cros_ec: Handle the single duplex requirement in cros_ec

With several chips using the SPI protocol it seems better to put the single
duplex functionality in the EC rather than the SPI driver.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/drivers/misc/cros_ec_spi.c b/drivers/misc/cros_ec_spi.c
index ac2ee86..0686925 100644 (file)
--- a/drivers/misc/cros_ec_spi.c
+++ b/drivers/misc/cros_ec_spi.c
@@ -25,6 +25,8 @@ int cros_ec_spi_packet(struct udevice *udev, int out_bytes, int in_bytes)
 {
        struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
        struct spi_slave *slave = dev_get_parentdata(dev->dev);
+       ulong start;
+       uint8_t byte;
        int rv;
 
        /* Do the transfer */
@@ -33,10 +35,25 @@ int cros_ec_spi_packet(struct udevice *udev, int out_bytes, int in_bytes)
                return -1;
        }
 
-       rv = spi_xfer(slave, max(out_bytes, in_bytes) * 8,
-                     dev->dout, dev->din,
-                     SPI_XFER_BEGIN | SPI_XFER_END);
+       rv = spi_xfer(slave, out_bytes * 8, dev->dout, NULL, SPI_XFER_BEGIN);
+       if (rv)
+               goto done;
+       start = get_timer(0);
+       while (1) {
+               rv = spi_xfer(slave, 8, NULL, &byte, 0);
+               if (byte == SPI_PREAMBLE_END_BYTE)
+                       break;
+               if (rv)
+                       goto done;
+               if (get_timer(start) > 100) {
+                       rv = -ETIMEDOUT;
+                       goto done;
+               }
+       }
 
+       rv = spi_xfer(slave, in_bytes * 8, NULL, dev->din, 0);
+done:
+       spi_xfer(slave, 0, NULL, NULL, SPI_XFER_END);
        spi_release_bus(slave);
 
        if (rv) {