[src/trunk]: src/sys/dev/i2c When matching, try a read in case this is an opt...

[jdc <jdc%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/be1cd6be9d51
branches:  trunk
changeset: 978816:be1cd6be9d51
user:      jdc <jdc%NetBSD.org@localhost>
date:      Sat Dec 05 14:48:09 2020 +0000

description:
When matching, try a read in case this is an optional device and isn't
actually present.
Make sure that we set sc->sc_sme to NULL in failure cases and when we
detach in order to avoid calling sysmon_envsys_unregister() with an
invalid struct.

diffstat:

 sys/dev/i2c/pcf8574.c |  25 +++++++++++++++++++++----
 1 files changed, 21 insertions(+), 4 deletions(-)

diffs (70 lines):

diff -r 8a32da389472 -r be1cd6be9d51 sys/dev/i2c/pcf8574.c
--- a/sys/dev/i2c/pcf8574.c     Sat Dec 05 14:28:09 2020 +0000
+++ b/sys/dev/i2c/pcf8574.c     Sat Dec 05 14:48:09 2020 +0000
@@ -1,3 +1,5 @@
+/* $NetBSD: pcf8574.c,v 1.3 2020/12/05 14:48:09 jdc Exp $ */
+
 /*-
  * Copyright (c) 2020 The NetBSD Foundation, Inc.
  * All rights reserved.
@@ -33,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pcf8574.c,v 1.2 2020/10/31 14:39:31 jdc Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pcf8574.c,v 1.3 2020/12/05 14:48:09 jdc Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -106,10 +108,21 @@
 pcf8574_match(device_t parent, cfdata_t cf, void *aux)
 {
        struct i2c_attach_args *ia = aux;
+       struct pcf8574_softc sc;
        int match_result;
 
-       if (iic_use_direct_match(ia, cf, compat_data, &match_result))
-               return match_result;
+       if (!iic_use_direct_match(ia, cf, compat_data, &match_result))
+               return 0;
+
+       /* Try a read so that we don't match on optional components */
+       if (match_result) {
+               sc.sc_tag = ia->ia_tag;
+               sc.sc_addr = ia->ia_addr;
+               if (pcf8574_read(&sc, &sc.sc_state))
+                       return 0;
+               else
+                       return 1;
+       }
 
        /* We don't support indirect matches */
        return 0;
@@ -190,6 +203,7 @@
                        if (sysmon_envsys_sensor_attach(sc->sc_sme,
                            &sc->sc_sensor[i])) {
                                sysmon_envsys_destroy(sc->sc_sme);
+                               sc->sc_sme = NULL;
                                aprint_error_dev(self,
                                    "unable to attach pin %d at sysmon\n", i);
                                return;
@@ -208,6 +222,7 @@
                        aprint_error_dev(self,
                            "unable to register with sysmon\n");
                        sysmon_envsys_destroy(sc->sc_sme);
+                       sc->sc_sme = NULL;
                        return;
                }
        }
@@ -219,8 +234,10 @@
        struct pcf8574_softc *sc = device_private(self);
        int i;
 
-       if (sc->sc_sme != NULL)
+       if (sc->sc_sme != NULL) {
                sysmon_envsys_unregister(sc->sc_sme);
+               sc->sc_sme = NULL;
+       }
 
        for (i = 0; i < sc->sc_nleds; i++)
                led_detach(sc->sc_leds[i].led);