commit 770de5802211e2231e3a20d70887fade6a88b54e
author Shawn McCarney <shawnmm@us.ibm.com> Fri Nov 05 02:28:35 2021 -0500
committer Shawn McCarney <shawnmm@us.ibm.com> Mon Nov 08 20:07:24 2021 -0600
tree 393b48096bb42204690748a63ddf3d91e95e82be
parent c0a0758034c655a78f307588895e63a5d4615abd

Add retry support to I2CInterface

Enhance the I2CInterface class hierarchy to support retrying failed I2C
operations.

Add an optional parameter to i2c::create() to specify the maximum number
of retries to perform for an I2C operation.  Default to 0 retries so
that existing code will not be affected.

Testing:
* Tested each modified function
  * When I2C operation succeeds
  * When I2C operation fails
    * When no retries are done
    * When retries are done
      * When retried operation succeeds
      * When retried operation fails
* See complete test plan at
  https://gist.github.com/smccarney/8d203a40d9984402ac495dc3d689c12d

Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: I2b0e782e5caaafa9908ef5625687377b959b38ff

tools/i2c/i2c.hpp

diff --git a/tools/i2c/i2c.hpp b/tools/i2c/i2c.hpp
index 738547c..23acdbc 100644
--- a/tools/i2c/i2c.hpp
+++ b/tools/i2c/i2c.hpp
@@ -19,11 +19,13 @@
      * @param[in] busId - The i2c bus ID
      * @param[in] devAddr - The device address of the I2C device
      * @param[in] initialState - Initial state of the I2CDevice object
+     * @param[in] maxRetries - Maximum number of times to retry an I2C operation
      */
     explicit I2CDevice(uint8_t busId, uint8_t devAddr,
-                       InitialState initialState = InitialState::OPEN) :
+                       InitialState initialState = InitialState::OPEN,
+                       int maxRetries = 0) :
         busId(busId),
-        devAddr(devAddr)
+        devAddr(devAddr), maxRetries(maxRetries)
     {
         busStr = "/dev/i2c-" + std::to_string(busId);
         if (initialState == InitialState::OPEN)
@@ -44,6 +46,9 @@
     /** @brief The i2c device address in the bus */
     uint8_t devAddr;
 
+    /** @brief Maximum number of times to retry an I2C operation */
+    int maxRetries = 0;
+
     /** @brief The file descriptor of the opened i2c device */
     int fd = INVALID_FD;
 
@@ -164,12 +169,14 @@
      * @param[in] busId - The i2c bus ID
      * @param[in] devAddr - The device address of the i2c
      * @param[in] initialState - Initial state of the I2CInterface object
+     * @param[in] maxRetries - Maximum number of times to retry an I2C operation
      *
      * @return The unique_ptr holding the I2CInterface
      */
     static std::unique_ptr<I2CInterface>
         create(uint8_t busId, uint8_t devAddr,
-               InitialState initialState = InitialState::OPEN);
+               InitialState initialState = InitialState::OPEN,
+               int maxRetries = 0);
 };
 
 } // namespace i2c