+Heikki Krogerus
Hello Hans, Heikki,
I have a question below, which isn't really a problem, but more of an
attempt to understand the current code and its limitations.
On Tue, Oct 5, 2021 at 1:23 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
>
> On some new laptops the LCD panel has a builtin electronic privacy-screen.
> We want to export this functionality as a property on the drm connector
> object. But often this functionality is not exposed on the GPU but on some
> other (ACPI) device.
>
> This commit adds a privacy-screen class allowing the driver for these
> other devices to register themselves as a privacy-screen provider; and
> allowing the drm/kms code to get a privacy-screen provider associated
> with a specific GPU/connector combo.
>
> Changes in v2:
> - Make CONFIG_DRM_PRIVACY_SCREEN a bool which controls if the drm_privacy
> code gets built as part of the main drm module rather then making it
> a tristate which builds its own module.
> - Add a #if IS_ENABLED(CONFIG_DRM_PRIVACY_SCREEN) check to
> drm_privacy_screen_consumer.h and define stubs when the check fails.
> Together these 2 changes fix several dependency issues.
> - Remove module related code now that this is part of the main drm.ko
> - Use drm_class as class for the privacy-screen devices instead of
> adding a separate class for this
>
> Changes in v3:
> - Make the static inline drm_privacy_screen_get_state() stub set sw_state
> and hw_state to PRIVACY_SCREEN_DISABLED to squelch an uninitialized
> variable warning when CONFIG_DRM_PRIVICAY_SCREEN is not set
>
> Changes in v4:
> - Make drm_privacy_screen_set_sw_state() skip calling out to the hw if
> hw_state == new_sw_state
>
> Reviewed-by: Emil Velikov <emil.l.velikov@xxxxxxxxx>
> Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
> Documentation/gpu/drm-kms-helpers.rst | 15 +
> MAINTAINERS | 8 +
> drivers/gpu/drm/Kconfig | 4 +
> drivers/gpu/drm/Makefile | 1 +
> drivers/gpu/drm/drm_drv.c | 4 +
> drivers/gpu/drm/drm_privacy_screen.c | 403 ++++++++++++++++++++++
> include/drm/drm_privacy_screen_consumer.h | 50 +++
> include/drm/drm_privacy_screen_driver.h | 80 +++++
> include/drm/drm_privacy_screen_machine.h | 41 +++
> 9 files changed, 606 insertions(+)
> create mode 100644 drivers/gpu/drm/drm_privacy_screen.c
> create mode 100644 include/drm/drm_privacy_screen_consumer.h
> create mode 100644 include/drm/drm_privacy_screen_driver.h
> create mode 100644 include/drm/drm_privacy_screen_machine.h
>
> diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst
> index ec2f65b31930..5bb55ec1b9b5 100644
> --- a/Documentation/gpu/drm-kms-helpers.rst
> +++ b/Documentation/gpu/drm-kms-helpers.rst
> @@ -435,3 +435,18 @@ Legacy CRTC/Modeset Helper Functions Reference
>
> .. kernel-doc:: drivers/gpu/drm/drm_crtc_helper.c
> :export:
> +
> +Privacy-screen class
> +====================
> +
> +.. kernel-doc:: drivers/gpu/drm/drm_privacy_screen.c
> + :doc: overview
> +
> +.. kernel-doc:: include/drm/drm_privacy_screen_driver.h
> + :internal:
> +
> +.. kernel-doc:: include/drm/drm_privacy_screen_machine.h
> + :internal:
> +
> +.. kernel-doc:: drivers/gpu/drm/drm_privacy_screen.c
> + :export:
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 28e5f0ae1009..cb94bb3b8724 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6423,6 +6423,14 @@ F: drivers/gpu/drm/drm_panel.c
> F: drivers/gpu/drm/panel/
> F: include/drm/drm_panel.h
>
> +DRM PRIVACY-SCREEN CLASS
> +M: Hans de Goede <hdegoede@xxxxxxxxxx>
> +L: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> +S: Maintained
> +T: git git://anongit.freedesktop.org/drm/drm-misc
> +F: drivers/gpu/drm/drm_privacy_screen*
> +F: include/drm/drm_privacy_screen*
> +
> DRM TTM SUBSYSTEM
> M: Christian Koenig <christian.koenig@xxxxxxx>
> M: Huang Rui <ray.huang@xxxxxxx>
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 2a926d0de423..c686c08447ac 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -481,3 +481,7 @@ config DRM_PANEL_ORIENTATION_QUIRKS
> config DRM_LIB_RANDOM
> bool
> default n
> +
> +config DRM_PRIVACY_SCREEN
> + bool
> + default n
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 0dff40bb863c..788fc37096f6 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -32,6 +32,7 @@ drm-$(CONFIG_OF) += drm_of.o
> drm-$(CONFIG_PCI) += drm_pci.o
> drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o
> drm-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
> +drm-$(CONFIG_DRM_PRIVACY_SCREEN) += drm_privacy_screen.o
>
> obj-$(CONFIG_DRM_DP_AUX_BUS) += drm_dp_aux_bus.o
>
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 7a5097467ba5..dc293b771c3f 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -43,6 +43,7 @@
> #include <drm/drm_managed.h>
> #include <drm/drm_mode_object.h>
> #include <drm/drm_print.h>
> +#include <drm/drm_privacy_screen_machine.h>
>
> #include "drm_crtc_internal.h"
> #include "drm_internal.h"
> @@ -1029,6 +1030,7 @@ static const struct file_operations drm_stub_fops = {
>
> static void drm_core_exit(void)
> {
> + drm_privacy_screen_lookup_exit();
> unregister_chrdev(DRM_MAJOR, "drm");
> debugfs_remove(drm_debugfs_root);
> drm_sysfs_destroy();
> @@ -1056,6 +1058,8 @@ static int __init drm_core_init(void)
> if (ret < 0)
> goto error;
>
> + drm_privacy_screen_lookup_init();
> +
> drm_core_init_complete = true;
>
> DRM_DEBUG("Initialized\n");
> diff --git a/drivers/gpu/drm/drm_privacy_screen.c b/drivers/gpu/drm/drm_privacy_screen.c
> new file mode 100644
> index 000000000000..183a6011adf0
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_privacy_screen.c
> @@ -0,0 +1,403 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright (C) 2020 - 2021 Red Hat, Inc.
> + *
> + * Authors:
> + * Hans de Goede <hdegoede@xxxxxxxxxx>
> + */
> +
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/slab.h>
> +#include <drm/drm_privacy_screen_machine.h>
> +#include <drm/drm_privacy_screen_consumer.h>
> +#include <drm/drm_privacy_screen_driver.h>
> +#include "drm_internal.h"
> +
> +/**
> + * DOC: overview
> + *
> + * This class allows non KMS drivers, from e.g. drivers/platform/x86 to
> + * register a privacy-screen device, which the KMS drivers can then use
> + * to implement the standard privacy-screen properties, see
> + * :ref:`Standard Connector Properties<standard_connector_properties>`.
> + *
> + * KMS drivers using a privacy-screen class device are advised to use the
> + * drm_connector_attach_privacy_screen_provider() and
> + * drm_connector_update_privacy_screen() helpers for dealing with this.
> + */
> +
> +#define to_drm_privacy_screen(dev) \
> + container_of(dev, struct drm_privacy_screen, dev)
> +
> +static DEFINE_MUTEX(drm_privacy_screen_lookup_lock);
> +static LIST_HEAD(drm_privacy_screen_lookup_list);
> +
> +static DEFINE_MUTEX(drm_privacy_screen_devs_lock);
> +static LIST_HEAD(drm_privacy_screen_devs);
> +
> +/*** drm_privacy_screen_machine.h functions ***/
> +
> +/**
> + * drm_privacy_screen_lookup_add - add an entry to the static privacy-screen
> + * lookup list
> + * @lookup: lookup list entry to add
> + *
> + * Add an entry to the static privacy-screen lookup list. Note the
> + * &struct list_head which is part of the &struct drm_privacy_screen_lookup
> + * gets added to a list owned by the privacy-screen core. So the passed in
> + * &struct drm_privacy_screen_lookup must not be free-ed until it is removed
> + * from the lookup list by calling drm_privacy_screen_lookup_remove().
> + */
> +void drm_privacy_screen_lookup_add(struct drm_privacy_screen_lookup *lookup)
> +{
> + mutex_lock(&drm_privacy_screen_lookup_lock);
> + list_add(&lookup->list, &drm_privacy_screen_lookup_list);
> + mutex_unlock(&drm_privacy_screen_lookup_lock);
> +}
> +EXPORT_SYMBOL(drm_privacy_screen_lookup_add);
> +
> +/**
> + * drm_privacy_screen_lookup_remove - remove an entry to the static
> + * privacy-screen lookup list
> + * @lookup: lookup list entry to remove
> + *
> + * Remove an entry previously added with drm_privacy_screen_lookup_add()
> + * from the static privacy-screen lookup list.
> + */
> +void drm_privacy_screen_lookup_remove(struct drm_privacy_screen_lookup *lookup)
> +{
> + mutex_lock(&drm_privacy_screen_lookup_lock);
> + list_del(&lookup->list);
> + mutex_unlock(&drm_privacy_screen_lookup_lock);
> +}
> +EXPORT_SYMBOL(drm_privacy_screen_lookup_remove);
> +
> +/*** drm_privacy_screen_consumer.h functions ***/
> +
> +static struct drm_privacy_screen *drm_privacy_screen_get_by_name(
> + const char *name)
> +{
> + struct drm_privacy_screen *priv;
> + struct device *dev = NULL;
> +
> + mutex_lock(&drm_privacy_screen_devs_lock);
> +
> + list_for_each_entry(priv, &drm_privacy_screen_devs, list) {
> + if (strcmp(dev_name(&priv->dev), name) == 0) {
> + dev = get_device(&priv->dev);
> + break;
> + }
> + }
> +
> + mutex_unlock(&drm_privacy_screen_devs_lock);
> +
> + return dev ? to_drm_privacy_screen(dev) : NULL;
> +}
> +
> +/**
> + * drm_privacy_screen_get - get a privacy-screen provider
> + * @dev: consumer-device for which to get a privacy-screen provider
> + * @con_id: (video)connector name for which to get a privacy-screen provider
> + *
> + * Get a privacy-screen provider for a privacy-screen attached to the
> + * display described by the @dev and @con_id parameters.
> + *
> + * Return:
> + * * A pointer to a &struct drm_privacy_screen on success.
> + * * ERR_PTR(-ENODEV) if no matching privacy-screen is found
> + * * ERR_PTR(-EPROBE_DEFER) if there is a matching privacy-screen,
> + * but it has not been registered yet.
> + */
> +struct drm_privacy_screen *drm_privacy_screen_get(struct device *dev,
> + const char *con_id)
> +{
> + const char *dev_id = dev ? dev_name(dev) : NULL;
> + struct drm_privacy_screen_lookup *l;
> + struct drm_privacy_screen *priv;
> + const char *provider = NULL;
> + int match, best = -1;
> +
> + /*
> + * For now we only support using a static lookup table, which is
> + * populated by the drm_privacy_screen_arch_init() call. This should()
> + * be extended with device-tree / fw_node lookup when support is added
> + * for device-tree using hardware with a privacy-screen.
Do I understand it right that given the state of affairs today, the
drm_connector->fwnode gets populated AFTER the drm_connectors are
initialized and the connector properties have already been attached?
[intel_acpi_assign_connector_fwnodes() gets called later]. If so, the
fwnode, can't really be used to tweak certain properties of the
drm-connector?
Specifically, if someone wants to use device-tree / fwnodes for
drm_connector to provide a privacy-screen property, we have a
chicken-and-egg situation because:
- privacy-screen providers need to register privacy-screen, BEFORE
drm_connector begins to probe and attach properties.
- the drm_connector->fwnode gets assigned AFTER drm_connector has
attached the properties.
Is the above a correct understanding of the current situation?
Thanks & Best regards,
Rajat
> + *
> + * The lookup algorithm was shamelessly taken from the clock
> + * framework:
> + *
> + * We do slightly fuzzy matching here:
> + * An entry with a NULL ID is assumed to be a wildcard.
> + * If an entry has a device ID, it must match
> + * If an entry has a connection ID, it must match
> + * Then we take the most specific entry - with the following order
> + * of precedence: dev+con > dev only > con only.
> + */
> + mutex_lock(&drm_privacy_screen_lookup_lock);
> +
> + list_for_each_entry(l, &drm_privacy_screen_lookup_list, list) {
> + match = 0;
> +
> + if (l->dev_id) {
> + if (!dev_id || strcmp(l->dev_id, dev_id))
> + continue;
> +
> + match += 2;
> + }
> +
> + if (l->con_id) {
> + if (!con_id || strcmp(l->con_id, con_id))
> + continue;
> +
> + match += 1;
> + }
> +
> + if (match > best) {
> + provider = l->provider;
> + best = match;
> + }
> + }
> +
> + mutex_unlock(&drm_privacy_screen_lookup_lock);
> +
> + if (!provider)
> + return ERR_PTR(-ENODEV);
> +
> + priv = drm_privacy_screen_get_by_name(provider);
> + if (!priv)
> + return ERR_PTR(-EPROBE_DEFER);
> +
> + return priv;
> +}
> +EXPORT_SYMBOL(drm_privacy_screen_get);
> +
> +/**
> + * drm_privacy_screen_put - release a privacy-screen reference
> + * @priv: privacy screen reference to release
> + *
> + * Release a privacy-screen provider reference gotten through
> + * drm_privacy_screen_get(). May be called with a NULL or ERR_PTR,
> + * in which case it is a no-op.
> + */
> +void drm_privacy_screen_put(struct drm_privacy_screen *priv)
> +{
> + if (IS_ERR_OR_NULL(priv))
> + return;
> +
> + put_device(&priv->dev);
> +}
> +EXPORT_SYMBOL(drm_privacy_screen_put);
> +
> +/**
> + * drm_privacy_screen_set_sw_state - set a privacy-screen's sw-state
> + * @priv: privacy screen to set the sw-state for
> + * @sw_state: new sw-state value to set
> + *
> + * Set the sw-state of a privacy screen. If the privacy-screen is not
> + * in a locked hw-state, then the actual and hw-state of the privacy-screen
> + * will be immediately updated to the new value. If the privacy-screen is
> + * in a locked hw-state, then the new sw-state will be remembered as the
> + * requested state to put the privacy-screen in when it becomes unlocked.
> + *
> + * Return: 0 on success, negative error code on failure.
> + */
> +int drm_privacy_screen_set_sw_state(struct drm_privacy_screen *priv,
> + enum drm_privacy_screen_status sw_state)
> +{
> + int ret = 0;
> +
> + mutex_lock(&priv->lock);
> +
> + if (!priv->ops) {
> + ret = -ENODEV;
> + goto out;
> + }
> +
> + /*
> + * As per the DRM connector properties documentation, setting the
> + * sw_state while the hw_state is locked is allowed. In this case
> + * it is a no-op other then storing the new sw_state so that it
> + * can be honored when the state gets unlocked.
> + * Also skip the set if the hw already is in the desired state.
> + */
> + if (priv->hw_state >= PRIVACY_SCREEN_DISABLED_LOCKED ||
> + priv->hw_state == sw_state) {
> + priv->sw_state = sw_state;
> + goto out;
> + }
> +
> + ret = priv->ops->set_sw_state(priv, sw_state);
> +out:
> + mutex_unlock(&priv->lock);
> + return ret;
> +}
> +EXPORT_SYMBOL(drm_privacy_screen_set_sw_state);
> +
> +/**
> + * drm_privacy_screen_get_state - get privacy-screen's current state
> + * @priv: privacy screen to get the state for
> + * @sw_state_ret: address where to store the privacy-screens current sw-state
> + * @hw_state_ret: address where to store the privacy-screens current hw-state
> + *
> + * Get the current state of a privacy-screen, both the sw-state and the
> + * hw-state.
> + */
> +void drm_privacy_screen_get_state(struct drm_privacy_screen *priv,
> + enum drm_privacy_screen_status *sw_state_ret,
> + enum drm_privacy_screen_status *hw_state_ret)
> +{
> + mutex_lock(&priv->lock);
> + *sw_state_ret = priv->sw_state;
> + *hw_state_ret = priv->hw_state;
> + mutex_unlock(&priv->lock);
> +}
> +EXPORT_SYMBOL(drm_privacy_screen_get_state);
> +
> +/*** drm_privacy_screen_driver.h functions ***/
> +
> +static ssize_t sw_state_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct drm_privacy_screen *priv = to_drm_privacy_screen(dev);
> + const char * const sw_state_names[] = {
> + "Disabled",
> + "Enabled",
> + };
> + ssize_t ret;
> +
> + mutex_lock(&priv->lock);
> +
> + if (!priv->ops)
> + ret = -ENODEV;
> + else if (WARN_ON(priv->sw_state >= ARRAY_SIZE(sw_state_names)))
> + ret = -ENXIO;
> + else
> + ret = sprintf(buf, "%s\n", sw_state_names[priv->sw_state]);
> +
> + mutex_unlock(&priv->lock);
> + return ret;
> +}
> +/*
> + * RO: Do not allow setting the sw_state through sysfs, this MUST be done
> + * through the drm_properties on the drm_connector.
> + */
> +static DEVICE_ATTR_RO(sw_state);
> +
> +static ssize_t hw_state_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct drm_privacy_screen *priv = to_drm_privacy_screen(dev);
> + const char * const hw_state_names[] = {
> + "Disabled",
> + "Enabled",
> + "Disabled, locked",
> + "Enabled, locked",
> + };
> + ssize_t ret;
> +
> + mutex_lock(&priv->lock);
> +
> + if (!priv->ops)
> + ret = -ENODEV;
> + else if (WARN_ON(priv->hw_state >= ARRAY_SIZE(hw_state_names)))
> + ret = -ENXIO;
> + else
> + ret = sprintf(buf, "%s\n", hw_state_names[priv->hw_state]);
> +
> + mutex_unlock(&priv->lock);
> + return ret;
> +}
> +static DEVICE_ATTR_RO(hw_state);
> +
> +static struct attribute *drm_privacy_screen_attrs[] = {
> + &dev_attr_sw_state.attr,
> + &dev_attr_hw_state.attr,
> + NULL
> +};
> +ATTRIBUTE_GROUPS(drm_privacy_screen);
> +
> +static struct device_type drm_privacy_screen_type = {
> + .name = "privacy_screen",
> + .groups = drm_privacy_screen_groups,
> +};
> +
> +static void drm_privacy_screen_device_release(struct device *dev)
> +{
> + struct drm_privacy_screen *priv = to_drm_privacy_screen(dev);
> +
> + kfree(priv);
> +}
> +
> +/**
> + * drm_privacy_screen_register - register a privacy-screen
> + * @parent: parent-device for the privacy-screen
> + * @ops: &struct drm_privacy_screen_ops pointer with ops for the privacy-screen
> + *
> + * Create and register a privacy-screen.
> + *
> + * Return:
> + * * A pointer to the created privacy-screen on success.
> + * * An ERR_PTR(errno) on failure.
> + */
> +struct drm_privacy_screen *drm_privacy_screen_register(
> + struct device *parent, const struct drm_privacy_screen_ops *ops)
> +{
> + struct drm_privacy_screen *priv;
> + int ret;
> +
> + priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return ERR_PTR(-ENOMEM);
> +
> + mutex_init(&priv->lock);
> +
> + priv->dev.class = drm_class;
> + priv->dev.type = &drm_privacy_screen_type;
> + priv->dev.parent = parent;
> + priv->dev.release = drm_privacy_screen_device_release;
> + dev_set_name(&priv->dev, "privacy_screen-%s", dev_name(parent));
> + priv->ops = ops;
> +
> + priv->ops->get_hw_state(priv);
> +
> + ret = device_register(&priv->dev);
> + if (ret) {
> + put_device(&priv->dev);
> + return ERR_PTR(ret);
> + }
> +
> + mutex_lock(&drm_privacy_screen_devs_lock);
> + list_add(&priv->list, &drm_privacy_screen_devs);
> + mutex_unlock(&drm_privacy_screen_devs_lock);
> +
> + return priv;
> +}
> +EXPORT_SYMBOL(drm_privacy_screen_register);
> +
> +/**
> + * drm_privacy_screen_unregister - unregister privacy-screen
> + * @priv: privacy-screen to unregister
> + *
> + * Unregister a privacy-screen registered with drm_privacy_screen_register().
> + * May be called with a NULL or ERR_PTR, in which case it is a no-op.
> + */
> +void drm_privacy_screen_unregister(struct drm_privacy_screen *priv)
> +{
> + if (IS_ERR_OR_NULL(priv))
> + return;
> +
> + mutex_lock(&drm_privacy_screen_devs_lock);
> + list_del(&priv->list);
> + mutex_unlock(&drm_privacy_screen_devs_lock);
> +
> + mutex_lock(&priv->lock);
> + priv->ops = NULL;
> + mutex_unlock(&priv->lock);
> +
> + device_unregister(&priv->dev);
> +}
> +EXPORT_SYMBOL(drm_privacy_screen_unregister);
> diff --git a/include/drm/drm_privacy_screen_consumer.h b/include/drm/drm_privacy_screen_consumer.h
> new file mode 100644
> index 000000000000..0cbd23b0453d
> --- /dev/null
> +++ b/include/drm/drm_privacy_screen_consumer.h
> @@ -0,0 +1,50 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright (C) 2020 Red Hat, Inc.
> + *
> + * Authors:
> + * Hans de Goede <hdegoede@xxxxxxxxxx>
> + */
> +
> +#ifndef __DRM_PRIVACY_SCREEN_CONSUMER_H__
> +#define __DRM_PRIVACY_SCREEN_CONSUMER_H__
> +
> +#include <linux/device.h>
> +#include <drm/drm_connector.h>
> +
> +struct drm_privacy_screen;
> +
> +#if IS_ENABLED(CONFIG_DRM_PRIVACY_SCREEN)
> +struct drm_privacy_screen *drm_privacy_screen_get(struct device *dev,
> + const char *con_id);
> +void drm_privacy_screen_put(struct drm_privacy_screen *priv);
> +
> +int drm_privacy_screen_set_sw_state(struct drm_privacy_screen *priv,
> + enum drm_privacy_screen_status sw_state);
> +void drm_privacy_screen_get_state(struct drm_privacy_screen *priv,
> + enum drm_privacy_screen_status *sw_state_ret,
> + enum drm_privacy_screen_status *hw_state_ret);
> +#else
> +static inline struct drm_privacy_screen *drm_privacy_screen_get(struct device *dev,
> + const char *con_id)
> +{
> + return ERR_PTR(-ENODEV);
> +}
> +static inline void drm_privacy_screen_put(struct drm_privacy_screen *priv)
> +{
> +}
> +static inline int drm_privacy_screen_set_sw_state(struct drm_privacy_screen *priv,
> + enum drm_privacy_screen_status sw_state)
> +{
> + return -ENODEV;
> +}
> +static inline void drm_privacy_screen_get_state(struct drm_privacy_screen *priv,
> + enum drm_privacy_screen_status *sw_state_ret,
> + enum drm_privacy_screen_status *hw_state_ret)
> +{
> + *sw_state_ret = PRIVACY_SCREEN_DISABLED;
> + *hw_state_ret = PRIVACY_SCREEN_DISABLED;
> +}
> +#endif
> +
> +#endif
> diff --git a/include/drm/drm_privacy_screen_driver.h b/include/drm/drm_privacy_screen_driver.h
> new file mode 100644
> index 000000000000..5187ae52eb03
> --- /dev/null
> +++ b/include/drm/drm_privacy_screen_driver.h
> @@ -0,0 +1,80 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright (C) 2020 Red Hat, Inc.
> + *
> + * Authors:
> + * Hans de Goede <hdegoede@xxxxxxxxxx>
> + */
> +
> +#ifndef __DRM_PRIVACY_SCREEN_DRIVER_H__
> +#define __DRM_PRIVACY_SCREEN_DRIVER_H__
> +
> +#include <linux/device.h>
> +#include <linux/list.h>
> +#include <linux/mutex.h>
> +#include <drm/drm_connector.h>
> +
> +struct drm_privacy_screen;
> +
> +/**
> + * struct drm_privacy_screen_ops - drm_privacy_screen operations
> + *
> + * Defines the operations which the privacy-screen class code may call.
> + * These functions should be implemented by the privacy-screen driver.
> + */
> +struct drm_privacy_screen_ops {
> + /**
> + * @set_sw_state: Called to request a change of the privacy-screen
> + * state. The privacy-screen class code contains a check to avoid this
> + * getting called when the hw_state reports the state is locked.
> + * It is the driver's responsibility to update sw_state and hw_state.
> + * This is always called with the drm_privacy_screen's lock held.
> + */
> + int (*set_sw_state)(struct drm_privacy_screen *priv,
> + enum drm_privacy_screen_status sw_state);
> + /**
> + * @get_hw_state: Called to request that the driver gets the current
> + * privacy-screen state from the hardware and then updates sw_state and
> + * hw_state accordingly. This will be called by the core just before
> + * the privacy-screen is registered in sysfs.
> + */
> + void (*get_hw_state)(struct drm_privacy_screen *priv);
> +};
> +
> +/**
> + * struct drm_privacy_screen - central privacy-screen structure
> + *
> + * Central privacy-screen structure, this contains the struct device used
> + * to register the screen in sysfs, the screen's state, ops, etc.
> + */
> +struct drm_privacy_screen {
> + /** @dev: device used to register the privacy-screen in sysfs. */
> + struct device dev;
> + /** @lock: mutex protection all fields in this struct. */
> + struct mutex lock;
> + /** @list: privacy-screen devices list list-entry. */
> + struct list_head list;
> + /**
> + * @ops: &struct drm_privacy_screen_ops for this privacy-screen.
> + * This is NULL if the driver has unregistered the privacy-screen.
> + */
> + const struct drm_privacy_screen_ops *ops;
> + /**
> + * @sw_state: The privacy-screen's software state, see
> + * :ref:`Standard Connector Properties<standard_connector_properties>`
> + * for more info.
> + */
> + enum drm_privacy_screen_status sw_state;
> + /**
> + * @hw_state: The privacy-screen's hardware state, see
> + * :ref:`Standard Connector Properties<standard_connector_properties>`
> + * for more info.
> + */
> + enum drm_privacy_screen_status hw_state;
> +};
> +
> +struct drm_privacy_screen *drm_privacy_screen_register(
> + struct device *parent, const struct drm_privacy_screen_ops *ops);
> +void drm_privacy_screen_unregister(struct drm_privacy_screen *priv);
> +
> +#endif
> diff --git a/include/drm/drm_privacy_screen_machine.h b/include/drm/drm_privacy_screen_machine.h
> new file mode 100644
> index 000000000000..aaa0d38cce92
> --- /dev/null
> +++ b/include/drm/drm_privacy_screen_machine.h
> @@ -0,0 +1,41 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright (C) 2020 Red Hat, Inc.
> + *
> + * Authors:
> + * Hans de Goede <hdegoede@xxxxxxxxxx>
> + */
> +
> +#ifndef __DRM_PRIVACY_SCREEN_MACHINE_H__
> +#define __DRM_PRIVACY_SCREEN_MACHINE_H__
> +
> +#include <linux/list.h>
> +
> +/**
> + * struct drm_privacy_screen_lookup - static privacy-screen lookup list entry
> + *
> + * Used for the static lookup-list for mapping privacy-screen consumer
> + * dev-connector pairs to a privacy-screen provider.
> + */
> +struct drm_privacy_screen_lookup {
> + /** @list: Lookup list list-entry. */
> + struct list_head list;
> + /** @dev_id: Consumer device name or NULL to match all devices. */
> + const char *dev_id;
> + /** @con_id: Consumer connector name or NULL to match all connectors. */
> + const char *con_id;
> + /** @provider: dev_name() of the privacy_screen provider. */
> + const char *provider;
> +};
> +
> +void drm_privacy_screen_lookup_add(struct drm_privacy_screen_lookup *lookup);
> +void drm_privacy_screen_lookup_remove(struct drm_privacy_screen_lookup *lookup);
> +
> +static inline void drm_privacy_screen_lookup_init(void)
> +{
> +}
> +static inline void drm_privacy_screen_lookup_exit(void)
> +{
> +}
> +
> +#endif
> --
> 2.31.1
>
