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1// SPDX-License-Identifier: GPL-2.02 3/*4 * ChromeOS Privacy Screen support5 *6 * Copyright (C) 2022 Google LLC7 *8 * This is the Chromeos privacy screen provider, present on certain chromebooks,9 * represented by a GOOG0010 device in the ACPI. This ACPI device, if present,10 * will cause the i915 drm driver to probe defer until this driver registers11 * the privacy-screen.12 */13 14#include <linux/acpi.h>15#include <drm/drm_privacy_screen_driver.h>16 17/*18 * The DSM (Device Specific Method) constants below are the agreed API with19 * the firmware team, on how to control privacy screen using ACPI methods.20 */21#define PRIV_SCRN_DSM_REVID 1 /* DSM version */22#define PRIV_SCRN_DSM_FN_GET_STATUS 1 /* Get privacy screen status */23#define PRIV_SCRN_DSM_FN_ENABLE 2 /* Enable privacy screen */24#define PRIV_SCRN_DSM_FN_DISABLE 3 /* Disable privacy screen */25 26static const guid_t chromeos_privacy_screen_dsm_guid =27 GUID_INIT(0xc7033113, 0x8720, 0x4ceb,28 0x90, 0x90, 0x9d, 0x52, 0xb3, 0xe5, 0x2d, 0x73);29 30static void31chromeos_privacy_screen_get_hw_state(struct drm_privacy_screen32 *drm_privacy_screen)33{34 union acpi_object *obj;35 acpi_handle handle;36 struct device *privacy_screen =37 drm_privacy_screen_get_drvdata(drm_privacy_screen);38 39 handle = acpi_device_handle(to_acpi_device(privacy_screen));40 obj = acpi_evaluate_dsm(handle, &chromeos_privacy_screen_dsm_guid,41 PRIV_SCRN_DSM_REVID,42 PRIV_SCRN_DSM_FN_GET_STATUS, NULL);43 if (!obj) {44 dev_err(privacy_screen,45 "_DSM failed to get privacy-screen state\n");46 return;47 }48 49 if (obj->type != ACPI_TYPE_INTEGER)50 dev_err(privacy_screen,51 "Bad _DSM to get privacy-screen state\n");52 else if (obj->integer.value == 1)53 drm_privacy_screen->hw_state = drm_privacy_screen->sw_state =54 PRIVACY_SCREEN_ENABLED;55 else56 drm_privacy_screen->hw_state = drm_privacy_screen->sw_state =57 PRIVACY_SCREEN_DISABLED;58 59 ACPI_FREE(obj);60}61 62static int63chromeos_privacy_screen_set_sw_state(struct drm_privacy_screen64 *drm_privacy_screen,65 enum drm_privacy_screen_status state)66{67 union acpi_object *obj = NULL;68 acpi_handle handle;69 struct device *privacy_screen =70 drm_privacy_screen_get_drvdata(drm_privacy_screen);71 72 handle = acpi_device_handle(to_acpi_device(privacy_screen));73 74 if (state == PRIVACY_SCREEN_DISABLED) {75 obj = acpi_evaluate_dsm(handle,76 &chromeos_privacy_screen_dsm_guid,77 PRIV_SCRN_DSM_REVID,78 PRIV_SCRN_DSM_FN_DISABLE, NULL);79 } else if (state == PRIVACY_SCREEN_ENABLED) {80 obj = acpi_evaluate_dsm(handle,81 &chromeos_privacy_screen_dsm_guid,82 PRIV_SCRN_DSM_REVID,83 PRIV_SCRN_DSM_FN_ENABLE, NULL);84 } else {85 dev_err(privacy_screen,86 "Bad attempt to set privacy-screen status to %u\n",87 state);88 return -EINVAL;89 }90 91 if (!obj) {92 dev_err(privacy_screen,93 "_DSM failed to set privacy-screen state\n");94 return -EIO;95 }96 97 drm_privacy_screen->hw_state = drm_privacy_screen->sw_state = state;98 ACPI_FREE(obj);99 return 0;100}101 102static const struct drm_privacy_screen_ops chromeos_privacy_screen_ops = {103 .get_hw_state = chromeos_privacy_screen_get_hw_state,104 .set_sw_state = chromeos_privacy_screen_set_sw_state,105};106 107static int chromeos_privacy_screen_add(struct acpi_device *adev)108{109 struct drm_privacy_screen *drm_privacy_screen =110 drm_privacy_screen_register(&adev->dev,111 &chromeos_privacy_screen_ops,112 &adev->dev);113 114 if (IS_ERR(drm_privacy_screen)) {115 dev_err(&adev->dev, "Error registering privacy-screen\n");116 return PTR_ERR(drm_privacy_screen);117 }118 119 adev->driver_data = drm_privacy_screen;120 dev_info(&adev->dev, "registered privacy-screen '%s'\n",121 dev_name(&drm_privacy_screen->dev));122 123 return 0;124}125 126static void chromeos_privacy_screen_remove(struct acpi_device *adev)127{128 struct drm_privacy_screen *drm_privacy_screen = acpi_driver_data(adev);129 130 drm_privacy_screen_unregister(drm_privacy_screen);131}132 133static const struct acpi_device_id chromeos_privacy_screen_device_ids[] = {134 {"GOOG0010", 0}, /* Google's electronic privacy screen for eDP-1 */135 {}136};137MODULE_DEVICE_TABLE(acpi, chromeos_privacy_screen_device_ids);138 139static struct acpi_driver chromeos_privacy_screen_driver = {140 .name = "chromeos_privacy_screen_driver",141 .class = "ChromeOS",142 .ids = chromeos_privacy_screen_device_ids,143 .ops = {144 .add = chromeos_privacy_screen_add,145 .remove = chromeos_privacy_screen_remove,146 },147};148 149module_acpi_driver(chromeos_privacy_screen_driver);150MODULE_LICENSE("GPL v2");151MODULE_DESCRIPTION("ChromeOS ACPI Privacy Screen driver");152MODULE_AUTHOR("Rajat Jain <rajatja@google.com>");153