[CI 07/32] drm/i915/display: Add macro to get DDI port width from a register value

[Mika Kahola <mika.kahola@intel.com>]

From: Imre Deak <imre.deak@intel.com>

A follow-up change will need to retrieve the DDI port field from the
register value, add a macro for this. Make things symmetric with setting
the field in the register.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
---
 drivers/gpu/drm/i915/display/intel_display_regs.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_regs.h b/drivers/gpu/drm/i915/display/intel_display_regs.h
index 9d71e26a4fa2..c14d3caa73a7 100644
--- a/drivers/gpu/drm/i915/display/intel_display_regs.h
+++ b/drivers/gpu/drm/i915/display/intel_display_regs.h
@@ -2349,8 +2349,13 @@ enum skl_power_gate {
 #define  DDI_BUF_CTL_TC_PHY_OWNERSHIP		REG_BIT(6)
 #define  DDI_A_4_LANES				REG_BIT(4)
 #define  DDI_PORT_WIDTH_MASK			REG_GENMASK(3, 1)
+#define  DDI_PORT_WIDTH_ENCODE(width)		((width) == 3 ? 4 : (width) - 1)
+#define  DDI_PORT_WIDTH_DECODE(regval)		((regval) == 4 ? 3 : (regval) + 1)
 #define  DDI_PORT_WIDTH(width)			REG_FIELD_PREP(DDI_PORT_WIDTH_MASK, \
-							       ((width) == 3 ? 4 : (width) - 1))
+							       DDI_PORT_WIDTH_ENCODE(width))
+#define  DDI_PORT_WIDTH_GET(regval)		DDI_PORT_WIDTH_DECODE(REG_FIELD_GET(DDI_PORT_WIDTH_MASK, \
+										    (regval)))
+
 #define  DDI_PORT_WIDTH_SHIFT			1
 #define  DDI_INIT_DISPLAY_DETECTED		REG_BIT(0)
 
-- 
2.34.1