From 14407d3afed07c48a536be01d92dcd9812bcb3d5 Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Wed, 16 Jun 2021 16:15:27 +0200 Subject: drm/dp_helper: Rework the drm_dp_aux documentation Split the existing documentation to move the comments on particular fields next to them. Suggested-by: Daniel Vetter Signed-off-by: Maxime Ripard Acked-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210616141529.630719-1-maxime@cerno.tech --- include/drm/drm_dp_helper.h | 102 ++++++++++++++++++++++++++++++-------------- 1 file changed, 69 insertions(+), 33 deletions(-) (limited to 'include') diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 0bd6396648b4..683aa9892bad 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -1859,35 +1859,6 @@ struct drm_dp_aux_cec { /** * struct drm_dp_aux - DisplayPort AUX channel - * @name: user-visible name of this AUX channel and the I2C-over-AUX adapter - * @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 - * @drm_dev: pointer to the &drm_device that owns this AUX channel. Beware, this - * may be %NULL before drm_dp_aux_register() has been called. - * @crtc: backpointer to the crtc that is currently using this AUX channel - * @hw_mutex: internal mutex used for locking transfers - * @crc_work: worker that captures CRCs for each frame - * @crc_count: counter of captured frame CRCs - * @transfer: transfers a message representing a single AUX transaction - * - * The @dev field should be set to a pointer to the device that implements the - * AUX channel. As well, the @drm_dev field should be set to the &drm_device - * that will be using this AUX channel as early as possible. For many graphics - * drivers this should happen before drm_dp_aux_init(), however it's perfectly - * fine to set this field later so long as it's assigned before calling - * drm_dp_aux_register(). - * - * The @name field may be used to specify the name of the I2C adapter. If set to - * %NULL, dev_name() of @dev will be used. - * - * Drivers provide a hardware-specific implementation of how transactions are - * executed via the @transfer() function. A pointer to a &drm_dp_aux_msg - * structure describing the transaction is passed into this function. Upon - * success, the implementation should return the number of payload bytes that - * were transferred, or a negative error-code on failure. Helpers 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 @@ -1898,22 +1869,87 @@ struct drm_dp_aux_cec { * transfers by default; if a partial response is received, the adapter will * drop down to the size given by the partial response for this transaction * only. - * - * Note that the aux helper code assumes that the @transfer() function only - * modifies the reply field of the &drm_dp_aux_msg structure. The retry logic - * and i2c helpers assume this is the case. */ struct drm_dp_aux { + /** + * @name: user-visible name of this AUX channel and the + * I2C-over-AUX adapter. + * + * It's also used to specify the name of the I2C adapter. If set + * to %NULL, dev_name() of @dev will be used. + */ const char *name; + + /** + * @ddc: I2C adapter that can be used for I2C-over-AUX + * communication + */ struct i2c_adapter ddc; + + /** + * @dev: pointer to struct device that is the parent for this + * AUX channel. + */ struct device *dev; + + /** + * @drm_dev: pointer to the &drm_device that owns this AUX channel. + * Beware, this may be %NULL before drm_dp_aux_register() has been + * called. + * + * It should be set to the &drm_device that will be using this AUX + * channel as early as possible. For many graphics drivers this should + * happen before drm_dp_aux_init(), however it's perfectly fine to set + * this field later so long as it's assigned before calling + * drm_dp_aux_register(). + */ struct drm_device *drm_dev; + + /** + * @crtc: backpointer to the crtc that is currently using this + * AUX channel + */ struct drm_crtc *crtc; + + /** + * @hw_mutex: internal mutex used for locking transfers. + */ struct mutex hw_mutex; + + /** + * @crc_work: worker that captures CRCs for each frame + */ struct work_struct crc_work; + + /** + * @crc_count: counter of captured frame CRCs + */ u8 crc_count; + + /** + * @transfer: transfers a message representing a single AUX + * transaction. + * + * This is a hardware-specific implementation of how + * transactions are executed that the drivers must provide. + * + * A pointer to a &drm_dp_aux_msg structure describing the + * transaction is passed into this function. Upon success, the + * implementation should return the number of payload bytes that + * were transferred, or a negative error-code on failure. + * + * Helpers will propagate these errors, 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. + * + * The @transfer() function must only modify the reply field of + * the &drm_dp_aux_msg structure. The retry logic and i2c + * helpers assume this is the case. + */ ssize_t (*transfer)(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg); + /** * @i2c_nack_count: Counts I2C NACKs, used for DP validation. */ -- cgit v1.2.3