Allow custom data sync for community modules (#25955)

* Allow custom data sync for community modules

* Stub out community_config.h codegen

* Fix SPLIT_TRANSACTION_RPC logic

builddefs/build_keyboard.mk

@@ -187,6 +187,11 @@ include $(COMMUNITY_RULES_MK)
 
 ifneq ($(COMMUNITY_MODULES),)
 
+$(INTERMEDIATE_OUTPUT)/src/community_config.h: $(KEYMAP_JSON) $(DD_CONFIG_FILES)
+	@$(SILENT) || printf "$(MSG_GENERATING) $@" | $(AWK_CMD)
+	$(eval CMD=$(QMK_BIN) generate-community-config-h -kb $(KEYBOARD) --quiet --output $(INTERMEDIATE_OUTPUT)/src/community_config.h $(KEYMAP_JSON))
+	@$(BUILD_CMD)
+
 $(INTERMEDIATE_OUTPUT)/src/community_modules.h: $(KEYMAP_JSON) $(DD_CONFIG_FILES)
 	@$(SILENT) || printf "$(MSG_GENERATING) $@" | $(AWK_CMD)
 	$(eval CMD=$(QMK_BIN) generate-community-modules-h -kb $(KEYBOARD) --quiet --output $(INTERMEDIATE_OUTPUT)/src/community_modules.h $(KEYMAP_JSON))
@@ -217,9 +222,15 @@ $(INTERMEDIATE_OUTPUT)/src/rgb_matrix_community_modules.inc: $(KEYMAP_JSON) $(DD
 	$(eval CMD=$(QMK_BIN) generate-rgb-matrix-community-modules-inc -kb $(KEYBOARD) --quiet --output $(INTERMEDIATE_OUTPUT)/src/rgb_matrix_community_modules.inc $(KEYMAP_JSON))
 	@$(BUILD_CMD)
 
+$(INTERMEDIATE_OUTPUT)/src/split_transaction_id_community_modules.inc: $(KEYMAP_JSON) $(DD_CONFIG_FILES)
+	@$(SILENT) || printf "$(MSG_GENERATING) $@" | $(AWK_CMD)
+	$(eval CMD=$(QMK_BIN) generate-split-transaction-id-community-modules-inc -kb $(KEYBOARD) --quiet --output $(INTERMEDIATE_OUTPUT)/src/split_transaction_id_community_modules.inc $(KEYMAP_JSON))
+	@$(BUILD_CMD)
+
+COMMUNITY_CONFIG_H = $(INTERMEDIATE_OUTPUT)/src/community_config.h
 SRC += $(INTERMEDIATE_OUTPUT)/src/community_modules.c
 
-generated-files: $(INTERMEDIATE_OUTPUT)/src/community_modules.h $(INTERMEDIATE_OUTPUT)/src/community_modules.c $(INTERMEDIATE_OUTPUT)/src/community_modules_introspection.c $(INTERMEDIATE_OUTPUT)/src/community_modules_introspection.h $(INTERMEDIATE_OUTPUT)/src/led_matrix_community_modules.inc $(INTERMEDIATE_OUTPUT)/src/rgb_matrix_community_modules.inc
+generated-files: $(INTERMEDIATE_OUTPUT)/src/community_config.h $(INTERMEDIATE_OUTPUT)/src/community_modules.h $(INTERMEDIATE_OUTPUT)/src/community_modules.c $(INTERMEDIATE_OUTPUT)/src/community_modules_introspection.c $(INTERMEDIATE_OUTPUT)/src/community_modules_introspection.h $(INTERMEDIATE_OUTPUT)/src/led_matrix_community_modules.inc $(INTERMEDIATE_OUTPUT)/src/rgb_matrix_community_modules.inc $(INTERMEDIATE_OUTPUT)/src/split_transaction_id_community_modules.inc
 
 endif
 
@@ -320,6 +331,10 @@ define config_h_community_module_appender
 endef
 $(foreach module,$(COMMUNITY_MODULE_PATHS),$(eval $(call config_h_community_module_appender,$(module))))
 
+ifneq ($(COMMUNITY_CONFIG_H),)
+    CONFIG_H += $(COMMUNITY_CONFIG_H)
+endif
+
 ifneq ("$(wildcard $(KEYBOARD_PATH_5)/config.h)","")
     CONFIG_H += $(KEYBOARD_PATH_5)/config.h
 endif

data/constants/module_hooks/1.1.2.hjson

@@ -0,0 +1,3 @@
+{
+    // This version exists to signify addition of split data sync support.
+}

docs/features/community_modules.md

@@ -95,6 +95,10 @@ The use of `features` matches the definition normally provided within `keyboard.
 
 The `keycodes` array allows a module to provide new keycodes (as well as corresponding aliases) to a keymap.
 
+### `config.h`
+
+This file will be automatically added to the build as if it were present in the keyboard or keymap.
+
 ### `rules.mk` / `post_rules.mk`
 
 These two files follows standard QMK build system logic, allowing for `Makefile`-style customisation as if it were present in the keyboard or keymap.
@@ -131,6 +135,10 @@ This file defines LED matrix effects in the same form as used with `led_matrix_k
 
 This file defines RGB matrix effects in the same form as used with `rgb_matrix_kb.inc` and `rgb_matrix_user.inc` (see [Custom RGB Matrix Effects](rgb_matrix#custom-rgb-matrix-effects)). Effect mode names are prepended with `RGB_MATRIX_COMMUNITY_MODULE_`.
 
+### Custom split keyboard data sync
+
+Defines follow the convention, `SPLIT_TRANSACTION_IDS_MODULE_<MODULE>` (see [Custom LED Matrix Effects](split_keyboard#custom-data-sync)). 
+
 ### Compatible APIs
 
 Community Modules may provide specializations for the following APIs:

lib/python/qmk/cli/generate/community_modules.py

@@ -194,6 +194,38 @@ def generate_community_modules_rules_mk(cli):
             cli.log.info('Wrote rules.mk to %s.', cli.args.output)
 
 
+@cli.argument('-o', '--output', arg_only=True, type=qmk.path.normpath, help='File to write to')
+@cli.argument('-q', '--quiet', arg_only=True, action='store_true', help="Quiet mode, only output error messages")
+@cli.argument('-kb', '--keyboard', arg_only=True, type=keyboard_folder, completer=keyboard_completer, help='Keyboard to generate community_config.h for.')
+@cli.argument('filename', nargs='?', type=qmk.path.FileType('r'), arg_only=True, completer=FilesCompleter('.json'), help='Configurator JSON file')
+@cli.subcommand('Creates a community_config.h from a keymap.json file.')
+def generate_community_config_h(cli):
+    """Creates a community_config.h from a keymap.json file
+    """
+    if cli.args.output and cli.args.output.name == '-':
+        cli.args.output = None
+
+    lines = [
+        GPL2_HEADER_C_LIKE,
+        GENERATED_HEADER_C_LIKE,
+        '#pragma once',
+        '',
+    ]
+
+    modules = get_modules(cli.args.keyboard, cli.args.filename)
+    if len(modules) > 0:
+        lines.append('// Split transactions')
+        for module in modules:
+            lines.extend([
+                f'#ifdef SPLIT_TRANSACTION_IDS_MODULE_{Path(module).name.upper()}',
+                '#    define SPLIT_TRANSACTION_RPC',
+                '#endif',
+            ])
+        lines.append('')
+
+    dump_lines(cli.args.output, lines, cli.args.quiet, remove_repeated_newlines=True)
+
+
 @cli.argument('-o', '--output', arg_only=True, type=qmk.path.normpath, help='File to write to')
 @cli.argument('-q', '--quiet', arg_only=True, action='store_true', help="Quiet mode, only output error messages")
 @cli.argument('-kb', '--keyboard', arg_only=True, type=keyboard_folder, completer=keyboard_completer, help='Keyboard to generate community_modules.h for.')
@@ -339,3 +371,26 @@ def generate_rgb_matrix_community_modules_inc(cli):
     """Creates an rgb_matrix_community_modules.inc from a keymap.json file
     """
     _generate_include_per_module(cli, 'rgb_matrix_module.inc')
+
+
+@cli.argument('-o', '--output', arg_only=True, type=qmk.path.normpath, help='File to write to')
+@cli.argument('-q', '--quiet', arg_only=True, action='store_true', help="Quiet mode, only output error messages")
+@cli.argument('-kb', '--keyboard', arg_only=True, type=keyboard_folder, completer=keyboard_completer, help='Keyboard to generate split_transaction_id_community_modules.inc for.')
+@cli.argument('filename', nargs='?', type=qmk.path.FileType('r'), arg_only=True, completer=FilesCompleter('.json'), help='Configurator JSON file')
+@cli.subcommand('Creates an split_transaction_id_community_modules.inc from a keymap.json file.')
+def generate_split_transaction_id_community_modules_inc(cli):
+    """Creates an split_transaction_id_community_modules.inc from a keymap.json file
+    """
+    if cli.args.output and cli.args.output.name == '-':
+        cli.args.output = None
+
+    lines = [GPL2_HEADER_C_LIKE, GENERATED_HEADER_C_LIKE]
+
+    for module in get_modules(cli.args.keyboard, cli.args.filename):
+        lines.extend([
+            f'#ifdef SPLIT_TRANSACTION_IDS_MODULE_{Path(module).name.upper()}',
+            f'    SPLIT_TRANSACTION_IDS_MODULE_{Path(module).name.upper()},',
+            '#endif',
+        ])
+
+    dump_lines(cli.args.output, lines, cli.args.quiet, remove_repeated_newlines=True)

modules/qmk/split_data_sync/config.h

@@ -0,0 +1,5 @@
+// Copyright 2026 QMK
+// SPDX-License-Identifier: GPL-2.0-or-later
+#pragma once
+
+#define SPLIT_TRANSACTION_IDS_MODULE_SPLIT_DATA_SYNC EXAMPLE_MODULE_SYNC_A

modules/qmk/split_data_sync/qmk_module.json

@@ -0,0 +1,5 @@
+{
+    "module_name": "Example split data sync",
+    "maintainer": "QMK Maintainers",
+    "license": "GPL-2.0-or-later"
+}

modules/qmk/split_data_sync/split_data_sync.c

@@ -0,0 +1,40 @@
+// Copyright 2026 QMK
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include "debug.h"
+#include "timer.h"
+#include "transactions.h"
+
+typedef struct _master_to_slave_t {
+    int m2s_data;
+} master_to_slave_t;
+
+typedef struct _slave_to_master_t {
+    int s2m_data;
+} slave_to_master_t;
+
+static void module_sync_slave_handler(uint8_t in_buflen, const void *in_data, uint8_t out_buflen, void *out_data) {
+    const master_to_slave_t *m2s = (const master_to_slave_t *)in_data;
+    slave_to_master_t       *s2m = (slave_to_master_t *)out_data;
+    s2m->s2m_data                = m2s->m2s_data + 5; // whatever comes in, add 5 so it can be sent back
+}
+
+void keyboard_post_init_split_data_sync(void) {
+    transaction_register_rpc(EXAMPLE_MODULE_SYNC_A, module_sync_slave_handler);
+}
+
+void housekeeping_task_split_data_sync(void) {
+    if (is_keyboard_master()) {
+        // Interact with slave every 500ms
+        static uint32_t last_sync = 0;
+        if (timer_elapsed32(last_sync) > 500) {
+            master_to_slave_t m2s = {6};
+            slave_to_master_t s2m = {0};
+            if (transaction_rpc_exec(EXAMPLE_MODULE_SYNC_A, sizeof(m2s), &m2s, sizeof(s2m), &s2m)) {
+                last_sync = timer_read32();
+                dprintf("Slave value: %d\n", s2m.s2m_data); // this will now be 11, as the slave adds 5
+            } else {
+                dprint("Slave sync failed!\n");
+            }
+        }
+    }
+}

quantum/split_common/transaction_id_define.h

@@ -18,6 +18,10 @@
 
 #include "compiler_support.h"
 
+#if defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
+#    define SPLIT_TRANSACTION_RPC
+#endif
+
 enum serial_transaction_id {
 #ifdef USE_I2C
     I2C_EXECUTE_CALLBACK,
@@ -99,12 +103,12 @@ enum serial_transaction_id {
     PUT_ACTIVITY,
 #endif // SPLIT_ACTIVITY_ENABLE
 
-#if defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
+#if defined(SPLIT_TRANSACTION_RPC)
     PUT_RPC_INFO,
     PUT_RPC_REQ_DATA,
     EXECUTE_RPC,
     GET_RPC_RESP_DATA,
-#endif // defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
+#endif // defined(SPLIT_TRANSACTION_RPC)
 
 // keyboard-specific
 #ifdef SPLIT_TRANSACTION_IDS_KB
@@ -116,6 +120,11 @@ enum serial_transaction_id {
     SPLIT_TRANSACTION_IDS_USER,
 #endif // SPLIT_TRANSACTION_IDS_USER
 
+// community module specific
+#ifdef COMMUNITY_MODULES_ENABLE
+#    include "split_transaction_id_community_modules.inc"
+#endif // COMMUNITY_MODULES_ENABLE
+
 #if defined(OS_DETECTION_ENABLE) && defined(SPLIT_DETECTED_OS_ENABLE)
     PUT_DETECTED_OS,
 #endif // defined(OS_DETECTION_ENABLE) && defined(SPLIT_DETECTED_OS_ENABLE)

quantum/split_common/transactions.c

@@ -85,11 +85,11 @@
 #define transport_read(id, data, length) transport_execute_transaction(id, NULL, 0, data, length)
 #define transport_exec(id) transport_execute_transaction(id, NULL, 0, NULL, 0)
 
-#if defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
+#if defined(SPLIT_TRANSACTION_RPC)
 // Forward-declare the RPC callback handlers
 void slave_rpc_info_callback(uint8_t initiator2target_buffer_size, const void *initiator2target_buffer, uint8_t target2initiator_buffer_size, void *target2initiator_buffer);
 void slave_rpc_exec_callback(uint8_t initiator2target_buffer_size, const void *initiator2target_buffer, uint8_t target2initiator_buffer_size, void *target2initiator_buffer);
-#endif // defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
+#endif // defined(SPLIT_TRANSACTION_RPC)
 
 ////////////////////////////////////////////////////
 // Helpers
@@ -943,12 +943,12 @@ split_transaction_desc_t split_transaction_table[NUM_TOTAL_TRANSACTIONS] = {
     TRANSACTIONS_DETECTED_OS_REGISTRATIONS
 // clang-format on
 
-#if defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
+#if defined(SPLIT_TRANSACTION_RPC)
         [PUT_RPC_INFO]  = trans_initiator2target_initializer_cb(rpc_info, slave_rpc_info_callback),
     [PUT_RPC_REQ_DATA]  = trans_initiator2target_initializer(rpc_m2s_buffer),
     [EXECUTE_RPC]       = trans_initiator2target_initializer_cb(rpc_info.payload.transaction_id, slave_rpc_exec_callback),
     [GET_RPC_RESP_DATA] = trans_target2initiator_initializer(rpc_s2m_buffer),
-#endif // defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
+#endif // defined(SPLIT_TRANSACTION_RPC)
 };
 
 bool transactions_master(matrix_row_t master_matrix[], matrix_row_t slave_matrix[]) {
@@ -996,7 +996,7 @@ void transactions_slave(matrix_row_t master_matrix[], matrix_row_t slave_matrix[
     TRANSACTIONS_DETECTED_OS_SLAVE();
 }
 
-#if defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
+#if defined(SPLIT_TRANSACTION_RPC)
 
 void transaction_register_rpc(int8_t transaction_id, slave_callback_t callback) {
     // Prevent invoking RPC on QMK core sync data
@@ -1073,4 +1073,4 @@ void slave_rpc_exec_callback(uint8_t initiator2target_buffer_size, const void *i
     }
 }
 
-#endif // defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
+#endif // defined(SPLIT_TRANSACTION_RPC)

quantum/split_common/transport.h

@@ -22,6 +22,7 @@
 #include "progmem.h"
 #include "action_layer.h"
 #include "matrix.h"
+#include "transaction_id_define.h"
 
 #ifndef RPC_M2S_BUFFER_SIZE
 #    define RPC_M2S_BUFFER_SIZE 32
@@ -132,7 +133,7 @@ typedef struct _split_slave_activity_sync_t {
 } split_slave_activity_sync_t;
 #endif // defined(SPLIT_ACTIVITY_ENABLE)
 
-#if defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
+#if defined(SPLIT_TRANSACTION_RPC)
 typedef struct _rpc_sync_info_t {
     uint8_t checksum;
     struct {
@@ -141,7 +142,7 @@ typedef struct _rpc_sync_info_t {
         uint8_t s2m_length;
     } payload;
 } rpc_sync_info_t;
-#endif // defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
+#endif // defined(SPLIT_TRANSACTION_RPC)
 
 #if defined(OS_DETECTION_ENABLE) && defined(SPLIT_DETECTED_OS_ENABLE)
 #    include "os_detection.h"
@@ -222,11 +223,11 @@ typedef struct _split_shared_memory_t {
     split_slave_activity_sync_t activity_sync;
 #endif // defined(SPLIT_ACTIVITY_ENABLE)
 
-#if defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
+#if defined(SPLIT_TRANSACTION_RPC)
     rpc_sync_info_t rpc_info;
     uint8_t         rpc_m2s_buffer[RPC_M2S_BUFFER_SIZE];
     uint8_t         rpc_s2m_buffer[RPC_S2M_BUFFER_SIZE];
-#endif // defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
+#endif // defined(SPLIT_TRANSACTION_RPC)
 
 #if defined(OS_DETECTION_ENABLE) && defined(SPLIT_DETECTED_OS_ENABLE)
     os_variant_t detected_os;