tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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/mod_devicetable.h>
14#include <linux/module.h>
15#include <linux/of.h>
16#include <linux/platform_data/cros_ec_commands.h>
17#include <linux/platform_data/cros_ec_proto.h>
18#include <linux/platform_device.h>
19#include <linux/property.h>
20#include <linux/slab.h>
21
22struct keyboard_led {
23 struct led_classdev cdev;
24 struct cros_ec_device *ec;
25};
26
27/**
28 * struct keyboard_led_drvdata - keyboard LED driver data.
29 * @init: Init function.
30 * @brightness_get: Get LED brightness level.
31 * @brightness_set: Set LED brightness level. Must not sleep.
32 * @brightness_set_blocking: Set LED brightness level. It can block the
33 * caller for the time required for accessing a
34 * LED device register
35 * @max_brightness: Maximum brightness.
36 *
37 * See struct led_classdev in include/linux/leds.h for more details.
38 */
39struct keyboard_led_drvdata {
40 int (*init)(struct platform_device *pdev);
41
42 enum led_brightness (*brightness_get)(struct led_classdev *led_cdev);
43
44 void (*brightness_set)(struct led_classdev *led_cdev,
45 enum led_brightness brightness);
46 int (*brightness_set_blocking)(struct led_classdev *led_cdev,
47 enum led_brightness brightness);
48
49 enum led_brightness max_brightness;
50};
51
52#define KEYBOARD_BACKLIGHT_MAX 100
53
54#ifdef CONFIG_ACPI
55
56/* Keyboard LED ACPI Device must be defined in firmware */
57#define ACPI_KEYBOARD_BACKLIGHT_DEVICE "\\_SB.KBLT"
58#define ACPI_KEYBOARD_BACKLIGHT_READ ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBQC"
59#define ACPI_KEYBOARD_BACKLIGHT_WRITE ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBCM"
60
61static void keyboard_led_set_brightness_acpi(struct led_classdev *cdev,
62 enum led_brightness brightness)
63{
64 union acpi_object param;
65 struct acpi_object_list input;
66 acpi_status status;
67
68 param.type = ACPI_TYPE_INTEGER;
69 param.integer.value = brightness;
70 input.count = 1;
71 input.pointer = ¶m;
72
73 status = acpi_evaluate_object(NULL, ACPI_KEYBOARD_BACKLIGHT_WRITE,
74 &input, NULL);
75 if (ACPI_FAILURE(status))
76 dev_err(cdev->dev, "Error setting keyboard LED value: %d\n",
77 status);
78}
79
80static enum led_brightness
81keyboard_led_get_brightness_acpi(struct led_classdev *cdev)
82{
83 unsigned long long brightness;
84 acpi_status status;
85
86 status = acpi_evaluate_integer(NULL, ACPI_KEYBOARD_BACKLIGHT_READ,
87 NULL, &brightness);
88 if (ACPI_FAILURE(status)) {
89 dev_err(cdev->dev, "Error getting keyboard LED value: %d\n",
90 status);
91 return -EIO;
92 }
93
94 return brightness;
95}
96
97static int keyboard_led_init_acpi(struct platform_device *pdev)
98{
99 acpi_handle handle;
100 acpi_status status;
101
102 /* Look for the keyboard LED ACPI Device */
103 status = acpi_get_handle(ACPI_ROOT_OBJECT,
104 ACPI_KEYBOARD_BACKLIGHT_DEVICE,
105 &handle);
106 if (ACPI_FAILURE(status)) {
107 dev_err(&pdev->dev, "Unable to find ACPI device %s: %d\n",
108 ACPI_KEYBOARD_BACKLIGHT_DEVICE, status);
109 return -ENXIO;
110 }
111
112 return 0;
113}
114
115static const struct keyboard_led_drvdata keyboard_led_drvdata_acpi = {
116 .init = keyboard_led_init_acpi,
117 .brightness_set = keyboard_led_set_brightness_acpi,
118 .brightness_get = keyboard_led_get_brightness_acpi,
119 .max_brightness = KEYBOARD_BACKLIGHT_MAX,
120};
121
122#endif /* CONFIG_ACPI */
123
124#if IS_ENABLED(CONFIG_MFD_CROS_EC_DEV)
125static int keyboard_led_init_ec_pwm_mfd(struct platform_device *pdev)
126{
127 struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
128 struct cros_ec_device *cros_ec = ec_dev->ec_dev;
129 struct keyboard_led *keyboard_led = platform_get_drvdata(pdev);
130
131 keyboard_led->ec = cros_ec;
132
133 return 0;
134}
135
136static int
137keyboard_led_set_brightness_ec_pwm(struct led_classdev *cdev,
138 enum led_brightness brightness)
139{
140 struct {
141 struct cros_ec_command msg;
142 struct ec_params_pwm_set_keyboard_backlight params;
143 } __packed buf;
144 struct ec_params_pwm_set_keyboard_backlight *params = &buf.params;
145 struct cros_ec_command *msg = &buf.msg;
146 struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
147
148 memset(&buf, 0, sizeof(buf));
149
150 msg->command = EC_CMD_PWM_SET_KEYBOARD_BACKLIGHT;
151 msg->outsize = sizeof(*params);
152
153 params->percent = brightness;
154
155 return cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
156}
157
158static enum led_brightness
159keyboard_led_get_brightness_ec_pwm(struct led_classdev *cdev)
160{
161 struct {
162 struct cros_ec_command msg;
163 struct ec_response_pwm_get_keyboard_backlight resp;
164 } __packed buf;
165 struct ec_response_pwm_get_keyboard_backlight *resp = &buf.resp;
166 struct cros_ec_command *msg = &buf.msg;
167 struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
168 int ret;
169
170 memset(&buf, 0, sizeof(buf));
171
172 msg->command = EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT;
173 msg->insize = sizeof(*resp);
174
175 ret = cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
176 if (ret < 0)
177 return ret;
178
179 return resp->percent;
180}
181
182static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {
183 .init = keyboard_led_init_ec_pwm_mfd,
184 .brightness_set_blocking = keyboard_led_set_brightness_ec_pwm,
185 .brightness_get = keyboard_led_get_brightness_ec_pwm,
186 .max_brightness = KEYBOARD_BACKLIGHT_MAX,
187};
188
189#else /* IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) */
190
191static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {};
192
193#endif /* IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) */
194
195static int keyboard_led_is_mfd_device(struct platform_device *pdev)
196{
197 return IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) && mfd_get_cell(pdev);
198}
199
200static int keyboard_led_probe(struct platform_device *pdev)
201{
202 const struct keyboard_led_drvdata *drvdata;
203 struct keyboard_led *keyboard_led;
204 int err;
205
206 if (keyboard_led_is_mfd_device(pdev))
207 drvdata = &keyboard_led_drvdata_ec_pwm_mfd;
208 else
209 drvdata = device_get_match_data(&pdev->dev);
210 if (!drvdata)
211 return -EINVAL;
212
213 keyboard_led = devm_kzalloc(&pdev->dev, sizeof(*keyboard_led), GFP_KERNEL);
214 if (!keyboard_led)
215 return -ENOMEM;
216 platform_set_drvdata(pdev, keyboard_led);
217
218 if (drvdata->init) {
219 err = drvdata->init(pdev);
220 if (err)
221 return err;
222 }
223
224 keyboard_led->cdev.name = "chromeos::kbd_backlight";
225 keyboard_led->cdev.flags |= LED_CORE_SUSPENDRESUME | LED_REJECT_NAME_CONFLICT;
226 keyboard_led->cdev.max_brightness = drvdata->max_brightness;
227 keyboard_led->cdev.brightness_set = drvdata->brightness_set;
228 keyboard_led->cdev.brightness_set_blocking = drvdata->brightness_set_blocking;
229 keyboard_led->cdev.brightness_get = drvdata->brightness_get;
230
231 err = devm_led_classdev_register(&pdev->dev, &keyboard_led->cdev);
232 if (err == -EEXIST) /* Already bound via other mechanism */
233 return -ENODEV;
234 return err;
235}
236
237#ifdef CONFIG_ACPI
238static const struct acpi_device_id keyboard_led_acpi_match[] = {
239 { "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi },
240 { }
241};
242MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match);
243#endif
244
245static const struct platform_device_id keyboard_led_id[] = {
246 { "cros-keyboard-leds", 0 },
247 {}
248};
249MODULE_DEVICE_TABLE(platform, keyboard_led_id);
250
251static struct platform_driver keyboard_led_driver = {
252 .driver = {
253 .name = "cros-keyboard-leds",
254 .acpi_match_table = ACPI_PTR(keyboard_led_acpi_match),
255 },
256 .probe = keyboard_led_probe,
257 .id_table = keyboard_led_id,
258};
259module_platform_driver(keyboard_led_driver);
260
261MODULE_AUTHOR("Simon Que <sque@chromium.org>");
262MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver");
263MODULE_LICENSE("GPL");