commit 34fb8bda4700734ea886e94510916bf0633e0aa6
author Lei YU <mine260309@gmail.com> Thu Nov 07 14:24:20 2019 +0800
committer Lei YU <mine260309@gmail.com> Mon Dec 09 14:14:41 2019 +0800
tree 76208030c07e648a0c7daa9532fd1611ffe3a3fd
parent 92e89eb5bd184c6bdd569a2bc905bce12cad488e

i2c: Implement write function

Implement I2CDevice::write() by invoking i2c_smbus_write_xxx() APIs.
The code is referenced from i2c-tools' i2cset.c:

 https://github.com/ev3dev/i2c-tools/blob/ev3dev-stretch/tools/i2cset.c

Tested: Verify on Witherspoon that it writes the PSU unlock upgrade
        command and boot flag successfully.

Signed-off-by: Lei YU <mine260309@gmail.com>
Change-Id: I9fb014c787ef3ebb2f7793a0d012b1d652ef069f

tools/i2c/i2c.cpp

diff --git a/tools/i2c/i2c.cpp b/tools/i2c/i2c.cpp
index da121d8..76756be 100644
--- a/tools/i2c/i2c.cpp
+++ b/tools/i2c/i2c.cpp
@@ -83,6 +83,52 @@
     }
 }
 
+void I2CDevice::checkWriteFuncs(int type)
+{
+    unsigned long funcs;
+
+    /* Check adapter functionality */
+    if (ioctl(fd, I2C_FUNCS, &funcs) < 0)
+    {
+        throw I2CException("Failed to get funcs", busStr, devAddr, errno);
+    }
+
+    switch (type)
+    {
+        case I2C_SMBUS_BYTE:
+            if (!(funcs & I2C_FUNC_SMBUS_WRITE_BYTE))
+            {
+                throw I2CException("Missing SMBUS_WRITE_BYTE", busStr, devAddr);
+            }
+            break;
+        case I2C_SMBUS_BYTE_DATA:
+            if (!(funcs & I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
+            {
+                throw I2CException("Missing SMBUS_WRITE_BYTE_DATA", busStr,
+                                   devAddr);
+            }
+            break;
+
+        case I2C_SMBUS_WORD_DATA:
+            if (!(funcs & I2C_FUNC_SMBUS_WRITE_WORD_DATA))
+            {
+                throw I2CException("Missing SMBUS_WRITE_WORD_DATA", busStr,
+                                   devAddr);
+            }
+            break;
+        case I2C_SMBUS_BLOCK_DATA:
+            if (!(funcs & I2C_FUNC_SMBUS_WRITE_BLOCK_DATA))
+            {
+                throw I2CException("Missing SMBUS_WRITE_BLOCK_DATA", busStr,
+                                   devAddr);
+            }
+            break;
+        default:
+            fprintf(stderr, "Unexpected read size type: %d\n", type);
+            assert(false);
+    }
+}
+
 void I2CDevice::read(uint8_t& data)
 {
     checkReadFuncs(I2C_SMBUS_BYTE);
@@ -132,30 +178,43 @@
 
 void I2CDevice::write(uint8_t data)
 {
-    // TODO
-    (void)data;
+    checkWriteFuncs(I2C_SMBUS_BYTE);
+
+    if (i2c_smbus_write_byte(fd, data) < 0)
+    {
+        throw I2CException("Failed to write byte", busStr, devAddr, errno);
+    }
 }
 
 void I2CDevice::write(uint8_t addr, uint8_t data)
 {
-    // TODO
-    (void)addr;
-    (void)data;
+    checkWriteFuncs(I2C_SMBUS_BYTE_DATA);
+
+    if (i2c_smbus_write_byte_data(fd, addr, data) < 0)
+    {
+        throw I2CException("Failed to write byte data", busStr, devAddr, errno);
+    }
 }
 
 void I2CDevice::write(uint8_t addr, uint16_t data)
 {
-    // TODO
-    (void)addr;
-    (void)data;
+    checkWriteFuncs(I2C_SMBUS_WORD_DATA);
+
+    if (i2c_smbus_write_word_data(fd, addr, data) < 0)
+    {
+        throw I2CException("Failed to write word data", busStr, devAddr, errno);
+    }
 }
 
 void I2CDevice::write(uint8_t addr, uint8_t size, const uint8_t* data)
 {
-    // TODO
-    (void)addr;
-    (void)size;
-    (void)data;
+    checkWriteFuncs(I2C_SMBUS_BLOCK_DATA);
+
+    if (i2c_smbus_write_block_data(fd, addr, size, data) < 0)
+    {
+        throw I2CException("Failed to write block data", busStr, devAddr,
+                           errno);
+    }
 }
 
 std::unique_ptr<I2CInterface> I2CDevice::create(uint8_t busId, uint8_t devAddr)

tools/i2c/i2c.hpp

diff --git a/tools/i2c/i2c.hpp b/tools/i2c/i2c.hpp
index 7fe064f..befeaba 100644
--- a/tools/i2c/i2c.hpp
+++ b/tools/i2c/i2c.hpp
@@ -53,6 +53,17 @@
      */
     void checkReadFuncs(int type);
 
+    /** @brief Check i2c adapter write functionality
+     *
+     * Check if the i2c adapter has the functionality specified by the SMBus
+     * transaction type
+     *
+     * @param[in] type - The SMBus transaction type defined in linux/i2c.h
+     *
+     * @throw I2CException if the function is not supported
+     */
+    void checkWriteFuncs(int type);
+
   public:
     ~I2CDevice()
     {