From c3098356927254be270e5dc186a2ca144b64463b Mon Sep 17 00:00:00 2001 From: Dmitry Khromov Date: Tue, 12 May 2015 22:29:44 +0300 Subject: w1: introduce an ability to specify microseconds bus scanning intervals Some of 1-Wire devices commonly associated with physical access control systems are attached/generate presence for as short as 100 ms - hence the tens-to-hundreds milliseconds scan intervals are required. Signed-off-by: Dmitry Khromov Acked-by: Evgeniy Polyakov Signed-off-by: Greg Kroah-Hartman --- drivers/w1/w1.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) (limited to 'drivers/w1/w1.c') diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index 181f41cb960b..c9a7ff67d395 100644 --- a/drivers/w1/w1.c +++ b/drivers/w1/w1.c @@ -46,11 +46,15 @@ MODULE_AUTHOR("Evgeniy Polyakov "); 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"); /* 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 @@ -317,6 +321,14 @@ static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct devic return count; } +static ssize_t w1_master_attribute_show_timeout_us(struct device *dev, + struct device_attribute *attr, char *buf) +{ + ssize_t count; + count = sprintf(buf, "%d\n", w1_timeout_us); + return count; +} + static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { @@ -543,6 +555,7 @@ static W1_MASTER_ATTR_RO(slave_count, S_IRUGO); static W1_MASTER_ATTR_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP); static W1_MASTER_ATTR_RO(attempts, S_IRUGO); static W1_MASTER_ATTR_RO(timeout, S_IRUGO); +static W1_MASTER_ATTR_RO(timeout_us, S_IRUGO); static W1_MASTER_ATTR_RO(pointer, S_IRUGO); static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP); static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP); @@ -556,6 +569,7 @@ static struct attribute *w1_master_default_attrs[] = { &w1_master_attribute_max_slave_count.attr, &w1_master_attribute_attempts.attr, &w1_master_attribute_timeout.attr, + &w1_master_attribute_timeout_us.attr, &w1_master_attribute_pointer.attr, &w1_master_attribute_search.attr, &w1_master_attribute_pullup.attr, @@ -1108,7 +1122,8 @@ int w1_process(void *data) /* As long as w1_timeout is only set by a module parameter the sleep * time can be calculated in jiffies once. */ - const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000); + const unsigned long jtime = + usecs_to_jiffies(w1_timeout * 1000000 + w1_timeout_us); /* remainder if it woke up early */ unsigned long jremain = 0; -- cgit v1.2.3-59-g8ed1b