Input: add Apple SPI keyboard and trackpad driver

The keyboard and trackpad on recent MacBook's (since 8,1) and
MacBookPro's (13,* and 14,*) are attached to an SPI controller instead
of USB, as previously. The higher level protocol is not publicly
documented and hence has been reverse engineered. As a consequence there
are still a number of unknown fields and commands. However, the known
parts have been working well and received extensive testing and use.

In order for this driver to work, the proper SPI drivers need to be
loaded too; for MB8,1 these are spi_pxa2xx_platform and spi_pxa2xx_pci;
for all others they are spi_pxa2xx_platform and intel_lpss_pci.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=99891
Link: https://bugzilla.kernel.org/show_bug.cgi?id=108331
Signed-off-by: Ronald Tschalär <ronald@innovation.ch>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/Kconfig

@@ -71,6 +71,22 @@ config KEYBOARD_AMIGA
 config ATARI_KBD_CORE
 	bool
 
+config KEYBOARD_APPLESPI
+	tristate "Apple SPI keyboard and trackpad"
+	depends on ACPI && EFI
+	depends on SPI
+	depends on X86 || COMPILE_TEST
+	help
+	  Say Y here if you are running Linux on any Apple MacBook8,1 or later,
+	  or any MacBookPro13,* or MacBookPro14,*.
+
+	  You will also need to enable appropriate SPI master controllers:
+	  spi_pxa2xx_platform and spi_pxa2xx_pci for MacBook8,1, and
+	  spi_pxa2xx_platform and intel_lpss_pci for the rest.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called applespi.
+
 config KEYBOARD_ATARI
 	tristate "Atari keyboard"
 	depends on ATARI

drivers/input/keyboard/Makefile

@@ -10,6 +10,7 @@ obj-$(CONFIG_KEYBOARD_ADP5520)		+= adp5520-keys.o
 obj-$(CONFIG_KEYBOARD_ADP5588)		+= adp5588-keys.o
 obj-$(CONFIG_KEYBOARD_ADP5589)		+= adp5589-keys.o
 obj-$(CONFIG_KEYBOARD_AMIGA)		+= amikbd.o
+obj-$(CONFIG_KEYBOARD_APPLESPI)		+= applespi.o
 obj-$(CONFIG_KEYBOARD_ATARI)		+= atakbd.o
 obj-$(CONFIG_KEYBOARD_ATKBD)		+= atkbd.o
 obj-$(CONFIG_KEYBOARD_BCM)		+= bcm-keypad.o

drivers/input/keyboard/applespi.h

@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * MacBook (Pro) SPI keyboard and touchpad driver
+ *
+ * Copyright (c) 2015-2019 Federico Lorenzi
+ * Copyright (c) 2017-2019 Ronald Tschalär
+ */
+
+#ifndef _APPLESPI_H_
+#define _APPLESPI_H_
+
+enum applespi_evt_type {
+	ET_CMD_TP_INI = BIT(0),
+	ET_CMD_BL = BIT(1),
+	ET_CMD_CL = BIT(2),
+	ET_RD_KEYB = BIT(8),
+	ET_RD_TPAD = BIT(9),
+	ET_RD_UNKN = BIT(10),
+	ET_RD_IRQ = BIT(11),
+	ET_RD_CRC = BIT(12),
+};
+
+enum applespi_pkt_type {
+	PT_READ,
+	PT_WRITE,
+	PT_STATUS,
+};
+
+#endif /* _APPLESPI_H_ */

drivers/input/keyboard/applespi_trace.h

@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * MacBook (Pro) SPI keyboard and touchpad driver
+ *
+ * Copyright (c) 2015-2019 Federico Lorenzi
+ * Copyright (c) 2017-2019 Ronald Tschalär
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM applespi
+
+#if !defined(_APPLESPI_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ)
+#define _APPLESPI_TRACE_H_
+
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+
+#include "applespi.h"
+
+DECLARE_EVENT_CLASS(dump_message_template,
+	TP_PROTO(enum applespi_evt_type evt_type,
+		 enum applespi_pkt_type pkt_type,
+		 u8 *buf,
+		 size_t len),
+
+	TP_ARGS(evt_type, pkt_type, buf, len),
+
+	TP_STRUCT__entry(
+		__field(enum applespi_evt_type, evt_type)
+		__field(enum applespi_pkt_type, pkt_type)
+		__field(size_t, len)
+		__dynamic_array(u8, buf, len)
+	),
+
+	TP_fast_assign(
+		__entry->evt_type = evt_type;
+		__entry->pkt_type = pkt_type;
+		__entry->len = len;
+		memcpy(__get_dynamic_array(buf), buf, len);
+	),
+
+	TP_printk("%-6s: %s",
+		  __print_symbolic(__entry->pkt_type,
+				   { PT_READ, "read" },
+				   { PT_WRITE, "write" },
+				   { PT_STATUS, "status" }
+		  ),
+		  __print_hex(__get_dynamic_array(buf), __entry->len))
+);
+
+#define DEFINE_DUMP_MESSAGE_EVENT(name)			\
+DEFINE_EVENT(dump_message_template, name,		\
+	TP_PROTO(enum applespi_evt_type evt_type,	\
+		 enum applespi_pkt_type pkt_type,	\
+		 u8 *buf,				\
+		 size_t len),				\
+	TP_ARGS(evt_type, pkt_type, buf, len)		\
+)
+
+DEFINE_DUMP_MESSAGE_EVENT(applespi_tp_ini_cmd);
+DEFINE_DUMP_MESSAGE_EVENT(applespi_backlight_cmd);
+DEFINE_DUMP_MESSAGE_EVENT(applespi_caps_lock_cmd);
+DEFINE_DUMP_MESSAGE_EVENT(applespi_keyboard_data);
+DEFINE_DUMP_MESSAGE_EVENT(applespi_touchpad_data);
+DEFINE_DUMP_MESSAGE_EVENT(applespi_unknown_data);
+DEFINE_DUMP_MESSAGE_EVENT(applespi_bad_crc);
+
+TRACE_EVENT(applespi_irq_received,
+	TP_PROTO(enum applespi_evt_type evt_type,
+		 enum applespi_pkt_type pkt_type),
+
+	TP_ARGS(evt_type, pkt_type),
+
+	TP_STRUCT__entry(
+		__field(enum applespi_evt_type, evt_type)
+		__field(enum applespi_pkt_type, pkt_type)
+	),
+
+	TP_fast_assign(
+		__entry->evt_type = evt_type;
+		__entry->pkt_type = pkt_type;
+	),
+
+	"\n"
+);
+
+#endif /* _APPLESPI_TRACE_H_ */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH ../../drivers/input/keyboard
+#define TRACE_INCLUDE_FILE applespi_trace
+#include <trace/define_trace.h>