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_MFD_CROS_EC_DEV) 125 static 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 } 135 136 static int 137 keyboard_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 } 153 154 static enum led_brightness 155 keyboard_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 } 173 174 static 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) */ 182 183 static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {}; 184 185 #endif /* IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) */ 186 187 static 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 } 191 192 static 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 230 static const struct acpi_device_id keyboard_led_acpi_match[] = { 231 { "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi }, 232 { } 233 }; 234 MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match); 235 #endif 236 237 static const struct platform_device_id keyboard_led_id[] = { 238 { "cros-keyboard-leds", 0 }, 239 {} 240 }; 241 MODULE_DEVICE_TABLE(platform, keyboard_led_id); 242 243 static 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 }; 251 module_platform_driver(keyboard_led_driver); 252 253 MODULE_AUTHOR("Simon Que <sque@chromium.org>"); 254 MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver"); 255 MODULE_LICENSE("GPL"); 256