From 6341d629d889336408fed3ff878e219df4263787 Mon Sep 17 00:00:00 2001
From: Adam Honse <calcprogrammer1@gmail.com>
Date: Thu, 29 Sep 2022 16:37:49 -0500
Subject: [PATCH] AMD ADL SMBus improvements   * Allow word (2 byte) transfers 
  * Fix block writes not sending data size

---
 i2c_smbus/i2c_smbus_amdadl.cpp | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/i2c_smbus/i2c_smbus_amdadl.cpp b/i2c_smbus/i2c_smbus_amdadl.cpp
index 39f2ec27..e67d3a6f 100644
--- a/i2c_smbus/i2c_smbus_amdadl.cpp
+++ b/i2c_smbus/i2c_smbus_amdadl.cpp
@@ -128,16 +128,20 @@ s32 i2c_smbus_amdadl::i2c_smbus_xfer(u8 addr, char read_write, u8 command, int s
 {
     int PrimaryDisplay;
     int ret;
+    int data_size = 0;
+    char* data_ptr;
 
     ADLI2C* pI2C;
     ADLI2C I2Cstore;
     pI2C = &I2Cstore;
 
+    char i2c_buf[I2C_SMBUS_BLOCK_MAX + 8];
+
     pI2C->iSize = sizeof(ADLI2C);
     pI2C->iSpeed = 100;
     pI2C->iLine = 1; //location of the Aura chip
     pI2C->iAddress = addr << 1;
-    pI2C->iOffset = command;
+    pI2C->iOffset = 0;
     pI2C->pcData = (char*)data;
 
     if (ADL_OK != ADL2_Adapter_Primary_Get(context, &PrimaryDisplay))
@@ -159,16 +163,18 @@ s32 i2c_smbus_amdadl::i2c_smbus_xfer(u8 addr, char read_write, u8 command, int s
         //break;
 
     case I2C_SMBUS_BYTE_DATA:
-        pI2C->iDataSize = 1;
+        data_size = 1;
+        data_ptr = (char*)data;
         break;
 
     case I2C_SMBUS_WORD_DATA:
-        return -1;
+        data_size = 2;
+        data_ptr = (char*)data;
         break;
 
     case I2C_SMBUS_BLOCK_DATA:
-        pI2C->iDataSize = data->block[0];
-        pI2C->pcData = (char*)&data->block[1];
+        data_size = data->block[0] + 1;
+        data_ptr = (char*)&data->block[0];
         break;
 
     default:
@@ -177,12 +183,24 @@ s32 i2c_smbus_amdadl::i2c_smbus_xfer(u8 addr, char read_write, u8 command, int s
 
     if (read_write == I2C_SMBUS_READ)
     {
+        /* An SMBus read can be achieved by setting the offset to the command (register address) */
+        pI2C->iOffset = command;
         pI2C->iAction = ADL_DL_I2C_ACTIONREAD;
+        pI2C->iDataSize = data_size;
+        pI2C->pcData = (char *)data_ptr;
+
         ret = ADL2_Display_WriteAndReadI2C(context, PrimaryDisplay, pI2C);
     }
     else
     {
+        /* An SMBus write has one extra byte, the register address, before the data */
         pI2C->iAction = ADL_DL_I2C_ACTIONWRITE;
+        pI2C->iDataSize = data_size + 1;
+        pI2C->pcData = i2c_buf;
+
+        i2c_buf[0] = command;
+        memcpy(&i2c_buf[1], data_ptr, data_size);
+
         ret = ADL2_Display_WriteAndReadI2C(context, PrimaryDisplay, pI2C);
     }