drm/i915/mtl: Add gmbus and gpio support

Add tables to map the GMBUS pin pairs to GPIO registers and port to DDC.
From spec we have registers GPIO_CTL[1-5] mapped to native display phys and
GPIO_CTL[9-12] are mapped to TC ports.

v2:
 - Drop unused GPIO pins(MattR)

BSpec: 49306

Cc: Matt Roper <matthew.d.roper@intel.com>
Original Author: Brian J Lovin
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Reviewed-by: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220902060342.151824-6-radhakrishna.sripada@intel.com

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

@@ -117,6 +117,18 @@ static const struct gmbus_pin gmbus_pins_dg2[] = {
 	[GMBUS_PIN_9_TC1_ICP] = { "tc1", GPIOJ },
 };
 
+static const struct gmbus_pin gmbus_pins_mtp[] = {
+	[GMBUS_PIN_1_BXT] = { "dpa", GPIOB },
+	[GMBUS_PIN_2_BXT] = { "dpb", GPIOC },
+	[GMBUS_PIN_3_BXT] = { "dpc", GPIOD },
+	[GMBUS_PIN_4_CNP] = { "dpd", GPIOE },
+	[GMBUS_PIN_5_MTP] = { "dpe", GPIOF },
+	[GMBUS_PIN_9_TC1_ICP] = { "tc1", GPIOJ },
+	[GMBUS_PIN_10_TC2_ICP] = { "tc2", GPIOK },
+	[GMBUS_PIN_11_TC3_ICP] = { "tc3", GPIOL },
+	[GMBUS_PIN_12_TC4_ICP] = { "tc4", GPIOM },
+};
+
 static const struct gmbus_pin *get_gmbus_pin(struct drm_i915_private *i915,
 					     unsigned int pin)
 {
@@ -129,6 +141,9 @@ static const struct gmbus_pin *get_gmbus_pin(struct drm_i915_private *i915,
 	} else if (INTEL_PCH_TYPE(i915) >= PCH_DG1) {
 		pins = gmbus_pins_dg1;
 		size = ARRAY_SIZE(gmbus_pins_dg1);
+	} else if (INTEL_PCH_TYPE(i915) >= PCH_MTP) {
+		pins = gmbus_pins_mtp;
+		size = ARRAY_SIZE(gmbus_pins_mtp);
 	} else if (INTEL_PCH_TYPE(i915) >= PCH_ICP) {
 		pins = gmbus_pins_icp;
 		size = ARRAY_SIZE(gmbus_pins_icp);

drivers/gpu/drm/i915/display/intel_gmbus.h

@@ -24,6 +24,7 @@ struct i2c_adapter;
 #define GMBUS_PIN_2_BXT		2
 #define GMBUS_PIN_3_BXT		3
 #define GMBUS_PIN_4_CNP		4
+#define GMBUS_PIN_5_MTP		5
 #define GMBUS_PIN_9_TC1_ICP	9
 #define GMBUS_PIN_10_TC2_ICP	10
 #define GMBUS_PIN_11_TC3_ICP	11