diff options
Diffstat (limited to 'drivers/gpu/drm/drm_bridge.c')
| -rw-r--r-- | drivers/gpu/drm/drm_bridge.c | 69 |
1 files changed, 26 insertions, 43 deletions
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 6b8f7211e543..bd93453afa61 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 attached 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. * |