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/mod_devicetable.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 21struct 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 * @max_brightness: Maximum brightness. 35 * 36 * See struct led_classdev in include/linux/leds.h for more details. 37 */ 38struct keyboard_led_drvdata { 39 int (*init)(struct platform_device *pdev); 40 41 enum led_brightness (*brightness_get)(struct led_classdev *led_cdev); 42 43 void (*brightness_set)(struct led_classdev *led_cdev, 44 enum led_brightness brightness); 45 int (*brightness_set_blocking)(struct led_classdev *led_cdev, 46 enum led_brightness brightness); 47 48 enum led_brightness max_brightness; 49}; 50 51#define KEYBOARD_BACKLIGHT_MAX 100 52 53#ifdef CONFIG_ACPI 54 55/* Keyboard LED ACPI Device must be defined in firmware */ 56#define ACPI_KEYBOARD_BACKLIGHT_DEVICE "\\_SB.KBLT" 57#define ACPI_KEYBOARD_BACKLIGHT_READ ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBQC" 58#define ACPI_KEYBOARD_BACKLIGHT_WRITE ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBCM" 59 60static void keyboard_led_set_brightness_acpi(struct led_classdev *cdev, 61 enum led_brightness brightness) 62{ 63 union acpi_object param; 64 struct acpi_object_list input; 65 acpi_status status; 66 67 param.type = ACPI_TYPE_INTEGER; 68 param.integer.value = brightness; 69 input.count = 1; 70 input.pointer = ¶m; 71 72 status = acpi_evaluate_object(NULL, ACPI_KEYBOARD_BACKLIGHT_WRITE, 73 &input, NULL); 74 if (ACPI_FAILURE(status)) 75 dev_err(cdev->dev, "Error setting keyboard LED value: %d\n", 76 status); 77} 78 79static enum led_brightness 80keyboard_led_get_brightness_acpi(struct led_classdev *cdev) 81{ 82 unsigned long long brightness; 83 acpi_status status; 84 85 status = acpi_evaluate_integer(NULL, ACPI_KEYBOARD_BACKLIGHT_READ, 86 NULL, &brightness); 87 if (ACPI_FAILURE(status)) { 88 dev_err(cdev->dev, "Error getting keyboard LED value: %d\n", 89 status); 90 return -EIO; 91 } 92 93 return brightness; 94} 95 96static int keyboard_led_init_acpi(struct platform_device *pdev) 97{ 98 acpi_handle handle; 99 acpi_status status; 100 101 /* Look for the keyboard LED ACPI Device */ 102 status = acpi_get_handle(ACPI_ROOT_OBJECT, 103 ACPI_KEYBOARD_BACKLIGHT_DEVICE, 104 &handle); 105 if (ACPI_FAILURE(status)) { 106 dev_err(&pdev->dev, "Unable to find ACPI device %s: %d\n", 107 ACPI_KEYBOARD_BACKLIGHT_DEVICE, status); 108 return -ENXIO; 109 } 110 111 return 0; 112} 113 114static const struct keyboard_led_drvdata keyboard_led_drvdata_acpi = { 115 .init = keyboard_led_init_acpi, 116 .brightness_set = keyboard_led_set_brightness_acpi, 117 .brightness_get = keyboard_led_get_brightness_acpi, 118 .max_brightness = KEYBOARD_BACKLIGHT_MAX, 119}; 120 121#endif /* CONFIG_ACPI */ 122 123#if IS_ENABLED(CONFIG_CROS_EC) 124 125static int 126keyboard_led_set_brightness_ec_pwm(struct led_classdev *cdev, 127 enum led_brightness brightness) 128{ 129 struct { 130 struct cros_ec_command msg; 131 struct ec_params_pwm_set_keyboard_backlight params; 132 } __packed buf; 133 struct ec_params_pwm_set_keyboard_backlight *params = &buf.params; 134 struct cros_ec_command *msg = &buf.msg; 135 struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev); 136 137 memset(&buf, 0, sizeof(buf)); 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 147static enum led_brightness 148keyboard_led_get_brightness_ec_pwm(struct led_classdev *cdev) 149{ 150 struct { 151 struct cros_ec_command msg; 152 struct ec_response_pwm_get_keyboard_backlight resp; 153 } __packed buf; 154 struct ec_response_pwm_get_keyboard_backlight *resp = &buf.resp; 155 struct cros_ec_command *msg = &buf.msg; 156 struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev); 157 int ret; 158 159 memset(&buf, 0, sizeof(buf)); 160 161 msg->command = EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT; 162 msg->insize = sizeof(*resp); 163 164 ret = cros_ec_cmd_xfer_status(keyboard_led->ec, msg); 165 if (ret < 0) 166 return ret; 167 168 return resp->percent; 169} 170 171static int keyboard_led_init_ec_pwm(struct platform_device *pdev) 172{ 173 struct keyboard_led *keyboard_led = platform_get_drvdata(pdev); 174 175 keyboard_led->ec = dev_get_drvdata(pdev->dev.parent); 176 if (!keyboard_led->ec) { 177 dev_err(&pdev->dev, "no parent EC device\n"); 178 return -EINVAL; 179 } 180 181 return 0; 182} 183 184static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = { 185 .init = keyboard_led_init_ec_pwm, 186 .brightness_set_blocking = keyboard_led_set_brightness_ec_pwm, 187 .brightness_get = keyboard_led_get_brightness_ec_pwm, 188 .max_brightness = KEYBOARD_BACKLIGHT_MAX, 189}; 190 191#else /* IS_ENABLED(CONFIG_CROS_EC) */ 192 193static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {}; 194 195#endif /* IS_ENABLED(CONFIG_CROS_EC) */ 196 197static int keyboard_led_probe(struct platform_device *pdev) 198{ 199 const struct keyboard_led_drvdata *drvdata; 200 struct keyboard_led *keyboard_led; 201 int error; 202 203 drvdata = device_get_match_data(&pdev->dev); 204 if (!drvdata) 205 return -EINVAL; 206 207 keyboard_led = devm_kzalloc(&pdev->dev, sizeof(*keyboard_led), GFP_KERNEL); 208 if (!keyboard_led) 209 return -ENOMEM; 210 platform_set_drvdata(pdev, keyboard_led); 211 212 if (drvdata->init) { 213 error = drvdata->init(pdev); 214 if (error) 215 return error; 216 } 217 218 keyboard_led->cdev.name = "chromeos::kbd_backlight"; 219 keyboard_led->cdev.flags |= LED_CORE_SUSPENDRESUME; 220 keyboard_led->cdev.max_brightness = drvdata->max_brightness; 221 keyboard_led->cdev.brightness_set = drvdata->brightness_set; 222 keyboard_led->cdev.brightness_set_blocking = drvdata->brightness_set_blocking; 223 keyboard_led->cdev.brightness_get = drvdata->brightness_get; 224 225 error = devm_led_classdev_register(&pdev->dev, &keyboard_led->cdev); 226 if (error) 227 return error; 228 229 return 0; 230} 231 232#ifdef CONFIG_ACPI 233static const struct acpi_device_id keyboard_led_acpi_match[] = { 234 { "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi }, 235 { } 236}; 237MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match); 238#endif 239 240#ifdef CONFIG_OF 241static const struct of_device_id keyboard_led_of_match[] = { 242 { 243 .compatible = "google,cros-kbd-led-backlight", 244 .data = &keyboard_led_drvdata_ec_pwm, 245 }, 246 {} 247}; 248MODULE_DEVICE_TABLE(of, keyboard_led_of_match); 249#endif 250 251static const struct platform_device_id keyboard_led_id[] = { 252 { "cros-keyboard-leds", 0 }, 253 {} 254}; 255MODULE_DEVICE_TABLE(platform, keyboard_led_id); 256 257static struct platform_driver keyboard_led_driver = { 258 .driver = { 259 .name = "cros-keyboard-leds", 260 .acpi_match_table = ACPI_PTR(keyboard_led_acpi_match), 261 .of_match_table = of_match_ptr(keyboard_led_of_match), 262 }, 263 .probe = keyboard_led_probe, 264 .id_table = keyboard_led_id, 265}; 266module_platform_driver(keyboard_led_driver); 267 268MODULE_AUTHOR("Simon Que <sque@chromium.org>"); 269MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver"); 270MODULE_LICENSE("GPL"); 271