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/module.h>
12 #include <linux/platform_device.h>
13 #include <linux/platform_data/cros_ec_commands.h>
14 #include <linux/platform_data/cros_ec_proto.h>
15
16 static const char * const cros_ec_led_functions[] = {
17 [EC_LED_ID_BATTERY_LED] = LED_FUNCTION_CHARGING,
18 [EC_LED_ID_POWER_LED] = LED_FUNCTION_POWER,
19 [EC_LED_ID_ADAPTER_LED] = "adapter",
20 [EC_LED_ID_LEFT_LED] = "left",
21 [EC_LED_ID_RIGHT_LED] = "right",
22 [EC_LED_ID_RECOVERY_HW_REINIT_LED] = "recovery-hw-reinit",
23 [EC_LED_ID_SYSRQ_DEBUG_LED] = "sysrq-debug",
24 };
25
26 static_assert(ARRAY_SIZE(cros_ec_led_functions) == EC_LED_ID_COUNT);
27
28 static const int cros_ec_led_to_linux_id[] = {
29 [EC_LED_COLOR_RED] = LED_COLOR_ID_RED,
30 [EC_LED_COLOR_GREEN] = LED_COLOR_ID_GREEN,
31 [EC_LED_COLOR_BLUE] = LED_COLOR_ID_BLUE,
32 [EC_LED_COLOR_YELLOW] = LED_COLOR_ID_YELLOW,
33 [EC_LED_COLOR_WHITE] = LED_COLOR_ID_WHITE,
34 [EC_LED_COLOR_AMBER] = LED_COLOR_ID_AMBER,
35 };
36
37 static_assert(ARRAY_SIZE(cros_ec_led_to_linux_id) == EC_LED_COLOR_COUNT);
38
39 static const int cros_ec_linux_to_ec_id[] = {
40 [LED_COLOR_ID_RED] = EC_LED_COLOR_RED,
41 [LED_COLOR_ID_GREEN] = EC_LED_COLOR_GREEN,
42 [LED_COLOR_ID_BLUE] = EC_LED_COLOR_BLUE,
43 [LED_COLOR_ID_YELLOW] = EC_LED_COLOR_YELLOW,
44 [LED_COLOR_ID_WHITE] = EC_LED_COLOR_WHITE,
45 [LED_COLOR_ID_AMBER] = EC_LED_COLOR_AMBER,
46 };
47
48 struct cros_ec_led_priv {
49 struct led_classdev_mc led_mc_cdev;
50 struct cros_ec_device *cros_ec;
51 enum ec_led_id led_id;
52 };
53
cros_ec_led_cdev_to_priv(struct led_classdev * led_cdev)54 static inline struct cros_ec_led_priv *cros_ec_led_cdev_to_priv(struct led_classdev *led_cdev)
55 {
56 return container_of(lcdev_to_mccdev(led_cdev), struct cros_ec_led_priv, led_mc_cdev);
57 }
58
59 union cros_ec_led_cmd_data {
60 struct ec_params_led_control req;
61 struct ec_response_led_control resp;
62 };
63
cros_ec_led_send_cmd(struct cros_ec_device * cros_ec,union cros_ec_led_cmd_data * arg)64 static int cros_ec_led_send_cmd(struct cros_ec_device *cros_ec,
65 union cros_ec_led_cmd_data *arg)
66 {
67 int ret;
68
69 ret = cros_ec_cmd(cros_ec, 1, EC_CMD_LED_CONTROL, &arg->req,
70 sizeof(arg->req), &arg->resp, sizeof(arg->resp));
71 if (ret < 0)
72 return ret;
73
74 return 0;
75 }
76
cros_ec_led_trigger_activate(struct led_classdev * led_cdev)77 static int cros_ec_led_trigger_activate(struct led_classdev *led_cdev)
78 {
79 struct cros_ec_led_priv *priv = cros_ec_led_cdev_to_priv(led_cdev);
80 union cros_ec_led_cmd_data arg = {};
81
82 arg.req.led_id = priv->led_id;
83 arg.req.flags = EC_LED_FLAGS_AUTO;
84
85 return cros_ec_led_send_cmd(priv->cros_ec, &arg);
86 }
87
88 static struct led_hw_trigger_type cros_ec_led_trigger_type;
89
90 static struct led_trigger cros_ec_led_trigger = {
91 .name = "chromeos-auto",
92 .trigger_type = &cros_ec_led_trigger_type,
93 .activate = cros_ec_led_trigger_activate,
94 };
95
cros_ec_led_brightness_set_blocking(struct led_classdev * led_cdev,enum led_brightness brightness)96 static int cros_ec_led_brightness_set_blocking(struct led_classdev *led_cdev,
97 enum led_brightness brightness)
98 {
99 struct cros_ec_led_priv *priv = cros_ec_led_cdev_to_priv(led_cdev);
100 union cros_ec_led_cmd_data arg = {};
101 enum ec_led_colors led_color;
102 struct mc_subled *subled;
103 size_t i;
104
105 led_mc_calc_color_components(&priv->led_mc_cdev, brightness);
106
107 arg.req.led_id = priv->led_id;
108
109 for (i = 0; i < priv->led_mc_cdev.num_colors; i++) {
110 subled = &priv->led_mc_cdev.subled_info[i];
111 led_color = cros_ec_linux_to_ec_id[subled->color_index];
112 arg.req.brightness[led_color] = subled->brightness;
113 }
114
115 return cros_ec_led_send_cmd(priv->cros_ec, &arg);
116 }
117
cros_ec_led_count_subleds(struct device * dev,struct ec_response_led_control * resp,unsigned int * max_brightness)118 static int cros_ec_led_count_subleds(struct device *dev,
119 struct ec_response_led_control *resp,
120 unsigned int *max_brightness)
121 {
122 unsigned int range, common_range = 0;
123 int num_subleds = 0;
124 size_t i;
125
126 for (i = 0; i < EC_LED_COLOR_COUNT; i++) {
127 range = resp->brightness_range[i];
128
129 if (!range)
130 continue;
131
132 num_subleds++;
133
134 if (!common_range)
135 common_range = range;
136
137 if (common_range != range) {
138 /* The multicolor LED API expects a uniform max_brightness */
139 dev_err(dev, "Inconsistent LED brightness values\n");
140 return -EINVAL;
141 }
142 }
143
144 *max_brightness = common_range;
145 return num_subleds;
146 }
147
cros_ec_led_get_color_name(struct led_classdev_mc * led_mc_cdev)148 static const char *cros_ec_led_get_color_name(struct led_classdev_mc *led_mc_cdev)
149 {
150 int color;
151
152 if (led_mc_cdev->num_colors == 1)
153 color = led_mc_cdev->subled_info[0].color_index;
154 else
155 color = LED_COLOR_ID_MULTI;
156
157 return led_get_color_name(color);
158 }
159
cros_ec_led_probe_one(struct device * dev,struct cros_ec_device * cros_ec,enum ec_led_id id)160 static int cros_ec_led_probe_one(struct device *dev, struct cros_ec_device *cros_ec,
161 enum ec_led_id id)
162 {
163 union cros_ec_led_cmd_data arg = {};
164 struct cros_ec_led_priv *priv;
165 struct led_classdev *led_cdev;
166 struct mc_subled *subleds;
167 int i, ret, num_subleds;
168 size_t subled;
169
170 arg.req.led_id = id;
171 arg.req.flags = EC_LED_FLAGS_QUERY;
172 ret = cros_ec_led_send_cmd(cros_ec, &arg);
173 if (ret == -EINVAL)
174 return 0; /* Unknown LED, skip */
175 if (ret == -EOPNOTSUPP)
176 return -ENODEV;
177 if (ret < 0)
178 return ret;
179
180 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
181 if (!priv)
182 return -ENOMEM;
183
184 num_subleds = cros_ec_led_count_subleds(dev, &arg.resp,
185 &priv->led_mc_cdev.led_cdev.max_brightness);
186 if (num_subleds < 0)
187 return num_subleds;
188 if (num_subleds == 0)
189 return 0; /* LED without any colors, skip */
190
191 priv->cros_ec = cros_ec;
192 priv->led_id = id;
193
194 subleds = devm_kcalloc(dev, num_subleds, sizeof(*subleds), GFP_KERNEL);
195 if (!subleds)
196 return -ENOMEM;
197
198 subled = 0;
199 for (i = 0; i < EC_LED_COLOR_COUNT; i++) {
200 if (!arg.resp.brightness_range[i])
201 continue;
202
203 subleds[subled].color_index = cros_ec_led_to_linux_id[i];
204 if (subled == 0)
205 subleds[subled].intensity = 100;
206 subled++;
207 }
208
209 priv->led_mc_cdev.subled_info = subleds;
210 priv->led_mc_cdev.num_colors = num_subleds;
211
212 led_cdev = &priv->led_mc_cdev.led_cdev;
213 led_cdev->brightness_set_blocking = cros_ec_led_brightness_set_blocking;
214 led_cdev->trigger_type = &cros_ec_led_trigger_type;
215 led_cdev->default_trigger = cros_ec_led_trigger.name;
216 led_cdev->hw_control_trigger = cros_ec_led_trigger.name;
217
218 led_cdev->name = devm_kasprintf(dev, GFP_KERNEL, "chromeos:%s:%s",
219 cros_ec_led_get_color_name(&priv->led_mc_cdev),
220 cros_ec_led_functions[id]);
221 if (!led_cdev->name)
222 return -ENOMEM;
223
224 return devm_led_classdev_multicolor_register(dev, &priv->led_mc_cdev);
225 }
226
cros_ec_led_probe(struct platform_device * pdev)227 static int cros_ec_led_probe(struct platform_device *pdev)
228 {
229 struct device *dev = &pdev->dev;
230 struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
231 struct cros_ec_device *cros_ec = ec_dev->ec_dev;
232 int i, ret = 0;
233
234 ret = devm_led_trigger_register(dev, &cros_ec_led_trigger);
235 if (ret)
236 return ret;
237
238 for (i = 0; i < EC_LED_ID_COUNT; i++) {
239 ret = cros_ec_led_probe_one(dev, cros_ec, i);
240 if (ret)
241 break;
242 }
243
244 return ret;
245 }
246
247 static const struct platform_device_id cros_ec_led_id[] = {
248 { "cros-ec-led", 0 },
249 {}
250 };
251 MODULE_DEVICE_TABLE(platform, cros_ec_led_id);
252
253 static struct platform_driver cros_ec_led_driver = {
254 .driver.name = "cros-ec-led",
255 .probe = cros_ec_led_probe,
256 .id_table = cros_ec_led_id,
257 };
258 module_platform_driver(cros_ec_led_driver);
259
260 MODULE_DESCRIPTION("ChromeOS EC LED Driver");
261 MODULE_AUTHOR("Thomas Weißschuh <linux@weissschuh.net");
262 MODULE_LICENSE("GPL");
263