From f50bd7fccce5dd97076d6b721f9be7c93f947bcd Mon Sep 17 00:00:00 2001
From: Ian Burwell <iburwell@greensightag.com>
Date: Fri, 7 Jun 2024 18:24:32 -0400
Subject: [PATCH] AP_Scripting: Add I2C transfer binding

---
 libraries/AP_Scripting/docs/docs.lua          |  7 ++++
 .../generator/description/bindings.desc       |  1 +
 libraries/AP_Scripting/lua_bindings.cpp       | 42 +++++++++++++++++++
 libraries/AP_Scripting/lua_bindings.h         |  1 +
 4 files changed, 51 insertions(+)

diff --git a/libraries/AP_Scripting/docs/docs.lua b/libraries/AP_Scripting/docs/docs.lua
index f88cdeecae4731..4e3758dad4ff87 100644
--- a/libraries/AP_Scripting/docs/docs.lua
+++ b/libraries/AP_Scripting/docs/docs.lua
@@ -1173,6 +1173,13 @@ local AP_HAL__I2CDevice_ud = {}
 ---@param address integer
 function AP_HAL__I2CDevice_ud:set_address(address) end
 
+-- Performs an I2C transfer, sending data_table bytes and
+-- returning a table of any requested read bytes
+---@param data_table table
+---@param read_length integer
+---@return table|nil
+function AP_HAL__I2CDevice_ud:transfer(data_table, read_length) end
+
 -- If no read length is provided a single register will be read and returned.
 -- If read length is provided a table of register values are returned.
 ---@param register_num integer
diff --git a/libraries/AP_Scripting/generator/description/bindings.desc b/libraries/AP_Scripting/generator/description/bindings.desc
index f9ca18bb44a9ff..d0237e88b7b22b 100644
--- a/libraries/AP_Scripting/generator/description/bindings.desc
+++ b/libraries/AP_Scripting/generator/description/bindings.desc
@@ -578,6 +578,7 @@ ap_object AP_HAL::I2CDevice semaphore-pointer
 ap_object AP_HAL::I2CDevice method set_retries void uint8_t 0 20
 ap_object AP_HAL::I2CDevice method write_register boolean uint8_t'skip_check uint8_t'skip_check
 ap_object AP_HAL::I2CDevice manual read_registers AP_HAL__I2CDevice_read_registers 2 1
+ap_object AP_HAL::I2CDevice manual transfer AP_HAL__I2CDevice_transfer 2 1
 ap_object AP_HAL::I2CDevice method set_address void uint8_t'skip_check
 
 include AP_HAL/utility/Socket.h depends (AP_NETWORKING_ENABLED==1)
diff --git a/libraries/AP_Scripting/lua_bindings.cpp b/libraries/AP_Scripting/lua_bindings.cpp
index 81f58703fe5910..1952190fd7986d 100644
--- a/libraries/AP_Scripting/lua_bindings.cpp
+++ b/libraries/AP_Scripting/lua_bindings.cpp
@@ -638,6 +638,48 @@ int AP_HAL__I2CDevice_read_registers(lua_State *L) {
     return success;
 }
 
+int AP_HAL__I2CDevice_transfer(lua_State *L) {
+    const int args = lua_gettop(L);
+    if (args != 3){
+        return luaL_argerror(L, args, "expected 2 arguments");
+    }
+    if (!lua_istable(L, 2)) {
+        return luaL_argerror(L, 2, "expected a table as the first argument");
+    }
+
+    AP_HAL::I2CDevice * ud = *check_AP_HAL__I2CDevice(L, 1);
+
+    // Parse table of bytes to send
+    uint32_t send_len = lua_rawlen(L, 2);
+    uint8_t send_data[send_len] = {};
+    for (unsigned int i = 0; i < send_len; i++){
+        lua_rawgeti(L, 2, i + 1); // Grab value from table
+        send_data[i] = get_uint8_t(L, -1); // Parse/check uint8_t
+        lua_pop(L, 1);
+    }
+
+    // Parse and setup rx buffer
+    uint32_t rx_len = get_uint32(L, 3, 0, UINT32_MAX);
+    uint8_t rx_data[rx_len];
+
+    // Transfer
+    ud->get_semaphore()->take_blocking();
+    const bool success = static_cast<bool>(ud->transfer(send_data, send_len, rx_data, rx_len));
+    ud->get_semaphore()->give();
+
+    // Return a table
+    if (success) {
+        // push to table
+        lua_newtable(L);
+        for (uint8_t i=0; i < rx_len; i++) {
+            lua_pushinteger(L, i+1);
+            lua_pushinteger(L, rx_data[i]);
+            lua_settable(L, -3);
+        }
+    }
+    return success;
+}
+
 int AP_HAL__UARTDriver_readstring(lua_State *L) {
     binding_argcheck(L, 2);
 
diff --git a/libraries/AP_Scripting/lua_bindings.h b/libraries/AP_Scripting/lua_bindings.h
index add40faa0a7bd8..14850e6f57a8e7 100644
--- a/libraries/AP_Scripting/lua_bindings.h
+++ b/libraries/AP_Scripting/lua_bindings.h
@@ -8,6 +8,7 @@ int lua_mission_receive(lua_State *L);
 int AP_Logger_Write(lua_State *L);
 int lua_get_i2c_device(lua_State *L);
 int AP_HAL__I2CDevice_read_registers(lua_State *L);
+int AP_HAL__I2CDevice_transfer(lua_State *L);
 int AP_HAL__UARTDriver_readstring(lua_State *L);
 int lua_get_CAN_device(lua_State *L);
 int lua_get_CAN_device2(lua_State *L);