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/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 21 struct 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 * 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, struct keyboard_led *keyboard_led); 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 48 #ifdef CONFIG_ACPI 49 50 /* Keyboard LED ACPI Device must be defined in firmware */ 51 #define ACPI_KEYBOARD_BACKLIGHT_DEVICE "\\_SB.KBLT" 52 #define ACPI_KEYBOARD_BACKLIGHT_READ ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBQC" 53 #define ACPI_KEYBOARD_BACKLIGHT_WRITE ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBCM" 54 55 static void keyboard_led_set_brightness_acpi(struct led_classdev *cdev, 56 enum led_brightness brightness) 57 { 58 union acpi_object param; 59 struct acpi_object_list input; 60 acpi_status status; 61 62 param.type = ACPI_TYPE_INTEGER; 63 param.integer.value = brightness; 64 input.count = 1; 65 input.pointer = ¶m; 66 67 status = acpi_evaluate_object(NULL, ACPI_KEYBOARD_BACKLIGHT_WRITE, 68 &input, NULL); 69 if (ACPI_FAILURE(status)) 70 dev_err(cdev->dev, "Error setting keyboard LED value: %d\n", 71 status); 72 } 73 74 static enum led_brightness 75 keyboard_led_get_brightness_acpi(struct led_classdev *cdev) 76 { 77 unsigned long long brightness; 78 acpi_status status; 79 80 status = acpi_evaluate_integer(NULL, ACPI_KEYBOARD_BACKLIGHT_READ, 81 NULL, &brightness); 82 if (ACPI_FAILURE(status)) { 83 dev_err(cdev->dev, "Error getting keyboard LED value: %d\n", 84 status); 85 return -EIO; 86 } 87 88 return brightness; 89 } 90 91 static int keyboard_led_init_acpi(struct platform_device *pdev, 92 struct keyboard_led *keyboard_led) 93 { 94 acpi_handle handle; 95 acpi_status status; 96 97 /* Look for the keyboard LED ACPI Device */ 98 status = acpi_get_handle(ACPI_ROOT_OBJECT, 99 ACPI_KEYBOARD_BACKLIGHT_DEVICE, 100 &handle); 101 if (ACPI_FAILURE(status)) { 102 dev_err(&pdev->dev, "Unable to find ACPI device %s: %d\n", 103 ACPI_KEYBOARD_BACKLIGHT_DEVICE, status); 104 return -ENXIO; 105 } 106 107 return 0; 108 } 109 110 static const struct keyboard_led_drvdata keyboard_led_drvdata_acpi = { 111 .init = keyboard_led_init_acpi, 112 .brightness_set = keyboard_led_set_brightness_acpi, 113 .brightness_get = keyboard_led_get_brightness_acpi, 114 }; 115 116 #endif /* CONFIG_ACPI */ 117 118 static int keyboard_led_init_ec_pwm_mfd(struct platform_device *pdev, 119 struct keyboard_led *keyboard_led) 120 { 121 struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent); 122 struct cros_ec_device *cros_ec = ec_dev->ec_dev; 123 124 keyboard_led->ec = cros_ec; 125 126 return 0; 127 } 128 129 static int 130 keyboard_led_set_brightness_ec_pwm(struct led_classdev *cdev, 131 enum led_brightness brightness) 132 { 133 DEFINE_RAW_FLEX(struct cros_ec_command, msg, data, 134 sizeof(struct ec_params_pwm_set_keyboard_backlight)); 135 struct ec_params_pwm_set_keyboard_backlight *params = 136 (struct ec_params_pwm_set_keyboard_backlight *)msg->data; 137 struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev); 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 } 146 147 static enum led_brightness 148 keyboard_led_get_brightness_ec_pwm(struct led_classdev *cdev) 149 { 150 DEFINE_RAW_FLEX(struct cros_ec_command, msg, data, 151 sizeof(struct ec_response_pwm_get_keyboard_backlight)); 152 struct ec_response_pwm_get_keyboard_backlight *resp = 153 (struct ec_response_pwm_get_keyboard_backlight *)msg->data; 154 struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev); 155 int ret; 156 157 msg->command = EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT; 158 msg->insize = sizeof(*resp); 159 160 ret = cros_ec_cmd_xfer_status(keyboard_led->ec, msg); 161 if (ret < 0) 162 return ret; 163 164 return resp->percent; 165 } 166 167 static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = { 168 .init = keyboard_led_init_ec_pwm_mfd, 169 .brightness_set_blocking = keyboard_led_set_brightness_ec_pwm, 170 .brightness_get = keyboard_led_get_brightness_ec_pwm, 171 }; 172 173 static int keyboard_led_is_mfd_device(struct platform_device *pdev) 174 { 175 return IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) && mfd_get_cell(pdev); 176 } 177 178 static int keyboard_led_probe(struct platform_device *pdev) 179 { 180 const struct keyboard_led_drvdata *drvdata; 181 struct keyboard_led *keyboard_led; 182 int err; 183 184 if (keyboard_led_is_mfd_device(pdev)) 185 drvdata = &keyboard_led_drvdata_ec_pwm_mfd; 186 else 187 drvdata = device_get_match_data(&pdev->dev); 188 if (!drvdata) 189 return -EINVAL; 190 191 keyboard_led = devm_kzalloc(&pdev->dev, sizeof(*keyboard_led), GFP_KERNEL); 192 if (!keyboard_led) 193 return -ENOMEM; 194 195 if (drvdata->init) { 196 err = drvdata->init(pdev, keyboard_led); 197 if (err) 198 return err; 199 } 200 201 keyboard_led->cdev.name = "chromeos::kbd_backlight"; 202 keyboard_led->cdev.flags |= LED_CORE_SUSPENDRESUME | LED_REJECT_NAME_CONFLICT; 203 keyboard_led->cdev.max_brightness = 100; 204 keyboard_led->cdev.brightness_set = drvdata->brightness_set; 205 keyboard_led->cdev.brightness_set_blocking = drvdata->brightness_set_blocking; 206 keyboard_led->cdev.brightness_get = drvdata->brightness_get; 207 208 err = devm_led_classdev_register(&pdev->dev, &keyboard_led->cdev); 209 if (err == -EEXIST) /* Already bound via other mechanism */ 210 return -ENODEV; 211 return err; 212 } 213 214 #ifdef CONFIG_ACPI 215 static const struct acpi_device_id keyboard_led_acpi_match[] = { 216 { "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi }, 217 { } 218 }; 219 MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match); 220 #endif 221 222 static const struct platform_device_id keyboard_led_id[] = { 223 { "cros-keyboard-leds", 0 }, 224 {} 225 }; 226 MODULE_DEVICE_TABLE(platform, keyboard_led_id); 227 228 static struct platform_driver keyboard_led_driver = { 229 .driver = { 230 .name = "cros-keyboard-leds", 231 .acpi_match_table = ACPI_PTR(keyboard_led_acpi_match), 232 }, 233 .probe = keyboard_led_probe, 234 .id_table = keyboard_led_id, 235 }; 236 module_platform_driver(keyboard_led_driver); 237 238 MODULE_AUTHOR("Simon Que <sque@chromium.org>"); 239 MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver"); 240 MODULE_LICENSE("GPL"); 241