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 20 struct 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 */ 37 struct 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 59 static 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 = ¶m; 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 78 static enum led_brightness 79 keyboard_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 95 static 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 } 112 113 static 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) 123 124 static int 125 keyboard_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 } 145 146 static enum led_brightness 147 keyboard_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 } 169 170 static 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 } 182 183 static 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) */ 191 192 static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {}; 193 194 #endif /* IS_ENABLED(CONFIG_CROS_EC) */ 195 196 static 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 232 static const struct acpi_device_id keyboard_led_acpi_match[] = { 233 { "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi }, 234 { } 235 }; 236 MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match); 237 #endif 238 239 #ifdef CONFIG_OF 240 static 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 }; 247 MODULE_DEVICE_TABLE(of, keyboard_led_of_match); 248 #endif 249 250 static 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 }; 258 module_platform_driver(keyboard_led_driver); 259 260 MODULE_AUTHOR("Simon Que <sque@chromium.org>"); 261 MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver"); 262 MODULE_LICENSE("GPL"); 263 MODULE_ALIAS("platform:chromeos-keyboard-leds"); 264