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/mfd/core.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/platform_data/cros_ec_commands.h>
16 #include <linux/platform_data/cros_ec_proto.h>
17 #include <linux/platform_device.h>
18 #include <linux/property.h>
19 #include <linux/slab.h>
20
21 struct keyboard_led {
22 struct led_classdev cdev;
23 struct cros_ec_device *ec;
24 };
25
26 /**
27 * struct keyboard_led_drvdata - keyboard LED driver data.
28 * @init: Init function.
29 * @brightness_get: Get LED brightness level.
30 * @brightness_set: Set LED brightness level. Must not sleep.
31 * @brightness_set_blocking: Set LED brightness level. It can block the
32 * caller for the time required for accessing a
33 * LED device register
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, struct keyboard_led *keyboard_led);
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
48 #ifdef CONFIG_ACPI
49
50 /* Keyboard LED ACPI Device must be defined in firmware */
51 #define ACPI_KEYBOARD_BACKLIGHT_DEVICE "\\_SB.KBLT"
52 #define ACPI_KEYBOARD_BACKLIGHT_READ ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBQC"
53 #define ACPI_KEYBOARD_BACKLIGHT_WRITE ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBCM"
54
keyboard_led_set_brightness_acpi(struct led_classdev * cdev,enum led_brightness brightness)55 static void keyboard_led_set_brightness_acpi(struct led_classdev *cdev,
56 enum led_brightness brightness)
57 {
58 union acpi_object param;
59 struct acpi_object_list input;
60 acpi_status status;
61
62 param.type = ACPI_TYPE_INTEGER;
63 param.integer.value = brightness;
64 input.count = 1;
65 input.pointer = ¶m;
66
67 status = acpi_evaluate_object(NULL, ACPI_KEYBOARD_BACKLIGHT_WRITE,
68 &input, NULL);
69 if (ACPI_FAILURE(status))
70 dev_err(cdev->dev, "Error setting keyboard LED value: %d\n",
71 status);
72 }
73
74 static enum led_brightness
keyboard_led_get_brightness_acpi(struct led_classdev * cdev)75 keyboard_led_get_brightness_acpi(struct led_classdev *cdev)
76 {
77 unsigned long long brightness;
78 acpi_status status;
79
80 status = acpi_evaluate_integer(NULL, ACPI_KEYBOARD_BACKLIGHT_READ,
81 NULL, &brightness);
82 if (ACPI_FAILURE(status)) {
83 dev_err(cdev->dev, "Error getting keyboard LED value: %d\n",
84 status);
85 return -EIO;
86 }
87
88 return brightness;
89 }
90
keyboard_led_init_acpi(struct platform_device * pdev,struct keyboard_led * keyboard_led)91 static int keyboard_led_init_acpi(struct platform_device *pdev,
92 struct keyboard_led *keyboard_led)
93 {
94 acpi_handle handle;
95 acpi_status status;
96
97 /* Look for the keyboard LED ACPI Device */
98 status = acpi_get_handle(ACPI_ROOT_OBJECT,
99 ACPI_KEYBOARD_BACKLIGHT_DEVICE,
100 &handle);
101 if (ACPI_FAILURE(status)) {
102 dev_err(&pdev->dev, "Unable to find ACPI device %s: %d\n",
103 ACPI_KEYBOARD_BACKLIGHT_DEVICE, status);
104 return -ENXIO;
105 }
106
107 return 0;
108 }
109
110 static const struct keyboard_led_drvdata keyboard_led_drvdata_acpi = {
111 .init = keyboard_led_init_acpi,
112 .brightness_set = keyboard_led_set_brightness_acpi,
113 .brightness_get = keyboard_led_get_brightness_acpi,
114 };
115
116 #endif /* CONFIG_ACPI */
117
keyboard_led_init_ec_pwm_mfd(struct platform_device * pdev,struct keyboard_led * keyboard_led)118 static int keyboard_led_init_ec_pwm_mfd(struct platform_device *pdev,
119 struct keyboard_led *keyboard_led)
120 {
121 struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
122 struct cros_ec_device *cros_ec = ec_dev->ec_dev;
123
124 keyboard_led->ec = cros_ec;
125
126 return 0;
127 }
128
129 static int
keyboard_led_set_brightness_ec_pwm(struct led_classdev * cdev,enum led_brightness brightness)130 keyboard_led_set_brightness_ec_pwm(struct led_classdev *cdev,
131 enum led_brightness brightness)
132 {
133 DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
134 sizeof(struct ec_params_pwm_set_keyboard_backlight));
135 struct ec_params_pwm_set_keyboard_backlight *params =
136 (struct ec_params_pwm_set_keyboard_backlight *)msg->data;
137 struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
138
139 msg->command = EC_CMD_PWM_SET_KEYBOARD_BACKLIGHT;
140 msg->outsize = sizeof(*params);
141
142 params->percent = brightness;
143
144 return cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
145 }
146
147 static enum led_brightness
keyboard_led_get_brightness_ec_pwm(struct led_classdev * cdev)148 keyboard_led_get_brightness_ec_pwm(struct led_classdev *cdev)
149 {
150 DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
151 sizeof(struct ec_response_pwm_get_keyboard_backlight));
152 struct ec_response_pwm_get_keyboard_backlight *resp =
153 (struct ec_response_pwm_get_keyboard_backlight *)msg->data;
154 struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
155 int ret;
156
157 msg->command = EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT;
158 msg->insize = sizeof(*resp);
159
160 ret = cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
161 if (ret < 0)
162 return ret;
163
164 return resp->percent;
165 }
166
167 static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {
168 .init = keyboard_led_init_ec_pwm_mfd,
169 .brightness_set_blocking = keyboard_led_set_brightness_ec_pwm,
170 .brightness_get = keyboard_led_get_brightness_ec_pwm,
171 };
172
keyboard_led_is_mfd_device(struct platform_device * pdev)173 static int keyboard_led_is_mfd_device(struct platform_device *pdev)
174 {
175 return IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) && mfd_get_cell(pdev);
176 }
177
keyboard_led_probe(struct platform_device * pdev)178 static int keyboard_led_probe(struct platform_device *pdev)
179 {
180 const struct keyboard_led_drvdata *drvdata;
181 struct keyboard_led *keyboard_led;
182 int err;
183
184 if (keyboard_led_is_mfd_device(pdev))
185 drvdata = &keyboard_led_drvdata_ec_pwm_mfd;
186 else
187 drvdata = device_get_match_data(&pdev->dev);
188 if (!drvdata)
189 return -EINVAL;
190
191 keyboard_led = devm_kzalloc(&pdev->dev, sizeof(*keyboard_led), GFP_KERNEL);
192 if (!keyboard_led)
193 return -ENOMEM;
194
195 if (drvdata->init) {
196 err = drvdata->init(pdev, keyboard_led);
197 if (err)
198 return err;
199 }
200
201 keyboard_led->cdev.name = "chromeos::kbd_backlight";
202 keyboard_led->cdev.flags |= LED_CORE_SUSPENDRESUME | LED_REJECT_NAME_CONFLICT;
203 keyboard_led->cdev.max_brightness = 100;
204 keyboard_led->cdev.brightness_set = drvdata->brightness_set;
205 keyboard_led->cdev.brightness_set_blocking = drvdata->brightness_set_blocking;
206 keyboard_led->cdev.brightness_get = drvdata->brightness_get;
207
208 err = devm_led_classdev_register(&pdev->dev, &keyboard_led->cdev);
209 if (err == -EEXIST) /* Already bound via other mechanism */
210 return -ENODEV;
211 return err;
212 }
213
214 #ifdef CONFIG_ACPI
215 static const struct acpi_device_id keyboard_led_acpi_match[] = {
216 { "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi },
217 { }
218 };
219 MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match);
220 #endif
221
222 static const struct platform_device_id keyboard_led_id[] = {
223 { .name = "cros-keyboard-leds" },
224 { }
225 };
226 MODULE_DEVICE_TABLE(platform, keyboard_led_id);
227
228 static struct platform_driver keyboard_led_driver = {
229 .driver = {
230 .name = "cros-keyboard-leds",
231 .acpi_match_table = ACPI_PTR(keyboard_led_acpi_match),
232 },
233 .probe = keyboard_led_probe,
234 .id_table = keyboard_led_id,
235 };
236 module_platform_driver(keyboard_led_driver);
237
238 MODULE_AUTHOR("Simon Que <sque@chromium.org>");
239 MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver");
240 MODULE_LICENSE("GPL");
241