[GitHub] [incubator-nuttx] gustavonihei commented on a change in pull request #3795: S32K1XX LSPI Double word up to 64 bits support

[GitBox <gi...@apache.org>]

gustavonihei commented on a change in pull request #3795:
URL: https://github.com/apache/incubator-nuttx/pull/3795#discussion_r640632208



##########
File path: arch/arm/src/s32k1xx/s32k1xx_lpspi.c
##########
@@ -1293,13 +1386,176 @@ static void s32k1xx_lpspi_exchange_nodma(FAR struct spi_dev_s *dev,
 #endif
 {
   FAR struct s32k1xx_lpspidev_s *priv = (FAR struct s32k1xx_lpspidev_s *)dev;
+  uint16_t framesize;
   DEBUGASSERT(priv && priv->spibase);
 
   spiinfo("txbuffer=%p rxbuffer=%p nwords=%d\n", txbuffer, rxbuffer, nwords);
 
-  /* 8- or 16-bit mode? */
+  /* bit mode? */
 
-  if (s32k1xx_lpspi_9to16bitmode(priv))
+  framesize = s32k1xx_lpspi_9to16bitmode(priv);
+  if (framesize > 16 && framesize % 32 != 0)
+    {
+      /* 17-bit or higher, byte transfer due to padding
+       * take care of big endian mode of hardware !!
+       */
+
+      const uint8_t *src = (const uint8_t *)txbuffer;
+      uint8_t *dest = (uint8_t *) rxbuffer;
+      uint32_t word = 0x0;
+#ifdef CONFIG_S32K1XX_LPSPI_DWORD
+      uint32_t word1 = 0x0;
+      uint32_t rword1;
+      bool     dwords = false;
+#endif
+
+      while (nwords-- > 0)
+        {
+          /* Get the next word to write.  Is there a source buffer? */
+
+          if (src)
+            {
+              /* read the required number of bytes */
+
+            switch (framesize)
+              {
+#ifdef CONFIG_S32K1XX_LPSPI_DWORD
+              case 40:
+                   word = (src[0] << 24) + (src[1] << 16)
+                          + (src[2] << 8) + src[3];
+                   word1 = src[4];
+                   src += 5;
+                   dwords = true;
+                   break;
+#endif
+              default:
+                      break;
+              }
+            }
+          else
+            {
+              word = 0xffffffff;
+            }
+
+#ifdef CONFIG_S32K1XX_LPSPI_DWORD
+          /* Exchange 2 words */
+
+          if (dwords)
+            {
+              word = s32k1xx_lpspi_send_dword(dev, word, word1, &rword1);
+            }
+          else
+#endif
+            {
+            word = s32k1xx_lpspi_send(dev, word);

Review comment:
       Alignment here seems wrong.
   I am surprised that NxStyle didn't catch this.




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