4 Dec
2015
4 Dec
'15
10:43 a.m.
On 12/04/2015 02:15 PM, Daniel Vetter wrote:
Especially document the assumptions and semantics of the callbacks carefully. Just a warm-up excercise really.
v2: Spelling fixes (Eric).
v3: Consolidate more with existing docs:
Remove the overview section explaining the bridge funcs, that's now all in the drm_bridge_funcs kerneldoc in much more detail.
Use & to reference structs so that kerneldoc automatically inserts hyperlinks.
Reviewed-by: Archit Taneja architt@codeaurora.org
Cc: Eric Anholt eric@anholt.net Cc: Archit Taneja architt@codeaurora.org Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch
drivers/gpu/drm/drm_bridge.c | 69 +++++++++++------------------ include/drm/drm_crtc.h | 102 ++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 122 insertions(+), 49 deletions(-)
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 6b8f7211e543..26dd1cfb6078 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -31,14 +31,14 @@ /**
- DOC: overview
- drm_bridge represents a device that hangs on to an encoder. These are handy
- when a regular drm_encoder entity isn't enough to represent the entire
- struct &drm_bridge represents a device that hangs on to an encoder. These are
- handy when a regular &drm_encoder entity isn't enough to represent the entire
- encoder chain.
- A bridge is always associated to a single drm_encoder at a time, but can be
- A bridge is always associated to a single &drm_encoder at a time, but can be
- either connected to it directly, or through an intermediate bridge:
- encoder ---> bridge B ---> bridge A
encoder ---> bridge B ---> bridge A- Here, the output of the encoder feeds to bridge B, and that furthers feeds to
- bridge A.
@@ -46,11 +46,16 @@
- The driver using the bridge is responsible to make the associations between
- the encoder and bridges. Once these links are made, the bridges will
- participate along with encoder functions to perform mode_set/enable/disable
- through the ops provided in drm_bridge_funcs.
- through the ops provided in &drm_bridge_funcs.
- drm_bridge, like drm_panel, aren't drm_mode_object entities like planes,
- crtcs, encoders or connectors. They just provide additional hooks to get the
- desired output at the end of the encoder chain.
- crtcs, encoders or connectors and hence are not visible to userspace. They
- just provide additional hooks to get the desired output at the end of the
- encoder chain.
- Bridges can also be chained up using the next pointer in struct &drm_bridge.
- Both legacy CRTC helpers and the new atomic modeset helpers support bridges.
*/
static DEFINE_MUTEX(bridge_lock);
@@ -122,34 +127,12 @@ EXPORT_SYMBOL(drm_bridge_attach); /**
- DOC: bridge callbacks
- The drm_bridge_funcs ops are populated by the bridge driver. The drm
- internals(atomic and crtc helpers) use the helpers defined in drm_bridge.c
- These helpers call a specific drm_bridge_funcs op for all the bridges
- The &drm_bridge_funcs ops are populated by the bridge driver. The drm
- internals (atomic and crtc helpers) use the helpers defined in drm_bridge.c
- These helpers call a specific &drm_bridge_funcs op for all the bridges
- during encoder configuration.
- When creating a bridge driver, one can implement drm_bridge_funcs op with
- the help of these rough rules:
- pre_enable: this contains things needed to be done for the bridge before
- its clock and timings are enabled by its source. For a bridge, its source
- is generally the encoder or bridge just before it in the encoder chain.
- enable: this contains things needed to be done for the bridge once its
- source is enabled. In other words, enable is called once the source is
- ready with clock and timing needed by the bridge.
- disable: this contains things needed to be done for the bridge assuming
- that its source is still enabled, i.e. clock and timings are still on.
- post_disable: this contains things needed to be done for the bridge once
- its source is disabled, i.e. once clocks and timings are off.
- mode_fixup: this should fixup the given mode for the bridge. It is called
- after the encoder's mode fixup. mode_fixup can also reject a mode completely
- if it's unsuitable for the hardware.
- mode_set: this sets up the mode for the bridge. It assumes that its source
- (an encoder or a bridge) has set the mode too.
- For detailed specification of the bridge callbacks see &drm_bridge_funcs.
*/
/**
@@ -159,7 +142,7 @@ EXPORT_SYMBOL(drm_bridge_attach);
- @mode: desired mode to be set for the bridge
- @adjusted_mode: updated mode that works for this bridge
- Calls 'mode_fixup' drm_bridge_funcs op for all the bridges in the
- Calls 'mode_fixup' &drm_bridge_funcs op for all the bridges in the
- encoder chain, starting from the first bridge to the last.
- Note: the bridge passed should be the one closest to the encoder
@@ -186,11 +169,11 @@ bool drm_bridge_mode_fixup(struct drm_bridge *bridge, EXPORT_SYMBOL(drm_bridge_mode_fixup);
/**
- drm_bridge_disable - calls 'disable' drm_bridge_funcs op for all
- drm_bridge_disable - calls 'disable' &drm_bridge_funcs op for all
bridges in the encoder chain.- @bridge: bridge control structure
- Calls 'disable' drm_bridge_funcs op for all the bridges in the encoder
- Calls 'disable' &drm_bridge_funcs op for all the bridges in the encoder
- chain, starting from the last bridge to the first. These are called before
- calling the encoder's prepare op.
@@ -208,11 +191,11 @@ void drm_bridge_disable(struct drm_bridge *bridge) EXPORT_SYMBOL(drm_bridge_disable);
/**
- drm_bridge_post_disable - calls 'post_disable' drm_bridge_funcs op for
- drm_bridge_post_disable - calls 'post_disable' &drm_bridge_funcs op for
all bridges in the encoder chain.- @bridge: bridge control structure
- Calls 'post_disable' drm_bridge_funcs op for all the bridges in the
- Calls 'post_disable' &drm_bridge_funcs op for all the bridges in the
- encoder chain, starting from the first bridge to the last. These are called
- after completing the encoder's prepare op.
@@ -236,7 +219,7 @@ EXPORT_SYMBOL(drm_bridge_post_disable);
- @mode: desired mode to be set for the bridge
- @adjusted_mode: updated mode that works for this bridge
- Calls 'mode_set' drm_bridge_funcs op for all the bridges in the
- Calls 'mode_set' &drm_bridge_funcs op for all the bridges in the
- encoder chain, starting from the first bridge to the last.
- Note: the bridge passed should be the one closest to the encoder
@@ -256,11 +239,11 @@ void drm_bridge_mode_set(struct drm_bridge *bridge, EXPORT_SYMBOL(drm_bridge_mode_set);
/**
- drm_bridge_pre_enable - calls 'pre_enable' drm_bridge_funcs op for all
- drm_bridge_pre_enable - calls 'pre_enable' &drm_bridge_funcs op for all
bridges in the encoder chain.- @bridge: bridge control structure
- Calls 'pre_enable' drm_bridge_funcs op for all the bridges in the encoder
- Calls 'pre_enable' &drm_bridge_funcs op for all the bridges in the encoder
- chain, starting from the last bridge to the first. These are called
- before calling the encoder's commit op.
@@ -278,11 +261,11 @@ void drm_bridge_pre_enable(struct drm_bridge *bridge) EXPORT_SYMBOL(drm_bridge_pre_enable);
/**
- drm_bridge_enable - calls 'enable' drm_bridge_funcs op for all bridges
- drm_bridge_enable - calls 'enable' &drm_bridge_funcs op for all bridges
in the encoder chain.- @bridge: bridge control structure
- Calls 'enable' drm_bridge_funcs op for all the bridges in the encoder
- Calls 'enable' &drm_bridge_funcs op for all the bridges in the encoder
- chain, starting from the first bridge to the last. These are called
- after completing the encoder's commit op.
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index e8f8e4e9a6a1..ec3632e62b3f 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -883,24 +883,114 @@ struct drm_plane { /**
- struct drm_bridge_funcs - drm_bridge control functions
- @attach: Called during drm_bridge_attach
- @mode_fixup: Try to fixup (or reject entirely) proposed mode for this bridge
- @disable: Called right before encoder prepare, disables the bridge
- @post_disable: Called right after encoder prepare, for lockstepped disable
- @mode_set: Set this mode to the bridge
- @pre_enable: Called right before encoder commit, for lockstepped commit
*/ struct drm_bridge_funcs { int (*attach)(struct drm_bridge *bridge);
- @enable: Called right after encoder commit, enables the bridge
- /**
* @mode_fixup:** This callback is used to validate and adjust a mode. The paramater* mode is the display mode that should be fed to the next element in* the display chain, either the final &drm_connector or the next* &drm_bridge. The parameter adjusted_mode is the input mode the bridge* requires. It can be modified by this callback and does not need to* match mode.** This is the only hook that allows a bridge to reject a modeset. If* this function passes all other callbacks must succeed for this* configuration.** NOTE:** This function is called in the check phase of atomic modesets, which* can be aborted for any reason (including on userspace's request to* just check whether a configuration would be possible). Drivers MUST* NOT touch any persistent state (hardware or software) or data* structures except the passed in adjusted_mode parameter.** RETURNS:** True if an acceptable configuration is possible, false if the modeset* operation should be rejected.*/- /**
* @disable:** This callback should disable the bridge. It is called right before* the preceding element in the display pipe is disabled. If the* preceding element is a bridge this means it's called before that* bridge's ->disaable function. If the preceding element is a* &drm_encoder it's called right before the encoder's ->disable,* ->prepare or ->dpms hook from struct &drm_encoder_helper_funcs.** The bridge can assume that the display pipe (i.e. clocks and timing* signals) feeding it is still running when this callback is called.*/- /**
* @post_disable:** This callback should disable the bridge. It is called right after* the preceding element in the display pipe is disabled. If the* preceding element is a bridge this means it's called after that* bridge's ->post_disaable function. If the preceding element is a* &drm_encoder it's called right after the encoder's ->disable,* ->prepare or ->dpms hook from struct &drm_encoder_helper_funcs.** The bridge must assume that the display pipe (i.e. clocks and timing* singals) feeding it is no longer running when this callback is* called.*/- /**
* @mode_set:** This callback should set the given mode on the bridge. It is called* after the ->mode_set callback for the preceding element in the* display pipeline has been called already. The display pipe (i.e.* clocks and timing signals) is off when this function is called.*/- /**
* @pre_enable:** This callback should enable the bridge. It is called right before* the preceding element in the display pipe is enabled. If the* preceding element is a bridge this means it's called before that* bridge's ->pre_enable function. If the preceding element is a* &drm_encoder it's called right before the encoder's ->enable,* ->commit or ->dpms hook from struct &drm_encoder_helper_funcs.** The display pipe (i.e. clocks and timing signals) feeding this bridge* will not yet be running when this callback is called. The bridge must* not enable the display link feeding the next bridge in the chain (if* there is one) when this callback is called.*/- /**
* @enable:** This callback should enable the bridge. It is called right after* the preceding element in the display pipe is enabled. If the* preceding element is a bridge this means it's called after that* bridge's ->enable function. If the preceding element is a* &drm_encoder it's called right after the encoder's ->enable,* ->commit or ->dpms hook from struct &drm_encoder_helper_funcs.** The bridge can assume that the display pipe (i.e. clocks and timing* signals) feeding it is running when this callback is called. This* callback must enable the display link feeding the next bridge in the* chain if there is one.*/
--
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