Initial crack at RT-21 rotor backend

Even though the Green Heron RT-21 rotor controller is billed as being
RotorEZ compatible, it returns its value as 'XXX;' instead of ';XXX'.
As a new backend model is being written anyway, the backend query's the
controller to return the real value which is 'XXX.Y;'.

include/hamlib/rotlist.h

@@ -122,12 +122,19 @@
  *  The Rotor-EZ backend can be used with rotators that support the
  *  DCU command set by DF9GR (currently the ERC).
  */
+/*! \def ROT_MODEL_RT21
+ *  \brief A macro that returns the model number of the RT21 backend.
+ *
+ *  The Rotor-EZ backend can be used with rotators that support the
+ *  DCU command set by Green Heron (currently the RT-21).
+ */
 #define ROT_ROTOREZ 4
 #define ROT_BACKEND_ROTOREZ "rotorez"
 #define ROT_MODEL_ROTOREZ ROT_MAKE_MODEL(ROT_ROTOREZ, 1)
 #define ROT_MODEL_ROTORCARD ROT_MAKE_MODEL(ROT_ROTOREZ, 2)
 #define ROT_MODEL_DCU ROT_MAKE_MODEL(ROT_ROTOREZ, 3)
 #define ROT_MODEL_ERC ROT_MAKE_MODEL(ROT_ROTOREZ, 4)
+#define ROT_MODEL_RT21 ROT_MAKE_MODEL(ROT_ROTOREZ, 5)
 
 /*! \def ROT_MODEL_SARTEK1
  *  \brief A macro that returns the model number of the SARtek-1 backend.

rotorez/rotorez.c

@@ -60,6 +60,7 @@ static int rotorez_rot_cleanup(ROT *rot);
 static int rotorez_rot_set_position(ROT *rot, azimuth_t azimuth, elevation_t elevation);
 static int rotorez_rot_get_position(ROT *rot, azimuth_t *azimuth, elevation_t *elevation);
 static int erc_rot_get_position(ROT *rot, azimuth_t *azimuth, elevation_t *elevation);
+static int rt21_rot_get_position(ROT *rot, azimuth_t *azimuth, elevation_t *elevation);
 
 static int rotorez_rot_reset(ROT *rot, rot_reset_t reset);
 static int rotorez_rot_stop(ROT *rot);
@@ -287,6 +288,45 @@ const struct rot_caps erc_rot_caps = {
 };
 
 
+const struct rot_caps rt21_rot_caps = {
+	.rot_model =		ROT_MODEL_RT21,
+	.model_name =		"RT-21",
+	.mfg_name =		"Green Heron",
+	.version =		"2014-09-08",
+	.copyright =		"LGPL",
+	.status =		RIG_STATUS_ALPHA,
+	.rot_type =		ROT_TYPE_OTHER,
+	.port_type =		RIG_PORT_SERIAL,
+	.serial_rate_min =	4800,
+	.serial_rate_max =	4800,
+	.serial_data_bits =	8,
+	.serial_stop_bits =	1,
+	.serial_parity =	RIG_PARITY_NONE,
+	.serial_handshake =	RIG_HANDSHAKE_NONE,
+	.write_delay =		0,
+	.post_write_delay =	500,
+	.timeout =		1500,
+	.retry =		2,
+
+	.min_az =		0,
+	.max_az =		360,
+	.min_el =		0,
+	.max_el =		0,
+
+	.priv =			NULL,	/* priv */
+//	.cfgparams =		rotorez_cfg_params,
+
+	.rot_init =		rotorez_rot_init,
+	.rot_cleanup =		rotorez_rot_cleanup,
+	.set_position =		rotorez_rot_set_position,
+	.get_position =		rt21_rot_get_position,
+//	.stop =				rotorez_rot_stop,
+//	.set_conf =			rotorez_rot_set_conf,
+//	.get_info =			rotorez_rot_get_info,
+
+};
+
+
 /* ************************************
  *
  * API functions
@@ -541,6 +581,77 @@ static int erc_rot_get_position(ROT *rot, azimuth_t *azimuth, elevation_t *eleva
 }
 
 
+/*
+ * Get position from Green Heron RT-21 series of controllers
+ * Returns current azimuth position in degrees and tenths.
+ * Range returned from RT-21 is a float, 0.0 to 359.9 degrees
+ * Elevation is set to 0
+ */
+
+static int rt21_rot_get_position(ROT *rot, azimuth_t *azimuth, elevation_t *elevation) {
+	struct rot_state *rs;
+	char cmdstr[5] = "BI1;";
+	char az[7];		/* read azimuth string */
+	char *p = NULL;
+	azimuth_t tmp = 0;
+	int err;
+
+	rig_debug(RIG_DEBUG_VERBOSE, "%s called\n", __func__);
+
+	if (!rot)
+		return -RIG_EINVAL;
+
+	do {
+		err = rotorez_send_priv_cmd(rot, cmdstr);
+		if (err != RIG_OK)
+			return err;
+
+		rs = &rot->state;
+
+		err = read_block(&rs->rotport, az, RT21_AZ_LEN);
+		if (err != RT21_AZ_LEN)
+			return -RIG_ETRUNC;
+
+		/* The azimuth string should be 'xxx.y;' beginning at offset 0.  If the
+		 * first character is not a digit, it's likely something needs
+		 * debugging.
+		 */
+		if (err == RT21_AZ_LEN && isdigit(az[0])) {
+			continue;
+		} else {
+			err = -RIG_EINVAL;
+		}
+
+	} while (err == -RIG_EINVAL);
+
+	/*
+	 * RT-21 returns a six octet string consisting of by three octets
+	 * containing the rotor's position in degrees, one octet containing a
+	 * decimal '.', one octet containing the rotor's position in tenths of a
+	 * degree, and one octet with the terminating ';'--'XXX.Y;'.  The
+	 * semi-colon is ignored when passing the string to atof().
+	 */
+	az[5] = 0x00;		/* NULL terminated string, truncating ';' */
+	p = az;
+	tmp = (azimuth_t)atof(p);
+	rig_debug(RIG_DEBUG_TRACE, "%s: \"%s\" after conversion = %.1f\n",
+			__func__, p, tmp);
+
+	if (tmp == 360.0)
+		tmp = 0;
+	else if (tmp < 0.0 || tmp > 359.9)
+		return -RIG_EINVAL;
+
+	*azimuth = tmp;
+	*elevation = 0.0;	/* RT-21 backend does not support el at this time. */
+	rig_debug(RIG_DEBUG_TRACE,
+			"%s: azimuth = %.1f deg; elevation = %.1f deg\n",
+			__func__, *azimuth, *elevation);
+
+	return RIG_OK;
+}
+
+
 /*
  * Stop rotation on RotorEZ, reset on DCU-1
  *
@@ -743,6 +854,7 @@ DECLARE_INITROT_BACKEND(rotorez)
 	rot_register(&rotorcard_rot_caps);
 	rot_register(&dcu_rot_caps);
 	rot_register(&erc_rot_caps);
+	rot_register(&rt21_rot_caps);
 
 	return RIG_OK;
 }

rotorez/rotorez.h

@@ -31,11 +31,13 @@
 #include "token.h"
 
 #define AZ_READ_LEN 4
+#define RT21_AZ_LEN 6
 
 extern const struct rot_caps rotorez_rot_caps;
 extern const struct rot_caps rotorcard_rot_caps;
 extern const struct rot_caps dcu_rot_caps;
 extern const struct rot_caps erc_rot_caps;
+extern const struct rot_caps rt21_rot_caps;
 
 /*
  * Tokens used by rotorez_rot_set_conf and the 'C' command in rotctl