G28.2: home the machine from G-code (all joints, or Pn per joint)

docs/src/gcode.html.in

@@ -165,6 +165,7 @@ tr.head td, tr.head th { background: black; color: white; }
     <tr><td><a href="gcode/g-code.html#gcode:g10-l2">G10 L2</a></td><td>P R</td><td>Set Coordinate System</td></tr>
     <tr><td><a href="gcode/g-code.html#gcode:g10-l20">G10 L20</a></td><td>P</td><td>Set Coordinate System</td></tr>
     <tr><td><a href="gcode/g-code.html#gcode:g28-g28.1">G28, G28.1</a></td><td/><td>Go/Set Predefined Position</td></tr>
+    <tr><td><a href="gcode/g-code.html#gcode:g28.2">G28.2</a></td><td>P</td><td>Home from G-code</td></tr>
     <tr><td><a href="gcode/g-code.html#gcode:g30-g30.1">G30, G30.1</a></td><td/><td>Go/Set Predefined Position</td></tr>
     <tr><td><a href="gcode/g-code.html#gcode:g53">G53</a></td><td/><td>Move in Machine Coordinates</td></tr>
     <tr><td><a href="gcode/g-code.html#gcode:g92">G52, G92</a></td><td/><td>Coordinate System Offset</td></tr>

docs/src/gcode/g-code.adoc

@@ -74,6 +74,7 @@ as the 'L number', and so on for any other letter.
 |<<gcode:g17-g19.1,G17 - G19.1>>   |Plane Select
 |<<gcode:g20-g21,G20 G21>>         |Set Units of Measure
 |<<gcode:g28-g28.1,G28 - G28.1>>   |Go to Predefined Position
+|<<gcode:g28.2,G28.2>>             |Home from G-code
 |<<gcode:g30-g30.1,G30 - G30.1>>   |Go to Predefined Position
 |<<gcode:g33,G33>>                 |Spindle Synchronized Motion
 |<<gcode:g33.1,G33.1>>             |Rigid Tapping
@@ -1070,6 +1071,81 @@ It is an error if :
 
 * Cutter Compensation is turned on
 
+[[gcode:g28.2]]
+== G28.2 Home from G-code(((G28.2 Home from G-code)))
+
+This non-modal code lets a program or MDI line reference the machine
+instead of requiring the operator to use the GUI's *Home All* button. It
+follows the same modal-group-0 pattern as `G28.1`/`G30.1`, takes no axis
+words, and *requires* a `P` word saying what to home.
+
+* 'G28.2 P-1' - runs the homing cycle on every joint, in `HOME_SEQUENCE`
+  order (the same operation as the GUI *Home All*). This form requires the
+  config to set `[JOINT_n]HOME_SEQUENCE`; exactly as with *Home All*, a
+  config with no `HOME_SEQUENCE` cannot home all joints at once and the
+  command fails, leaving the machine in joint mode.
+* 'G28.2 Pn' - runs the homing cycle on joint 'n' only, where 'n' is the
+  0-based joint number matching its `[JOINT_n]` INI section (the same
+  numbering used by `HOME_SEQUENCE` and by joint jogging). Other joints are
+  left as they are, and `HOME_SEQUENCE` is not required for the `Pn` form.
+  How many joints actually home depends on the `HOME_SEQUENCE` of joint 'n':
++
+--
+** a *negative* (synchronized) sequence homes the whole synchronized group -
+   `Pn` on either joint of a gantry pair homes both;
+** a *positive* sequence shared with other joints homes only joint 'n' -
+   use `G28.2 P-1` to home the shared group together;
+** no sequence, or a sequence not shared with any other joint, homes just
+   joint 'n'.
+--
+
+[WARNING]
+There is no bare `G28.2`. Homing drives joints onto their switches at
+homing speed, ignoring soft limits, from wherever the machine happens to
+be, so homing the whole machine has to be asked for explicitly with `P-1`
+rather than being what a truncated or mistyped line does. A `G28.2` with no
+`P` word is an error and stops the program.
+
+.G28.2 Example Lines
+[source,ngc]
+----
+G28.2 P-1   (home all joints, in HOME_SEQUENCE order)
+G28.2 P1    (home joint 1 only)
+----
+
+A queued `G28.2` dips motion into free mode for the duration of the homing
+cycle and restores whatever mode (manual/MDI/auto) was active once it
+finishes, so the mode dip is invisible at the task level. Motion still
+enforces its own safety: the home is honored only when the machine is idle
+(in position with no queued motion) or in joint mode, and a home is refused
+mid-motion. Homing inhibits and per-joint limit handling are unchanged.
+
+[NOTE]
+When the homing cycle finishes, the interpreter resyncs its model of the
+current position from the machine (the same way it does after probing or a
+tool change), so a following move made in incremental distance mode
+(`G91`), or an arc whose center is given with `I`/`J`/`K`, is computed from
+where the machine actually is after homing. `G28.2` is a queue point: read
+ahead stops at it and resumes once the cycle has run. `G5x`/`G92` offsets
+that were active before the `G28.2` are still applied afterward and now
+refer to the newly established machine zero; clear or re-establish them if
+that is not what you want.
+
+[NOTE]
+There is no G-code unhome. Clearing a joint's reference is done from the
+GUI, halui or linuxcncrsh.
+
+[NOTE]
+`G28.2` is a LinuxCNC extension; there is no standard Fanuc equivalent.
+
+It is an error if:
+
+* Cutter radius compensation is active (`G41`, `G41.1`, `G42` or `G42.1`).
+* An axis word is present ('G28.2' takes no axis words).
+* The 'P' word is missing.
+* The 'P' word is not a whole number, or is negative other than `P-1`.
+* The 'P' word names a joint number the machine does not have.
+
 [[gcode:g30-g30.1]]
 == G30, G30.1 Go/Set Predefined Position(((G30 Go/Set Predefined Position)))
 

docs/src/gcode/overview.adoc

@@ -964,7 +964,7 @@ The modal groups are shown in the following Table.
 [width="80%",cols="4,6",options="header"]
 |===
 |Modal Group Meaning                    | Member Words
-|Non-modal codes (Group 0)              | G4, G10 G28, G30, G52, G53, G92, G92.1, G92.2, G92.3,
+|Non-modal codes (Group 0)              | G4, G10 G28, G28.2, G30, G52, G53, G92, G92.1, G92.2, G92.3,
 |Motion (Group 1)                       | G0, G1, G2, G3, G33, G38.n, G73, G76, G80, G81
                                           G82, G83, G84, G85, G86, G87, G88, G89
 |Plane selection (Group 2)              | G17, G18, G19, G17.1, G18.1, G19.1

docs/src/remap/remap.adoc

@@ -1851,7 +1851,7 @@ All the listed G-codes are already defined in the current implementation of Linu
 |25 |    |      |      |      |      |      |      |      |      | 
 |26 |    |      |      |      |      |      |      |      |      | 
 |27 |    |      |      |      |      |      |      |      |      | 
-|28 |G28 |G28.1 |      |      |      |      |      |      |      | 
+|28 |G28 |G28.1 |G28.2 |      |      |      |      |      |      |
 |29 |    |      |      |      |      |      |      |      |      | 
 |===
 

lib/python/common/hal_glib.py

@@ -287,7 +287,7 @@ class _GStat(GObject.GObject):
     STATE_ON = linuxcnc.STATE_ON
     STATE_OFF = linuxcnc.STATE_OFF
 
-    group0 = ('G4', 'G10','G28', 'G30', 'G52', 'G53', 'G92', 'G92.1', 'G92.2', 'G92.3')
+    group0 = ('G4', 'G10','G28', 'G28.2', 'G30', 'G52', 'G53', 'G92', 'G92.1', 'G92.2', 'G92.3')
     group1 = ('G0', 'G1', 'G2', 'G3', 'G33', 'G38.n', 'G73', 'G76', 'G80', 'G81',\
              'G82', 'G83', 'G84', 'G85', 'G86', 'G87', 'G88', 'G89')
     group2 = ('G17', 'G18', 'G19', 'G17.1', 'G18.1', 'G19.1')

lib/python/qtvcp/lib/mdi_text.py

@@ -27,6 +27,7 @@ def gcode_titles():
               'G21': 'Set Units to Millimeters',
               'G28': 'Go to Predefined Position',
               'G28.1': 'Set Predefined Position',
+              'G28.2': 'Home from G-code',
               'G30': 'Go to Predefined Position',
               'G30.1': 'Set Predefined Position',
               'G33': 'Spindle Synchronized Motion',
@@ -209,6 +210,7 @@ def gcode_descriptions(gcode):
                   'G21': G21,
                   'G28': G28,
                   'G28.1': G28_1,
+                  'G28.2': G28_2,
                   'G30': G30,
                   'G30.1': G30_1,
                   'G33': G33,
@@ -467,6 +469,29 @@ def gcode_descriptions(gcode):
 G28.1 - stores the current absolute position into
 parameters 5161-5166.
 """
+
+G28_2 = """G28.2 Home from G-code
+Runs the homing cycle, the same operation as the GUI
+Home All button, so a program or MDI line can
+reference the machine. Takes no axis words, and
+requires a P word saying what to home.
+
+G28.2 P-1 - homes all joints, in HOME_SEQUENCE order
+(the config must set HOME_SEQUENCE).
+
+G28.2 Pn - homes joint n only, where n is the
+0-based joint number matching its [JOINT_n] INI
+section. On a synchronized (negative HOME_SEQUENCE)
+joint pair, Pn on either joint homes both.
+
+There is no bare G28.2: homing the whole machine has
+to be asked for with P-1.
+
+It is an error if cutter compensation is on, if the P
+word is missing or is not -1 or a whole joint number,
+or if Pn names a joint the machine does not have.
+"""
+
 G30 = """G30 Go to Predefined Position
 G30 uses the values stored in parameters 5181-5189
 as the X Y Z A B C U V W final point to move to.

src/emc/motion/command.c

@@ -1505,8 +1505,23 @@ void emcmotCommandHandler_locked(void *arg, long servo_period)
 	    rtapi_print_msg(RTAPI_MSG_DBG, "JOINT_HOME");
 	    rtapi_print_msg(RTAPI_MSG_DBG, " %d", joint_num);
 
-	    if (emcmotStatus->motion_state != EMCMOT_MOTION_FREE) {
-		/* can't home unless in free mode */
+	    /* Normally homing requires free (joint) mode. The queued G28.2 path
+	     * (emctaskmain EMC_TASK_EXEC::WAITING_FOR_HOMING) dips motion into
+	     * FREE before issuing this command; while that transition is still
+	     * settling motion_state can read non-FREE for a cycle. Accept the
+	     * command in exactly that window -- in position, nothing queued, and
+	     * a FREE transition already pending (teleop and coord both cleared)
+	     * -- so a G-code-triggered home from MDI / a program is honored.
+	     *
+	     * Do NOT accept it merely because motion is idle: an immediate home
+	     * (halui, linuxcncrsh, c.home(n)) on an already-homed machine sitting
+	     * in TELEOP is idle too, and do_homing() only advances in FREE
+	     * (control.c), so accepting it there would silently drop the
+	     * request (found in review of PR #4172). */
+	    if (emcmotStatus->motion_state != EMCMOT_MOTION_FREE
+		&& !(GET_MOTION_INPOS_FLAG() && emcmotStatus->depth == 0
+		     && !emcmotInternal->teleoperating
+		     && !emcmotInternal->coordinating)) {
 		reportError(_("must be in joint mode to home"));
 		return;
 	    }

src/emc/motion/control.c

@@ -2273,6 +2273,7 @@ static void update_status(void)
     }
 
     emcmotStatus->jogging_active = hal_get_bool(emcmot_hal_data->jog_is_active);
+    emcmotStatus->homing_active = get_homing_is_active();
 
     /*! \todo FIXME - the rest of this function is stuff that was apparently
        dropped in the initial move from emcmot.c to control.c.  I

src/emc/motion/motion.h

@@ -675,6 +675,10 @@ Suggestion: Split this in to an Error and a Status flag register..
 	int numExtraJoints;
     int stepping;
     bool jogging_active;
+    bool homing_active;	/* homing state machine is running (get_homing_is_active()).
+			   Aggregate: stays true across the gap between
+			   HOME_SEQUENCE groups, when every joint's per-joint
+			   .homing flag is momentarily false. */
 
 	int    switchkins_seq;  /* echoes the config counter once acted on */
 	int    switchkins_type; /* switchkins type now in force */

src/emc/nml_intf/canon.hh

@@ -243,6 +243,13 @@ extern void SET_G92_OFFSET(double x, double y, double z,
 
 extern void SET_XY_ROTATION(double t);
 
+/* G28.2: trigger the machine homing cycle from G-code (bare form = all
+ * joints, in HOME_SEQUENCE order). Maps to EMC_JOINT_HOME(-1). */
+extern void HOME_CYCLE(void);
+/* G28.2 Pn: home a single joint by its 0-based joint number (matching
+ * [JOINT_n] INI section numbering). Maps to EMC_JOINT_HOME(joint). */
+extern void HOME_CYCLE_JOINT(int joint);
+
 /* Offset the origin to the point with absolute coordinates x, y, z,
 a, b, c, u, v, and w. Values of x, y, z, a, b, c, u, v, and w are real 
 numbers. The units are whatever length units are being used at the time 

src/emc/nml_intf/emc.cc

@@ -1864,6 +1864,7 @@ void EMC_MOTION_STAT::update(CMS * cms)
     EmcPose_update(cms, &eoffset_pose);
     cms->update(numExtraJoints);
     cms->update(jogging_active);
+    cms->update(homing_active);
     cms->update(heartbeat);
 }
 

src/emc/nml_intf/emc.hh

@@ -216,7 +216,8 @@ enum class EMC_TASK_EXEC {
     WAITING_FOR_DELAY = 8,
     WAITING_FOR_SYSTEM_CMD = 9,
     WAITING_FOR_SPINDLE_ORIENTED = 10,
-    WAITING_FOR_KINS_SWITCH = 11
+    WAITING_FOR_KINS_SWITCH = 11,
+    WAITING_FOR_HOMING = 12
 };
 
 // types for EMC_TASK interpState

src/emc/nml_intf/emc_nml.hh

@@ -1189,6 +1189,12 @@ class EMC_MOTION_STAT:public EMC_MOTION_STAT_MSG {
     EmcPose eoffset_pose;
     int numExtraJoints;
     bool jogging_active;
+    // Aggregate "the homing state machine is running", from
+    // get_homing_is_active() in motion. Unlike the per-joint EMC_JOINT_STAT
+    // .homing flags, this stays true across the gap between HOME_SEQUENCE
+    // groups, where every joint momentarily reads .homing == false while the
+    // machine is still homing (see the race note in motion/homing.c).
+    bool homing_active;
     uint64_t heartbeat;  // motion controller's heartbeat counter
 
 };

src/emc/nml_intf/emcops.cc

@@ -117,6 +117,7 @@ EMC_MOTION_STAT::EMC_MOTION_STAT()
     eoffset_pose{},
     numExtraJoints(0),
     jogging_active(0),
+    homing_active(false),
     heartbeat(0)
 {
 }

src/emc/rs274ngc/gcodemodule.cc

@@ -544,6 +544,9 @@ void SELECT_PLANE(CANON_PLANE pl) {
     parse_state.canon->set_plane(static_cast<int>(pl));
 }
 
+void HOME_CYCLE(void) {}
+void HOME_CYCLE_JOINT(int) {}
+
 void SET_TRAVERSE_RATE(double rate) {
     parse_state.canon->set_traverse_rate(rate);
 }

src/emc/rs274ngc/interp_array.cc

@@ -84,7 +84,7 @@ const int Interp::gees[] = {
 /* 220 */  -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
 /* 240 */  -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
 /* 260 */  -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-/* 280 */   0, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+/* 280 */   0, 0, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,	// 282=G28.2
 /* 300 */   0, 0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
 /* 320 */  -1,-1,-1,-1,-1,-1,-1,-1,-1,-1, 1, 1,-1,-1,-1,-1,-1,-1,-1,-1,
 /* 340 */  -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,

src/emc/rs274ngc/interp_check.cc

@@ -100,6 +100,7 @@ int Interp::check_g_codes(block_pointer block,   //!< pointer to a block to be c
   } else if (mode1 == G_5_2){
   } else if (mode1 == G_6_2){
   } else if (mode0 == G_28_1 || mode0 == G_30_1) {
+  } else if (mode0 == G_28_2) {   // G-code homing
   } else if (mode0 == G_52) {
   } else if (mode0 == G_53) {
     CHKS(((block->motion_to_be != G_0) && (block->motion_to_be != G_1)),
@@ -331,12 +332,14 @@ int Interp::check_other_codes(block_pointer block)       //!< pointer to a block
 					(motion != G_6) && (motion != G_6_2) &&
           (motion != G_2) && (motion != G_3) &&
 	  (motion != G_74) && (motion != G_84) &&
+	  (block->g_modes[GM_MODAL_0] != G_28_2) &&
           (block->m_modes[9] != 50) && (block->m_modes[9] != 51) && (block->m_modes[9] != 52) &&
           (block->m_modes[9] != 53) && (block->m_modes[5] != 62) && (block->m_modes[5] != 63) &&
           (block->m_modes[5] != 64) && (block->m_modes[5] != 65) && (block->m_modes[5] != 66) &&
           (block->m_modes[7] != 19) && (block->user_m != 1) &&
           (block->o_type != M_98)),
           _("P word with no G2 G3 G4 G10 G12.1 G64 G5 G5.2 G6, G6.2, G76 G82 G86 G88 G89"
+            " G28.2"
             " or M50 M51 M52 M53 M62 M63 M64 M65 M66 M98 "
             "or user M code to use it"));
       int p_value = round_to_int(block->p_number);