MFC r259126:

Activate the device before attempt to access any of its registers.  Without
this change we may end up with a panic (Fatal kernel mode data abort:
'External Non-Linefetch Abort (S)') as described in
http://e2e.ti.com/support/arm/sitara_arm/f/791/t/276862.aspx.

It is now possible to bring up I2C1 and I2C2 on BBB.

1 files changed, 8 insertions, 8 deletions

diff --git a/sys/arm/ti/ti_i2c.c b/sys/arm/ti/ti_i2c.c
index 28bf3ca..f23a8ea 100644
--- a/sys/arm/ti/ti_i2c.c
+++ b/sys/arm/ti/ti_i2c.c
@@ -1076,20 +1076,20 @@ ti_i2c_attach(device_t dev)
 		goto out;
 	}
 
-	/* XXXOMAP3: FIXME get proper revision here */
-	/* First read the version number of the I2C module */
-	sc->sc_rev = ti_i2c_read_2(sc, I2C_REG_REVNB_HI) & 0xff;
-
-	device_printf(dev, "I2C revision %d.%d\n", sc->sc_rev >> 4,
-	    sc->sc_rev & 0xf);
-
-	/* Activate the H/W */
+	/* First we _must_ activate the H/W */
 	err = ti_i2c_activate(dev);
 	if (err) {
 		device_printf(dev, "ti_i2c_activate failed\n");
 		goto out;
 	}
 
+	/* XXXOMAP3: FIXME get proper revision here */
+	/* Read the version number of the I2C module */
+	sc->sc_rev = ti_i2c_read_2(sc, I2C_REG_REVNB_HI) & 0xff;
+
+	device_printf(dev, "I2C revision %d.%d\n", sc->sc_rev >> 4,
+	    sc->sc_rev & 0xf);
+
 	/* activate the interrupt */
 	err = bus_setup_intr(dev, sc->sc_irq_res, INTR_TYPE_MISC | INTR_MPSAFE,
 				NULL, ti_i2c_intr, sc, &sc->sc_irq_h);