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

Add framework to hook up the generic src/drivers/intel/gma ACPI
backlight control for platforms using SOC_INTEL_COMMON_BLOCK_GRAPHICS.
Add a weak function to get the struct i915_gpu_controller_info needed
to generate the SSDT, defaulting to NULL, which SoC's will override.

Each SoC will need to override intel_igd_get_controller_info, and
individual boards will need to populate the struct in order for
the backlight control methods to be added to the SSDT.

Change-Id: I993770fdcd0a28cee756df2bd6a795498f175952
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32549
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/common/block/graphics/graphics.c

@@ -18,6 +18,7 @@
 #include <device/mmio.h>
 #include <device/pci.h>
 #include <device/pci_ids.h>
+#include <drivers/intel/gma/i915.h>
 #include <intelblocks/graphics.h>
 #include <soc/pci_devs.h>
 
@@ -32,6 +33,20 @@ __weak void graphics_soc_init(struct device *dev)
 	pci_dev_init(dev);
 }
 
+__weak const struct i915_gpu_controller_info *
+intel_igd_get_controller_info(struct device *device)
+{
+	return NULL;
+}
+
+static void gma_generate_ssdt(struct device *device)
+{
+	const struct i915_gpu_controller_info *gfx = intel_igd_get_controller_info(device);
+
+	if (gfx)
+		drivers_intel_gma_displays_ssdt_generate(gfx);
+}
+
 static int is_graphics_disabled(struct device *dev)
 {
 	/* Check if Graphics PCI device is disabled */
@@ -118,6 +133,7 @@ static const struct device_operations graphics_ops = {
 	.ops_pci			= &pci_dev_ops_pci,
 #if CONFIG(HAVE_ACPI_TABLES)
 	.write_acpi_tables		= graphics_soc_write_acpi_opregion,
+	.acpi_fill_ssdt_generator	= gma_generate_ssdt,
 #endif
 	.scan_bus			= scan_generic_bus,
 };

src/soc/intel/common/block/include/intelblocks/graphics.h

@@ -44,6 +44,10 @@ void graphics_soc_init(struct device *dev);
 uintptr_t graphics_soc_write_acpi_opregion(struct device *device,
 		uintptr_t current, struct acpi_rsdp *rsdp);
 
+/* i915 controller info for ACPI backlight controls */
+const struct i915_gpu_controller_info *
+intel_igd_get_controller_info(struct device *device);
+
 /* Graphics MMIO register read/write APIs */
 uint32_t graphics_gtt_read(unsigned long reg);
 void graphics_gtt_write(unsigned long reg, uint32_t data);