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Commit 7529d6af authored by Mika Kahola's avatar Mika Kahola Committed by Jani Nikula
Browse files

drm: Helper to read max bits per component 



Helper routine to read out maximum supported bits per
component for DisplayPort legay converters.

v2: Return early if detailed port cap info is not available.
    Replace if-else ladder with switch-case (Ville)

Reviewed-by: default avatarJim Bride <jim.bride@linux.intel.com>
Signed-off-by: default avatarMika Kahola <mika.kahola@intel.com>
Acked-by: default avatarDave Airlie <airlied@gmail.com>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1473419458-17080-5-git-send-email-mika.kahola@intel.com
parent 1c29bd3d

drivers/gpu/drm/drm_dp_helper.c

+42 −0
Original line number Diff line number Diff line
@@ -471,6 +471,48 @@ int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], 
}

EXPORT_SYMBOL(drm_dp_downstream_max_clock);



/**

 * drm_dp_downstream_max_bpc() - extract branch device max

 *                               bits per component

 * @dpcd: DisplayPort configuration data

 * @port_cap: port capabilities

 *

 * Returns max bpc on success or 0 if max bpc not defined

 */

int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],

			      const u8 port_cap[4])

{

	int type = port_cap[0] & DP_DS_PORT_TYPE_MASK;

	bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] &

		DP_DETAILED_CAP_INFO_AVAILABLE;

	int bpc;



	if (!detailed_cap_info)

		return 0;



	switch (type) {

	case DP_DS_PORT_TYPE_VGA:

	case DP_DS_PORT_TYPE_DVI:

	case DP_DS_PORT_TYPE_HDMI:

	case DP_DS_PORT_TYPE_DP_DUALMODE:

		bpc = port_cap[2] & DP_DS_MAX_BPC_MASK;



		switch (bpc) {

		case DP_DS_8BPC:

			return 8;

		case DP_DS_10BPC:

			return 10;

		case DP_DS_12BPC:

			return 12;

		case DP_DS_16BPC:

			return 16;

		}

	default:

		return 0;

	}

}

EXPORT_SYMBOL(drm_dp_downstream_max_bpc);



/*

 * I2C-over-AUX implementation

 */

include/drm/drm_dp_helper.h

+2 −0
Original line number Diff line number Diff line
@@ -817,6 +817,8 @@ int drm_dp_link_power_down(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_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],

				const u8 port_cap[4]);

int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],

			      const u8 port_cap[4]);



void drm_dp_aux_init(struct drm_dp_aux *aux);

int drm_dp_aux_register(struct drm_dp_aux *aux);