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Commit 8d4adc6a authored by Thierry Reding's avatar Thierry Reding
Browse files

drm/dp: Add drm_dp_dpcd_read_link_status() 



The function reads the link status (6 bytes starting at offset 0x202)
from the DPCD so that it can be conveniently passed to other DPCD
helpers.

Reviewed-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: default avatarJani Nikula <jani.nikula@intel.com>
Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
parent c197db75

drivers/gpu/drm/drm_dp_helper.c

+16 −0
Original line number Diff line number Diff line
@@ -456,3 +456,19 @@ ssize_t drm_dp_dpcd_write(struct drm_dp_aux *aux, unsigned int offset, 
				  size);

}

EXPORT_SYMBOL(drm_dp_dpcd_write);



/**

 * drm_dp_dpcd_read_link_status() - read DPCD link status (bytes 0x202-0x207)

 * @aux: DisplayPort AUX channel

 * @status: buffer to store the link status in (must be at least 6 bytes)

 *

 * Returns the number of bytes transferred on success or a negative error

 * code on failure.

 */

int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux,

				 u8 status[DP_LINK_STATUS_SIZE])

{

	return drm_dp_dpcd_read(aux, DP_LANE0_1_STATUS, status,

				DP_LINK_STATUS_SIZE);

}

EXPORT_SYMBOL(drm_dp_dpcd_read_link_status);

include/drm/drm_dp_helper.h

+3 −0
Original line number Diff line number Diff line
@@ -477,4 +477,7 @@ static inline ssize_t drm_dp_dpcd_writeb(struct drm_dp_aux *aux, 
	return drm_dp_dpcd_write(aux, offset, &value, 1);

}



int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux,

				 u8 status[DP_LINK_STATUS_SIZE]);



#endif /* _DRM_DP_HELPER_H_ */