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-rw-r--r--include/drm/drm_connector.h52
-rw-r--r--include/drm/drm_drv.h81
-rw-r--r--include/drm/drm_edid.h1
-rw-r--r--include/drm/drm_file.h267
-rw-r--r--include/drm/drm_gem.h26
-rw-r--r--include/drm/drm_gem_cma_helper.h26
-rw-r--r--include/drm/drm_scdc_helper.h159
7 files changed, 578 insertions, 34 deletions
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index fabb35aba5f6..f8b766d70a46 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -87,6 +87,53 @@ enum subpixel_order {
SubPixelVerticalRGB,
SubPixelVerticalBGR,
SubPixelNone,
+
+};
+
+/**
+ * struct drm_scrambling: sink's scrambling support.
+ */
+struct drm_scrambling {
+ /**
+ * @supported: scrambling supported for rates > 340 Mhz.
+ */
+ bool supported;
+ /**
+ * @low_rates: scrambling supported for rates <= 340 Mhz.
+ */
+ bool low_rates;
+};
+
+/*
+ * struct drm_scdc - Information about scdc capabilities of a HDMI 2.0 sink
+ *
+ * Provides SCDC register support and capabilities related information on a
+ * HDMI 2.0 sink. In case of a HDMI 1.4 sink, all parameter must be 0.
+ */
+struct drm_scdc {
+ /**
+ * @supported: status control & data channel present.
+ */
+ bool supported;
+ /**
+ * @read_request: sink is capable of generating scdc read request.
+ */
+ bool read_request;
+ /**
+ * @scrambling: sink's scrambling capabilities
+ */
+ struct drm_scrambling scrambling;
+};
+
+
+/**
+ * struct drm_hdmi_info - runtime information about the connected HDMI sink
+ *
+ * Describes if a given display supports advanced HDMI 2.0 features.
+ * This information is available in CEA-861-F extension blocks (like HF-VSDB).
+ */
+struct drm_hdmi_info {
+ struct drm_scdc scdc;
};
/**
@@ -204,6 +251,11 @@ struct drm_display_info {
* @cea_rev: CEA revision of the HDMI sink.
*/
u8 cea_rev;
+
+ /**
+ * @hdmi: advance features of a HDMI sink.
+ */
+ struct drm_hdmi_info hdmi;
};
int drm_display_info_set_bus_formats(struct drm_display_info *info,
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index 4321d012c4ba..8f900fb30275 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -64,7 +64,6 @@ struct drm_mode_create_dumb;
* structure for GEM drivers.
*/
struct drm_driver {
-
/**
* @load:
*
@@ -76,14 +75,94 @@ struct drm_driver {
* See drm_dev_init() and drm_dev_register() for proper and
* race-free way to set up a &struct drm_device.
*
+ * This is deprecated, do not use!
+ *
* Returns:
*
* Zero on success, non-zero value on failure.
*/
int (*load) (struct drm_device *, unsigned long flags);
+
+ /**
+ * @open:
+ *
+ * Driver callback when a new &struct drm_file is opened. Useful for
+ * setting up driver-private data structures like buffer allocators,
+ * execution contexts or similar things. Such driver-private resources
+ * must be released again in @postclose.
+ *
+ * Since the display/modeset side of DRM can only be owned by exactly
+ * one &struct drm_file (see &drm_file.is_master and &drm_device.master)
+ * there should never be a need to set up any modeset related resources
+ * in this callback. Doing so would be a driver design bug.
+ *
+ * Returns:
+ *
+ * 0 on success, a negative error code on failure, which will be
+ * promoted to userspace as the result of the open() system call.
+ */
int (*open) (struct drm_device *, struct drm_file *);
+
+ /**
+ * @preclose:
+ *
+ * One of the driver callbacks when a new &struct drm_file is closed.
+ * Useful for tearing down driver-private data structures allocated in
+ * @open like buffer allocators, execution contexts or similar things.
+ *
+ * Since the display/modeset side of DRM can only be owned by exactly
+ * one &struct drm_file (see &drm_file.is_master and &drm_device.master)
+ * there should never be a need to tear down any modeset related
+ * resources in this callback. Doing so would be a driver design bug.
+ *
+ * FIXME: It is not really clear why there's both @preclose and
+ * @postclose. Without a really good reason, use @postclose only.
+ */
void (*preclose) (struct drm_device *, struct drm_file *file_priv);
+
+ /**
+ * @postclose:
+ *
+ * One of the driver callbacks when a new &struct drm_file is closed.
+ * Useful for tearing down driver-private data structures allocated in
+ * @open like buffer allocators, execution contexts or similar things.
+ *
+ * Since the display/modeset side of DRM can only be owned by exactly
+ * one &struct drm_file (see &drm_file.is_master and &drm_device.master)
+ * there should never be a need to tear down any modeset related
+ * resources in this callback. Doing so would be a driver design bug.
+ *
+ * FIXME: It is not really clear why there's both @preclose and
+ * @postclose. Without a really good reason, use @postclose only.
+ */
void (*postclose) (struct drm_device *, struct drm_file *);
+
+ /**
+ * @lastclose:
+ *
+ * Called when the last &struct drm_file has been closed and there's
+ * currently no userspace client for the &struct drm_device.
+ *
+ * Modern drivers should only use this to force-restore the fbdev
+ * framebuffer using drm_fb_helper_restore_fbdev_mode_unlocked().
+ * Anything else would indicate there's something seriously wrong.
+ * Modern drivers can also use this to execute delayed power switching
+ * state changes, e.g. in conjunction with the :ref:`vga_switcheroo`
+ * infrastructure.
+ *
+ * This is called after @preclose and @postclose have been called.
+ *
+ * NOTE:
+ *
+ * All legacy drivers use this callback to de-initialize the hardware.
+ * This is purely because of the shadow-attach model, where the DRM
+ * kernel driver does not really own the hardware. Instead ownershipe is
+ * handled with the help of userspace through an inheritedly racy dance
+ * to set/unset the VT into raw mode.
+ *
+ * Legacy drivers initialize the hardware in the @firstopen callback,
+ * which isn't even called for modern drivers.
+ */
void (*lastclose) (struct drm_device *);
/**
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index 3ead84d93792..7b9f48b62e07 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -476,5 +476,4 @@ void drm_edid_get_monitor_name(struct edid *edid, char *name,
struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
int hsize, int vsize, int fresh,
bool rb);
-
#endif /* __DRM_EDID_H__ */
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index d1a25cc17fd1..5dd27ae5c47c 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -45,6 +45,7 @@ struct drm_device;
* FIXME: Not sure we want to have drm_minor here in the end, but to avoid
* header include loops we need it here for now.
*/
+
enum drm_minor_type {
DRM_MINOR_PRIMARY,
DRM_MINOR_CONTROL,
@@ -52,12 +53,19 @@ enum drm_minor_type {
};
/**
- * DRM minor structure. This structure represents a drm minor number.
+ * struct drm_minor - DRM device minor structure
+ *
+ * This structure represents a DRM minor number for device nodes in /dev.
+ * Entirely opaque to drivers and should never be inspected directly by drivers.
+ * Drivers instead should only interact with &struct drm_file and of course
+ * &struct drm_device, which is also where driver-private data and resources can
+ * be attached to.
*/
struct drm_minor {
- int index; /**< Minor device number */
- int type; /**< Control or render */
- struct device *kdev; /**< Linux device */
+ /* private: */
+ int index; /* Minor device number */
+ int type; /* Control or render */
+ struct device *kdev; /* Linux device */
struct drm_device *dev;
struct dentry *debugfs_root;
@@ -66,91 +74,286 @@ struct drm_minor {
struct mutex debugfs_lock; /* Protects debugfs_list. */
};
-/* Event queued up for userspace to read */
+/**
+ * struct drm_pending_event - Event queued up for userspace to read
+ *
+ * This represents a DRM event. Drivers can use this as a generic completion
+ * mechanism, which supports kernel-internal &struct completion, &struct dma_fence
+ * and also the DRM-specific &struct drm_event delivery mechanism.
+ */
struct drm_pending_event {
+ /**
+ * @completion:
+ *
+ * Optional pointer to a kernel internal completion signalled when
+ * drm_send_event() is called, useful to internally synchronize with
+ * nonblocking operations.
+ */
struct completion *completion;
+
+ /**
+ * @completion_release:
+ *
+ * Optional callback currently only used by the atomic modeset helpers
+ * to clean up the reference count for the structure @completion is
+ * stored in.
+ */
void (*completion_release)(struct completion *completion);
+
+ /**
+ * @event:
+ *
+ * Pointer to the actual event that should be sent to userspace to be
+ * read using drm_read(). Can be optional, since nowadays events are
+ * also used to signal kernel internal threads with @completion or DMA
+ * transactions using @fence.
+ */
struct drm_event *event;
+
+ /**
+ * @fence:
+ *
+ * Optional DMA fence to unblock other hardware transactions which
+ * depend upon the nonblocking DRM operation this event represents.
+ */
struct dma_fence *fence;
+
+ /**
+ * @file_priv:
+ *
+ * &struct drm_file where @event should be delivered to. Only set when
+ * @event is set.
+ */
+ struct drm_file *file_priv;
+
+ /**
+ * @link:
+ *
+ * Double-linked list to keep track of this event. Can be used by the
+ * driver up to the point when it calls drm_send_event(), after that
+ * this list entry is owned by the core for its own book-keeping.
+ */
struct list_head link;
+
+ /**
+ * @pending_link:
+ *
+ * Entry on &drm_file.pending_event_list, to keep track of all pending
+ * events for @file_priv, to allow correct unwinding of them when
+ * userspace closes the file before the event is delivered.
+ */
struct list_head pending_link;
- struct drm_file *file_priv;
- pid_t pid; /* pid of requester, no guarantee it's valid by the time
- we deliver the event, for tracing only */
};
-/** File private data */
+/**
+ * struct drm_file - DRM file private data
+ *
+ * This structure tracks DRM state per open file descriptor.
+ */
struct drm_file {
+ /**
+ * @authenticated:
+ *
+ * Whether the client is allowed to submit rendering, which for legacy
+ * nodes means it must be authenticated.
+ *
+ * See also the :ref:`section on primary nodes and authentication
+ * <drm_primary_node>`.
+ */
unsigned authenticated :1;
- /* true when the client has asked us to expose stereo 3D mode flags */
+
+ /**
+ * @stereo_allowed:
+ *
+ * True when the client has asked us to expose stereo 3D mode flags.
+ */
unsigned stereo_allowed :1;
- /*
- * true if client understands CRTC primary planes and cursor planes
- * in the plane list
+
+ /**
+ * @universal_planes:
+ *
+ * True if client understands CRTC primary planes and cursor planes
+ * in the plane list. Automatically set when @atomic is set.
*/
unsigned universal_planes:1;
- /* true if client understands atomic properties */
+
+ /** @atomic: True if client understands atomic properties. */
unsigned atomic:1;
- /*
- * This client is the creator of @master.
- * Protected by struct drm_device::master_mutex.
+
+ /**
+ * @is_master:
+ *
+ * This client is the creator of @master. Protected by struct
+ * &drm_device.master_mutex.
+ *
+ * See also the :ref:`section on primary nodes and authentication
+ * <drm_primary_node>`.
*/
unsigned is_master:1;
+ /**
+ * @master:
+ *
+ * Master this node is currently associated with. Only relevant if
+ * drm_is_primary_client() returns true. Note that this only
+ * matches &drm_device.master if the master is the currently active one.
+ *
+ * See also @authentication and @is_master and the :ref:`section on
+ * primary nodes and authentication <drm_primary_node>`.
+ */
+ struct drm_master *master;
+
+ /** @pid: Process that opened this file. */
struct pid *pid;
+
+ /** @magic: Authentication magic, see @authenticated. */
drm_magic_t magic;
+
+ /**
+ * @lhead:
+ *
+ * List of all open files of a DRM device, linked into
+ * &drm_device.filelist. Protected by &drm_device.filelist_mutex.
+ */
struct list_head lhead;
+
+ /** @minor: &struct drm_minor for this file. */
struct drm_minor *minor;
- unsigned long lock_count;
- /** Mapping of mm object handles to object pointers. */
+ /**
+ * @object_idr:
+ *
+ * Mapping of mm object handles to object pointers. Used by the GEM
+ * subsystem. Protected by @table_lock.
+ */
struct idr object_idr;
- /** Lock for synchronization of access to object_idr. */
+
+ /** @table_lock: Protects @object_idr. */
spinlock_t table_lock;
+ /** @filp: Pointer to the core file structure. */
struct file *filp;
+
+ /**
+ * @driver_priv:
+ *
+ * Optional pointer for driver private data. Can be allocated in
+ * &drm_driver.open and should be freed in &drm_driver.postclose.
+ */
void *driver_priv;
- struct drm_master *master; /* master this node is currently associated with
- N.B. not always dev->master */
/**
- * fbs - List of framebuffers associated with this file.
+ * @fbs:
+ *
+ * List of &struct drm_framebuffer associated with this file, using the
+ * &drm_framebuffer.filp_head entry.
*
- * Protected by fbs_lock. Note that the fbs list holds a reference on
- * the fb object to prevent it from untimely disappearing.
+ * Protected by @fbs_lock. Note that the @fbs list holds a reference on
+ * the framebuffer object to prevent it from untimely disappearing.
*/
struct list_head fbs;
+
+ /** @fbs_lock: Protects @fbs. */
struct mutex fbs_lock;
- /** User-created blob properties; this retains a reference on the
- * property. */
+ /**
+ * @blobs:
+ *
+ * User-created blob properties; this retains a reference on the
+ * property.
+ *
+ * Protected by @drm_mode_config.blob_lock;
+ */
struct list_head blobs;
+ /** @event_wait: Waitqueue for new events added to @event_list. */
wait_queue_head_t event_wait;
+
+ /**
+ * @pending_event_list:
+ *
+ * List of pending &struct drm_pending_event, used to clean up pending
+ * events in case this file gets closed before the event is signalled.
+ * Uses the &drm_pending_event.pending_link entry.
+ *
+ * Protect by &drm_device.event_lock.
+ */
struct list_head pending_event_list;
+
+ /**
+ * @event_list:
+ *
+ * List of &struct drm_pending_event, ready for delivery to userspace
+ * through drm_read(). Uses the &drm_pending_event.link entry.
+ *
+ * Protect by &drm_device.event_lock.
+ */
struct list_head event_list;
+
+ /**
+ * @event_space:
+ *
+ * Available event space to prevent userspace from
+ * exhausting kernel memory. Currently limited to the fairly arbitrary
+ * value of 4KB.
+ */
int event_space;
+ /** @event_read_lock: Serializes drm_read(). */
struct mutex event_read_lock;
+ /**
+ * @prime:
+ *
+ * Per-file buffer caches used by the PRIME buffer sharing code.
+ */
struct drm_prime_file_private prime;
+
+ /* private: */
+ unsigned long lock_count; /* DRI1 legacy lock count */
};
+/**
+ * drm_is_primary_client - is this an open file of the primary node
+ * @file_priv: DRM file
+ *
+ * Returns true if this is an open file of the primary node, i.e.
+ * &drm_file.minor of @file_priv is a primary minor.
+ *
+ * See also the :ref:`section on primary nodes and authentication
+ * <drm_primary_node>`.
+ */
+static inline bool drm_is_primary_client(const struct drm_file *file_priv)
+{
+ return file_priv->minor->type == DRM_MINOR_PRIMARY;
+}
+
+/**
+ * drm_is_render_client - is this an open file of the render node
+ * @file_priv: DRM file
+ *
+ * Returns true if this is an open file of the render node, i.e.
+ * &drm_file.minor of @file_priv is a render minor.
+ *
+ * See also the :ref:`section on render nodes <drm_render_node>`.
+ */
static inline bool drm_is_render_client(const struct drm_file *file_priv)
{
return file_priv->minor->type == DRM_MINOR_RENDER;
}
+/**
+ * drm_is_control_client - is this an open file of the control node
+ * @file_priv: DRM file
+ *
+ * Control nodes are deprecated and in the process of getting removed from the
+ * DRM userspace API. Do not ever use!
+ */
static inline bool drm_is_control_client(const struct drm_file *file_priv)
{
return file_priv->minor->type == DRM_MINOR_CONTROL;
}
-static inline bool drm_is_primary_client(const struct drm_file *file_priv)
-{
- return file_priv->minor->type == DRM_MINOR_PRIMARY;
-}
-
int drm_open(struct inode *inode, struct file *filp);
ssize_t drm_read(struct file *filp, char __user *buffer,
size_t count, loff_t *offset);
diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index b9ade75ecd82..663d80358057 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -178,6 +178,32 @@ struct drm_gem_object {
struct dma_buf_attachment *import_attach;
};
+/**
+ * DEFINE_DRM_GEM_FOPS() - macro to generate file operations for GEM drivers
+ * @name: name for the generated structure
+ *
+ * This macro autogenerates a suitable &struct file_operations for GEM based
+ * drivers, which can be assigned to &drm_driver.fops. Note that this structure
+ * cannot be shared between drivers, because it contains a reference to the
+ * current module using THIS_MODULE.
+ *
+ * Note that the declaration is already marked as static - if you need a
+ * non-static version of this you're probably doing it wrong and will break the
+ * THIS_MODULE reference by accident.
+ */
+#define DEFINE_DRM_GEM_FOPS(name) \
+ static const struct file_operations name = {\
+ .owner = THIS_MODULE,\
+ .open = drm_open,\
+ .release = drm_release,\
+ .unlocked_ioctl = drm_ioctl,\
+ .compat_ioctl = drm_compat_ioctl,\
+ .poll = drm_poll,\
+ .read = drm_read,\
+ .llseek = noop_llseek,\
+ .mmap = drm_gem_mmap,\
+ }
+
void drm_gem_object_release(struct drm_gem_object *obj);
void drm_gem_object_free(struct kref *kref);
int drm_gem_object_init(struct drm_device *dev,
diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h
index 2abcd5190cc1..f962d33667cf 100644
--- a/include/drm/drm_gem_cma_helper.h
+++ b/include/drm/drm_gem_cma_helper.h
@@ -26,6 +26,32 @@ to_drm_gem_cma_obj(struct drm_gem_object *gem_obj)
return container_of(gem_obj, struct drm_gem_cma_object, base);
}
+/**
+ * DEFINE_DRM_GEM_CMA_FOPS() - macro to generate file operations for CMA drivers
+ * @name: name for the generated structure
+ *
+ * This macro autogenerates a suitable &struct file_operations for CMA based
+ * drivers, which can be assigned to &drm_driver.fops. Note that this structure
+ * cannot be shared between drivers, because it contains a reference to the
+ * current module using THIS_MODULE.
+ *
+ * Note that the declaration is already marked as static - if you need a
+ * non-static version of this you're probably doing it wrong and will break the
+ * THIS_MODULE reference by accident.
+ */
+#define DEFINE_DRM_GEM_CMA_FOPS(name) \
+ static const struct file_operations name = {\
+ .owner = THIS_MODULE,\
+ .open = drm_open,\
+ .release = drm_release,\
+ .unlocked_ioctl = drm_ioctl,\
+ .compat_ioctl = drm_compat_ioctl,\
+ .poll = drm_poll,\
+ .read = drm_read,\
+ .llseek = noop_llseek,\
+ .mmap = drm_gem_cma_mmap,\
+ }
+
/* free GEM object */
void drm_gem_cma_free_object(struct drm_gem_object *gem_obj);
diff --git a/include/drm/drm_scdc_helper.h b/include/drm/drm_scdc_helper.h
new file mode 100644
index 000000000000..ab6bcfbceba9
--- /dev/null
+++ b/include/drm/drm_scdc_helper.h
@@ -0,0 +1,159 @@
+/*
+ * Copyright (c) 2015 NVIDIA Corporation. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sub license,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef DRM_SCDC_HELPER_H
+#define DRM_SCDC_HELPER_H
+
+#include <linux/i2c.h>
+#include <linux/types.h>
+
+#define SCDC_SINK_VERSION 0x01
+
+#define SCDC_SOURCE_VERSION 0x02
+
+#define SCDC_UPDATE_0 0x10
+#define SCDC_READ_REQUEST_TEST (1 << 2)
+#define SCDC_CED_UPDATE (1 << 1)
+#define SCDC_STATUS_UPDATE (1 << 0)
+
+#define SCDC_UPDATE_1 0x11
+
+#define SCDC_TMDS_CONFIG 0x20
+#define SCDC_TMDS_BIT_CLOCK_RATIO_BY_40 (1 << 1)
+#define SCDC_TMDS_BIT_CLOCK_RATIO_BY_10 (0 << 1)
+#define SCDC_SCRAMBLING_ENABLE (1 << 0)
+
+#define SCDC_SCRAMBLER_STATUS 0x21
+#define SCDC_SCRAMBLING_STATUS (1 << 0)
+
+#define SCDC_CONFIG_0 0x30
+#define SCDC_READ_REQUEST_ENABLE (1 << 0)
+
+#define SCDC_STATUS_FLAGS_0 0x40
+#define SCDC_CH2_LOCK (1 < 3)
+#define SCDC_CH1_LOCK (1 < 2)
+#define SCDC_CH0_LOCK (1 < 1)
+#define SCDC_CH_LOCK_MASK (SCDC_CH2_LOCK | SCDC_CH1_LOCK | SCDC_CH0_LOCK)
+#define SCDC_CLOCK_DETECT (1 << 0)
+
+#define SCDC_STATUS_FLAGS_1 0x41
+
+#define SCDC_ERR_DET_0_L 0x50
+#define SCDC_ERR_DET_0_H 0x51
+#define SCDC_ERR_DET_1_L 0x52
+#define SCDC_ERR_DET_1_H 0x53
+#define SCDC_ERR_DET_2_L 0x54
+#define SCDC_ERR_DET_2_H 0x55
+#define SCDC_CHANNEL_VALID (1 << 7)
+
+#define SCDC_ERR_DET_CHECKSUM 0x56
+
+#define SCDC_TEST_CONFIG_0 0xc0
+#define SCDC_TEST_READ_REQUEST (1 << 7)
+#define SCDC_TEST_READ_REQUEST_DELAY(x) ((x) & 0x7f)
+
+#define SCDC_MANUFACTURER_IEEE_OUI 0xd0
+#define SCDC_MANUFACTURER_IEEE_OUI_SIZE 3
+
+#define SCDC_DEVICE_ID 0xd3
+#define SCDC_DEVICE_ID_SIZE 8
+
+#define SCDC_DEVICE_HARDWARE_REVISION 0xdb
+#define SCDC_GET_DEVICE_HARDWARE_REVISION_MAJOR(x) (((x) >> 4) & 0xf)
+#define SCDC_GET_DEVICE_HARDWARE_REVISION_MINOR(x) (((x) >> 0) & 0xf)
+
+#define SCDC_DEVICE_SOFTWARE_MAJOR_REVISION 0xdc
+#define SCDC_DEVICE_SOFTWARE_MINOR_REVISION 0xdd
+
+#define SCDC_MANUFACTURER_SPECIFIC 0xde
+#define SCDC_MANUFACTURER_SPECIFIC_SIZE 34
+
+ssize_t drm_scdc_read(struct i2c_adapter *adapter, u8 offset, void *buffer,
+ size_t size);
+ssize_t drm_scdc_write(struct i2c_adapter *adapter, u8 offset,
+ const void *buffer, size_t size);
+
+/**
+ * drm_scdc_readb - read a single byte from SCDC
+ * @adapter: I2C adapter
+ * @offset: offset of register to read
+ * @value: return location for the register value
+ *
+ * Reads a single byte from SCDC. This is a convenience wrapper around the
+ * drm_scdc_read() function.
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+static inline int drm_scdc_readb(struct i2c_adapter *adapter, u8 offset,
+ u8 *value)
+{
+ return drm_scdc_read(adapter, offset, value, sizeof(*value));
+}
+
+/**
+ * drm_scdc_writeb - write a single byte to SCDC
+ * @adapter: I2C adapter
+ * @offset: offset of register to read
+ * @value: return location for the register value
+ *
+ * Writes a single byte to SCDC. This is a convenience wrapper around the
+ * drm_scdc_write() function.
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+static inline int drm_scdc_writeb(struct i2c_adapter *adapter, u8 offset,
+ u8 value)
+{
+ return drm_scdc_write(adapter, offset, &value, sizeof(value));
+}
+
+/**
+ * drm_scdc_set_scrambling - enable scrambling
+ * @adapter: I2C adapter for DDC channel
+ * @enable: bool to indicate if scrambling is to be enabled/disabled
+ *
+ * Writes the TMDS config register over SCDC channel, and:
+ * enables scrambling when enable = 1
+ * disables scrambling when enable = 0
+ *
+ * Returns:
+ * True if scrambling is set/reset successfully, false otherwise.
+ */
+bool drm_scdc_set_scrambling(struct i2c_adapter *adapter, bool enable);
+
+/**
+ * drm_scdc_set_high_tmds_clock_ratio - set TMDS clock ratio
+ * @adapter: I2C adapter for DDC channel
+ * @set: ret or reset the high clock ratio
+ *
+ * Writes to the TMDS config register over SCDC channel, and:
+ * sets TMDS clock ratio to 1/40 when set = 1
+ * sets TMDS clock ratio to 1/10 when set = 0
+ *
+ * Returns:
+ * True if write is successful, false otherwise.
+ */
+bool drm_scdc_set_high_tmds_clock_ratio(struct i2c_adapter *adapter, bool set);
+#endif