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 22 struct 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 */ 39 struct 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 61 static 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 = ¶m; 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 80 static enum led_brightness 81 keyboard_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 97 static 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 } 114 115 static 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) 125 126 static int 127 keyboard_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 } 147 148 static enum led_brightness 149 keyboard_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 } 171 172 static 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 } 184 185 static 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) */ 193 194 static 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) 199 static 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 } 209 210 static 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) */ 218 219 static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {}; 220 221 #endif /* IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) */ 222 223 static 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 } 227 228 static 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 269 static const struct acpi_device_id keyboard_led_acpi_match[] = { 270 { "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi }, 271 { } 272 }; 273 MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match); 274 #endif 275 276 #ifdef CONFIG_OF 277 static 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 }; 284 MODULE_DEVICE_TABLE(of, keyboard_led_of_match); 285 #endif 286 287 static const struct platform_device_id keyboard_led_id[] = { 288 { "cros-keyboard-leds", 0 }, 289 {} 290 }; 291 MODULE_DEVICE_TABLE(platform, keyboard_led_id); 292 293 static 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 }; 302 module_platform_driver(keyboard_led_driver); 303 304 MODULE_AUTHOR("Simon Que <sque@chromium.org>"); 305 MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver"); 306 MODULE_LICENSE("GPL"); 307