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_CROS_EC)
125
126static int
127keyboard_led_set_brightness_ec_pwm(struct led_classdev *cdev,
128				   enum led_brightness brightness)
129{
130	struct {
131		struct cros_ec_command msg;
132		struct ec_params_pwm_set_keyboard_backlight params;
133	} __packed buf;
134	struct ec_params_pwm_set_keyboard_backlight *params = &buf.params;
135	struct cros_ec_command *msg = &buf.msg;
136	struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
137
138	memset(&buf, 0, sizeof(buf));
139
140	msg->command = EC_CMD_PWM_SET_KEYBOARD_BACKLIGHT;
141	msg->outsize = sizeof(*params);
142
143	params->percent = brightness;
144
145	return cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
146}
147
148static enum led_brightness
149keyboard_led_get_brightness_ec_pwm(struct led_classdev *cdev)
150{
151	struct {
152		struct cros_ec_command msg;
153		struct ec_response_pwm_get_keyboard_backlight resp;
154	} __packed buf;
155	struct ec_response_pwm_get_keyboard_backlight *resp = &buf.resp;
156	struct cros_ec_command *msg = &buf.msg;
157	struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
158	int ret;
159
160	memset(&buf, 0, sizeof(buf));
161
162	msg->command = EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT;
163	msg->insize = sizeof(*resp);
164
165	ret = cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
166	if (ret < 0)
167		return ret;
168
169	return resp->percent;
170}
171
172static int keyboard_led_init_ec_pwm(struct platform_device *pdev)
173{
174	struct keyboard_led *keyboard_led = platform_get_drvdata(pdev);
175
176	keyboard_led->ec = dev_get_drvdata(pdev->dev.parent);
177	if (!keyboard_led->ec) {
178		dev_err(&pdev->dev, "no parent EC device\n");
179		return -EINVAL;
180	}
181
182	return 0;
183}
184
185static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {
186	.init = keyboard_led_init_ec_pwm,
187	.brightness_set_blocking = keyboard_led_set_brightness_ec_pwm,
188	.brightness_get = keyboard_led_get_brightness_ec_pwm,
189	.max_brightness = KEYBOARD_BACKLIGHT_MAX,
190};
191
192#else /* IS_ENABLED(CONFIG_CROS_EC) */
193
194static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {};
195
196#endif /* IS_ENABLED(CONFIG_CROS_EC) */
197
198#if IS_ENABLED(CONFIG_MFD_CROS_EC_DEV)
199static int keyboard_led_init_ec_pwm_mfd(struct platform_device *pdev)
200{
201	struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
202	struct cros_ec_device *cros_ec = ec_dev->ec_dev;
203	struct keyboard_led *keyboard_led = platform_get_drvdata(pdev);
204
205	keyboard_led->ec = cros_ec;
206
207	return 0;
208}
209
210static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {
211	.init = keyboard_led_init_ec_pwm_mfd,
212	.brightness_set_blocking = keyboard_led_set_brightness_ec_pwm,
213	.brightness_get = keyboard_led_get_brightness_ec_pwm,
214	.max_brightness = KEYBOARD_BACKLIGHT_MAX,
215};
216
217#else /* IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) */
218
219static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {};
220
221#endif /* IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) */
222
223static int keyboard_led_is_mfd_device(struct platform_device *pdev)
224{
225	return IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) && mfd_get_cell(pdev);
226}
227
228static int keyboard_led_probe(struct platform_device *pdev)
229{
230	const struct keyboard_led_drvdata *drvdata;
231	struct keyboard_led *keyboard_led;
232	int error;
233
234	if (keyboard_led_is_mfd_device(pdev))
235		drvdata = &keyboard_led_drvdata_ec_pwm_mfd;
236	else
237		drvdata = device_get_match_data(&pdev->dev);
238	if (!drvdata)
239		return -EINVAL;
240
241	keyboard_led = devm_kzalloc(&pdev->dev, sizeof(*keyboard_led), GFP_KERNEL);
242	if (!keyboard_led)
243		return -ENOMEM;
244	platform_set_drvdata(pdev, keyboard_led);
245
246	if (drvdata->init) {
247		error = drvdata->init(pdev);
248		if (error)
249			return error;
250	}
251
252	keyboard_led->cdev.name = "chromeos::kbd_backlight";
253	keyboard_led->cdev.flags |= LED_CORE_SUSPENDRESUME | LED_REJECT_NAME_CONFLICT;
254	keyboard_led->cdev.max_brightness = drvdata->max_brightness;
255	keyboard_led->cdev.brightness_set = drvdata->brightness_set;
256	keyboard_led->cdev.brightness_set_blocking = drvdata->brightness_set_blocking;
257	keyboard_led->cdev.brightness_get = drvdata->brightness_get;
258
259	error = devm_led_classdev_register(&pdev->dev, &keyboard_led->cdev);
260	if (error == -EEXIST) /* Already bound via other mechanism */
261		return -ENODEV;
262	if (error)
263		return error;
264
265	return 0;
266}
267
268#ifdef CONFIG_ACPI
269static const struct acpi_device_id keyboard_led_acpi_match[] = {
270	{ "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi },
271	{ }
272};
273MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match);
274#endif
275
276#ifdef CONFIG_OF
277static const struct of_device_id keyboard_led_of_match[] = {
278	{
279		.compatible = "google,cros-kbd-led-backlight",
280		.data = &keyboard_led_drvdata_ec_pwm,
281	},
282	{}
283};
284MODULE_DEVICE_TABLE(of, keyboard_led_of_match);
285#endif
286
287static const struct platform_device_id keyboard_led_id[] = {
288	{ "cros-keyboard-leds", 0 },
289	{}
290};
291MODULE_DEVICE_TABLE(platform, keyboard_led_id);
292
293static struct platform_driver keyboard_led_driver = {
294	.driver		= {
295		.name	= "cros-keyboard-leds",
296		.acpi_match_table = ACPI_PTR(keyboard_led_acpi_match),
297		.of_match_table = of_match_ptr(keyboard_led_of_match),
298	},
299	.probe		= keyboard_led_probe,
300	.id_table	= keyboard_led_id,
301};
302module_platform_driver(keyboard_led_driver);
303
304MODULE_AUTHOR("Simon Que <sque@chromium.org>");
305MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver");
306MODULE_LICENSE("GPL");