include/drm/drm_bridge.h

   1 /*
   2  * Copyright (c) 2016 Intel Corporation
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software and its
   5  * documentation for any purpose is hereby granted without fee, provided that
   6  * the above copyright notice appear in all copies and that both that copyright
   7  * notice and this permission notice appear in supporting documentation, and
   8  * that the name of the copyright holders not be used in advertising or
   9  * publicity pertaining to distribution of the software without specific,
  10  * written prior permission.  The copyright holders make no representations
  11  * about the suitability of this software for any purpose.  It is provided "as
  12  * is" without express or implied warranty.
  13  *
  14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  16  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  20  * OF THIS SOFTWARE.
  21  */
  22
  23 #ifndef __DRM_BRIDGE_H__
  24 #define __DRM_BRIDGE_H__
  25
  26 #include <linux/list.h>
  27 #include <linux/ctype.h>
  28 #include <drm/drm_mode_object.h>
  29 #include <drm/drm_modes.h>
  30
  31 struct drm_bridge;
  32 struct drm_bridge_timings;
  33 struct drm_panel;
  34
  35 /**
  36  * struct drm_bridge_funcs - drm_bridge control functions
  37  */
  38 struct drm_bridge_funcs {
  39         /**
  40          * @attach:
  41          *
  42          * This callback is invoked whenever our bridge is being attached to a
  43          * &drm_encoder.
  44          *
  45          * The attach callback is optional.
  46          *
  47          * RETURNS:
  48          *
  49          * Zero on success, error code on failure.
  50          */
  51         int (*attach)(struct drm_bridge *bridge);
  52
  53         /**
  54          * @detach:
  55          *
  56          * This callback is invoked whenever our bridge is being detached from a
  57          * &drm_encoder.
  58          *
  59          * The detach callback is optional.
  60          */
  61         void (*detach)(struct drm_bridge *bridge);
  62
  63         /**
  64          * @mode_valid:
  65          *
  66          * This callback is used to check if a specific mode is valid in this
  67          * bridge. This should be implemented if the bridge has some sort of
  68          * restriction in the modes it can display. For example, a given bridge
  69          * may be responsible to set a clock value. If the clock can not
  70          * produce all the values for the available modes then this callback
  71          * can be used to restrict the number of modes to only the ones that
  72          * can be displayed.
  73          *
  74          * This hook is used by the probe helpers to filter the mode list in
  75          * drm_helper_probe_single_connector_modes(), and it is used by the
  76          * atomic helpers to validate modes supplied by userspace in
  77          * drm_atomic_helper_check_modeset().
  78          *
  79          * This function is optional.
  80          *
  81          * NOTE:
  82          *
  83          * Since this function is both called from the check phase of an atomic
  84          * commit, and the mode validation in the probe paths it is not allowed
  85          * to look at anything else but the passed-in mode, and validate it
  86          * against configuration-invariant hardward constraints. Any further
  87          * limits which depend upon the configuration can only be checked in
  88          * @mode_fixup.
  89          *
  90          * RETURNS:
  91          *
  92          * drm_mode_status Enum
  93          */
  94         enum drm_mode_status (*mode_valid)(struct drm_bridge *bridge,
  95                                            const struct drm_display_mode *mode);
  96
  97         /**
  98          * @mode_fixup:
  99          *
 100          * This callback is used to validate and adjust a mode. The parameter
 101          * mode is the display mode that should be fed to the next element in
 102          * the display chain, either the final &drm_connector or the next
 103          * &drm_bridge. The parameter adjusted_mode is the input mode the bridge
 104          * requires. It can be modified by this callback and does not need to
 105          * match mode. See also &drm_crtc_state.adjusted_mode for more details.
 106          *
 107          * This is the only hook that allows a bridge to reject a modeset. If
 108          * this function passes all other callbacks must succeed for this
 109          * configuration.
 110          *
 111          * The mode_fixup callback is optional.
 112          *
 113          * NOTE:
 114          *
 115          * This function is called in the check phase of atomic modesets, which
 116          * can be aborted for any reason (including on userspace's request to
 117          * just check whether a configuration would be possible). Drivers MUST
 118          * NOT touch any persistent state (hardware or software) or data
 119          * structures except the passed in @state parameter.
 120          *
 121          * Also beware that userspace can request its own custom modes, neither
 122          * core nor helpers filter modes to the list of probe modes reported by
 123          * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
 124          * that modes are filtered consistently put any bridge constraints and
 125          * limits checks into @mode_valid.
 126          *
 127          * RETURNS:
 128          *
 129          * True if an acceptable configuration is possible, false if the modeset
 130          * operation should be rejected.
 131          */
 132         bool (*mode_fixup)(struct drm_bridge *bridge,
 133                            const struct drm_display_mode *mode,
 134                            struct drm_display_mode *adjusted_mode);
 135         /**
 136          * @disable:
 137          *
 138          * This callback should disable the bridge. It is called right before
 139          * the preceding element in the display pipe is disabled. If the
 140          * preceding element is a bridge this means it's called before that
 141          * bridge's @disable vfunc. If the preceding element is a &drm_encoder
 142          * it's called right before the &drm_encoder_helper_funcs.disable,
 143          * &drm_encoder_helper_funcs.prepare or &drm_encoder_helper_funcs.dpms
 144          * hook.
 145          *
 146          * The bridge can assume that the display pipe (i.e. clocks and timing
 147          * signals) feeding it is still running when this callback is called.
 148          *
 149          * The disable callback is optional.
 150          */
 151         void (*disable)(struct drm_bridge *bridge);
 152
 153         /**
 154          * @post_disable:
 155          *
 156          * This callback should disable the bridge. It is called right after the
 157          * preceding element in the display pipe is disabled. If the preceding
 158          * element is a bridge this means it's called after that bridge's
 159          * @post_disable function. If the preceding element is a &drm_encoder
 160          * it's called right after the encoder's
 161          * &drm_encoder_helper_funcs.disable, &drm_encoder_helper_funcs.prepare
 162          * or &drm_encoder_helper_funcs.dpms hook.
 163          *
 164          * The bridge must assume that the display pipe (i.e. clocks and timing
 165          * singals) feeding it is no longer running when this callback is
 166          * called.
 167          *
 168          * The post_disable callback is optional.
 169          */
 170         void (*post_disable)(struct drm_bridge *bridge);
 171
 172         /**
 173          * @mode_set:
 174          *
 175          * This callback should set the given mode on the bridge. It is called
 176          * after the @mode_set callback for the preceding element in the display
 177          * pipeline has been called already. If the bridge is the first element
 178          * then this would be &drm_encoder_helper_funcs.mode_set. The display
 179          * pipe (i.e.  clocks and timing signals) is off when this function is
 180          * called.
 181          *
 182          * The adjusted_mode parameter is the mode output by the CRTC for the
 183          * first bridge in the chain. It can be different from the mode
 184          * parameter that contains the desired mode for the connector at the end
 185          * of the bridges chain, for instance when the first bridge in the chain
 186          * performs scaling. The adjusted mode is mostly useful for the first
 187          * bridge in the chain and is likely irrelevant for the other bridges.
 188          *
 189          * For atomic drivers the adjusted_mode is the mode stored in
 190          * &drm_crtc_state.adjusted_mode.
 191          *
 192          * NOTE:
 193          *
 194          * If a need arises to store and access modes adjusted for other
 195          * locations than the connection between the CRTC and the first bridge,
 196          * the DRM framework will have to be extended with DRM bridge states.
 197          */
 198         void (*mode_set)(struct drm_bridge *bridge,
 199                          struct drm_display_mode *mode,
 200                          struct drm_display_mode *adjusted_mode);
 201         /**
 202          * @pre_enable:
 203          *
 204          * This callback should enable the bridge. It is called right before
 205          * the preceding element in the display pipe is enabled. If the
 206          * preceding element is a bridge this means it's called before that
 207          * bridge's @pre_enable function. If the preceding element is a
 208          * &drm_encoder it's called right before the encoder's
 209          * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
 210          * &drm_encoder_helper_funcs.dpms hook.
 211          *
 212          * The display pipe (i.e. clocks and timing signals) feeding this bridge
 213          * will not yet be running when this callback is called. The bridge must
 214          * not enable the display link feeding the next bridge in the chain (if
 215          * there is one) when this callback is called.
 216          *
 217          * The pre_enable callback is optional.
 218          */
 219         void (*pre_enable)(struct drm_bridge *bridge);
 220
 221         /**
 222          * @enable:
 223          *
 224          * This callback should enable the bridge. It is called right after
 225          * the preceding element in the display pipe is enabled. If the
 226          * preceding element is a bridge this means it's called after that
 227          * bridge's @enable function. If the preceding element is a
 228          * &drm_encoder it's called right after the encoder's
 229          * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
 230          * &drm_encoder_helper_funcs.dpms hook.
 231          *
 232          * The bridge can assume that the display pipe (i.e. clocks and timing
 233          * signals) feeding it is running when this callback is called. This
 234          * callback must enable the display link feeding the next bridge in the
 235          * chain if there is one.
 236          *
 237          * The enable callback is optional.
 238          */
 239         void (*enable)(struct drm_bridge *bridge);
 240 };
 241
 242 /**
 243  * struct drm_bridge_timings - timing information for the bridge
 244  */
 245 struct drm_bridge_timings {
 246         /**
 247          * @sampling_edge:
 248          *
 249          * Tells whether the bridge samples the digital input signal
 250          * from the display engine on the positive or negative edge of the
 251          * clock, this should reuse the DRM_BUS_FLAG_PIXDATA_[POS|NEG]EDGE
 252          * bitwise flags from the DRM connector (bit 2 and 3 valid).
 253          */
 254         u32 sampling_edge;
 255         /**
 256          * @setup_time_ps:
 257          *
 258          * Defines the time in picoseconds the input data lines must be
 259          * stable before the clock edge.
 260          */
 261         u32 setup_time_ps;
 262         /**
 263          * @hold_time_ps:
 264          *
 265          * Defines the time in picoseconds taken for the bridge to sample the
 266          * input signal after the clock edge.
 267          */
 268         u32 hold_time_ps;
 269 };
 270
 271 /**
 272  * struct drm_bridge - central DRM bridge control structure
 273  */
 274 struct drm_bridge {
 275         /** @dev: DRM device this bridge belongs to */
 276         struct drm_device *dev;
 277         /** @encoder: encoder to which this bridge is connected */
 278         struct drm_encoder *encoder;
 279         /** @next: the next bridge in the encoder chain */
 280         struct drm_bridge *next;
 281 #ifdef CONFIG_OF
 282         /** @of_node: device node pointer to the bridge */
 283         struct device_node *of_node;
 284 #endif
 285         /** @list: to keep track of all added bridges */
 286         struct list_head list;
 287         /**
 288          * @timings:
 289          *
 290          * the timing specification for the bridge, if any (may be NULL)
 291          */
 292         const struct drm_bridge_timings *timings;
 293         /** @funcs: control functions */
 294         const struct drm_bridge_funcs *funcs;
 295         /** @driver_private: pointer to the bridge driver's internal context */
 296         void *driver_private;
 297 };
 298
 299 void drm_bridge_add(struct drm_bridge *bridge);
 300 void drm_bridge_remove(struct drm_bridge *bridge);
 301 struct drm_bridge *of_drm_find_bridge(struct device_node *np);
 302 int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
 303                       struct drm_bridge *previous);
 304
 305 bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
 306                            const struct drm_display_mode *mode,
 307                            struct drm_display_mode *adjusted_mode);
 308 enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
 309                                            const struct drm_display_mode *mode);
 310 void drm_bridge_disable(struct drm_bridge *bridge);
 311 void drm_bridge_post_disable(struct drm_bridge *bridge);
 312 void drm_bridge_mode_set(struct drm_bridge *bridge,
 313                          struct drm_display_mode *mode,
 314                          struct drm_display_mode *adjusted_mode);
 315 void drm_bridge_pre_enable(struct drm_bridge *bridge);
 316 void drm_bridge_enable(struct drm_bridge *bridge);
 317
 318 #ifdef CONFIG_DRM_PANEL_BRIDGE
 319 struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel,
 320                                         u32 connector_type);
 321 void drm_panel_bridge_remove(struct drm_bridge *bridge);
 322 struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev,
 323                                              struct drm_panel *panel,
 324                                              u32 connector_type);
 325 #endif
 326
 327 #endif