diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/drm/drm_dp_helper.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 28ab6f4e3b09..b7488c9849ad 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -421,6 +421,7 @@ struct drm_dp_aux_msg { /** * struct drm_dp_aux - DisplayPort AUX channel + * @ddc: I2C adapter that can be used for I2C-over-AUX communication * @dev: pointer to struct device that is the parent for this AUX channel * @transfer: transfers a message representing a single AUX transaction * @@ -435,8 +436,16 @@ struct drm_dp_aux_msg { * propagate errors from the .transfer() function, with the exception of * the -EBUSY error, which causes a transaction to be retried. On a short, * helpers will return -EPROTO to make it simpler to check for failure. + * + * An AUX channel can also be used to transport I2C messages to a sink. A + * typical application of that is to access an EDID that's present in the + * sink device. The .transfer() function can also be used to execute such + * transactions. The drm_dp_aux_register_i2c_bus() function registers an + * I2C adapter that can be passed to drm_probe_ddc(). Upon removal, drivers + * should call drm_dp_aux_unregister_i2c_bus() to remove the I2C adapter. */ struct drm_dp_aux { + struct i2c_adapter ddc; struct device *dev; ssize_t (*transfer)(struct drm_dp_aux *aux, @@ -497,4 +506,7 @@ int drm_dp_link_probe(struct drm_dp_aux *aux, struct drm_dp_link *link); int drm_dp_link_power_up(struct drm_dp_aux *aux, struct drm_dp_link *link); int drm_dp_link_configure(struct drm_dp_aux *aux, struct drm_dp_link *link); +int drm_dp_aux_register_i2c_bus(struct drm_dp_aux *aux); +void drm_dp_aux_unregister_i2c_bus(struct drm_dp_aux *aux); + #endif /* _DRM_DP_HELPER_H_ */ |