HDQ/1-wire registers are 32 bits long, even if the register contents
fit into 8 bits, so accesses must be 32-bit aligned. Evidently the
OMAP2/3 interconnects allowed the driver to get away with 8 bit accesses,
but the OMAP4 puts a stop to that:
[ 1.488800] Driver for 1-wire Dallas network protocol.
[ 1.495025] Bad mode in data abort handler detected
[ 1.500122] Internal error: Oops - bad mode: 0 [#1] SMP
[ 1.505615] Modules linked in:
[ 1.508819] CPU: 0 Not tainted (3.3.0-rc1-00008-g45030e9 #992)
[ 1.515289] PC is at 0xffff0018
[ 1.518615] LR is at omap_hdq_probe+0xd4/0x2cc
The OMAP4430 ES2 Rev X TRM does warn about this restriction in section
23.2.6.2 "HDQ/1-Wire Registers".
Fixes the crash on OMAP4430 ES2 Pandaboard. Tested also on OMAP34xx and
OMAP2420; it seems to work fine on those chips, although due to the lack
of boards with HDQ/1-wire devices here, a more indepth test was not
possible.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
2acd089471