This adds the ACPI driver for the ChromeOS privacy screen that is present on some chromeos devices.
Note that I found that ACPI drivers are bound to their devices AFTER the drm probe. So on chromebooks with privacy-screen, this causes a probe deferral for i915 driver, which results in a delay of about 250ms in my experiments. However, per my personal experience, it did not result in any user perceived delay of splash screen (https://hansdegoede.livejournal.com/25948.html) In future if this probe deferral turns out to be an issue, we can consider turning this ACPI driver into something that is probed earlier than the drm drivers. Signed-off-by: Rajat Jain <raja...@google.com> --- This patch is rebased on top of linux-next/master drivers/platform/chrome/Kconfig | 10 ++ drivers/platform/chrome/Makefile | 1 + drivers/platform/chrome/chromeos_priv_scrn.c | 133 +++++++++++++++++++ 3 files changed, 144 insertions(+) create mode 100644 drivers/platform/chrome/chromeos_priv_scrn.c diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig index ccc23d8686e8..3f874bbd3d03 100644 --- a/drivers/platform/chrome/Kconfig +++ b/drivers/platform/chrome/Kconfig @@ -243,6 +243,16 @@ config CROS_USBPD_NOTIFY To compile this driver as a module, choose M here: the module will be called cros_usbpd_notify. +config CHROMEOS_PRIVACY_SCREEN + bool "ChromeOS Privacy Screen support" + depends on ACPI + depends on DRM + default n + select DRM_PRIVACY_SCREEN + help + This driver provides the support needed for the in-built electronic + privacy screen that is present on some ChromeOS devices. + source "drivers/platform/chrome/wilco_ec/Kconfig" endif # CHROMEOS_PLATFORMS diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile index f901d2e43166..cfa0bb4e9e34 100644 --- a/drivers/platform/chrome/Makefile +++ b/drivers/platform/chrome/Makefile @@ -4,6 +4,7 @@ CFLAGS_cros_ec_trace.o:= -I$(src) obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o +obj-$(CONFIG_CHROMEOS_PRIVACY_SCREEN) += chromeos_priv_scrn.o obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o obj-$(CONFIG_CHROMEOS_TBMC) += chromeos_tbmc.o obj-$(CONFIG_CROS_EC) += cros_ec.o diff --git a/drivers/platform/chrome/chromeos_priv_scrn.c b/drivers/platform/chrome/chromeos_priv_scrn.c new file mode 100644 index 000000000000..00536154acd6 --- /dev/null +++ b/drivers/platform/chrome/chromeos_priv_scrn.c @@ -0,0 +1,133 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * chromeos_priv_scrn.c - ChromeOS Privacy Screen support + * + * Copyright (C) 2022 The Chromium OS Authors + * + */ + +#include <linux/acpi.h> +#include <drm/drm_privacy_screen_driver.h> + +/* + * The DSM (Define Specific Method) constants below are the agreed API with + * the firmware team, on how to control privacy screen using ACPI methods. + */ +#define PRIV_SCRN_DSM_REVID 1 /* DSM version */ +#define PRIV_SCRN_DSM_FN_GET_STATUS 1 /* Get privacy screen status */ +#define PRIV_SCRN_DSM_FN_ENABLE 2 /* Enable privacy screen */ +#define PRIV_SCRN_DSM_FN_DISABLE 3 /* Disable privacy screen */ + +static const guid_t chromeos_priv_scrn_dsm_guid = + GUID_INIT(0xc7033113, 0x8720, 0x4ceb, + 0x90, 0x90, 0x9d, 0x52, 0xb3, 0xe5, 0x2d, 0x73); + +static void +chromeos_priv_scrn_get_hw_state(struct drm_privacy_screen *drm_priv_scrn) +{ + union acpi_object *obj; + acpi_handle handle; + struct device *priv_scrn = drm_priv_scrn->dev.parent; + + if (!priv_scrn) + return; + + handle = acpi_device_handle(to_acpi_device(priv_scrn)); + obj = acpi_evaluate_dsm(handle, &chromeos_priv_scrn_dsm_guid, + PRIV_SCRN_DSM_REVID, + PRIV_SCRN_DSM_FN_GET_STATUS, NULL); + if (!obj) { + dev_err(priv_scrn, "_DSM failed to get privacy-screen state\n"); + return; + } + + if (obj->type != ACPI_TYPE_INTEGER) + dev_err(priv_scrn, "Bad _DSM to get privacy-screen state\n"); + else if (obj->integer.value == 1) + drm_priv_scrn->hw_state = drm_priv_scrn->sw_state = + PRIVACY_SCREEN_ENABLED; + else + drm_priv_scrn->hw_state = drm_priv_scrn->sw_state = + PRIVACY_SCREEN_DISABLED; + + ACPI_FREE(obj); +} + +static int +chromeos_priv_scrn_set_sw_state(struct drm_privacy_screen *drm_priv_scrn, + enum drm_privacy_screen_status state) +{ + union acpi_object *obj = NULL; + acpi_handle handle; + struct device *priv_scrn = drm_priv_scrn->dev.parent; + + if (!priv_scrn) + return -ENODEV; + + handle = acpi_device_handle(to_acpi_device(priv_scrn)); + + if (state == PRIVACY_SCREEN_DISABLED) { + obj = acpi_evaluate_dsm(handle, &chromeos_priv_scrn_dsm_guid, + PRIV_SCRN_DSM_REVID, + PRIV_SCRN_DSM_FN_DISABLE, NULL); + } else if (state == PRIVACY_SCREEN_ENABLED) { + obj = acpi_evaluate_dsm(handle, &chromeos_priv_scrn_dsm_guid, + PRIV_SCRN_DSM_REVID, + PRIV_SCRN_DSM_FN_ENABLE, NULL); + } else { + dev_err(priv_scrn, "Bad attempt to set privacy-screen status\n"); + return -EINVAL; + } + + if (!obj) { + dev_err(priv_scrn, "_DSM failed to set privacy-screen state\n"); + return -EIO; + } + + drm_priv_scrn->hw_state = drm_priv_scrn->sw_state = state; + ACPI_FREE(obj); + return 0; +} + +static const struct drm_privacy_screen_ops chromeos_priv_scrn_ops = { + .get_hw_state = chromeos_priv_scrn_get_hw_state, + .set_sw_state = chromeos_priv_scrn_set_sw_state, +}; + +static int chromeos_priv_scrn_add(struct acpi_device *adev) +{ + struct drm_privacy_screen *drm_priv_scrn = + drm_privacy_screen_register(&adev->dev, &chromeos_priv_scrn_ops); + + if (IS_ERR(drm_priv_scrn)) { + dev_err(&adev->dev, "Error registering privacy-screen\n"); + return PTR_ERR(drm_priv_scrn); + } + + dev_info(&adev->dev, " registered privacy-screen '%s'\n", + dev_name(&drm_priv_scrn->dev)); + + return 0; +} + +static const struct acpi_device_id chromeos_priv_scrn_device_ids[] = { + {"GOOG0010", 0}, /* Google's electronic privacy screen for eDP-1 */ + {} +}; +MODULE_DEVICE_TABLE(acpi, chromeos_priv_scrn_device_ids); + +static struct acpi_driver chromeos_priv_scrn_driver = { + .name = "chromeos_priv_scrn_drvr", + .class = "ChromeOS", + .ids = chromeos_priv_scrn_device_ids, + .ops = { + .add = chromeos_priv_scrn_add, + }, + .owner = THIS_MODULE, +}; + +module_acpi_driver(chromeos_priv_scrn_driver); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("ChromeOS ACPI Privacy Screen driver"); +MODULE_AUTHOR("Rajat Jain <raja...@google.com>"); -- 2.34.1.173.g76aa8bc2d0-goog
