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 struct { 141 struct cros_ec_command msg; 142 struct ec_params_pwm_set_keyboard_backlight params; 143 } __packed buf; 144 struct ec_params_pwm_set_keyboard_backlight *params = &buf.params; 145 struct cros_ec_command *msg = &buf.msg; 146 struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev); 147 148 memset(&buf, 0, sizeof(buf)); 149 150 msg->command = EC_CMD_PWM_SET_KEYBOARD_BACKLIGHT; 151 msg->outsize = sizeof(*params); 152 153 params->percent = brightness; 154 155 return cros_ec_cmd_xfer_status(keyboard_led->ec, msg); 156 } 157 158 static enum led_brightness 159 keyboard_led_get_brightness_ec_pwm(struct led_classdev *cdev) 160 { 161 struct { 162 struct cros_ec_command msg; 163 struct ec_response_pwm_get_keyboard_backlight resp; 164 } __packed buf; 165 struct ec_response_pwm_get_keyboard_backlight *resp = &buf.resp; 166 struct cros_ec_command *msg = &buf.msg; 167 struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev); 168 int ret; 169 170 memset(&buf, 0, sizeof(buf)); 171 172 msg->command = EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT; 173 msg->insize = sizeof(*resp); 174 175 ret = cros_ec_cmd_xfer_status(keyboard_led->ec, msg); 176 if (ret < 0) 177 return ret; 178 179 return resp->percent; 180 } 181 182 static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = { 183 .init = keyboard_led_init_ec_pwm_mfd, 184 .brightness_set_blocking = keyboard_led_set_brightness_ec_pwm, 185 .brightness_get = keyboard_led_get_brightness_ec_pwm, 186 .max_brightness = KEYBOARD_BACKLIGHT_MAX, 187 }; 188 189 #else /* IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) */ 190 191 static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {}; 192 193 #endif /* IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) */ 194 195 static int keyboard_led_is_mfd_device(struct platform_device *pdev) 196 { 197 return IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) && mfd_get_cell(pdev); 198 } 199 200 static int keyboard_led_probe(struct platform_device *pdev) 201 { 202 const struct keyboard_led_drvdata *drvdata; 203 struct keyboard_led *keyboard_led; 204 int err; 205 206 if (keyboard_led_is_mfd_device(pdev)) 207 drvdata = &keyboard_led_drvdata_ec_pwm_mfd; 208 else 209 drvdata = device_get_match_data(&pdev->dev); 210 if (!drvdata) 211 return -EINVAL; 212 213 keyboard_led = devm_kzalloc(&pdev->dev, sizeof(*keyboard_led), GFP_KERNEL); 214 if (!keyboard_led) 215 return -ENOMEM; 216 platform_set_drvdata(pdev, keyboard_led); 217 218 if (drvdata->init) { 219 err = drvdata->init(pdev); 220 if (err) 221 return err; 222 } 223 224 keyboard_led->cdev.name = "chromeos::kbd_backlight"; 225 keyboard_led->cdev.flags |= LED_CORE_SUSPENDRESUME | LED_REJECT_NAME_CONFLICT; 226 keyboard_led->cdev.max_brightness = drvdata->max_brightness; 227 keyboard_led->cdev.brightness_set = drvdata->brightness_set; 228 keyboard_led->cdev.brightness_set_blocking = drvdata->brightness_set_blocking; 229 keyboard_led->cdev.brightness_get = drvdata->brightness_get; 230 231 err = devm_led_classdev_register(&pdev->dev, &keyboard_led->cdev); 232 if (err == -EEXIST) /* Already bound via other mechanism */ 233 return -ENODEV; 234 return err; 235 } 236 237 #ifdef CONFIG_ACPI 238 static const struct acpi_device_id keyboard_led_acpi_match[] = { 239 { "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi }, 240 { } 241 }; 242 MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match); 243 #endif 244 245 static const struct platform_device_id keyboard_led_id[] = { 246 { "cros-keyboard-leds", 0 }, 247 {} 248 }; 249 MODULE_DEVICE_TABLE(platform, keyboard_led_id); 250 251 static struct platform_driver keyboard_led_driver = { 252 .driver = { 253 .name = "cros-keyboard-leds", 254 .acpi_match_table = ACPI_PTR(keyboard_led_acpi_match), 255 }, 256 .probe = keyboard_led_probe, 257 .id_table = keyboard_led_id, 258 }; 259 module_platform_driver(keyboard_led_driver); 260 261 MODULE_AUTHOR("Simon Que <sque@chromium.org>"); 262 MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver"); 263 MODULE_LICENSE("GPL"); 264