mfd: cros_ec: Check result code from EC messages

Just because the host was able to talk to the EC doesn't mean that the EC
was happy with what it was told. Errors in communincation are not the same
as error messages from the EC itself.

This change lets the EC report its errors separately.

[dianders: Added common function to cros_ec.c]
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/cros_ec.c

@@ -44,6 +44,24 @@ int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
 }
 EXPORT_SYMBOL(cros_ec_prepare_tx);
 
+int cros_ec_check_result(struct cros_ec_device *ec_dev,
+			 struct cros_ec_command *msg)
+{
+	switch (msg->result) {
+	case EC_RES_SUCCESS:
+		return 0;
+	case EC_RES_IN_PROGRESS:
+		dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
+			msg->command);
+		return -EAGAIN;
+	default:
+		dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
+			msg->command, msg->result);
+		return 0;
+	}
+}
+EXPORT_SYMBOL(cros_ec_check_result);
+
 static irqreturn_t ec_irq_thread(int irq, void *data)
 {
 	struct cros_ec_device *ec_dev = data;

drivers/mfd/cros_ec_i2c.c

@@ -92,12 +92,10 @@ static int cros_ec_cmd_xfer_i2c(struct cros_ec_device *ec_dev,
 	}
 
 	/* check response error code */
-	if (i2c_msg[1].buf[0]) {
-		dev_warn(ec_dev->dev, "command 0x%02x returned an error %d\n",
-			 msg->command, i2c_msg[1].buf[0]);
-		ret = -EINVAL;
+	msg->result = i2c_msg[1].buf[0];
+	ret = cros_ec_check_result(ec_dev, msg);
+	if (ret)
 		goto done;
-	}
 
 	/* copy response packet payload and compute checksum */
 	sum = in_buf[0] + in_buf[1];

drivers/mfd/cros_ec_spi.c

@@ -285,21 +285,14 @@ static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
 		goto exit;
 	}
 
-	/* check response error code */
 	ptr = ec_dev->din;
-	if (ptr[0]) {
-		if (ptr[0] == EC_RES_IN_PROGRESS) {
-			dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
-				ec_msg->command);
-			ret = -EAGAIN;
-			goto exit;
-		}
-		dev_warn(ec_dev->dev, "command 0x%02x returned an error %d\n",
-			 ec_msg->command, ptr[0]);
-		debug_packet(ec_dev->dev, "in_err", ptr, len);
-		ret = -EINVAL;
+
+	/* check response error code */
+	ec_msg->result = ptr[0];
+	ret = cros_ec_check_result(ec_dev, ec_msg);
+	if (ret)
 		goto exit;
-	}
+
 	len = ptr[1];
 	sum = ptr[0] + ptr[1];
 	if (len > ec_msg->insize) {

include/linux/mfd/cros_ec.h

@@ -142,6 +142,18 @@ int cros_ec_resume(struct cros_ec_device *ec_dev);
 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
 		       struct cros_ec_command *msg);
 
+/**
+ * cros_ec_check_result - Check ec_msg->result
+ *
+ * This is used by ChromeOS EC drivers to check the ec_msg->result for
+ * errors and to warn about them.
+ *
+ * @ec_dev: EC device
+ * @msg: Message to check
+ */
+int cros_ec_check_result(struct cros_ec_device *ec_dev,
+			 struct cros_ec_command *msg);
+
 /**
  * cros_ec_remove - Remove a ChromeOS EC
  *