From ad52ee58e1bcfabc455f51af259e4268931f2d6c Mon Sep 17 00:00:00 2001
From: Andreas Tobler <andreast@FreeBSD.org>
Date: Sun, 8 Nov 2015 21:06:51 +0000
Subject: [PATCH] Improve r290373, do a runtime check rather than a compile
 time switch. I learned that the Power8 and the PS3 have a mix of OFW and FDT.
 Both have AIM defined. But currently they are not affected. They have no I2C
 devices under OFW.

This version was tested on a Quad G5 and build tested for armv6*.

Discussed with	nwhitehorn@
Reviewed by:	ian@
---
 sys/dev/ofw/ofw_iicbus.c | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/sys/dev/ofw/ofw_iicbus.c b/sys/dev/ofw/ofw_iicbus.c
index badefed6847..e27cc09c236 100644
--- a/sys/dev/ofw/ofw_iicbus.c
+++ b/sys/dev/ofw/ofw_iicbus.c
@@ -101,9 +101,13 @@ ofw_iicbus_attach(device_t dev)
 {
 	struct iicbus_softc *sc = IICBUS_SOFTC(dev);
 	struct ofw_iicbus_devinfo *dinfo;
-	phandle_t child, node;
+	phandle_t child, node, root;
 	pcell_t freq, paddr;
 	device_t childdev;
+	ssize_t compatlen;
+	char compat[255];
+	char *curstr;
+	u_int iic_addr_8bit = 0;
 
 	sc->dev = dev;
 	mtx_init(&sc->lock, "iicbus", NULL, MTX_DEF);
@@ -124,6 +128,21 @@ ofw_iicbus_attach(device_t dev)
 	bus_generic_probe(dev);
 	bus_enumerate_hinted_children(dev);
 
+	/*
+	 * Check if we're running on a PowerMac, needed for the I2C
+	 * address below.
+	 */
+	root = OF_peer(0);
+	compatlen = OF_getprop(root, "compatible", compat,
+				sizeof(compat));
+	if (compatlen != -1) {
+	    for (curstr = compat; curstr < compat + compatlen;
+		curstr += strlen(curstr) + 1) {
+		if (strncmp(curstr, "MacRISC", 7) == 0)
+		    iic_addr_8bit = 1;
+	    }
+	}
+
 	/*
 	 * Attach those children represented in the device tree.
 	 */
@@ -153,11 +172,11 @@ ofw_iicbus_attach(device_t dev)
 		 * Linux FDT data contains 7-bit values, so shift them up to
 		 * 8-bit format.
 		 */
-#ifdef AIM
-		dinfo->opd_dinfo.addr = paddr;
-#else
-		dinfo->opd_dinfo.addr = paddr << 1;
-#endif
+		if (iic_addr_8bit)
+		    dinfo->opd_dinfo.addr = paddr;
+		else
+		    dinfo->opd_dinfo.addr = paddr << 1;
+
 		if (ofw_bus_gen_setup_devinfo(&dinfo->opd_obdinfo, child) !=
 		    0) {
 			free(dinfo, M_DEVBUF);