platform/chrome/cros_kbd_led_backlight.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 // Keyboard backlight LED driver for ChromeOS
0003 //
0004 // Copyright (C) 2012 Google, Inc.
0005
0006 #include <linux/acpi.h>
0007 #include <linux/delay.h>
0008 #include <linux/err.h>
0009 #include <linux/init.h>
0010 #include <linux/kernel.h>
0011 #include <linux/leds.h>
0012 #include <linux/module.h>
0013 #include <linux/of.h>
0014 #include <linux/platform_data/cros_ec_commands.h>
0015 #include <linux/platform_data/cros_ec_proto.h>
0016 #include <linux/platform_device.h>
0017 #include <linux/property.h>
0018 #include <linux/slab.h>
0019
0020 struct keyboard_led {
0021     struct led_classdev cdev;
0022     struct cros_ec_device *ec;
0023 };
0024
0025 /**
0026  * struct keyboard_led_drvdata - keyboard LED driver data.
0027  * @init:           Init function.
0028  * @brightness_get:     Get LED brightness level.
0029  * @brightness_set:     Set LED brightness level.  Must not sleep.
0030  * @brightness_set_blocking:    Set LED brightness level.  It can block the
0031  *              caller for the time required for accessing a
0032  *              LED device register
0033  * @max_brightness:     Maximum brightness.
0034  *
0035  * See struct led_classdev in include/linux/leds.h for more details.
0036  */
0037 struct keyboard_led_drvdata {
0038     int (*init)(struct platform_device *pdev);
0039
0040     enum led_brightness (*brightness_get)(struct led_classdev *led_cdev);
0041
0042     void (*brightness_set)(struct led_classdev *led_cdev,
0043                    enum led_brightness brightness);
0044     int (*brightness_set_blocking)(struct led_classdev *led_cdev,
0045                        enum led_brightness brightness);
0046
0047     enum led_brightness max_brightness;
0048 };
0049
0050 #define KEYBOARD_BACKLIGHT_MAX 100
0051
0052 #ifdef CONFIG_ACPI
0053
0054 /* Keyboard LED ACPI Device must be defined in firmware */
0055 #define ACPI_KEYBOARD_BACKLIGHT_DEVICE  "\\_SB.KBLT"
0056 #define ACPI_KEYBOARD_BACKLIGHT_READ    ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBQC"
0057 #define ACPI_KEYBOARD_BACKLIGHT_WRITE   ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBCM"
0058
0059 static void keyboard_led_set_brightness_acpi(struct led_classdev *cdev,
0060                          enum led_brightness brightness)
0061 {
0062     union acpi_object param;
0063     struct acpi_object_list input;
0064     acpi_status status;
0065
0066     param.type = ACPI_TYPE_INTEGER;
0067     param.integer.value = brightness;
0068     input.count = 1;
0069     input.pointer = &param;
0070
0071     status = acpi_evaluate_object(NULL, ACPI_KEYBOARD_BACKLIGHT_WRITE,
0072                       &input, NULL);
0073     if (ACPI_FAILURE(status))
0074         dev_err(cdev->dev, "Error setting keyboard LED value: %d\n",
0075             status);
0076 }
0077
0078 static enum led_brightness
0079 keyboard_led_get_brightness_acpi(struct led_classdev *cdev)
0080 {
0081     unsigned long long brightness;
0082     acpi_status status;
0083
0084     status = acpi_evaluate_integer(NULL, ACPI_KEYBOARD_BACKLIGHT_READ,
0085                        NULL, &brightness);
0086     if (ACPI_FAILURE(status)) {
0087         dev_err(cdev->dev, "Error getting keyboard LED value: %d\n",
0088             status);
0089         return -EIO;
0090     }
0091
0092     return brightness;
0093 }
0094
0095 static int keyboard_led_init_acpi(struct platform_device *pdev)
0096 {
0097     acpi_handle handle;
0098     acpi_status status;
0099
0100     /* Look for the keyboard LED ACPI Device */
0101     status = acpi_get_handle(ACPI_ROOT_OBJECT,
0102                  ACPI_KEYBOARD_BACKLIGHT_DEVICE,
0103                  &handle);
0104     if (ACPI_FAILURE(status)) {
0105         dev_err(&pdev->dev, "Unable to find ACPI device %s: %d\n",
0106             ACPI_KEYBOARD_BACKLIGHT_DEVICE, status);
0107         return -ENXIO;
0108     }
0109
0110     return 0;
0111 }
0112
0113 static const struct keyboard_led_drvdata keyboard_led_drvdata_acpi = {
0114     .init = keyboard_led_init_acpi,
0115     .brightness_set = keyboard_led_set_brightness_acpi,
0116     .brightness_get = keyboard_led_get_brightness_acpi,
0117     .max_brightness = KEYBOARD_BACKLIGHT_MAX,
0118 };
0119
0120 #endif /* CONFIG_ACPI */
0121
0122 #if IS_ENABLED(CONFIG_CROS_EC)
0123
0124 static int
0125 keyboard_led_set_brightness_ec_pwm(struct led_classdev *cdev,
0126                    enum led_brightness brightness)
0127 {
0128     struct {
0129         struct cros_ec_command msg;
0130         struct ec_params_pwm_set_keyboard_backlight params;
0131     } __packed buf;
0132     struct ec_params_pwm_set_keyboard_backlight *params = &buf.params;
0133     struct cros_ec_command *msg = &buf.msg;
0134     struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
0135
0136     memset(&buf, 0, sizeof(buf));
0137
0138     msg->command = EC_CMD_PWM_SET_KEYBOARD_BACKLIGHT;
0139     msg->outsize = sizeof(*params);
0140
0141     params->percent = brightness;
0142
0143     return cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
0144 }
0145
0146 static enum led_brightness
0147 keyboard_led_get_brightness_ec_pwm(struct led_classdev *cdev)
0148 {
0149     struct {
0150         struct cros_ec_command msg;
0151         struct ec_response_pwm_get_keyboard_backlight resp;
0152     } __packed buf;
0153     struct ec_response_pwm_get_keyboard_backlight *resp = &buf.resp;
0154     struct cros_ec_command *msg = &buf.msg;
0155     struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
0156     int ret;
0157
0158     memset(&buf, 0, sizeof(buf));
0159
0160     msg->command = EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT;
0161     msg->insize = sizeof(*resp);
0162
0163     ret = cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
0164     if (ret < 0)
0165         return ret;
0166
0167     return resp->percent;
0168 }
0169
0170 static int keyboard_led_init_ec_pwm(struct platform_device *pdev)
0171 {
0172     struct keyboard_led *keyboard_led = platform_get_drvdata(pdev);
0173
0174     keyboard_led->ec = dev_get_drvdata(pdev->dev.parent);
0175     if (!keyboard_led->ec) {
0176         dev_err(&pdev->dev, "no parent EC device\n");
0177         return -EINVAL;
0178     }
0179
0180     return 0;
0181 }
0182
0183 static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {
0184     .init = keyboard_led_init_ec_pwm,
0185     .brightness_set_blocking = keyboard_led_set_brightness_ec_pwm,
0186     .brightness_get = keyboard_led_get_brightness_ec_pwm,
0187     .max_brightness = KEYBOARD_BACKLIGHT_MAX,
0188 };
0189
0190 #else /* IS_ENABLED(CONFIG_CROS_EC) */
0191
0192 static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {};
0193
0194 #endif /* IS_ENABLED(CONFIG_CROS_EC) */
0195
0196 static int keyboard_led_probe(struct platform_device *pdev)
0197 {
0198     const struct keyboard_led_drvdata *drvdata;
0199     struct keyboard_led *keyboard_led;
0200     int error;
0201
0202     drvdata = device_get_match_data(&pdev->dev);
0203     if (!drvdata)
0204         return -EINVAL;
0205
0206     keyboard_led = devm_kzalloc(&pdev->dev, sizeof(*keyboard_led), GFP_KERNEL);
0207     if (!keyboard_led)
0208         return -ENOMEM;
0209     platform_set_drvdata(pdev, keyboard_led);
0210
0211     if (drvdata->init) {
0212         error = drvdata->init(pdev);
0213         if (error)
0214             return error;
0215     }
0216
0217     keyboard_led->cdev.name = "chromeos::kbd_backlight";
0218     keyboard_led->cdev.flags |= LED_CORE_SUSPENDRESUME;
0219     keyboard_led->cdev.max_brightness = drvdata->max_brightness;
0220     keyboard_led->cdev.brightness_set = drvdata->brightness_set;
0221     keyboard_led->cdev.brightness_set_blocking = drvdata->brightness_set_blocking;
0222     keyboard_led->cdev.brightness_get = drvdata->brightness_get;
0223
0224     error = devm_led_classdev_register(&pdev->dev, &keyboard_led->cdev);
0225     if (error)
0226         return error;
0227
0228     return 0;
0229 }
0230
0231 #ifdef CONFIG_ACPI
0232 static const struct acpi_device_id keyboard_led_acpi_match[] = {
0233     { "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi },
0234     { }
0235 };
0236 MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match);
0237 #endif
0238
0239 #ifdef CONFIG_OF
0240 static const struct of_device_id keyboard_led_of_match[] = {
0241     {
0242         .compatible = "google,cros-kbd-led-backlight",
0243         .data = &keyboard_led_drvdata_ec_pwm,
0244     },
0245     {}
0246 };
0247 MODULE_DEVICE_TABLE(of, keyboard_led_of_match);
0248 #endif
0249
0250 static struct platform_driver keyboard_led_driver = {
0251     .driver     = {
0252         .name   = "chromeos-keyboard-leds",
0253         .acpi_match_table = ACPI_PTR(keyboard_led_acpi_match),
0254         .of_match_table = of_match_ptr(keyboard_led_of_match),
0255     },
0256     .probe      = keyboard_led_probe,
0257 };
0258 module_platform_driver(keyboard_led_driver);
0259
0260 MODULE_AUTHOR("Simon Que <sque@chromium.org>");
0261 MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver");
0262 MODULE_LICENSE("GPL");
0263 MODULE_ALIAS("platform:chromeos-keyboard-leds");