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
 20struct 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 */
 37struct 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
 59static 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 = &param;
 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
 78static enum led_brightness
 79keyboard_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
 95static 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
113static 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
124static int
125keyboard_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
146static enum led_brightness
147keyboard_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
170static 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
183static 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
192static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {};
193
194#endif /* IS_ENABLED(CONFIG_CROS_EC) */
195
196static 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
232static const struct acpi_device_id keyboard_led_acpi_match[] = {
233	{ "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi },
234	{ }
235};
236MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match);
237#endif
238
239#ifdef CONFIG_OF
240static 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};
247MODULE_DEVICE_TABLE(of, keyboard_led_of_match);
248#endif
249
250static 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};
258module_platform_driver(keyboard_led_driver);
259
260MODULE_AUTHOR("Simon Que <sque@chromium.org>");
261MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver");
262MODULE_LICENSE("GPL");
263MODULE_ALIAS("platform:chromeos-keyboard-leds");