git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@10055 35acf78f-673a-0410-8e92-d51de3d6d3f4

os/hal/lib/fallback/I2C/hal_i2c_lld.c

@@ -30,6 +30,11 @@
 /* Driver local definitions.                                                 */
 /*===========================================================================*/
 
+#define CHECK_ERROR(msg)                                                    \
+  if ((msg) < (msg_t)0) {                                                   \
+    return MSG_TIMEOUT;                                                     \
+  }
+
 /*===========================================================================*/
 /* Driver constants.                                                         */
 /*===========================================================================*/
@@ -66,6 +71,100 @@ I2CDriver I2CD4;
 /* Driver local functions.                                                   */
 /*===========================================================================*/
 
+static msg_t i2c_delay(I2CDriver *i2cp) {
+
+  if (!osalOsIsTimeWithinX(osalOsGetSystemTimeX(), i2cp->start, i2cp->end)) {
+    return MSG_TIMEOUT;
+  }
+
+#if SW_I2C_USE_OSAL_DELAY || defined(__DOXYGEN__)
+  osalThreadSleep(i2cp->config->ticks);
+#else
+  i2cp->config->delay();
+#endif
+  return MSG_OK;
+}
+
+static msg_t i2c_write_start(I2CDriver *i2cp) {
+
+}
+
+static msg_t i2c_write_restart(I2CDriver *i2cp) {
+
+}
+
+static msg_t i2c_write_stop(I2CDriver *i2cp) {
+
+}
+
+static msg_t i2c_writebit(I2CDriver *i2cp, unsigned bit) {
+
+  palWriteLine(i2cp->config->sda, bit);
+  CHECK_ERROR(i2c_delay(i2cp));
+  palSetLine(i2cp->config->scl);
+  CHECK_ERROR(i2c_delay(i2cp));
+
+  /* Clock stretching.*/
+  while (palReadLine(i2cp->config->scl) == PAL_LOW) {
+    CHECK_ERROR(i2c_delay(i2cp));
+  }
+
+  /* Arbitration check.*/
+  if ((bit == PAL_HIGH) && (palReadLine(i2cp->config->sda) == PAL_LOW)) {
+    i2cp->errors |= I2C_ARBITRATION_LOST;
+    return MSG_RESET;
+  }
+
+  palClearLine(i2cp->config->scl);
+
+  return MSG_OK;
+}
+
+static msg_t i2c_readbit(I2CDriver *i2cp) {
+  msg_t bit;
+
+  palSetLine(i2cp->config->sda);
+  CHECK_ERROR(i2c_delay(i2cp));
+  palSetLine(i2cp->config->scl);
+
+  /* Clock stretching.*/
+  while (palReadLine(i2cp->config->scl) == PAL_LOW) {
+    CHECK_ERROR(i2c_delay(i2cp));
+  }
+
+  CHECK_ERROR(i2c_delay(i2cp));
+  bit = palReadLine(i2cp->config->sda);
+  palClearLine(i2cp->config->scl);
+
+  return bit;
+}
+
+static msg_t i2c_writebyte(I2CDriver *i2cp, uint8_t byte) {
+  uint8_t mask;
+
+  for (mask = 0x80U; mask > 0U; mask >>= 1U) {
+    CHECK_ERROR(i2c_writebit(i2cp, (byte & mask) != 0));
+  }
+
+  return i2c_readbit(i2cp);
+}
+
+static msg_t i2c_readbyte(I2CDriver *i2cp, unsigned nack) {
+  msg_t byte;
+  unsigned i;
+
+  byte = 0U;
+  for (i = 0; i < 8; i++) {
+    msg_t msg = i2c_readbit(i2cp);
+    CHECK_ERROR(msg);
+    byte = (byte << 1U) | msg;
+  }
+
+  CHECK_ERROR(i2c_writebit(i2cp, PAL_LOW));
+
+  return byte;
+}
+
 /*===========================================================================*/
 /* Driver interrupt handlers.                                                */
 /*===========================================================================*/

os/hal/lib/fallback/I2C/hal_i2c_lld.h

@@ -39,6 +39,16 @@
  * @name    Configuration options
  * @{
  */
+/**
+ * @brief   Use OSAL delays.
+ * @details If set to @p TRUE then delays are implemented using the
+ *          thread-friendy delay function else a delay function must
+ *          be provided extenally.
+ */
+#if !defined(SW_I2C_USE_OSAL_DELAY) || defined(__DOXYGEN__)
+#define SW_I2C_USE_OSAL_DELAY               TRUE
+#endif
+
 /**
  * @brief   I2C1 driver enable switch.
  * @details If set to @p TRUE the support for I2C1 is included.
@@ -94,10 +104,34 @@ typedef uint16_t i2caddr_t;
  */
 typedef uint8_t i2cflags_t;
 
+/**
+ * @brief   Type of a delay function.
+ */
+typedef void (*i2c_delay_t)(void);
+
 /**
  * @brief   Type of I2C driver configuration structure.
  */
 typedef struct {
+  /**
+   * @brief   I2C clock line.
+   */
+  ioline_t                  scl;
+  /**
+   * @brief   I2C data line.
+   */
+  ioline_t                  sda;
+#if SW_I2C_USE_OSAL_DELAY || defined(__DOXYGEN__)
+  /**
+   * @brief   Delay of an half bit time in system ticks.
+   */
+  systime_t                 ticks;
+#else
+  /**
+   * @brief   Pointer to an externally defined delay function.
+   */
+  i2c_delay_t               delay;
+#endif
 } I2CConfig;
 
 /**
@@ -129,13 +163,13 @@ struct I2CDriver {
 #endif
   /* End of the mandatory fields.*/
   /**
-   * @brief   I2C clock line.
+   * @brief   Time of operation begin.
    */
-  ioline_t                  clk;
+  systime_t                 start;
   /**
-   * @brief   I2C data line.
+   * @brief   Time of operation timeout.
    */
-  ioline_t                  data;
+  systime_t                 end;
 };
 
 /*===========================================================================*/