To save power, unused lanes should be powered
down using the bitfield of PORT_CL_DW10.
v2: Review comments from Jani N
- Put default label next to case 4
- Include the shifts in the macros
Signed-off-by: Madhav Chauhan <madhav.chauhan@xxxxxxxxx>
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
---
drivers/gpu/drm/i915/icl_dsi.c | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/drivers/gpu/drm/i915/icl_dsi.c b/drivers/gpu/drm/i915/icl_dsi.c
index 64f97c7..9262e3f 100644
--- a/drivers/gpu/drm/i915/icl_dsi.c
+++ b/drivers/gpu/drm/i915/icl_dsi.c
@@ -74,6 +74,43 @@ static void gen11_dsi_enable_io_power(struct intel_encoder *encoder)
}
}
+static void gen11_dsi_power_up_lanes(struct intel_encoder *encoder)
+{
+ struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+ struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
+ enum port port;
+ u32 tmp;
+ u32 lane_mask;
+
+ switch (intel_dsi->lane_count) {
+ case 1:
+ lane_mask = PWR_DOWN_LN_3_1_0;
+ break;
+ case 2:
+ lane_mask = PWR_DOWN_LN_3_1;
+ break;
+ case 3:
+ lane_mask = PWR_DOWN_LN_3;
+ break;
+ case 4:
+ default:
+ lane_mask = PWR_UP_ALL_LANES;
+ break;
+ }
+
+ for_each_dsi_port(port, intel_dsi->ports) {
+ tmp = I915_READ(ICL_PORT_CL_DW10(port));
+ tmp &= ~PWR_DOWN_LN_MASK;
+ I915_WRITE(ICL_PORT_CL_DW10(port), tmp | lane_mask);
+ }
+}
+
+static void gen11_dsi_enable_port_and_phy(struct intel_encoder *encoder)
+{
+ /* step 4a: power up all lanes of the DDI used by DSI */
+ gen11_dsi_power_up_lanes(encoder);
+}
+
static void __attribute__((unused))
gen11_dsi_pre_enable(struct intel_encoder *encoder,
const struct intel_crtc_state *pipe_config,
@@ -84,4 +121,7 @@ gen11_dsi_pre_enable(struct intel_encoder *encoder,
/* step3: enable DSI PLL */
gen11_dsi_program_esc_clk_div(encoder);
+
+ /* step4: enable DSI port and DPHY */
+ gen11_dsi_enable_port_and_phy(encoder);
}
--
2.7.4
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