Input: add core support for Goodix Berlin Touchscreen IC

Add initial support for the new Goodix "Berlin" touchscreen ICs.

These touchscreen ICs support SPI, I2C and I3C interface, up to
10 finger touch, stylus and gestures events.

This initial driver is derived from the Goodix goodix_ts_berlin
available at [1] and [2] and only supports the GT9916 IC
present on the Qualcomm SM8550 MTP & QRD touch panel.

The current implementation only supports BerlinD, aka GT9916.

Support for advanced features like:
- Firmware & config update
- Stylus events
- Gestures events
- Previous revisions support (BerlinA or BerlinB)
is not included in current version.

The current support will work with currently flashed firmware
and config, and bail out if firmware or config aren't flashed yet.

[1] https://github.com/goodix/goodix_ts_berlin
[2] https://git.codelinaro.org/clo/la/platform/vendor/opensource/touch-drivers

Reviewed-by: Jeff LaBundy <jeff@labundy.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240129-topic-goodix-berlin-upstream-initial-v15-2-6f7d096c0a0a@linaro.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/Kconfig

@@ -416,6 +416,9 @@ config TOUCHSCREEN_GOODIX
 	  To compile this driver as a module, choose M here: the
 	  module will be called goodix.
 
+config TOUCHSCREEN_GOODIX_BERLIN_CORE
+	tristate
+
 config TOUCHSCREEN_HIDEEP
 	tristate "HiDeep Touch IC"
 	depends on I2C

drivers/input/touchscreen/Makefile

@@ -47,6 +47,7 @@ obj-$(CONFIG_TOUCHSCREEN_EGALAX_SERIAL)	+= egalax_ts_serial.o
 obj-$(CONFIG_TOUCHSCREEN_EXC3000)	+= exc3000.o
 obj-$(CONFIG_TOUCHSCREEN_FUJITSU)	+= fujitsu_ts.o
 obj-$(CONFIG_TOUCHSCREEN_GOODIX)	+= goodix_ts.o
+obj-$(CONFIG_TOUCHSCREEN_GOODIX_BERLIN_CORE)	+= goodix_berlin_core.o
 obj-$(CONFIG_TOUCHSCREEN_HIDEEP)	+= hideep.o
 obj-$(CONFIG_TOUCHSCREEN_HYNITRON_CSTXXX)	+= hynitron_cstxxx.o
 obj-$(CONFIG_TOUCHSCREEN_ILI210X)	+= ili210x.o

drivers/input/touchscreen/goodix_berlin.h

@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Goodix Touchscreen Driver
+ * Copyright (C) 2020 - 2021 Goodix, Inc.
+ * Copyright (C) 2023 Linaro Ltd.
+ *
+ * Based on goodix_berlin_berlin driver.
+ */
+
+#ifndef __GOODIX_BERLIN_H_
+#define __GOODIX_BERLIN_H_
+
+#include <linux/pm.h>
+
+struct device;
+struct input_id;
+struct regmap;
+
+int goodix_berlin_probe(struct device *dev, int irq, const struct input_id *id,
+			struct regmap *regmap);
+
+extern const struct dev_pm_ops goodix_berlin_pm_ops;
+
+#endif