linux/drivers/w1
Paul Walmsley 2acd089471 W1: OMAP HDQ1W: use 32-bit register accesses
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>
2012-06-21 21:40:37 -06:00
..
masters W1: OMAP HDQ1W: use 32-bit register accesses 2012-06-21 21:40:37 -06:00
slaves w1: w1_ds2408.c: quite sparse noise about using plaing integer as NULL pointer 2012-05-04 16:25:30 -07:00
Kconfig Kconfig: replace "--- help ---" with "---help---" 2012-05-07 15:01:22 +02:00
Makefile
w1_family.c drivers/w1: Add export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:32:00 -04:00
w1_family.h Revert "w1: Add 1-wire slave device driver for DS28E04-100" 2012-04-29 22:12:08 -04:00
w1_int.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
w1_int.h MAINTAINERS: Evgeniy has moved 2011-08-25 16:25:33 -07:00
w1_io.c w1: Disable irqs during 1-wire bus operations, extend 1-wire reset pulse 2012-04-11 16:44:10 -07:00
w1_log.h MAINTAINERS: Evgeniy has moved 2011-08-25 16:25:33 -07:00
w1_netlink.c MAINTAINERS: Evgeniy has moved 2011-08-25 16:25:33 -07:00
w1_netlink.h MAINTAINERS: Evgeniy has moved 2011-08-25 16:25:33 -07:00
w1.c w1: fix slave driver registration error message 2012-04-09 15:05:47 -07:00
w1.h MAINTAINERS: Evgeniy has moved 2011-08-25 16:25:33 -07:00