1 // SPDX-License-Identifier: GPL-2.0+
2 // Keyboard backlight LED driver for ChromeOS
3 //
4 // Copyright (C) 2012 Google, Inc.
5
6 #include <linux/acpi.h>
7 #include <linux/delay.h>
8 #include <linux/err.h>
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/leds.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/platform_data/cros_ec_commands.h>
15 #include <linux/platform_data/cros_ec_proto.h>
16 #include <linux/platform_device.h>
17 #include <linux/property.h>
18 #include <linux/slab.h>
19
20 struct keyboard_led {
21 struct led_classdev cdev;
22 struct cros_ec_device *ec;
23 };
24
25 /**
26 * struct keyboard_led_drvdata - keyboard LED driver data.
27 * @init: Init function.
28 * @brightness_get: Get LED brightness level.
29 * @brightness_set: Set LED brightness level. Must not sleep.
30 * @brightness_set_blocking: Set LED brightness level. It can block the
31 * caller for the time required for accessing a
32 * LED device register
33 * @max_brightness: Maximum brightness.
34 *
35 * See struct led_classdev in include/linux/leds.h for more details.
36 */
37 struct keyboard_led_drvdata {
38 int (*init)(struct platform_device *pdev);
39
40 enum led_brightness (*brightness_get)(struct led_classdev *led_cdev);
41
42 void (*brightness_set)(struct led_classdev *led_cdev,
43 enum led_brightness brightness);
44 int (*brightness_set_blocking)(struct led_classdev *led_cdev,
45 enum led_brightness brightness);
46
47 enum led_brightness max_brightness;
48 };
49
50 #define KEYBOARD_BACKLIGHT_MAX 100
51
52 #ifdef CONFIG_ACPI
53
54 /* Keyboard LED ACPI Device must be defined in firmware */
55 #define ACPI_KEYBOARD_BACKLIGHT_DEVICE "\\_SB.KBLT"
56 #define ACPI_KEYBOARD_BACKLIGHT_READ ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBQC"
57 #define ACPI_KEYBOARD_BACKLIGHT_WRITE ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBCM"
58
keyboard_led_set_brightness_acpi(struct led_classdev * cdev,enum led_brightness brightness)59 static void keyboard_led_set_brightness_acpi(struct led_classdev *cdev,
60 enum led_brightness brightness)
61 {
62 union acpi_object param;
63 struct acpi_object_list input;
64 acpi_status status;
65
66 param.type = ACPI_TYPE_INTEGER;
67 param.integer.value = brightness;
68 input.count = 1;
69 input.pointer = ¶m;
70
71 status = acpi_evaluate_object(NULL, ACPI_KEYBOARD_BACKLIGHT_WRITE,
72 &input, NULL);
73 if (ACPI_FAILURE(status))
74 dev_err(cdev->dev, "Error setting keyboard LED value: %d\n",
75 status);
76 }
77
78 static enum led_brightness
keyboard_led_get_brightness_acpi(struct led_classdev * cdev)79 keyboard_led_get_brightness_acpi(struct led_classdev *cdev)
80 {
81 unsigned long long brightness;
82 acpi_status status;
83
84 status = acpi_evaluate_integer(NULL, ACPI_KEYBOARD_BACKLIGHT_READ,
85 NULL, &brightness);
86 if (ACPI_FAILURE(status)) {
87 dev_err(cdev->dev, "Error getting keyboard LED value: %d\n",
88 status);
89 return -EIO;
90 }
91
92 return brightness;
93 }
94
keyboard_led_init_acpi(struct platform_device * pdev)95 static int keyboard_led_init_acpi(struct platform_device *pdev)
96 {
97 acpi_handle handle;
98 acpi_status status;
99
100 /* Look for the keyboard LED ACPI Device */
101 status = acpi_get_handle(ACPI_ROOT_OBJECT,
102 ACPI_KEYBOARD_BACKLIGHT_DEVICE,
103 &handle);
104 if (ACPI_FAILURE(status)) {
105 dev_err(&pdev->dev, "Unable to find ACPI device %s: %d\n",
106 ACPI_KEYBOARD_BACKLIGHT_DEVICE, status);
107 return -ENXIO;
108 }
109
110 return 0;
111 }
112
113 static const struct keyboard_led_drvdata keyboard_led_drvdata_acpi = {
114 .init = keyboard_led_init_acpi,
115 .brightness_set = keyboard_led_set_brightness_acpi,
116 .brightness_get = keyboard_led_get_brightness_acpi,
117 .max_brightness = KEYBOARD_BACKLIGHT_MAX,
118 };
119
120 #endif /* CONFIG_ACPI */
121
122 #if IS_ENABLED(CONFIG_CROS_EC)
123
124 static int
keyboard_led_set_brightness_ec_pwm(struct led_classdev * cdev,enum led_brightness brightness)125 keyboard_led_set_brightness_ec_pwm(struct led_classdev *cdev,
126 enum led_brightness brightness)
127 {
128 struct {
129 struct cros_ec_command msg;
130 struct ec_params_pwm_set_keyboard_backlight params;
131 } __packed buf;
132 struct ec_params_pwm_set_keyboard_backlight *params = &buf.params;
133 struct cros_ec_command *msg = &buf.msg;
134 struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
135
136 memset(&buf, 0, sizeof(buf));
137
138 msg->command = EC_CMD_PWM_SET_KEYBOARD_BACKLIGHT;
139 msg->outsize = sizeof(*params);
140
141 params->percent = brightness;
142
143 return cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
144 }
145
146 static enum led_brightness
keyboard_led_get_brightness_ec_pwm(struct led_classdev * cdev)147 keyboard_led_get_brightness_ec_pwm(struct led_classdev *cdev)
148 {
149 struct {
150 struct cros_ec_command msg;
151 struct ec_response_pwm_get_keyboard_backlight resp;
152 } __packed buf;
153 struct ec_response_pwm_get_keyboard_backlight *resp = &buf.resp;
154 struct cros_ec_command *msg = &buf.msg;
155 struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
156 int ret;
157
158 memset(&buf, 0, sizeof(buf));
159
160 msg->command = EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT;
161 msg->insize = sizeof(*resp);
162
163 ret = cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
164 if (ret < 0)
165 return ret;
166
167 return resp->percent;
168 }
169
keyboard_led_init_ec_pwm(struct platform_device * pdev)170 static int keyboard_led_init_ec_pwm(struct platform_device *pdev)
171 {
172 struct keyboard_led *keyboard_led = platform_get_drvdata(pdev);
173
174 keyboard_led->ec = dev_get_drvdata(pdev->dev.parent);
175 if (!keyboard_led->ec) {
176 dev_err(&pdev->dev, "no parent EC device\n");
177 return -EINVAL;
178 }
179
180 return 0;
181 }
182
183 static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {
184 .init = keyboard_led_init_ec_pwm,
185 .brightness_set_blocking = keyboard_led_set_brightness_ec_pwm,
186 .brightness_get = keyboard_led_get_brightness_ec_pwm,
187 .max_brightness = KEYBOARD_BACKLIGHT_MAX,
188 };
189
190 #else /* IS_ENABLED(CONFIG_CROS_EC) */
191
192 static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {};
193
194 #endif /* IS_ENABLED(CONFIG_CROS_EC) */
195
keyboard_led_probe(struct platform_device * pdev)196 static int keyboard_led_probe(struct platform_device *pdev)
197 {
198 const struct keyboard_led_drvdata *drvdata;
199 struct keyboard_led *keyboard_led;
200 int error;
201
202 drvdata = device_get_match_data(&pdev->dev);
203 if (!drvdata)
204 return -EINVAL;
205
206 keyboard_led = devm_kzalloc(&pdev->dev, sizeof(*keyboard_led), GFP_KERNEL);
207 if (!keyboard_led)
208 return -ENOMEM;
209 platform_set_drvdata(pdev, keyboard_led);
210
211 if (drvdata->init) {
212 error = drvdata->init(pdev);
213 if (error)
214 return error;
215 }
216
217 keyboard_led->cdev.name = "chromeos::kbd_backlight";
218 keyboard_led->cdev.flags |= LED_CORE_SUSPENDRESUME;
219 keyboard_led->cdev.max_brightness = drvdata->max_brightness;
220 keyboard_led->cdev.brightness_set = drvdata->brightness_set;
221 keyboard_led->cdev.brightness_set_blocking = drvdata->brightness_set_blocking;
222 keyboard_led->cdev.brightness_get = drvdata->brightness_get;
223
224 error = devm_led_classdev_register(&pdev->dev, &keyboard_led->cdev);
225 if (error)
226 return error;
227
228 return 0;
229 }
230
231 #ifdef CONFIG_ACPI
232 static const struct acpi_device_id keyboard_led_acpi_match[] = {
233 { "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi },
234 { }
235 };
236 MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match);
237 #endif
238
239 #ifdef CONFIG_OF
240 static const struct of_device_id keyboard_led_of_match[] = {
241 {
242 .compatible = "google,cros-kbd-led-backlight",
243 .data = &keyboard_led_drvdata_ec_pwm,
244 },
245 {}
246 };
247 MODULE_DEVICE_TABLE(of, keyboard_led_of_match);
248 #endif
249
250 static struct platform_driver keyboard_led_driver = {
251 .driver = {
252 .name = "chromeos-keyboard-leds",
253 .acpi_match_table = ACPI_PTR(keyboard_led_acpi_match),
254 .of_match_table = of_match_ptr(keyboard_led_of_match),
255 },
256 .probe = keyboard_led_probe,
257 };
258 module_platform_driver(keyboard_led_driver);
259
260 MODULE_AUTHOR("Simon Que <sque@chromium.org>");
261 MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver");
262 MODULE_LICENSE("GPL");
263 MODULE_ALIAS("platform:chromeos-keyboard-leds");
264