xref: /linux/drivers/leds/leds-cros_ec.c (revision e9ef810dfee7a2227da9d423aecb0ced35faddbe)
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 
17 static 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 
27 static_assert(ARRAY_SIZE(cros_ec_led_functions) == EC_LED_ID_COUNT);
28 
29 static 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 
38 static_assert(ARRAY_SIZE(cros_ec_led_to_linux_id) == EC_LED_COLOR_COUNT);
39 
40 static 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 
49 struct 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 
cros_ec_led_cdev_to_priv(struct led_classdev * led_cdev)55 static 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 
60 union cros_ec_led_cmd_data {
61 	struct ec_params_led_control req;
62 	struct ec_response_led_control resp;
63 };
64 
cros_ec_led_send_cmd(struct cros_ec_device * cros_ec,union cros_ec_led_cmd_data * arg)65 static 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 
70 	ret = cros_ec_cmd(cros_ec, 1, EC_CMD_LED_CONTROL, &arg->req,
71 			  sizeof(arg->req), &arg->resp, sizeof(arg->resp));
72 	if (ret < 0)
73 		return ret;
74 
75 	return 0;
76 }
77 
cros_ec_led_trigger_activate(struct led_classdev * led_cdev)78 static int cros_ec_led_trigger_activate(struct led_classdev *led_cdev)
79 {
80 	struct cros_ec_led_priv *priv = cros_ec_led_cdev_to_priv(led_cdev);
81 	union cros_ec_led_cmd_data arg = {};
82 
83 	arg.req.led_id = priv->led_id;
84 	arg.req.flags = EC_LED_FLAGS_AUTO;
85 
86 	return cros_ec_led_send_cmd(priv->cros_ec, &arg);
87 }
88 
89 static struct led_hw_trigger_type cros_ec_led_trigger_type;
90 
91 static struct led_trigger cros_ec_led_trigger = {
92 	.name = "chromeos-auto",
93 	.trigger_type = &cros_ec_led_trigger_type,
94 	.activate = cros_ec_led_trigger_activate,
95 };
96 
cros_ec_led_brightness_set_blocking(struct led_classdev * led_cdev,enum led_brightness brightness)97 static int cros_ec_led_brightness_set_blocking(struct led_classdev *led_cdev,
98 					       enum led_brightness brightness)
99 {
100 	struct cros_ec_led_priv *priv = cros_ec_led_cdev_to_priv(led_cdev);
101 	union cros_ec_led_cmd_data arg = {};
102 	enum ec_led_colors led_color;
103 	struct mc_subled *subled;
104 	size_t i;
105 
106 	led_mc_calc_color_components(&priv->led_mc_cdev, brightness);
107 
108 	arg.req.led_id = priv->led_id;
109 
110 	for (i = 0; i < priv->led_mc_cdev.num_colors; i++) {
111 		subled = &priv->led_mc_cdev.subled_info[i];
112 		led_color = cros_ec_linux_to_ec_id[subled->color_index];
113 		arg.req.brightness[led_color] = subled->brightness;
114 	}
115 
116 	return cros_ec_led_send_cmd(priv->cros_ec, &arg);
117 }
118 
cros_ec_led_count_subleds(struct device * dev,struct ec_response_led_control * resp,unsigned int * max_brightness)119 static int cros_ec_led_count_subleds(struct device *dev,
120 				     struct ec_response_led_control *resp,
121 				     unsigned int *max_brightness)
122 {
123 	unsigned int range, common_range = 0;
124 	int num_subleds = 0;
125 	size_t i;
126 
127 	for (i = 0; i < EC_LED_COLOR_COUNT; i++) {
128 		range = resp->brightness_range[i];
129 
130 		if (!range)
131 			continue;
132 
133 		num_subleds++;
134 
135 		if (!common_range)
136 			common_range = range;
137 
138 		if (common_range != range) {
139 			/* The multicolor LED API expects a uniform max_brightness */
140 			dev_err(dev, "Inconsistent LED brightness values\n");
141 			return -EINVAL;
142 		}
143 	}
144 
145 	if (!num_subleds)
146 		return -EINVAL;
147 
148 	*max_brightness = common_range;
149 	return num_subleds;
150 }
151 
cros_ec_led_get_color_name(struct led_classdev_mc * led_mc_cdev)152 static const char *cros_ec_led_get_color_name(struct led_classdev_mc *led_mc_cdev)
153 {
154 	int color;
155 
156 	if (led_mc_cdev->num_colors == 1)
157 		color = led_mc_cdev->subled_info[0].color_index;
158 	else
159 		color = LED_COLOR_ID_MULTI;
160 
161 	return led_get_color_name(color);
162 }
163 
cros_ec_led_probe_one(struct device * dev,struct cros_ec_device * cros_ec,enum ec_led_id id)164 static int cros_ec_led_probe_one(struct device *dev, struct cros_ec_device *cros_ec,
165 				 enum ec_led_id id)
166 {
167 	union cros_ec_led_cmd_data arg = {};
168 	struct cros_ec_led_priv *priv;
169 	struct led_classdev *led_cdev;
170 	struct mc_subled *subleds;
171 	int i, ret, num_subleds;
172 	size_t subled;
173 
174 	arg.req.led_id = id;
175 	arg.req.flags = EC_LED_FLAGS_QUERY;
176 	ret = cros_ec_led_send_cmd(cros_ec, &arg);
177 	if (ret == -EINVAL)
178 		return 0; /* Unknown LED, skip */
179 	if (ret == -EOPNOTSUPP)
180 		return -ENODEV;
181 	if (ret < 0)
182 		return ret;
183 
184 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
185 	if (!priv)
186 		return -ENOMEM;
187 
188 	num_subleds = cros_ec_led_count_subleds(dev, &arg.resp,
189 						&priv->led_mc_cdev.led_cdev.max_brightness);
190 	if (num_subleds < 0)
191 		return num_subleds;
192 
193 	priv->cros_ec = cros_ec;
194 	priv->led_id = id;
195 
196 	subleds = devm_kcalloc(dev, num_subleds, sizeof(*subleds), GFP_KERNEL);
197 	if (!subleds)
198 		return -ENOMEM;
199 
200 	subled = 0;
201 	for (i = 0; i < EC_LED_COLOR_COUNT; i++) {
202 		if (!arg.resp.brightness_range[i])
203 			continue;
204 
205 		subleds[subled].color_index = cros_ec_led_to_linux_id[i];
206 		if (subled == 0)
207 			subleds[subled].intensity = 100;
208 		subled++;
209 	}
210 
211 	priv->led_mc_cdev.subled_info = subleds;
212 	priv->led_mc_cdev.num_colors = num_subleds;
213 
214 	led_cdev = &priv->led_mc_cdev.led_cdev;
215 	led_cdev->brightness_set_blocking = cros_ec_led_brightness_set_blocking;
216 	led_cdev->trigger_type = &cros_ec_led_trigger_type;
217 	led_cdev->default_trigger = cros_ec_led_trigger.name;
218 	led_cdev->hw_control_trigger = cros_ec_led_trigger.name;
219 
220 	led_cdev->name = devm_kasprintf(dev, GFP_KERNEL, "chromeos:%s:%s",
221 					cros_ec_led_get_color_name(&priv->led_mc_cdev),
222 					cros_ec_led_functions[id]);
223 	if (!led_cdev->name)
224 		return -ENOMEM;
225 
226 	return devm_led_classdev_multicolor_register(dev, &priv->led_mc_cdev);
227 }
228 
cros_ec_led_probe(struct platform_device * pdev)229 static int cros_ec_led_probe(struct platform_device *pdev)
230 {
231 	struct device *dev = &pdev->dev;
232 	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
233 	struct cros_ec_device *cros_ec = ec_dev->ec_dev;
234 	int i, ret = 0;
235 
236 	ret = devm_led_trigger_register(dev, &cros_ec_led_trigger);
237 	if (ret)
238 		return ret;
239 
240 	for (i = 0; i < EC_LED_ID_COUNT; i++) {
241 		ret = cros_ec_led_probe_one(dev, cros_ec, i);
242 		if (ret)
243 			break;
244 	}
245 
246 	return ret;
247 }
248 
249 static const struct platform_device_id cros_ec_led_id[] = {
250 	{ "cros-ec-led", 0 },
251 	{}
252 };
253 
254 static struct platform_driver cros_ec_led_driver = {
255 	.driver.name	= "cros-ec-led",
256 	.probe		= cros_ec_led_probe,
257 	.id_table	= cros_ec_led_id,
258 };
259 module_platform_driver(cros_ec_led_driver);
260 
261 MODULE_DEVICE_TABLE(platform, cros_ec_led_id);
262 MODULE_DESCRIPTION("ChromeOS EC LED Driver");
263 MODULE_AUTHOR("Thomas Weißschuh <linux@weissschuh.net");
264 MODULE_LICENSE("GPL");
265