cros_ec: Clean up multiple EC protocol support

Version 1 protocols (without command version) were already no longer
supported in cros_ec.c.  This removes some dead code from the
cros_ec_i2c driver.

Version 2 protcols (with command version) are now called
protocol_version=2, instead of cmd_version_is_supported=1.

A subsequent change will introduce protocol version 3 for SPI.

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

@@ -501,18 +501,23 @@ static int cros_ec_check_version(struct cros_ec_dev *dev)
 	 *
 	 * So for now, just read all the data anyway.
 	 */
-	dev->cmd_version_is_supported = 1;
+
+	/* Try sending a version 2 packet */
+	dev->protocol_version = 2;
 	if (ec_command_inptr(dev, EC_CMD_HELLO, 0, &req, sizeof(req),
 		       (uint8_t **)&resp, sizeof(*resp)) > 0) {
-		/* It appears to understand new version commands */
-		dev->cmd_version_is_supported = 1;
-	} else {
-		printf("%s: ERROR: old EC interface not supported\n",
-		       __func__);
-		return -1;
+		return 0;
 	}
 
-	return 0;
+	/*
+	 * Fail if we're still here, since the EC doesn't understand any
+	 * protcol version we speak.  Version 1 interface without command
+	 * version is no longer supported, and we don't know about any new
+	 * protocol versions.
+	 */
+	dev->protocol_version = 0;
+	printf("%s: ERROR: old EC interface not supported\n", __func__);
+	return -1;
 }
 
 int cros_ec_test(struct cros_ec_dev *dev)

drivers/misc/cros_ec_i2c.c

@@ -35,7 +35,7 @@ int cros_ec_i2c_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
 	uint8_t *ptr;
 	/* Receive input data, so that args will be dword aligned */
 	uint8_t *in_ptr;
-	int ret;
+	int len, csum, ret;
 
 	old_bus = i2c_get_bus_num();
 
@@ -67,24 +67,24 @@ int cros_ec_i2c_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
 	 * will be dword aligned.
 	 */
 	in_ptr = dev->din + sizeof(int64_t);
-	if (!dev->cmd_version_is_supported) {
-		/* Send an old-style command */
-		*ptr++ = cmd;
-		out_bytes = dout_len + 1;
-		in_bytes = din_len + 2;
-		in_ptr--;	/* Expect just a status byte */
-	} else {
-		*ptr++ = EC_CMD_VERSION0 + cmd_version;
-		*ptr++ = cmd;
-		*ptr++ = dout_len;
-		in_ptr -= 2;	/* Expect status, length bytes */
+
+	if (dev->protocol_version != 2) {
+		/* Something we don't support */
+		debug("%s: Protocol version %d unsupported\n",
+		      __func__, dev->protocol_version);
+		return -1;
 	}
+
+	*ptr++ = EC_CMD_VERSION0 + cmd_version;
+	*ptr++ = cmd;
+	*ptr++ = dout_len;
+	in_ptr -= 2;	/* Expect status, length bytes */
+
 	memcpy(ptr, dout, dout_len);
 	ptr += dout_len;
 
-	if (dev->cmd_version_is_supported)
-		*ptr++ = (uint8_t)
-			 cros_ec_calc_checksum(dev->dout, dout_len + 3);
+	*ptr++ = (uint8_t)
+		cros_ec_calc_checksum(dev->dout, dout_len + 3);
 
 	/* Set to the proper i2c bus */
 	if (i2c_set_bus_num(dev->bus_num)) {
@@ -121,26 +121,20 @@ int cros_ec_i2c_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
 		return -(int)*in_ptr;
 	}
 
-	if (dev->cmd_version_is_supported) {
-		int len, csum;
-
-		len = in_ptr[1];
-		if (len + 3 > sizeof(dev->din)) {
-			debug("%s: Received length %#02x too large\n",
-			      __func__, len);
-			return -1;
-		}
-		csum = cros_ec_calc_checksum(in_ptr, 2 + len);
-		if (csum != in_ptr[2 + len]) {
-			debug("%s: Invalid checksum rx %#02x, calced %#02x\n",
-			      __func__, in_ptr[2 + din_len], csum);
-			return -1;
-		}
-		din_len = min(din_len, len);
-		cros_ec_dump_data("in", -1, in_ptr, din_len + 3);
-	} else {
-		cros_ec_dump_data("in (old)", -1, in_ptr, in_bytes);
+	len = in_ptr[1];
+	if (len + 3 > sizeof(dev->din)) {
+		debug("%s: Received length %#02x too large\n",
+		      __func__, len);
+		return -1;
 	}
+	csum = cros_ec_calc_checksum(in_ptr, 2 + len);
+	if (csum != in_ptr[2 + len]) {
+		debug("%s: Invalid checksum rx %#02x, calced %#02x\n",
+		      __func__, in_ptr[2 + din_len], csum);
+		return -1;
+	}
+	din_len = min(din_len, len);
+	cros_ec_dump_data("in", -1, in_ptr, din_len + 3);
 
 	/* Return pointer to dword-aligned input data, if any */
 	*dinp = dev->din + sizeof(int64_t);
@@ -178,7 +172,5 @@ int cros_ec_i2c_init(struct cros_ec_dev *dev, const void *blob)
 {
 	i2c_init(dev->max_frequency, dev->addr);
 
-	dev->cmd_version_is_supported = 0;
-
 	return 0;
 }

drivers/misc/cros_ec_spi.c

@@ -42,6 +42,12 @@ int cros_ec_spi_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
 	int csum, len;
 	int rv;
 
+	if (dev->protocol_version != 2) {
+		debug("%s: Unsupported EC protcol version %d\n",
+		      __func__, dev->protocol_version);
+		return -1;
+	}
+
 	/*
 	 * Sanity-check input size to make sure it plus transaction overhead
 	 * fits in the internal device buffer.

include/cros_ec.h

@@ -33,7 +33,7 @@ struct cros_ec_dev {
 	unsigned int bus_num;		/* Bus number (for I2C) */
 	unsigned int max_frequency;	/* Maximum interface frequency */
 	struct fdt_gpio_state ec_int;	/* GPIO used as EC interrupt line */
-	int cmd_version_is_supported;   /* Device supports command versions */
+	int protocol_version;           /* Protocol version to use */
 	int optimise_flash_write;	/* Don't write erased flash blocks */
 
 	/*
@@ -260,8 +260,7 @@ int cros_ec_spi_decode_fdt(struct cros_ec_dev *dev, const void *blob);
  * Check whether the LPC interface supports new-style commands.
  *
  * LPC has its own way of doing this, which involves checking LPC values
- * visible to the host. Do this, and update dev->cmd_version_is_supported
- * accordingly.
+ * visible to the host. Do this, and update dev->protocol_version accordingly.
  *
  * @param dev		CROS-EC device to check
  */