Updates to I2C driver to make it more Linux userspace compatible.

include/i2c-dev.h

@@ -37,6 +37,7 @@
 #if defined (__linux__)
     #include <linux/i2c-dev.h>
 #elif defined (__FreeRTOS__)
+    #include <stdint.h>
     /** magic number for this driver's ioctl calls */
     #define I2C_MAGIC ('i')
 
@@ -46,7 +47,19 @@
     #define I2C_SLAVE IOW(I2C_MAGIC, 1, sizeof(long))
 
     /** Combined R/W transfer, one stop only. */
-    #define I2C_RDWR  IOW(I2C_MAGIC, 2, sizeof(void*))
+    #define I2C_RDWR  IOWR(I2C_MAGIC, 2, sizeof(void*))
+
+    /** Combined R/W transfer, one stop only. */
+    #define I2C_SMBUS IOWR(I2C_MAGIC, 3, sizeof(void*))
+
+    /** This is the structure as used in the I2C_SMBUS ioctl call */
+    struct i2c_smbus_ioctl_data
+    {
+        uint8_t read_write;
+        uint8_t command;
+        uint32_t size;
+        union i2c_smbus_data *data;
+    };
 
     /** This is the structure as used in the I2C_RDWR ioctl call */
     struct i2c_rdwr_ioctl_data
@@ -56,7 +69,7 @@
     };
 
     /** maximum number of message segments in @ref i2c_rdwr_ioctl_data struct */
-    #define  I2C_RDRW_IOCTL_MAX_MSGS 2
+    #define  I2C_RDRW_IOCTL_MAX_MSGS 42
 #else
     #error I2C drivers not supported on this OS
 #endif

include/i2c.h

@@ -37,6 +37,7 @@
 #if defined (__linux__)
     #include <linux/i2c.h>
 #elif defined (__FreeRTOS__)
+    #include <stdint.h>
     /** Used in @ref i2c_rdwr_ioctl_data to describe a transaction segment. */
     struct i2c_msg
     {
@@ -46,6 +47,32 @@
         uint16_t len; /**< msg length */
         uint8_t *buf; /**< pointer to msg data */
     };
+
+    #define I2C_SMBUS_BLOCK_MAX 32  /* As specified in SMBus standard */
+
+    /** Data for SMBus Messages */
+    union i2c_smbus_data {
+        uint8_t byte;
+        uint16_t word;
+        uint8_t block[I2C_SMBUS_BLOCK_MAX + 2]; /* block[0] is used for length */
+                       /* and one more for user-space compatibility */
+    };
+
+/* i2c_smbus_xfer read or write markers */
+#define I2C_SMBUS_READ  1
+#define I2C_SMBUS_WRITE 0
+
+/* SMBus transaction types (size parameter in the above functions)
+   Note: these no longer correspond to the (arbitrary) PIIX4 internal codes! */
+#define I2C_SMBUS_QUICK         0
+#define I2C_SMBUS_BYTE          1
+#define I2C_SMBUS_BYTE_DATA     2
+#define I2C_SMBUS_WORD_DATA     3
+#define I2C_SMBUS_PROC_CALL     4
+#define I2C_SMBUS_BLOCK_DATA        5
+#define I2C_SMBUS_I2C_BLOCK_BROKEN  6
+#define I2C_SMBUS_BLOCK_PROC_CALL   7       /* SMBus 2.0 */
+#define I2C_SMBUS_I2C_BLOCK_DATA    8
 #else
     #error I2C drivers not supported on this OS
 #endif

src/freertos_drivers/common/I2C.cxx

@@ -40,45 +40,53 @@
  * @param file file reference for this device
  * @param buf location to place read data
  * @param count number of bytes to read
- * @return number of bytes read upon success, -1 upon failure with errno containing the cause
+ * @return number of bytes read upon success, -errno upon failure
  */
 ssize_t I2C::read(File *file, void *buf, size_t count)
 {
-    unsigned char *data = (unsigned char*)buf;
-    bool result;
+    int result;
+
+    struct i2c_msg msg;
+    msg.addr = (uintptr_t)file->priv;
+    msg.flags = I2C_M_RD;
+    msg.len = count;
+    msg.buf = (uint8_t*)buf;
 
-    Transaction t = {data, count, FLAG_START | FLAG_STOP | FLAG_RD};
     lock_.lock();
-    result = transfer(&t);
+    result = transfer(&msg, true);
     lock_.unlock();
 
-    return result == 0 ? count : -1;
+    return result;
 }
 
 /** Write to a file or device.
  * @param file file reference for this device
  * @param buf location to find write data
  * @param count number of bytes to write
- * @return number of bytes written upon success, -1 upon failure with errno containing the cause
+ * @return number of bytes written upon success, -errno upon failure
  */
 ssize_t I2C::write(File *file, const void *buf, size_t count)
 {
-    const unsigned char *data = (const unsigned char*)buf;
-    bool result;
+    int result;
+
+    struct i2c_msg msg;
+    msg.addr = (uintptr_t)file->priv;
+    msg.flags = 0;
+    msg.len = count;
+    msg.buf = (uint8_t*)buf;
 
-    Transaction t = {data, count, FLAG_START | FLAG_STOP};
     lock_.lock();
-    result = transfer(&t);
+    result = transfer(&msg, true);
     lock_.unlock();
 
-    return result == 0 ? count : -1;
+    return result;
 }
 
 /** Request an ioctl transaction
  * @param file file reference for this device
- * @param node node reference for this device
  * @param key ioctl key
  * @param data key data
+ * @return 0 upon success, -errno upon failure
  */
 int I2C::ioctl(File *file, unsigned long int key, unsigned long data)
 {
@@ -87,15 +95,80 @@ int I2C::ioctl(File *file, unsigned long int key, unsigned long data)
     switch (key)
     {
         default:
-            errno = EINVAL;
-            return -1;
+            return -EINVAL;
         case I2C_SLAVE:
-            address = data;
+            file->priv = (void*)data;
             break;
         case I2C_RDWR:
-            /* not yet implemented */
-            HASSERT(0 && "I2C_RDWR not yet implemented");
+        {
+            struct i2c_rdwr_ioctl_data *rdwr_data = (struct i2c_rdwr_ioctl_data*)data;
+            return transfer_messages(rdwr_data->msgs, rdwr_data->nmsgs);
+        }
+        case I2C_SMBUS:
+            return smbus(file, data);
     }
     return 0;
 }
 
+/** Conduct multiple message transfers with one stop at the end.
+ * @param msgs array of messages to transfer
+ * @param num number of messages to transfer
+ * @return total number of bytes transfered, -errno upon failure
+ */
+int I2C::transfer_messages(struct i2c_msg *msgs, int num)
+{
+    HASSERT(num > 0);
+
+    int count = 0;
+    int result;
+
+    lock_.lock();
+    for (int i = 0; i < num; ++i)
+    {
+        count += msgs[i].len;
+        result = transfer(msgs + i, (num == (i + 1)));
+        if (result < 0)
+        {
+            lock_.unlock();
+            return result;
+        }
+    }
+    lock_.unlock();
+
+    return  count;
+}
+
+/** Request an smbus (ioctl) transaction.
+ * @param file file reference for this device
+ * @param data smbus data
+ * @return 0 upon success, -errno upon failure
+ */
+int I2C::smbus(File *file, unsigned long data)
+{
+    struct i2c_smbus_ioctl_data *sm_data = (struct i2c_smbus_ioctl_data *)data;
+
+    /* check that we have a valid transaction type */
+    if ((sm_data->size != I2C_SMBUS_QUICK) &&
+        (sm_data->size != I2C_SMBUS_BYTE) &&
+        (sm_data->size != I2C_SMBUS_BYTE_DATA) &&
+        (sm_data->size != I2C_SMBUS_WORD_DATA) &&
+        (sm_data->size != I2C_SMBUS_PROC_CALL) &&
+        (sm_data->size != I2C_SMBUS_BLOCK_DATA) &&
+        (sm_data->size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
+        (sm_data->size != I2C_SMBUS_BLOCK_PROC_CALL) &&
+        (sm_data->size != I2C_SMBUS_I2C_BLOCK_DATA))
+    {
+        return -EINVAL;
+    }
+
+    /* check that we have a read or write */
+    if ((sm_data->read_write != I2C_SMBUS_READ) &&
+        (sm_data->read_write != I2C_SMBUS_WRITE))
+    {
+        return -EINVAL;
+    }
+
+    /// @todo need to finish implementation (Stuart Baker)
+    return 0;
+}  
+

src/freertos_drivers/common/I2C.hxx

@@ -46,34 +46,11 @@
 class I2C : public Node
 {
 protected:
-    /** Flags used to determine the kind of I2C transaction.
-     */
-    enum Flags
-    {
-        FLAG_START   = 0x01,
-        FLAG_REPEAT_START = 0x02,
-        FLAG_STOP    = 0x04,
-        FLAG_RD      = 0x08
-    };
-
-    /** Metadata for an I2C transaction */
-    struct Transaction
-    {
-        union
-        {
-            const unsigned char *tx_data;
-            unsigned char *rx_data;
-        };
-        size_t count;
-        int flags;
-    };
-
     /** Constructor
      * @param name device name in file system
      */
     I2C(const char *name)
         : Node(name)
-        , address(0)
     {
     }
 
@@ -85,39 +62,51 @@ protected:
     }
 
     /** Method to transmit/receive the data.
-     * @param t transaction to take place
-     * @return 0 upon success or -1 with errno set
+     * @param msg message to transact.
+     * @param stop produce a stop condition at the end of the transfer
+     * @return bytes transfered upon success or -1 with errno set
      */
-    virtual int transfer(Transaction *t) = 0;
-
-    /** Address of target I2C slave */
-    long address;
+    virtual int transfer(struct i2c_msg *msg, bool stop) = 0;
 
 private:
     /** Read from a file or device.
      * @param file file reference for this device
      * @param buf location to place read data
      * @param count number of bytes to read
-     * @return number of bytes read upon success, -1 upon failure with errno containing the cause
+     * @return number of bytes read upon success, -errno upon failure
      */
     ssize_t read(File *file, void *buf, size_t count) OVERRIDE;
 
     /** Write to a file or device.
      * @param file file reference for this device
      * @param buf location to find write data
      * @param count number of bytes to write
-     * @return number of bytes written upon success, -1 upon failure with errno containing the cause
+     * @return number of bytes written upon success, -errno upon failure
      */
     ssize_t write(File *file, const void *buf, size_t count) OVERRIDE;
 
     /** Request an ioctl transaction.
      * @param file file reference for this device
-     * @param node node reference for this device
      * @param key ioctl key
      * @param data key data
+     * @return >= 0 upon success, -errno upon failure
      */
     int ioctl(File *file, unsigned long int key, unsigned long data) OVERRIDE;
 
+    /** Conduct multiple message transfers with one stop at the end.
+     * @param msgs array of messages to transfer
+     * @param num number of messages to transfer
+     * @return total number of bytes transfered, -errno upon failure
+     */
+    int transfer_messages(struct i2c_msg *msgs, int num);
+
+    /** Request an smbus (ioctl) transaction.
+     * @param file file reference for this device
+     * @param data smbus data
+     * @return 0 upon success, -errno upon failure
+     */
+    int smbus(File *file, unsigned long data);    
+
     /** Discards all pending buffers. Called after disable(). */
     void flush_buffers() OVERRIDE {}
 

src/freertos_drivers/ti/TivaDev.hxx

@@ -221,14 +221,17 @@ private:
     void disable() OVERRIDE {}; /**< function to disable device */
 
     /** Method to transmit/receive the data.
-     * @param t transaction to take place
-     * @return 0 upon success or -1 with errno set
+     * @param msg message to transact.
+     * @param stop produce a stop condition at the end of the transfer
+     * @return bytes transfered upon success or -1 with errno set
      */
-    int transfer(Transaction *t) OVERRIDE;
+    int transfer(struct i2c_msg *msg, bool stop) OVERRIDE;
 
     unsigned long base; /**< base address of this device */
     unsigned long interrupt; /**< interrupt of this device */
-    Transaction *trans;
+    struct i2c_msg *msg_; /**< message for current transaction */
+    bool stop_; /**< current transaction ends in a stop if true */
+    int count_; /**< current count index within transaction */
 
     /** Semaphore to wakeup task level from ISR */
     OSSem sem;