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

Add function needed to generate ACPI backlight control SSDT, along with
Kconfig values for accessing the registers.

Tested by adding gfx register on system76/lemp11. Backlight controls
work on Windows 10 and Linux 6.1.

Change-Id: I1cc33bf0121ff44aea68a7e3615c5e58e2ab6ce2
Signed-off-by: Tim Crawford <tcrawford@system76.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69076
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/soc/intel/alderlake/Kconfig

@@ -484,4 +484,16 @@ config BUILDING_WITH_DEBUG_FSP
 	help
 	  Set this option if debug build of FSP is used.
 
+config INTEL_GMA_BCLV_OFFSET
+	default 0xc8258
+
+config INTEL_GMA_BCLV_WIDTH
+	default 32
+
+config INTEL_GMA_BCLM_OFFSET
+	default 0xc8254
+
+config INTEL_GMA_BCLM_WIDTH
+	default 32
+
 endif

src/soc/intel/alderlake/Makefile.inc

@@ -32,6 +32,7 @@ ramstage-y += elog.c
 ramstage-y += espi.c
 ramstage-y += finalize.c
 ramstage-y += fsp_params.c
+ramstage-y += graphics.c
 ramstage-y += hsphy.c
 ramstage-y += lockdown.c
 ramstage-y += me.c

src/soc/intel/alderlake/chip.h

@@ -4,6 +4,7 @@
 #define _SOC_CHIP_H_
 
 #include <drivers/i2c/designware/dw_i2c.h>
+#include <drivers/intel/gma/gma.h>
 #include <device/pci_ids.h>
 #include <intelblocks/cfg.h>
 #include <intelblocks/gpio.h>
@@ -647,6 +648,9 @@ struct soc_intel_alderlake_config {
 	 * Default is set to 0 and set to 1 to skip the MBP HOB.
 	 */
 	bool skip_mbp_hob;
+
+	/* i915 struct for GMA backlight control */
+	struct i915_gpu_controller_info gfx;
 };
 
 typedef struct soc_intel_alderlake_config config_t;

src/soc/intel/alderlake/graphics.c

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <intelblocks/graphics.h>
+#include <soc/ramstage.h>
+
+const struct i915_gpu_controller_info *
+intel_igd_get_controller_info(const struct device *const dev)
+{
+	const struct soc_intel_alderlake_config *const chip = dev->chip_info;
+	return &chip->gfx;
+}