[Core] Split support for pointing devices. (#15304)

* Draft implementation

* formatting

* fix combined buttons

* remove pimoroni throttle

* sync pointing on a throttle loop with checksum

* no longer used

* doh

Co-authored-by: Drashna Jaelre <drashna@live.com>

* switch pimoroni to a cpi equivalent

* add cpi support

* allow user modification of seperate mouse reports

* a little tidy up

* add *_RIGHT defines.

* docs

* doxygen comments

* basic changelog

* clean up pimoroni

* small doc fixes

* Update docs/feature_pointing_device.md

Co-authored-by: Drashna Jaelre <drashna@live.com>

* performance tweak if side has usb

* Don't run init funtions on wrong side

* renamed some variables for consistency

* fix pimoroni typos

* Clamp instead of OR

* Promote combined values to uint16_t

* Update pointing_device.c

Co-authored-by: Drashna Jaelre <drashna@live.com>
Co-authored-by: Nick Brassel <nick@tzarc.org>

6 files changed, 478 insertions, 46 deletions

diff --git a/quantum/pointing_device.c b/quantum/pointing_device.c
index 2fefdb67b6..23d93fa15f 100644
--- a/quantum/pointing_device.c
+++ b/quantum/pointing_device.c
@@ -18,24 +18,105 @@
 
 #include "pointing_device.h"
 #include <string.h>
+#include "timer.h"
 #ifdef MOUSEKEY_ENABLE
 #    include "mousekey.h"
 #endif
 #if (defined(POINTING_DEVICE_ROTATION_90) + defined(POINTING_DEVICE_ROTATION_180) + defined(POINTING_DEVICE_ROTATION_270)) > 1
 #    error More than one rotation selected.  This is not supported.
 #endif
+#if defined(SPLIT_POINTING_ENABLE)
+#    include "transactions.h"
+#    include "keyboard.h"
 
-static report_mouse_t mouseReport = {};
+report_mouse_t shared_mouse_report = {};
+uint16_t       shared_cpi          = 0;
+
+/**
+ * @brief Sets the shared mouse report used be pointing device task
+ *
+ * NOTE : Only available when using SPLIT_POINTING_ENABLE
+ *
+ * @param[in] new_mouse_report report_mouse_t
+ */
+void pointing_device_set_shared_report(report_mouse_t new_mouse_report) { shared_mouse_report = new_mouse_report; }
+
+/**
+ * @brief Gets current pointing device CPI if supported
+ *
+ * Gets current cpi of the shared report and returns it as uint16_t
+ *
+ * NOTE : Only available when using SPLIT_POINTING_ENABLE
+ *
+ * @return cpi value as uint16_t
+ */
+uint16_t pointing_device_get_shared_cpi(void) { return shared_cpi; }
+
+#    if defined(POINTING_DEVICE_LEFT)
+#        define POINTING_DEVICE_THIS_SIDE is_keyboard_left()
+#    elif defined(POINTING_DEVICE_RIGHT)
+#        define POINTING_DEVICE_THIS_SIDE !is_keyboard_left()
+#    elif defined(POINTING_DEVICE_COMBINED)
+#        define POINTING_DEVICE_THIS_SIDE true
+#    endif
+
+#endif  // defined(SPLIT_POINTING_ENABLE)
+
+static report_mouse_t local_mouse_report = {};
 
 extern const pointing_device_driver_t pointing_device_driver;
 
+/**
+ * @brief Compares 2 mouse reports for difference and returns result
+ *
+ * @param[in] new report_mouse_t
+ * @param[in] old report_mouse_t
+ * @return bool result
+ */
 __attribute__((weak)) bool has_mouse_report_changed(report_mouse_t new, report_mouse_t old) { return memcmp(&new, &old, sizeof(new)); }
 
-__attribute__((weak)) void           pointing_device_init_kb(void) {}
-__attribute__((weak)) void           pointing_device_init_user(void) {}
+/**
+ * @brief Keyboard level code pointing device initialisation
+ *
+ */
+__attribute__((weak)) void pointing_device_init_kb(void) {}
+
+/**
+ * @brief User level code pointing device initialisation
+ *
+ */
+__attribute__((weak)) void pointing_device_init_user(void) {}
+
+/**
+ * @brief Weak function allowing for keyboard level mouse report modification
+ *
+ * Takes report_mouse_t struct allowing modification at keyboard level then returns report_mouse_t.
+ *
+ * @param[in] mouse_report report_mouse_t
+ * @return report_mouse_t
+ */
 __attribute__((weak)) report_mouse_t pointing_device_task_kb(report_mouse_t mouse_report) { return pointing_device_task_user(mouse_report); }
+
+/**
+ * @brief Weak function allowing for user level mouse report modification
+ *
+ * Takes report_mouse_t struct allowing modification at user level then returns report_mouse_t.
+ *
+ * @param[in] mouse_report report_mouse_t
+ * @return report_mouse_t
+ */
 __attribute__((weak)) report_mouse_t pointing_device_task_user(report_mouse_t mouse_report) { return mouse_report; }
 
+/**
+ * @brief Handles pointing device buttons
+ *
+ * Returns modified button bitmask using bool pressed and selected pointing_device_buttons_t button in uint8_t buttons bitmask.
+ *
+ * @param buttons[in] uint8_t bitmask
+ * @param pressed[in] bool
+ * @param button[in] pointing_device_buttons_t value
+ * @return Modified uint8_t bitmask buttons
+ */
 __attribute__((weak)) uint8_t pointing_device_handle_buttons(uint8_t buttons, bool pressed, pointing_device_buttons_t button) {
     if (pressed) {
         buttons |= 1 << (button);
@@ -45,7 +126,17 @@ __attribute__((weak)) uint8_t pointing_device_handle_buttons(uint8_t buttons, bo
     return buttons;
 }
 
+/**
+ * @brief Initialises pointing device
+ *
+ * Initialises pointing device, perform driver init and optional keyboard/user level code.
+ */
 __attribute__((weak)) void pointing_device_init(void) {
+#if defined(SPLIT_POINTING_ENABLE)
+    if (!(POINTING_DEVICE_THIS_SIDE)) {
+        return;
+    }
+#endif
     pointing_device_driver.init();
 #ifdef POINTING_DEVICE_MOTION_PIN
     setPinInputHigh(POINTING_DEVICE_MOTION_PIN);
@@ -54,67 +145,299 @@ __attribute__((weak)) void pointing_device_init(void) {
     pointing_device_init_user();
 }
 
+/**
+ * @brief Sends processed mouse report to host
+ *
+ * This sends the mouse report generated by pointing_device_task if changed since the last report. Once send zeros mouse report except buttons.
+ *
+ */
 __attribute__((weak)) void pointing_device_send(void) {
     static report_mouse_t old_report = {};
 
     // If you need to do other things, like debugging, this is the place to do it.
-    if (has_mouse_report_changed(mouseReport, old_report)) {
-        host_mouse_send(&mouseReport);
+    if (has_mouse_report_changed(local_mouse_report, old_report)) {
+        host_mouse_send(&local_mouse_report);
     }
     // send it and 0 it out except for buttons, so those stay until they are explicity over-ridden using update_pointing_device
-    mouseReport.x = 0;
-    mouseReport.y = 0;
-    mouseReport.v = 0;
-    mouseReport.h = 0;
+    local_mouse_report.x = 0;
+    local_mouse_report.y = 0;
+    local_mouse_report.v = 0;
+    local_mouse_report.h = 0;
 
-    memcpy(&old_report, &mouseReport, sizeof(mouseReport));
+    memcpy(&old_report, &local_mouse_report, sizeof(local_mouse_report));
 }
 
-__attribute__((weak)) void pointing_device_task(void) {
-    // Gather report info
-#ifdef POINTING_DEVICE_MOTION_PIN
-    if (!readPin(POINTING_DEVICE_MOTION_PIN))
-#endif
-        mouseReport = pointing_device_driver.get_report(mouseReport);
-
-        // Support rotation of the sensor data
+/**
+ * @brief Adjust mouse report by any optional common pointing configuration defines
+ *
+ * This applies rotation or inversion to the mouse report as selected by the pointing device common configuration defines.
+ *
+ * @param mouse_report[in] takes a report_mouse_t to be adjusted
+ * @return report_mouse_t with adjusted values
+ */
+report_mouse_t pointing_device_adjust_by_defines(report_mouse_t mouse_report) {
+    // Support rotation of the sensor data
 #if defined(POINTING_DEVICE_ROTATION_90) || defined(POINTING_DEVICE_ROTATION_180) || defined(POINTING_DEVICE_ROTATION_270)
-    int8_t x = mouseReport.x, y = mouseReport.y;
+    int8_t x = mouse_report.x, y = mouse_report.y;
 #    if defined(POINTING_DEVICE_ROTATION_90)
-    mouseReport.x = y;
-    mouseReport.y = -x;
+    mouse_report.x = y;
+    mouse_report.y = -x;
 #    elif defined(POINTING_DEVICE_ROTATION_180)
-    mouseReport.x = -x;
-    mouseReport.y = -y;
+    mouse_report.x = -x;
+    mouse_report.y = -y;
 #    elif defined(POINTING_DEVICE_ROTATION_270)
-    mouseReport.x = -y;
-    mouseReport.y = x;
+    mouse_report.x = -y;
+    mouse_report.y = x;
 #    else
 #        error "How the heck did you get here?!"
 #    endif
 #endif
     // Support Inverting the X and Y Axises
 #if defined(POINTING_DEVICE_INVERT_X)
-    mouseReport.x = -mouseReport.x;
+    mouse_report.x = -mouse_report.x;
 #endif
 #if defined(POINTING_DEVICE_INVERT_Y)
-    mouseReport.y = -mouseReport.y;
+    mouse_report.y = -mouse_report.y;
+#endif
+    return mouse_report;
+}
+
+/**
+ * @brief Retrieves and processes pointing device data.
+ *
+ * This function is part of the keyboard loop and retrieves the mouse report from the pointing device driver.
+ * It applies any optional configuration e.g. rotation or axis inversion and then initiates a send.
+ *
+ */
+__attribute__((weak)) void pointing_device_task(void) {
+#if defined(SPLIT_POINTING_ENABLE)
+    // Don't poll the target side pointing device.
+    if (!is_keyboard_master()) {
+        return;
+    };
+#endif
+
+#if defined(POINTING_DEVICE_TASK_THROTTLE_MS)
+    static uint32_t last_exec = 0;
+    if (timer_elapsed32(last_exec) < POINTING_DEVICE_TASK_THROTTLE_MS) {
+        return;
+    }
+    last_exec = timer_read32();
+#else
+#    if defined(SPLIT_POINTING_ENABLE)
+#        pragma message("It's recommended you enable a throttle when sharing pointing devices.")
+#    endif
+#endif
+
+    // Gather report info
+#ifdef POINTING_DEVICE_MOTION_PIN
+#    if defined(SPLIT_POINTING_ENABLE)
+#        error POINTING_DEVICE_MOTION_PIN not supported when sharing the pointing device report between sides.
+#    endif
+    if (!readPin(POINTING_DEVICE_MOTION_PIN))
 #endif
 
+#if defined(SPLIT_POINTING_ENABLE)
+#    if defined(POINTING_DEVICE_COMBINED)
+        static uint8_t old_buttons = 0;
+    local_mouse_report.buttons = old_buttons;
+    local_mouse_report         = pointing_device_driver.get_report(local_mouse_report);
+    old_buttons                = local_mouse_report.buttons;
+#    elif defined(POINTING_DEVICE_LEFT) || defined(POINTING_DEVICE_RIGHT)
+        local_mouse_report = POINTING_DEVICE_THIS_SIDE ? pointing_device_driver.get_report(local_mouse_report) : shared_mouse_report;
+#    else
+#        error "You need to define the side(s) the pointing device is on. POINTING_DEVICE_COMBINED / POINTING_DEVICE_LEFT / POINTING_DEVICE_RIGHT"
+#    endif
+#else
+    local_mouse_report = pointing_device_driver.get_report(local_mouse_report);
+#endif  // defined(SPLIT_POINTING_ENABLE)
+
     // allow kb to intercept and modify report
-    mouseReport = pointing_device_task_kb(mouseReport);
+#if defined(SPLIT_POINTING_ENABLE) && defined(POINTING_DEVICE_COMBINED)
+    if (is_keyboard_left()) {
+        local_mouse_report  = pointing_device_adjust_by_defines(local_mouse_report);
+        shared_mouse_report = pointing_device_adjust_by_defines_right(shared_mouse_report);
+    } else {
+        local_mouse_report  = pointing_device_adjust_by_defines_right(local_mouse_report);
+        shared_mouse_report = pointing_device_adjust_by_defines(shared_mouse_report);
+    }
+    local_mouse_report = is_keyboard_left() ? pointing_device_task_combined_kb(local_mouse_report, shared_mouse_report) : pointing_device_task_combined_kb(shared_mouse_report, local_mouse_report);
+#else
+    local_mouse_report = pointing_device_adjust_by_defines(local_mouse_report);
+    local_mouse_report = pointing_device_task_kb(local_mouse_report);
+#endif
     // combine with mouse report to ensure that the combined is sent correctly
 #ifdef MOUSEKEY_ENABLE
     report_mouse_t mousekey_report = mousekey_get_report();
-    mouseReport.buttons            = mouseReport.buttons | mousekey_report.buttons;
+    local_mouse_report.buttons     = local_mouse_report.buttons | mousekey_report.buttons;
 #endif
     pointing_device_send();
 }
 
-report_mouse_t pointing_device_get_report(void) { return mouseReport; }
+/**
+ * @brief Gets current mouse report used by pointing device task
+ *
+ * @return report_mouse_t
+ */
+report_mouse_t pointing_device_get_report(void) { return local_mouse_report; }
+
+/**
+ * @brief Sets mouse report used be pointing device task
+ *
+ * @param[in] new_mouse_report
+ */
+void pointing_device_set_report(report_mouse_t new_mouse_report) { local_mouse_report = new_mouse_report; }
+
+/**
+ * @brief Gets current pointing device CPI if supported
+ *
+ * Gets current cpi from pointing device driver if supported and returns it as uint16_t
+ *
+ * @return cpi value as uint16_t
+ */
+uint16_t pointing_device_get_cpi(void) {
+#if defined(SPLIT_POINTING_ENABLE)
+    return POINTING_DEVICE_THIS_SIDE ? pointing_device_driver.get_cpi() : shared_cpi;
+#else
+    return pointing_device_driver.get_cpi();
+#endif
+}
 
-void pointing_device_set_report(report_mouse_t newMouseReport) { mouseReport = newMouseReport; }
+/**
+ * @brief Set pointing device CPI if supported
+ *
+ * Takes a uint16_t value to set pointing device cpi if supported by driver.
+ *
+ * @param[in] cpi uint16_t value.
+ */
+void pointing_device_set_cpi(uint16_t cpi) {
+#if defined(SPLIT_POINTING_ENABLE)
+    if (POINTING_DEVICE_THIS_SIDE) {
+        pointing_device_driver.set_cpi(cpi);
+    } else {
+        shared_cpi = cpi;
+    }
+#else
+    pointing_device_driver.set_cpi(cpi);
+#endif
+}
 
-uint16_t pointing_device_get_cpi(void) { return pointing_device_driver.get_cpi(); }
+#if defined(SPLIT_POINTING_ENABLE) && defined(POINTING_DEVICE_COMBINED)
+/**
+ * @brief Set pointing device CPI if supported
+ *
+ * Takes a bool and uint16_t and allows setting cpi for a single side when using 2 pointing devices with a split keyboard.
+ *
+ * NOTE: Only available when using SPLIT_POINTING_ENABLE and POINTING_DEVICE_COMBINED
+ *
+ * @param[in] left true = left, false = right.
+ * @param[in] cpi uint16_t value.
+ */
+void pointing_device_set_cpi_on_side(bool left, uint16_t cpi) {
+    bool local = (is_keyboard_left() & left) ? true : false;
+    if (local) {
+        pointing_device_driver.set_cpi(cpi);
+    } else {
+        shared_cpi = cpi;
+    }
+}
 
-void pointing_device_set_cpi(uint16_t cpi) { pointing_device_driver.set_cpi(cpi); }
+/**
+ * @brief clamps int16_t to int8_t
+ *
+ * @param[in] int16_t value
+ * @return int8_t clamped value
+ */
+static inline int8_t pointing_device_movement_clamp(int16_t value) {
+    if (value < INT8_MIN) {
+        return INT8_MIN;
+    } else if (value > INT8_MAX) {
+        return INT8_MAX;
+    } else {
+        return value;
+    }
+}
+
+/**
+ * @brief combines 2 mouse reports and returns 2
+ *
+ * Combines 2 report_mouse_t structs, clamping movement values to int8_t and ignores report_id then returns the resulting report_mouse_t struct.
+ *
+ * NOTE: Only available when using SPLIT_POINTING_ENABLE and POINTING_DEVICE_COMBINED
+ *
+ * @param[in] left_report left report_mouse_t
+ * @param[in] right_report right report_mouse_t
+ * @return combined report_mouse_t of left_report and right_report
+ */
+report_mouse_t pointing_device_combine_reports(report_mouse_t left_report, report_mouse_t right_report) {
+    left_report.x = pointing_device_movement_clamp((int16_t)left_report.x + right_report.x);
+    left_report.y = pointing_device_movement_clamp((int16_t)left_report.y + right_report.y);
+    left_report.h = pointing_device_movement_clamp((int16_t)left_report.h + right_report.h);
+    left_report.v = pointing_device_movement_clamp((int16_t)left_report.v + right_report.v);
+    left_report.buttons |= right_report.buttons;
+    return left_report;
+}
+
+/**
+ * @brief Adjust mouse report by any optional right pointing configuration defines
+ *
+ * This applies rotation or inversion to the mouse report as selected by the pointing device common configuration defines.
+ *
+ * NOTE: Only available when using SPLIT_POINTING_ENABLE and POINTING_DEVICE_COMBINED
+ *
+ * @param[in] mouse_report report_mouse_t to be adjusted
+ * @return report_mouse_t with adjusted values
+ */
+report_mouse_t pointing_device_adjust_by_defines_right(report_mouse_t mouse_report) {
+    // Support rotation of the sensor data
+#    if defined(POINTING_DEVICE_ROTATION_90_RIGHT) || defined(POINTING_DEVICE_ROTATION_RIGHT) || defined(POINTING_DEVICE_ROTATION_RIGHT)
+    int8_t x = mouse_report.x, y = mouse_report.y;
+#        if defined(POINTING_DEVICE_ROTATION_90_RIGHT)
+    mouse_report.x = y;
+    mouse_report.y = -x;
+#        elif defined(POINTING_DEVICE_ROTATION_180_RIGHT)
+    mouse_report.x = -x;
+    mouse_report.y = -y;
+#        elif defined(POINTING_DEVICE_ROTATION_270_RIGHT)
+    mouse_report.x = -y;
+    mouse_report.y = x;
+#        else
+#            error "How the heck did you get here?!"
+#        endif
+#    endif
+    // Support Inverting the X and Y Axises
+#    if defined(POINTING_DEVICE_INVERT_X_RIGHT)
+    mouse_report.x = -mouse_report.x;
+#    endif
+#    if defined(POINTING_DEVICE_INVERT_Y_RIGHT)
+    mouse_report.y = -mouse_report.y;
+#    endif
+    return mouse_report;
+}
+
+/**
+ * @brief Weak function allowing for keyboard level mouse report modification
+ *
+ * Takes 2 report_mouse_t structs allowing individual modification of sides at keyboard level then returns pointing_device_task_combined_user.
+ *
+ * NOTE: Only available when using SPLIT_POINTING_ENABLE and POINTING_DEVICE_COMBINED
+ *
+ * @param[in] left_report report_mouse_t
+ * @param[in] right_report report_mouse_t
+ * @return pointing_device_task_combined_user(left_report, right_report) by default
+ */
+__attribute__((weak)) report_mouse_t pointing_device_task_combined_kb(report_mouse_t left_report, report_mouse_t right_report) { return pointing_device_task_combined_user(left_report, right_report); }
+
+/**
+ * @brief Weak function allowing for user level mouse report modification
+ *
+ * Takes 2 report_mouse_t structs allowing individual modification of sides at user level then returns pointing_device_combine_reports.
+ *
+ * NOTE: Only available when using SPLIT_POINTING_ENABLE and POINTING_DEVICE_COMBINED
+ *
+ * @param[in] left_report report_mouse_t
+ * @param[in] right_report report_mouse_t
+ * @return pointing_device_combine_reports(left_report, right_report) by default
+ */
+__attribute__((weak)) report_mouse_t pointing_device_task_combined_user(report_mouse_t left_report, report_mouse_t right_report) { return pointing_device_combine_reports(left_report, right_report); }
+#endif
diff --git a/quantum/pointing_device.h b/quantum/pointing_device.h
index 5106c26660..78398d8999 100644
--- a/quantum/pointing_device.h
+++ b/quantum/pointing_device.h
@@ -86,3 +86,16 @@ void           pointing_device_init_user(void);
 report_mouse_t pointing_device_task_kb(report_mouse_t mouse_report);
 report_mouse_t pointing_device_task_user(report_mouse_t mouse_report);
 uint8_t        pointing_device_handle_buttons(uint8_t buttons, bool pressed, pointing_device_buttons_t button);
+report_mouse_t pointing_device_adjust_by_defines(report_mouse_t mouse_report);
+
+#if defined(SPLIT_POINTING_ENABLE)
+void     pointing_device_set_shared_report(report_mouse_t report);
+uint16_t pointing_device_get_shared_cpi(void);
+#    if defined(POINTING_DEVICE_COMBINED)
+void           pointing_device_set_cpi_on_side(bool left, uint16_t cpi);
+report_mouse_t pointing_device_combine_reports(report_mouse_t left_report, report_mouse_t right_report);
+report_mouse_t pointing_device_task_combined_kb(report_mouse_t left_report, report_mouse_t right_report);
+report_mouse_t pointing_device_task_combined_user(report_mouse_t left_report, report_mouse_t right_report);
+report_mouse_t pointing_device_adjust_by_defines_right(report_mouse_t mouse_report);
+#    endif //defined(POINTING_DEVICE_COMBINED)
+#endif //defined(SPLIT_POINTING_ENABLE)
diff --git a/quantum/pointing_device_drivers.c b/quantum/pointing_device_drivers.c
index 9ad5e76ba6..0852a0bea7 100644
--- a/quantum/pointing_device_drivers.c
+++ b/quantum/pointing_device_drivers.c
@@ -165,14 +165,13 @@ const pointing_device_driver_t pointing_device_driver = {
 // clang-format on
 
 #elif defined(POINTING_DEVICE_DRIVER_pimoroni_trackball)
-report_mouse_t pimorono_trackball_get_report(report_mouse_t mouse_report) {
-    static fast_timer_t throttle      = 0;
-    static uint16_t     debounce      = 0;
-    static uint8_t      error_count   = 0;
-    pimoroni_data_t     pimoroni_data = {0};
-    static int16_t      x_offset = 0, y_offset = 0;
-
-    if (error_count < PIMORONI_TRACKBALL_ERROR_COUNT && timer_elapsed_fast(throttle) >= PIMORONI_TRACKBALL_INTERVAL_MS) {
+report_mouse_t pimoroni_trackball_get_report(report_mouse_t mouse_report) {
+    static uint16_t debounce      = 0;
+    static uint8_t  error_count   = 0;
+    pimoroni_data_t pimoroni_data = {0};
+    static int16_t  x_offset = 0, y_offset = 0;
+
+    if (error_count < PIMORONI_TRACKBALL_ERROR_COUNT) {
         i2c_status_t status = read_pimoroni_trackball(&pimoroni_data);
 
         if (status == I2C_STATUS_SUCCESS) {
@@ -195,17 +194,16 @@ report_mouse_t pimorono_trackball_get_report(report_mouse_t mouse_report) {
         } else {
             error_count++;
         }
-        throttle = timer_read_fast();
     }
     return mouse_report;
 }
 
 // clang-format off
 const pointing_device_driver_t pointing_device_driver = {
-    .init       = pimironi_trackball_device_init,
-    .get_report = pimorono_trackball_get_report,
-    .set_cpi    = NULL,
-    .get_cpi    = NULL
+    .init       = pimoroni_trackball_device_init,
+    .get_report = pimoroni_trackball_get_report,
+    .set_cpi    = pimoroni_trackball_set_cpi,
+    .get_cpi    = pimoroni_trackball_get_cpi
 };
 // clang-format on
 #elif defined(POINTING_DEVICE_DRIVER_pmw3360)
diff --git a/quantum/split_common/transaction_id_define.h b/quantum/split_common/transaction_id_define.h
index 535bc21aea..aa71c3621e 100644
--- a/quantum/split_common/transaction_id_define.h
+++ b/quantum/split_common/transaction_id_define.h
@@ -78,6 +78,12 @@ enum serial_transaction_id {
     PUT_ST7565,
 #endif  // defined(ST7565_ENABLE) && defined(SPLIT_ST7565_ENABLE)
 
+#if defined(POINTING_DEVICE_ENABLE) && defined(SPLIT_POINTING_ENABLE)
+    GET_POINTING_CHECKSUM,
+    GET_POINTING_DATA,
+    PUT_POINTING_CPI,
+#endif  // defined(POINTING_DEVICE_ENABLE) && defined(SPLIT_POINTING_ENABLE)
+
 #if defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
     PUT_RPC_INFO,
     PUT_RPC_REQ_DATA,
diff --git a/quantum/split_common/transactions.c b/quantum/split_common/transactions.c
index 3ff87710e7..9622acb377 100644
--- a/quantum/split_common/transactions.c
+++ b/quantum/split_common/transactions.c
@@ -579,6 +579,82 @@ static void st7565_handlers_slave(matrix_row_t master_matrix[], matrix_row_t sla
 #endif  // defined(ST7565_ENABLE) && defined(SPLIT_ST7565_ENABLE)
 
 ////////////////////////////////////////////////////
+// POINTING
+
+#if defined(POINTING_DEVICE_ENABLE) && defined(SPLIT_POINTING_ENABLE)
+
+static bool pointing_handlers_master(matrix_row_t master_matrix[], matrix_row_t slave_matrix[]) {
+#    if defined(POINTING_DEVICE_LEFT)
+    if (is_keyboard_left()) {
+        return true;
+    }
+#    elif defined(POINTING_DEVICE_RIGHT)
+    if (!is_keyboard_left()) {
+        return true;
+    }
+#    endif
+    static uint32_t last_update = 0;
+    static uint16_t last_cpi    = 0;
+    report_mouse_t  temp_state;
+    uint16_t        temp_cpi;
+    bool            okay = read_if_checksum_mismatch(GET_POINTING_CHECKSUM, GET_POINTING_DATA, &last_update, &temp_state, &split_shmem->pointing.report, sizeof(temp_state));
+    if (okay) pointing_device_set_shared_report(temp_state);
+    temp_cpi = pointing_device_get_shared_cpi();
+    if (temp_cpi && memcmp(&last_cpi, &temp_cpi, sizeof(temp_cpi)) != 0) {
+        memcpy(&split_shmem->pointing.cpi, &temp_cpi, sizeof(temp_cpi));
+        okay = transport_write(PUT_POINTING_CPI, &split_shmem->pointing.cpi, sizeof(split_shmem->pointing.cpi));
+        if (okay) {
+            last_cpi = temp_cpi;
+        }
+    }
+    return okay;
+}
+
+extern const pointing_device_driver_t pointing_device_driver;
+
+static void pointing_handlers_slave(matrix_row_t master_matrix[], matrix_row_t slave_matrix[]) {
+#    if defined(POINTING_DEVICE_LEFT)
+    if (!is_keyboard_left()) {
+        return;
+    }
+#    elif defined(POINTING_DEVICE_RIGHT)
+    if (is_keyboard_left()) {
+        return;
+    }
+#    endif
+    report_mouse_t temp_report;
+    uint16_t       temp_cpi;
+#    ifdef POINTING_DEVICE_TASK_THROTTLE_MS
+    static uint32_t last_exec = 0;
+    if (timer_elapsed32(last_exec) < POINTING_DEVICE_TASK_THROTTLE_MS) {
+        return;
+    }
+    last_exec = timer_read32();
+#    endif
+    temp_cpi = pointing_device_driver.get_cpi();
+    if (split_shmem->pointing.cpi && memcmp(&split_shmem->pointing.cpi, &temp_cpi, sizeof(temp_cpi)) != 0) {
+        pointing_device_driver.set_cpi(split_shmem->pointing.cpi);
+    }
+    memset(&temp_report, 0, sizeof(temp_report));
+    temp_report = pointing_device_driver.get_report(temp_report);
+    memcpy(&split_shmem->pointing.report, &temp_report, sizeof(temp_report));
+    // Now update the checksum given that the pointing has been written to
+    split_shmem->pointing.checksum = crc8(&temp_report, sizeof(temp_report));
+}
+
+#    define TRANSACTIONS_POINTING_MASTER() TRANSACTION_HANDLER_MASTER(pointing)
+#    define TRANSACTIONS_POINTING_SLAVE() TRANSACTION_HANDLER_SLAVE(pointing)
+#    define TRANSACTIONS_POINTING_REGISTRATIONS [GET_POINTING_CHECKSUM] = trans_target2initiator_initializer(pointing.checksum), [GET_POINTING_DATA] = trans_target2initiator_initializer(pointing.report), [PUT_POINTING_CPI] = trans_initiator2target_initializer(pointing.cpi),
+
+#else  // defined(POINTING_DEVICE_ENABLE) && defined(SPLIT_POINTING_ENABLE)
+
+#    define TRANSACTIONS_POINTING_MASTER()
+#    define TRANSACTIONS_POINTING_SLAVE()
+#    define TRANSACTIONS_POINTING_REGISTRATIONS
+
+#endif  // defined(POINTING_DEVICE_ENABLE) && defined(SPLIT_POINTING_ENABLE)
+
+////////////////////////////////////////////////////
 
 uint8_t                  dummy;
 split_transaction_desc_t split_transaction_table[NUM_TOTAL_TRANSACTIONS] = {
@@ -604,6 +680,7 @@ split_transaction_desc_t split_transaction_table[NUM_TOTAL_TRANSACTIONS] = {
     TRANSACTIONS_WPM_REGISTRATIONS
     TRANSACTIONS_OLED_REGISTRATIONS
     TRANSACTIONS_ST7565_REGISTRATIONS
+    TRANSACTIONS_POINTING_REGISTRATIONS
 // clang-format on
 
 #if defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
@@ -629,6 +706,7 @@ bool transactions_master(matrix_row_t master_matrix[], matrix_row_t slave_matrix
     TRANSACTIONS_WPM_MASTER();
     TRANSACTIONS_OLED_MASTER();
     TRANSACTIONS_ST7565_MASTER();
+    TRANSACTIONS_POINTING_MASTER();
     return true;
 }
 
@@ -647,6 +725,7 @@ void transactions_slave(matrix_row_t master_matrix[], matrix_row_t slave_matrix[
     TRANSACTIONS_WPM_SLAVE();
     TRANSACTIONS_OLED_SLAVE();
     TRANSACTIONS_ST7565_SLAVE();
+    TRANSACTIONS_POINTING_SLAVE();
 }
 
 #if defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
diff --git a/quantum/split_common/transport.h b/quantum/split_common/transport.h
index 1d4f6ed0cd..31b804908b 100644
--- a/quantum/split_common/transport.h
+++ b/quantum/split_common/transport.h
@@ -106,6 +106,15 @@ typedef struct _split_mods_sync_t {
 } split_mods_sync_t;
 #endif  // SPLIT_MODS_ENABLE
 
+#if defined(POINTING_DEVICE_ENABLE) && defined(SPLIT_POINTING_ENABLE)
+#    include "pointing_device.h"
+typedef struct _split_slave_pointing_sync_t {
+    uint8_t        checksum;
+    report_mouse_t report;
+    uint16_t       cpi;
+} split_slave_pointing_sync_t;
+#endif  // defined(POINTING_DEVICE_ENABLE) && defined(SPLIT_POINTING_ENABLE)
+
 #if defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
 typedef struct _rpc_sync_info_t {
     int8_t  transaction_id;
@@ -173,6 +182,10 @@ typedef struct _split_shared_memory_t {
     uint8_t current_st7565_state;
 #endif  // ST7565_ENABLE(OLED_ENABLE) && defined(SPLIT_ST7565_ENABLE)
 
+#if defined(POINTING_DEVICE_ENABLE) && defined(SPLIT_POINTING_ENABLE)
+    split_slave_pointing_sync_t pointing;
+#endif  // defined(POINTING_DEVICE_ENABLE) && defined(SPLIT_POINTING_ENABLE)
+
 #if defined(SPLIT_TRANSACTION_IDS_KB) || defined(SPLIT_TRANSACTION_IDS_USER)
     rpc_sync_info_t rpc_info;
     uint8_t         rpc_m2s_buffer[RPC_M2S_BUFFER_SIZE];