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_panel;
  33
  34 /**
  35  * struct drm_bridge_funcs - drm_bridge control functions
  36  */
  37 struct drm_bridge_funcs {
  38         /**
  39          * @attach:
  40          *
  41          * This callback is invoked whenever our bridge is being attached to a
  42          * &drm_encoder.
  43          *
  44          * The attach callback is optional.
  45          *
  46          * RETURNS:
  47          *
  48          * Zero on success, error code on failure.
  49          */
  50         int (*attach)(struct drm_bridge *bridge);
  51
  52         /**
  53          * @detach:
  54          *
  55          * This callback is invoked whenever our bridge is being detached from a
  56          * &drm_encoder.
  57          *
  58          * The detach callback is optional.
  59          */
  60         void (*detach)(struct drm_bridge *bridge);
  61
  62         /**
  63          * @mode_valid:
  64          *
  65          * This callback is used to check if a specific mode is valid in this
  66          * bridge. This should be implemented if the bridge has some sort of
  67          * restriction in the modes it can display. For example, a given bridge
  68          * may be responsible to set a clock value. If the clock can not
  69          * produce all the values for the available modes then this callback
  70          * can be used to restrict the number of modes to only the ones that
  71          * can be displayed.
  72          *
  73          * This hook is used by the probe helpers to filter the mode list in
  74          * drm_helper_probe_single_connector_modes(), and it is used by the
  75          * atomic helpers to validate modes supplied by userspace in
  76          * drm_atomic_helper_check_modeset().
  77          *
  78          * This function is optional.
  79          *
  80          * NOTE:
  81          *
  82          * Since this function is both called from the check phase of an atomic
  83          * commit, and the mode validation in the probe paths it is not allowed
  84          * to look at anything else but the passed-in mode, and validate it
  85          * against configuration-invariant hardward constraints. Any further
  86          * limits which depend upon the configuration can only be checked in
  87          * @mode_fixup.
  88          *
  89          * RETURNS:
  90          *
  91          * drm_mode_status Enum
  92          */
  93         enum drm_mode_status (*mode_valid)(struct drm_bridge *crtc,
  94                                            const struct drm_display_mode *mode);
  95
  96         /**
  97          * @mode_fixup:
  98          *
  99          * This callback is used to validate and adjust a mode. The paramater
 100          * mode is the display mode that should be fed to the next element in
 101          * the display chain, either the final &drm_connector or the next
 102          * &drm_bridge. The parameter adjusted_mode is the input mode the bridge
 103          * requires. It can be modified by this callback and does not need to
 104          * match mode. See also &drm_crtc_state.adjusted_mode for more details.
 105          *
 106          * This is the only hook that allows a bridge to reject a modeset. If
 107          * this function passes all other callbacks must succeed for this
 108          * configuration.
 109          *
 110          * The mode_fixup callback is optional.
 111          *
 112          * NOTE:
 113          *
 114          * This function is called in the check phase of atomic modesets, which
 115          * can be aborted for any reason (including on userspace's request to
 116          * just check whether a configuration would be possible). Drivers MUST
 117          * NOT touch any persistent state (hardware or software) or data
 118          * structures except the passed in @state parameter.
 119          *
 120          * Also beware that userspace can request its own custom modes, neither
 121          * core nor helpers filter modes to the list of probe modes reported by
 122          * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
 123          * that modes are filtered consistently put any bridge constraints and
 124          * limits checks into @mode_valid.
 125          *
 126          * RETURNS:
 127          *
 128          * True if an acceptable configuration is possible, false if the modeset
 129          * operation should be rejected.
 130          */
 131         bool (*mode_fixup)(struct drm_bridge *bridge,
 132                            const struct drm_display_mode *mode,
 133                            struct drm_display_mode *adjusted_mode);
 134         /**
 135          * @disable:
 136          *
 137          * This callback should disable the bridge. It is called right before
 138          * the preceding element in the display pipe is disabled. If the
 139          * preceding element is a bridge this means it's called before that
 140          * bridge's @disable vfunc. If the preceding element is a &drm_encoder
 141          * it's called right before the &drm_encoder_helper_funcs.disable,
 142          * &drm_encoder_helper_funcs.prepare or &drm_encoder_helper_funcs.dpms
 143          * hook.
 144          *
 145          * The bridge can assume that the display pipe (i.e. clocks and timing
 146          * signals) feeding it is still running when this callback is called.
 147          *
 148          * The disable callback is optional.
 149          */
 150         void (*disable)(struct drm_bridge *bridge);
 151
 152         /**
 153          * @post_disable:
 154          *
 155          * This callback should disable the bridge. It is called right after the
 156          * preceding element in the display pipe is disabled. If the preceding
 157          * element is a bridge this means it's called after that bridge's
 158          * @post_disable function. If the preceding element is a &drm_encoder
 159          * it's called right after the encoder's
 160          * &drm_encoder_helper_funcs.disable, &drm_encoder_helper_funcs.prepare
 161          * or &drm_encoder_helper_funcs.dpms hook.
 162          *
 163          * The bridge must assume that the display pipe (i.e. clocks and timing
 164          * singals) feeding it is no longer running when this callback is
 165          * called.
 166          *
 167          * The post_disable callback is optional.
 168          */
 169         void (*post_disable)(struct drm_bridge *bridge);
 170
 171         /**
 172          * @mode_set:
 173          *
 174          * This callback should set the given mode on the bridge. It is called
 175          * after the @mode_set callback for the preceding element in the display
 176          * pipeline has been called already. If the bridge is the first element
 177          * then this would be &drm_encoder_helper_funcs.mode_set. The display
 178          * pipe (i.e.  clocks and timing signals) is off when this function is
 179          * called.
 180          */
 181         void (*mode_set)(struct drm_bridge *bridge,
 182                          struct drm_display_mode *mode,
 183                          struct drm_display_mode *adjusted_mode);
 184         /**
 185          * @pre_enable:
 186          *
 187          * This callback should enable the bridge. It is called right before
 188          * the preceding element in the display pipe is enabled. If the
 189          * preceding element is a bridge this means it's called before that
 190          * bridge's @pre_enable function. If the preceding element is a
 191          * &drm_encoder it's called right before the encoder's
 192          * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
 193          * &drm_encoder_helper_funcs.dpms hook.
 194          *
 195          * The display pipe (i.e. clocks and timing signals) feeding this bridge
 196          * will not yet be running when this callback is called. The bridge must
 197          * not enable the display link feeding the next bridge in the chain (if
 198          * there is one) when this callback is called.
 199          *
 200          * The pre_enable callback is optional.
 201          */
 202         void (*pre_enable)(struct drm_bridge *bridge);
 203
 204         /**
 205          * @enable:
 206          *
 207          * This callback should enable the bridge. It is called right after
 208          * the preceding element in the display pipe is enabled. If the
 209          * preceding element is a bridge this means it's called after that
 210          * bridge's @enable function. If the preceding element is a
 211          * &drm_encoder it's called right after the encoder's
 212          * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
 213          * &drm_encoder_helper_funcs.dpms hook.
 214          *
 215          * The bridge can assume that the display pipe (i.e. clocks and timing
 216          * signals) feeding it is running when this callback is called. This
 217          * callback must enable the display link feeding the next bridge in the
 218          * chain if there is one.
 219          *
 220          * The enable callback is optional.
 221          */
 222         void (*enable)(struct drm_bridge *bridge);
 223 };
 224
 225 /**
 226  * struct drm_bridge - central DRM bridge control structure
 227  * @dev: DRM device this bridge belongs to
 228  * @encoder: encoder to which this bridge is connected
 229  * @next: the next bridge in the encoder chain
 230  * @of_node: device node pointer to the bridge
 231  * @list: to keep track of all added bridges
 232  * @funcs: control functions
 233  * @driver_private: pointer to the bridge driver's internal context
 234  */
 235 struct drm_bridge {
 236         struct drm_device *dev;
 237         struct drm_encoder *encoder;
 238         struct drm_bridge *next;
 239 #ifdef CONFIG_OF
 240         struct device_node *of_node;
 241 #endif
 242         struct list_head list;
 243
 244         const struct drm_bridge_funcs *funcs;
 245         void *driver_private;
 246 };
 247
 248 int drm_bridge_add(struct drm_bridge *bridge);
 249 void drm_bridge_remove(struct drm_bridge *bridge);
 250 struct drm_bridge *of_drm_find_bridge(struct device_node *np);
 251 int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
 252                       struct drm_bridge *previous);
 253
 254 bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
 255                         const struct drm_display_mode *mode,
 256                         struct drm_display_mode *adjusted_mode);
 257 enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
 258                                            const struct drm_display_mode *mode);
 259 void drm_bridge_disable(struct drm_bridge *bridge);
 260 void drm_bridge_post_disable(struct drm_bridge *bridge);
 261 void drm_bridge_mode_set(struct drm_bridge *bridge,
 262                         struct drm_display_mode *mode,
 263                         struct drm_display_mode *adjusted_mode);
 264 void drm_bridge_pre_enable(struct drm_bridge *bridge);
 265 void drm_bridge_enable(struct drm_bridge *bridge);
 266
 267 #ifdef CONFIG_DRM_PANEL_BRIDGE
 268 struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel,
 269                                         u32 connector_type);
 270 void drm_panel_bridge_remove(struct drm_bridge *bridge);
 271 #endif
 272
 273 #endif