Messages in this thread |  | | Date | Tue, 14 Apr 2015 10:15:13 -0700 | From | Randy Dunlap <> | Subject | Re: [PATCH] Introduce an ability to specify microseconds bus scanning intervals in w1 core |
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On 04/14/15 00:40, Dmitry Khromov wrote: > DS1990* "iButtons" and compatible RFID card readers commonly found at > physical access control systems are usually attached/generate presence > for as short as 100 ms - hence the tens-to-hundreds milliseconds scan > intervals are required. > > Tested on Raspberry Pi model B+ with DS2482-100 bus master, > tens-of-milliseconds intervals are easily achieved without significant > CPU load (and with unknown accuracy), and though I doubt > microseconds-scale intervals are really feasible in terms of practical > use and underlying buses timings, I believe it makes sense to give the > ability of using them to those willing to try. > > Signed-off-by: Dmitry Khromov <dk@icelogic.net> > Acked-by: Evgeniy Polyakov <zbr@ioremap.net> > > drivers/w1/w1.c | 17 ++++++++++++++++- > 1 file changed, 16 insertions(+), 1 deletion(-) > --- > diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c > index 181f41c..73b4e2d 100644 > --- a/drivers/w1/w1.c > +++ b/drivers/w1/w1.c > @@ -46,11 +46,15 @@ MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>"); > MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol."); > > static int w1_timeout = 10; > +static int w1_timeout_us = 0; > int w1_max_slave_count = 64; > int w1_max_slave_ttl = 10; > > module_param_named(timeout, w1_timeout, int, 0); > MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches"); > +module_param_named(timeout_us, w1_timeout_us, int, 0); > +MODULE_PARM_DESC(timeout, "time in microseconds between automatic slave" > + "searches");
The description string needs a space between "slave" and "searches".
> /* A search stops when w1_max_slave_count devices have been found in that > * search. The next search will start over and detect the same set of devices > * on a static 1-wire bus. Memory is not allocated based on this number, just
-- ~Randy
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