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authorJean-François Dagenais <dagenaisj@sonatest.com>2011-05-26 16:26:01 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-26 17:12:38 -0700
commit67dfd54c2d83a76a5756760f7fee0c8cfac52b1c (patch)
tree67f60d8bf1fcfd64106e419c1de3cd6e5618dd1d /drivers/w1/w1.h
parent6f7bd76f05eb2bfbb48d58c0408a50a7e16b2423 (diff)
downloadlinux-67dfd54c2d83a76a5756760f7fee0c8cfac52b1c.tar.bz2
w1: add 1-wire (w1) reset and resume command API support
The first patch adds generic functionnality to w1_io for Resume Command [A5h] lots of slaves support. I found it useful for multi-commands/reset workflows with the same slave on a multi-slave bus. This DS2408 w1 slave driver is not complete for all the features of the chip, but its sufficient if you use it as a simple IO expander. Enjoy! The ds1wm had Kconfig dependencies towards ARM && HAVE_CLK. I took them out since I was using the ds1wm on an x86_64 platform (ds1wm in a FPGA through pcie) and found them irrelevant. The clock freq/divisors at the top of ds1wm.c did not have the MSB set to 1. This bit is CLK_EN which turns the whole prescaler and dividers on. The driver never mentionned this bit either, so I just included this bit right in the table entries. I also took the liberty to add a couple of entries to the table. The spec doesn't explicitely mentions these possibilities but the description and examination of the core shows the prescalers & dividers can be used for more than the table explicitely shows. The table I enlarged still doesn't cover all possibilities, but it's a good start. I also made a few tweaks to a couple of the read and write algorithms which made sense while I had my head very deep in the ds1wm documentation. We stressed it a lot with 10+ slaves on the bus, many ds2408, ds2431 and ds2433 at the same time doing extensive interaction. It proved quite stable in our production environment. This patch: Add generic functionnality to w1_io for Resume Command [A5h] lots of slaves support. Signed-off-by: Jean-François Dagenais <dagenaisj@sonatest.com> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Cc: Szabolcs Gyurko <szabolcs.gyurko@tlt.hu> Cc: Matt Reimer <mreimer@vpop.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/w1/w1.h')
-rw-r--r--drivers/w1/w1.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h
index d8a9709f3449..f804eba89b7b 100644
--- a/drivers/w1/w1.h
+++ b/drivers/w1/w1.h
@@ -55,6 +55,7 @@ struct w1_reg_num
#define W1_READ_ROM 0x33
#define W1_READ_PSUPPLY 0xB4
#define W1_MATCH_ROM 0x55
+#define W1_RESUME_CMD 0xA5
#define W1_SLAVE_ACTIVE 0
@@ -213,6 +214,7 @@ void w1_write_block(struct w1_master *, const u8 *, int);
void w1_touch_block(struct w1_master *, u8 *, int);
u8 w1_read_block(struct w1_master *, u8 *, int);
int w1_reset_select_slave(struct w1_slave *sl);
+int w1_reset_resume_command(struct w1_master *);
void w1_next_pullup(struct w1_master *, int);
static inline struct w1_slave* dev_to_w1_slave(struct device *dev)