drm/i915/adl_p: Enable/disable loadgen sharing

Disable loadgen sharing for DP link rate 1.62 GHz and HDMI 5.94 GHz.
For all other modes, we can enable loadgen sharing feature.

BSpec: 55359

Cc: Imre Deak <[email protected]>
Signed-off-by: Mika Kahola <[email protected]>
Signed-off-by: Clinton Taylor <[email protected]>
Signed-off-by: Matt Roper <[email protected]>
Reviewed-by: Anusha Srivatsa <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: mkahola

drivers/gpu/drm/i915/display/intel_ddi.c

@@ -1459,6 +1459,14 @@ tgl_dkl_phy_ddi_vswing_sequence(struct intel_encoder *encoder,
 		val = intel_de_read(dev_priv, DKL_TX_DPCNTL2(tc_port));
 		val &= ~DKL_TX_DP20BITMODE;
 		intel_de_write(dev_priv, DKL_TX_DPCNTL2(tc_port), val);
+
+		if ((intel_crtc_has_dp_encoder(crtc_state) &&
+		     crtc_state->port_clock == 162000) ||
+		    (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_HDMI) &&
+		     crtc_state->port_clock == 594000))
+			val |= DKL_TX_LOADGEN_SHARING_PMD_DISABLE;
+		else
+			val &= ~DKL_TX_LOADGEN_SHARING_PMD_DISABLE;
 	}
 }
 

drivers/gpu/drm/i915/i915_reg.h

@@ -10825,6 +10825,7 @@ enum skl_power_gate {
 						     _DKL_TX_DPCNTL1)
 
 #define _DKL_TX_DPCNTL2				0x2C8
+#define  DKL_TX_LOADGEN_SHARING_PMD_DISABLE            REG_BIT(12)
 #define  DKL_TX_DP20BITMODE				(1 << 2)
 #define DKL_TX_DPCNTL2(tc_port) _MMIO(_PORT(tc_port, \
 						     _DKL_PHY1_BASE, \