soc/intel/skylake: Hook up GMA ACPI brightness controls

Add struct i915_gpu_controller_info for boards to supply info needed
to generate ACPI backlight control SSDT. Hook into soc/common framework
by implementing intel_igd_get_controller_info().

Change-Id: I70e280e54d78e69a335f9a382261193c593ce430
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39883
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

src/soc/intel/skylake/chip.h

@@ -19,6 +19,7 @@
 #include <arch/acpi_device.h>
 #include <device/i2c_simple.h>
 #include <drivers/i2c/designware/dw_i2c.h>
+#include <drivers/intel/gma/i915.h>
 #include <intelblocks/cfg.h>
 #include <intelblocks/gspi.h>
 #include <intelblocks/lpc_lib.h>
@@ -583,6 +584,9 @@ struct soc_intel_skylake_config {
 
 	/* Enable/Disable Sata test mode */
 	u8 SataTestMode;
+
+	/* i915 struct for GMA backlight control */
+	struct i915_gpu_controller_info gfx;
 };
 
 typedef struct soc_intel_skylake_config config_t;

src/soc/intel/skylake/graphics.c

@@ -19,6 +19,7 @@
 #include <device/pci.h>
 #include <device/pci_ops.h>
 #include <device/resource.h>
+#include <drivers/intel/gma/i915.h>
 #include <drivers/intel/gma/i915_reg.h>
 #include <drivers/intel/gma/libgfxinit.h>
 #include <intelblocks/graphics.h>
@@ -185,3 +186,10 @@ uintptr_t graphics_soc_write_acpi_opregion(struct device *device,
 	printk(BIOS_DEBUG, "current = %lx\n", current);
 	return current;
 }
+
+const struct i915_gpu_controller_info *
+intel_igd_get_controller_info(struct device *device)
+{
+	struct soc_intel_skylake_config *chip = device->chip_info;
+	return &chip->gfx;
+}