cros_kbd_led_backlight.c

  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 = &param;
 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	DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
141			sizeof(struct ec_params_pwm_set_keyboard_backlight));
142	struct ec_params_pwm_set_keyboard_backlight *params =
143			(struct ec_params_pwm_set_keyboard_backlight *)msg->data;
144	struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
145
146	msg->command = EC_CMD_PWM_SET_KEYBOARD_BACKLIGHT;
147	msg->outsize = sizeof(*params);
148
149	params->percent = brightness;
150
151	return cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
152}
153
154static enum led_brightness
155keyboard_led_get_brightness_ec_pwm(struct led_classdev *cdev)
156{
157	DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
158			sizeof(struct ec_response_pwm_get_keyboard_backlight));
159	struct ec_response_pwm_get_keyboard_backlight *resp =
160			(struct ec_response_pwm_get_keyboard_backlight *)msg->data;
161	struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
162	int ret;
163
164	msg->command = EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT;
165	msg->insize = sizeof(*resp);
166
167	ret = cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
168	if (ret < 0)
169		return ret;
170
171	return resp->percent;
172}
173
174static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {
175	.init = keyboard_led_init_ec_pwm_mfd,
176	.brightness_set_blocking = keyboard_led_set_brightness_ec_pwm,
177	.brightness_get = keyboard_led_get_brightness_ec_pwm,
178	.max_brightness = KEYBOARD_BACKLIGHT_MAX,
179};
180
181#else /* IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) */
182
183static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {};
184
185#endif /* IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) */
186
187static int keyboard_led_is_mfd_device(struct platform_device *pdev)
188{
189	return IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) && mfd_get_cell(pdev);
190}
191
192static int keyboard_led_probe(struct platform_device *pdev)
193{
194	const struct keyboard_led_drvdata *drvdata;
195	struct keyboard_led *keyboard_led;
196	int err;
197
198	if (keyboard_led_is_mfd_device(pdev))
199		drvdata = &keyboard_led_drvdata_ec_pwm_mfd;
200	else
201		drvdata = device_get_match_data(&pdev->dev);
202	if (!drvdata)
203		return -EINVAL;
204
205	keyboard_led = devm_kzalloc(&pdev->dev, sizeof(*keyboard_led), GFP_KERNEL);
206	if (!keyboard_led)
207		return -ENOMEM;
208	platform_set_drvdata(pdev, keyboard_led);
209
210	if (drvdata->init) {
211		err = drvdata->init(pdev);
212		if (err)
213			return err;
214	}
215
216	keyboard_led->cdev.name = "chromeos::kbd_backlight";
217	keyboard_led->cdev.flags |= LED_CORE_SUSPENDRESUME | LED_REJECT_NAME_CONFLICT;
218	keyboard_led->cdev.max_brightness = drvdata->max_brightness;
219	keyboard_led->cdev.brightness_set = drvdata->brightness_set;
220	keyboard_led->cdev.brightness_set_blocking = drvdata->brightness_set_blocking;
221	keyboard_led->cdev.brightness_get = drvdata->brightness_get;
222
223	err = devm_led_classdev_register(&pdev->dev, &keyboard_led->cdev);
224	if (err == -EEXIST) /* Already bound via other mechanism */
225		return -ENODEV;
226	return err;
227}
228
229#ifdef CONFIG_ACPI
230static const struct acpi_device_id keyboard_led_acpi_match[] = {
231	{ "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi },
232	{ }
233};
234MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match);
235#endif
236
237static const struct platform_device_id keyboard_led_id[] = {
238	{ "cros-keyboard-leds", 0 },
239	{}
240};
241MODULE_DEVICE_TABLE(platform, keyboard_led_id);
242
243static struct platform_driver keyboard_led_driver = {
244	.driver		= {
245		.name	= "cros-keyboard-leds",
246		.acpi_match_table = ACPI_PTR(keyboard_led_acpi_match),
247	},
248	.probe		= keyboard_led_probe,
249	.id_table	= keyboard_led_id,
250};
251module_platform_driver(keyboard_led_driver);
252
253MODULE_AUTHOR("Simon Que <sque@chromium.org>");
254MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver");
255MODULE_LICENSE("GPL");