cros_ec: spi: Add support for EC protocol version 3

Protocol version 3 will be attempted first; if the EC doesn't support
it, u-boot will fall back to the old protocol version (2).

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/misc/cros_ec.c

@@ -218,6 +218,11 @@ static int send_command_proto3(struct cros_ec_dev *dev,
 		return in_bytes;
 
 	switch (dev->interface) {
+#ifdef CONFIG_CROS_EC_SPI
+	case CROS_EC_IF_SPI:
+		rv = cros_ec_spi_packet(dev, out_bytes, in_bytes);
+		break;
+#endif
 	case CROS_EC_IF_NONE:
 	/* TODO: support protocol 3 for LPC, I2C; for now fall through */
 	default:
@@ -665,6 +670,13 @@ static int cros_ec_check_version(struct cros_ec_dev *dev)
 	 * So for now, just read all the data anyway.
 	 */
 
+	/* Try sending a version 3 packet */
+	dev->protocol_version = 3;
+	if (ec_command_inptr(dev, EC_CMD_HELLO, 0, &req, sizeof(req),
+			     (uint8_t **)&resp, sizeof(*resp)) > 0) {
+		return 0;
+	}
+
 	/* Try sending a version 2 packet */
 	dev->protocol_version = 2;
 	if (ec_command_inptr(dev, EC_CMD_HELLO, 0, &req, sizeof(req),

drivers/misc/cros_ec_spi.c

@@ -17,6 +17,30 @@
 #include <cros_ec.h>
 #include <spi.h>
 
+int cros_ec_spi_packet(struct cros_ec_dev *dev, int out_bytes, int in_bytes)
+{
+	int rv;
+
+	/* Do the transfer */
+	if (spi_claim_bus(dev->spi)) {
+		debug("%s: Cannot claim SPI bus\n", __func__);
+		return -1;
+	}
+
+	rv = spi_xfer(dev->spi, max(out_bytes, in_bytes) * 8,
+		      dev->dout, dev->din,
+		      SPI_XFER_BEGIN | SPI_XFER_END);
+
+	spi_release_bus(dev->spi);
+
+	if (rv) {
+		debug("%s: Cannot complete SPI transfer\n", __func__);
+		return -1;
+	}
+
+	return in_bytes;
+}
+
 /**
  * Send a command to a LPC CROS_EC device and return the reply.
  *

include/cros_ec.h

@@ -311,6 +311,19 @@ int cros_ec_spi_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
 		     const uint8_t *dout, int dout_len,
 		     uint8_t **dinp, int din_len);
 
+/**
+ * Send a packet to a CROS-EC device and return the response packet.
+ *
+ * Expects the request packet to be stored in dev->dout.  Stores the response
+ * packet in dev->din.
+ *
+ * @param dev		CROS-EC device
+ * @param out_bytes	Size of request packet to output
+ * @param in_bytes	Maximum size of response packet to receive
+ * @return number of bytes in response packet, or <0 on error
+ */
+int cros_ec_spi_packet(struct cros_ec_dev *dev, int out_bytes, int in_bytes);
+
 /**
  * Dump a block of data for a command.
  *