spi_master: fix the command and address field when LSB_FIRST enabled

Resolves https://github.com/espressif/esp-idf/issues/2444.

diff --git a/components/driver/spi_master.c b/components/driver/spi_master.c
index 4641e4bca04f6fe19b1ccfb0865822a2955cfd2b..5c363a842ce86119ca98227f8ae0aad7069de41e 100644 (file)
--- a/components/driver/spi_master.c
+++ b/components/driver/spi_master.c
@@ -727,7 +727,11 @@ static void SPI_MASTER_ISR_ATTR spi_intr(void *arg)
         host->hw->user.usr_addr=addrlen?1:0;
         host->hw->user.usr_command=cmdlen?1:0;
 
-        // output command will be sent from bit 7 to 0 of command_value, and then bit 15 to 8 of the same register field.
+    if ((dev->cfg.flags & SPI_DEVICE_TXBIT_LSBFIRST)==0) {
+        /* Output command will be sent from bit 7 to 0 of command_value, and
+         * then bit 15 to 8 of the same register field. Shift and swap to send
+         * more straightly.
+         */
         uint16_t command = trans->cmd << (16-cmdlen);    //shift to MSB
         host->hw->user2.usr_command_value = (command>>8)|(command<<8);  //swap the first and second byte
         // shift the address to MSB of addr (and maybe slv_wr_status) register.
@@ -738,6 +742,22 @@ static void SPI_MASTER_ISR_ATTR spi_intr(void *arg)
         } else {
             host->hw->addr = trans->addr << (32 - addrlen);
         }
+    } else {
+        /* The output command start from bit0 to bit 15, kept as is.
+         * The output address start from the LSB of the highest byte, i.e.
+         * addr[24] -> addr[31]
+         * ...
+         * addr[0] -> addr[7]
+         * slv_wr_status[24] -> slv_wr_status[31]
+         * ...
+         * slv_wr_status[0] -> slv_wr_status[7]
+         * So swap the byte order to let the LSB sent first.
+         */
+        host->hw->user2.usr_command_value = trans->cmd;
+        uint64_t addr = __builtin_bswap64(trans->addr);
+        host->hw->addr = addr>>32;
+        host->hw->slv_wr_status = addr;
+        }
 
         host->hw->user.usr_mosi=( (!(dev->cfg.flags & SPI_DEVICE_HALFDUPLEX) && trans_buf->buffer_to_rcv) || trans_buf->buffer_to_send)?1:0;
         host->hw->user.usr_miso=(trans_buf->buffer_to_rcv)?1:0;