From: Quentin Schulz quentin.schulz@free-electrons.com
We already have functions to get the adjust request voltage and pre-emphasis for a lane so it makes also sense to be able to set them so that we can then easily update them via a DPCD write.
Add helpers for drm_dp_set_adjust_request_pre_emphasis and drm_dp_set_adjust_request_voltage that respectively set the pre-emphasis and voltage of a lane in the link status array.
Signed-off-by: Quentin Schulz quentin.schulz@free-electrons.com Signed-off-by: Damian Kos dkos@cadence.com --- drivers/gpu/drm/drm_dp_helper.c | 28 ++++++++++++++++++++++++++++ include/drm/drm_dp_helper.h | 4 ++++ 2 files changed, 32 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 3bc2e98..ca2f469 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -120,6 +120,34 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI } EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis);
+void drm_dp_set_adjust_request_voltage(u8 link_status[DP_LINK_STATUS_SIZE], + int lane, u8 volt) +{ + int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); + int s = ((lane & 1) ? + DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT : + DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT); + int idx = i - DP_LANE0_1_STATUS; + + link_status[idx] &= ~(DP_ADJUST_VOLTAGE_SWING_LANE0_MASK << s); + link_status[idx] |= volt << s; +} +EXPORT_SYMBOL(drm_dp_set_adjust_request_voltage); + +void drm_dp_set_adjust_request_pre_emphasis(u8 link_status[DP_LINK_STATUS_SIZE], + int lane, u8 pre_emphasis) +{ + int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); + int s = ((lane & 1) ? + DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT : + DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT); + int idx = i - DP_LANE0_1_STATUS; + + link_status[idx] &= ~(DP_ADJUST_PRE_EMPHASIS_LANE0_MASK << s); + link_status[idx] |= pre_emphasis << s; +} +EXPORT_SYMBOL(drm_dp_set_adjust_request_pre_emphasis); + void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) udelay(100); diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index a488af0..6e64b2a 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -946,6 +946,10 @@ u8 drm_dp_get_adjust_request_voltage(const u8 link_status[DP_LINK_STATUS_SIZE], int lane); u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SIZE], int lane); +void drm_dp_set_adjust_request_voltage(u8 link_status[DP_LINK_STATUS_SIZE], + int lane, u8 volt); +void drm_dp_set_adjust_request_pre_emphasis(u8 link_status[DP_LINK_STATUS_SIZE], + int lane, u8 pre_emphasis);
#define DP_BRANCH_OUI_HEADER_SIZE 0xc #define DP_RECEIVER_CAP_SIZE 0xf