.resp,
202 &priv->led_mc_cdev.led_cdev.max_brightness);
203 if (num_subleds < 0)
204 return num_subleds;
205
206 priv->cros_ec = cros_ec;
207 priv->led_id = id;
208
209 subleds = devm_kcalloc(dev, num_subleds, sizeof(*subleds), GFP_KERNEL);
210 if (!subleds)
211 return -ENOMEM;
212
213 subled = 0;
214 for (i = 0; i < EC_LED_COLOR_COUNT; i++) {
215 if (!arg.resp.brightness_range[i])
216 continue;
217
218 subleds[subled].color_index = cros_ec_led_to_linux_id[i];
219 if (subled == 0)
220 subleds[subled].intensity = 100;
221 subled++;
222 }
223
224 priv->led_mc_cdev.subled_info = subleds;
225 priv->led_mc_cdev.num_colors = num_subleds;
226
227 led_cdev = &priv->led_mc_cdev.led_cdev;
228 led_cdev->brightness_set_blocking = cros_ec_led_brightness_set_blocking;
229 led_cdev->trigger_type = &cros_ec_led_trigger_type;
230 led_cdev->default_trigger = cros_ec_led_trigger.name;
231 led_cdev->hw_control_trigger = cros_ec_led_trigger.name;
232
233 led_cdev->name = devm_kasprintf(dev, GFP_KERNEL, "chromeos:%s:%s",
234 cros_ec_led_get_color_name(&priv->led_mc_cdev),
235 cros_ec_led_functions[id]);
236 if (!led_cdev->name)
237 return -ENOMEM;
238
239 return devm_led_classdev_multicolor_register(dev, &priv->led_mc_cdev);
240}
241
242static int cros_ec_led_probe(struct platform_device *pdev)
243{
244 struct device *dev = &pdev->dev;
245 struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
246 struct cros_ec_device *cros_ec = ec_dev->ec_dev;
247 int i, ret = 0;
248
249 ret = devm_led_trigger_register(dev, &cros_ec_led_trigger);
250 if (ret)
251 return ret;
252
253 for (i = 0; i < EC_LED_ID_COUNT; i++) {
254 ret = cros_ec_led_probe_one(dev, cros_ec, i);
255 if (ret)
256 break;
257 }
258
259 return ret;
260}
261
262static const struct platform_device_id cros_ec_led_id[] = {
263 { "cros-ec-led", 0 },
264 {}
265};
266
267static struct platform_driver cros_ec_led_driver = {
268 .driver.name = "cros-ec-led",
269 .probe = cros_ec_led_probe,
270 .id_table = cros_ec_led_id,
271};
272module_platform_driver(cros_ec_led_driver);
273
274MODULE_DEVICE_TABLE(platform, cros_ec_led_id);
275MODULE_DESCRIPTION("ChromeOS EC LED Driver");
276MODULE_AUTHOR("Thomas Weißschuh <linux@weissschuh.net");
277MODULE_LICENSE("GPL");