ospi: driver is more restrictive than necessary

[sageve]

According to my tests the the OSPI supports not only instruction phase only, but also data phase only. However, the HAL driver does not allow this configuration.

I guess that the focus at the OSPI was on flash devices, where a single data phase is not intended, But there are other use cases.

I kindly ask for allowing single data phase instead of throwing an error. This won't break any software, but allows a broader usage of the OSPI. I am aware that this is an undocumented feature.

I can submit a pull request if you agree.

https://github.com/STMicroelectronics/stm32h7xx-hal-driver/blob/6f5e35e30ac09ba7bf44139a97b289d3df53cf9c/Src/stm32h7xx_hal_ospi.c#L3076C1-L3079C1

+      if (cmd->DataMode != HAL_OSPI_DATA_NONE)
+      {
+        /* ---- Command with data ---- */
+
+        /* Configure the CCR register with all communication parameters */
+        MODIFY_REG((*ccr_reg), (OCTOSPI_CCR_DMODE  | OCTOSPI_CCR_DDTR),
+                   (cmd->DataMode | cmd->DataDtrMode));
+      }
+      else
+      {
+        /* ---- invalid command configuration (no instruction, no address, no data) ---- */
+
+        status = HAL_ERROR;
+        hospi->ErrorCode = HAL_OSPI_ERROR_INVALID_PARAM;
+      }
+      /* MODIFIED */
+
       /* ---- Invalid command configuration (no instruction, no address) ---- */
-      status = HAL_ERROR;
-      hospi->ErrorCode = HAL_OSPI_ERROR_INVALID_PARAM;

[KRASTM]

Hello @sageve,

Thank you for the report.

As you said and according to the RM0468, for single phase command, the only case supported is instruction phase Any of these phases can be configured to be skipped but, in case of single-phase command, the only use case supported is instruction-phase-only.

However, I will share your proposal with our team in order to confirm it, and I will keep you informed.

With regards,