Acquire/release the i2c bus before/after reading the temperature register.

Prevents concurrent access to the smu(4) microcontroller on Apple G5
machines, which would result in errors reading the RTC.

ok deraadt@, mpi@

diff --git a/sys/dev/i2c/lm75.c b/sys/dev/i2c/lm75.c
index 844f1ef..60b1799 100644 (file)
--- a/sys/dev/i2c/lm75.c
+++ b/sys/dev/i2c/lm75.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: lm75.c,v 1.19 2015/03/14 03:38:47 jsg Exp $   */
+/*     $OpenBSD: lm75.c,v 1.20 2015/05/30 08:39:05 kettenis Exp $      */
 /*     $NetBSD: lm75.c,v 1.1 2003/09/30 00:35:31 thorpej Exp $ */
 /*
  * Copyright (c) 2006 Theo de Raadt <deraadt@openbsd.org>
@@ -216,13 +216,14 @@ lmtemp_attach(struct device *parent, struct device *self, void *aux)
 int
 lmtemp_temp_read(struct lmtemp_softc *sc, uint8_t which, int *valp)
 {
-       u_int8_t cmd;
+       u_int8_t cmd = which;
        u_int16_t data = 0x0000;
        int error;
 
-       cmd = which;
+       iic_acquire_bus(sc->sc_tag, 0);
        error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
            sc->sc_addr, &cmd, sizeof cmd, &data, sizeof data, 0);
+       iic_release_bus(sc->sc_tag, 0);
        if (error)
                return (error);