util/ectool: move `struct command` into `ectool.h`

This allows it to be used by private host binaries (such as the one in
https://crrev.com/i/1914158), which may wish to follow the same pattern
as `ectool`. While we're at it, add some documentation comments.

BRANCH=none
BUG=chromium:1008568
TEST=Check `ectool` builds and runs.

Change-Id: I94b02f9b734f65b1344a79d6ac8752c40ecf1f04
Signed-off-by: Harry Cutts <hcutts@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1861075
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>

util/ectool.c

@@ -8432,11 +8432,6 @@ int cmd_port80_read(int argc, char *argv[])
 	return 0;
 }
 
-struct command {
-	const char *name;
-	int (*handler)(int argc, char *argv[]);
-};
-
 int cmd_force_lid_open(int argc, char *argv[])
 {
 	struct ec_params_force_lid_open p;

util/ectool.h

@@ -3,6 +3,22 @@
  * found in the LICENSE file.
  */
 
+/** @brief A handler for an `ectool` command.  */
+struct command {
+	/** The name of the command. */
+	const char *name;
+
+	/**
+	 * The function to handle the command.
+	 *
+	 * @param argc The length of `argv`
+	 * @param argv The arguments passed, including the command itself but
+	 *             not 'ectool'.
+	 * @return 0 if successful, or a negative `enum ec_status` value.
+	 */
+	int (*handler)(int argc, char *argv[]);
+};
+
 /**
  * Test low-level key scanning
  *
@@ -22,9 +38,5 @@
  * <keys_pressed> is a (possibly empty) list of ASCII keys
  *
  * The key matrix is read from the fdt.
- *
- * @param argc	Number of arguments (excluding 'ectool')
- * @param argv	List of arguments
- * @return 0 if ok, -1 on error
  */
 int cmd_keyscan(int argc, char *argv[]);