* [PATCH] Introduce an ability to specify microseconds bus scanning intervals in w1 core [not found] ` <1040571428797306@web8j.yandex.ru> @ 2015-04-14 7:40 ` Dmitry Khromov 2015-04-14 17:15 ` Randy Dunlap 0 siblings, 1 reply; 10+ messages in thread From: Dmitry Khromov @ 2015-04-14 7:40 UTC (permalink / raw) To: linux-kernel; +Cc: gregkh, Evgeniy Polyakov 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"); /* 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; ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH] Introduce an ability to specify microseconds bus scanning intervals in w1 core 2015-04-14 7:40 ` [PATCH] Introduce an ability to specify microseconds bus scanning intervals in w1 core Dmitry Khromov @ 2015-04-14 17:15 ` Randy Dunlap 2015-04-22 21:55 ` [PATCH v2] w1: introduce an ability to specify microseconds bus scanning intervals Dmitry Khromov 0 siblings, 1 reply; 10+ messages in thread From: Randy Dunlap @ 2015-04-14 17:15 UTC (permalink / raw) To: Dmitry Khromov, linux-kernel; +Cc: gregkh, Evgeniy Polyakov 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 ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v2] w1: introduce an ability to specify microseconds bus scanning intervals 2015-04-14 17:15 ` Randy Dunlap @ 2015-04-22 21:55 ` Dmitry Khromov 2015-04-22 23:22 ` Evgeniy Polyakov 2015-04-23 9:20 ` Greg KH 0 siblings, 2 replies; 10+ messages in thread From: Dmitry Khromov @ 2015-04-22 21:55 UTC (permalink / raw) To: linux-kernel; +Cc: gregkh, zbr, rdunlap, Dmitry Khromov Signed-off-by: Dmitry Khromov <dk@icelogic.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..c9a7ff6 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"); /* 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; -- 2.3.5 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH v2] w1: introduce an ability to specify microseconds bus scanning intervals 2015-04-22 21:55 ` [PATCH v2] w1: introduce an ability to specify microseconds bus scanning intervals Dmitry Khromov @ 2015-04-22 23:22 ` Evgeniy Polyakov 2015-04-23 9:20 ` Greg KH 1 sibling, 0 replies; 10+ messages in thread From: Evgeniy Polyakov @ 2015-04-22 23:22 UTC (permalink / raw) To: Dmitry Khromov, linux-kernel@vger.kernel.org Cc: gregkh@linuxfoundation.org, rdunlap@infradead.org Hi Looks good to me. Greg, please pull it into your tree. Acked-by: Evgeniy Polyakov <zbr@ioremap.net> 23.04.2015, 00:56, "Dmitry Khromov" <dk@icelogic.net>: > Signed-off-by: Dmitry Khromov <dk@icelogic.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..c9a7ff6 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"); > /* 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; > > -- > 2.3.5 ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2] w1: introduce an ability to specify microseconds bus scanning intervals 2015-04-22 21:55 ` [PATCH v2] w1: introduce an ability to specify microseconds bus scanning intervals Dmitry Khromov 2015-04-22 23:22 ` Evgeniy Polyakov @ 2015-04-23 9:20 ` Greg KH 2015-04-23 11:30 ` Dmitry Khromov 2015-05-12 19:29 ` Dmitry Khromov 1 sibling, 2 replies; 10+ messages in thread From: Greg KH @ 2015-04-23 9:20 UTC (permalink / raw) To: Dmitry Khromov; +Cc: linux-kernel, zbr, rdunlap On Thu, Apr 23, 2015 at 12:55:35AM +0300, Dmitry Khromov wrote: > Signed-off-by: Dmitry Khromov <dk@icelogic.net> > --- > drivers/w1/w1.c | 17 ++++++++++++++++- > 1 file changed, 16 insertions(+), 1 deletion(-) You added a new sysfs file, without any documentation about it added to Documentation/ABI, nor any reason why this needs to be done in the changelog entry for the patch. I need _some_ kind of information here, sorry, I can't take this as-is. thanks, greg k-h ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2] w1: introduce an ability to specify microseconds bus scanning intervals 2015-04-23 9:20 ` Greg KH @ 2015-04-23 11:30 ` Dmitry Khromov 2015-04-23 11:33 ` [PATCH v3] " Dmitry Khromov 2015-05-12 19:29 ` Dmitry Khromov 1 sibling, 1 reply; 10+ messages in thread From: Dmitry Khromov @ 2015-04-23 11:30 UTC (permalink / raw) To: Greg KH, Evgeniy Polyakov; +Cc: linux-kernel, rdunlap On 23.04.2015 12:20, Greg KH wrote: > On Thu, Apr 23, 2015 at 12:55:35AM +0300, Dmitry Khromov wrote: >> Signed-off-by: Dmitry Khromov <dk@icelogic.net> >> --- >> drivers/w1/w1.c | 17 ++++++++++++++++- >> 1 file changed, 16 insertions(+), 1 deletion(-) > > You added a new sysfs file, without any documentation about it added to > Documentation/ABI, nor any reason why this needs to be done in the > changelog entry for the patch. Sorry for that, the complete reason was given in the original version of the patch, I've added a short summary in the changelog for v3. Thanks for reminding about the documentation. I've added a short description and minor cosmetics to Documentation/w1/w1.generic to give a slightly more detailed idea on what's going on during the bus scan. Please review. -- Regards, - Dmitry ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v3] w1: introduce an ability to specify microseconds bus scanning intervals 2015-04-23 11:30 ` Dmitry Khromov @ 2015-04-23 11:33 ` Dmitry Khromov 0 siblings, 0 replies; 10+ messages in thread From: Dmitry Khromov @ 2015-04-23 11:33 UTC (permalink / raw) To: gregkh, zbr; +Cc: linux-kernel, rdunlap, Dmitry Khromov 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 <dk@icelogic.net> --- Documentation/ABI/stable/sysfs-bus-w1 | 11 +++++++++++ Documentation/w1/w1.generic | 30 +++++++++++++++++++----------- drivers/w1/w1.c | 17 ++++++++++++++++- 3 files changed, 46 insertions(+), 12 deletions(-) create mode 100644 Documentation/ABI/stable/sysfs-bus-w1 diff --git a/Documentation/ABI/stable/sysfs-bus-w1 b/Documentation/ABI/stable/sysfs-bus-w1 new file mode 100644 index 0000000..140d85b --- /dev/null +++ b/Documentation/ABI/stable/sysfs-bus-w1 @@ -0,0 +1,11 @@ +What: /sys/bus/w1/devices/.../w1_master_timeout_us +Date: April 2015 +Contact: Dmitry Khromov <dk@icelogic.net> +Description: Bus scanning interval, microseconds component. + 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. + see Documentation/w1/w1.generic for detailed information. +Users: any user space application which wants to know bus scanning + interval diff --git a/Documentation/w1/w1.generic b/Documentation/w1/w1.generic index b2033c6..b3ffaf8 100644 --- a/Documentation/w1/w1.generic +++ b/Documentation/w1/w1.generic @@ -76,21 +76,24 @@ See struct w1_bus_master definition in w1.h for details. w1 master sysfs interface ------------------------------------------------------------------ -<xx-xxxxxxxxxxxxx> - a directory for a found device. The format is family-serial +<xx-xxxxxxxxxxxxx> - A directory for a found device. The format is family-serial bus - (standard) symlink to the w1 bus driver - (standard) symlink to the w1 driver -w1_master_add - Manually register a slave device -w1_master_attempts - the number of times a search was attempted +w1_master_add - (rw) manually register a slave device +w1_master_attempts - (ro) the number of times a search was attempted w1_master_max_slave_count - - maximum number of slaves to search for at a time -w1_master_name - the name of the device (w1_bus_masterX) -w1_master_pullup - 5V strong pullup 0 enabled, 1 disabled -w1_master_remove - Manually remove a slave device -w1_master_search - the number of searches left to do, -1=continual (default) + - (rw) maximum number of slaves to search for at a time +w1_master_name - (ro) the name of the device (w1_bus_masterX) +w1_master_pullup - (rw) 5V strong pullup 0 enabled, 1 disabled +w1_master_remove - (rw) manually remove a slave device +w1_master_search - (rw) the number of searches left to do, + -1=continual (default) w1_master_slave_count - - the number of slaves found -w1_master_slaves - the names of the slaves, one per line -w1_master_timeout - the delay in seconds between searches + - (ro) the number of slaves found +w1_master_slaves - (ro) the names of the slaves, one per line +w1_master_timeout - (ro) the delay in seconds between searches +w1_master_timeout_us + - (ro) the delay in microseconds beetwen searches If you have a w1 bus that never changes (you don't add or remove devices), you can set the module parameter search_count to a small positive number @@ -101,6 +104,11 @@ generally only make sense when searching is disabled, as a search will redetect manually removed devices that are present and timeout manually added devices that aren't on the bus. +Bus searches occur at an interval, specified as a summ of timeout and +timeout_us module parameters (either of which may be 0) for as long as +w1_master_search remains greater than 0 or is -1. Each search attempt +decrements w1_master_search by 1 (down to 0) and increments +w1_master_attempts by 1. w1 slave sysfs interface ------------------------------------------------------------------ diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index 181f41c..c9a7ff6 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"); /* 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; -- 2.3.5 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH v3] w1: introduce an ability to specify microseconds bus scanning intervals 2015-04-23 9:20 ` Greg KH 2015-04-23 11:30 ` Dmitry Khromov @ 2015-05-12 19:29 ` Dmitry Khromov 2015-05-13 15:00 ` Evgeniy Polyakov 1 sibling, 1 reply; 10+ messages in thread From: Dmitry Khromov @ 2015-05-12 19:29 UTC (permalink / raw) To: gregkh, zbr; +Cc: linux-kernel, Dmitry Khromov 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 <dk@icelogic.net> --- Documentation/ABI/stable/sysfs-bus-w1 | 11 +++++++++++ Documentation/w1/w1.generic | 30 +++++++++++++++++++----------- drivers/w1/w1.c | 17 ++++++++++++++++- 3 files changed, 46 insertions(+), 12 deletions(-) create mode 100644 Documentation/ABI/stable/sysfs-bus-w1 diff --git a/Documentation/ABI/stable/sysfs-bus-w1 b/Documentation/ABI/stable/sysfs-bus-w1 new file mode 100644 index 0000000..140d85b --- /dev/null +++ b/Documentation/ABI/stable/sysfs-bus-w1 @@ -0,0 +1,11 @@ +What: /sys/bus/w1/devices/.../w1_master_timeout_us +Date: April 2015 +Contact: Dmitry Khromov <dk@icelogic.net> +Description: Bus scanning interval, microseconds component. + 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. + see Documentation/w1/w1.generic for detailed information. +Users: any user space application which wants to know bus scanning + interval diff --git a/Documentation/w1/w1.generic b/Documentation/w1/w1.generic index b2033c6..b3ffaf8 100644 --- a/Documentation/w1/w1.generic +++ b/Documentation/w1/w1.generic @@ -76,21 +76,24 @@ See struct w1_bus_master definition in w1.h for details. w1 master sysfs interface ------------------------------------------------------------------ -<xx-xxxxxxxxxxxxx> - a directory for a found device. The format is family-serial +<xx-xxxxxxxxxxxxx> - A directory for a found device. The format is family-serial bus - (standard) symlink to the w1 bus driver - (standard) symlink to the w1 driver -w1_master_add - Manually register a slave device -w1_master_attempts - the number of times a search was attempted +w1_master_add - (rw) manually register a slave device +w1_master_attempts - (ro) the number of times a search was attempted w1_master_max_slave_count - - maximum number of slaves to search for at a time -w1_master_name - the name of the device (w1_bus_masterX) -w1_master_pullup - 5V strong pullup 0 enabled, 1 disabled -w1_master_remove - Manually remove a slave device -w1_master_search - the number of searches left to do, -1=continual (default) + - (rw) maximum number of slaves to search for at a time +w1_master_name - (ro) the name of the device (w1_bus_masterX) +w1_master_pullup - (rw) 5V strong pullup 0 enabled, 1 disabled +w1_master_remove - (rw) manually remove a slave device +w1_master_search - (rw) the number of searches left to do, + -1=continual (default) w1_master_slave_count - - the number of slaves found -w1_master_slaves - the names of the slaves, one per line -w1_master_timeout - the delay in seconds between searches + - (ro) the number of slaves found +w1_master_slaves - (ro) the names of the slaves, one per line +w1_master_timeout - (ro) the delay in seconds between searches +w1_master_timeout_us + - (ro) the delay in microseconds beetwen searches If you have a w1 bus that never changes (you don't add or remove devices), you can set the module parameter search_count to a small positive number @@ -101,6 +104,11 @@ generally only make sense when searching is disabled, as a search will redetect manually removed devices that are present and timeout manually added devices that aren't on the bus. +Bus searches occur at an interval, specified as a summ of timeout and +timeout_us module parameters (either of which may be 0) for as long as +w1_master_search remains greater than 0 or is -1. Each search attempt +decrements w1_master_search by 1 (down to 0) and increments +w1_master_attempts by 1. w1 slave sysfs interface ------------------------------------------------------------------ diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index 181f41c..c9a7ff6 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"); /* 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; -- 2.3.5 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH v3] w1: introduce an ability to specify microseconds bus scanning intervals 2015-05-12 19:29 ` Dmitry Khromov @ 2015-05-13 15:00 ` Evgeniy Polyakov 2015-05-13 15:31 ` gregkh 0 siblings, 1 reply; 10+ messages in thread From: Evgeniy Polyakov @ 2015-05-13 15:00 UTC (permalink / raw) To: Dmitry Khromov, gregkh@linuxfoundation.org; +Cc: linux-kernel@vger.kernel.org Hi 12.05.2015, 22:30, "Dmitry Khromov" <dk@icelogic.net>: > 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 <dk@icelogic.net> Greg, please pull it upstream Acked-by: Evgeniy Polyakov <zbr@ioremap.net> ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v3] w1: introduce an ability to specify microseconds bus scanning intervals 2015-05-13 15:00 ` Evgeniy Polyakov @ 2015-05-13 15:31 ` gregkh 0 siblings, 0 replies; 10+ messages in thread From: gregkh @ 2015-05-13 15:31 UTC (permalink / raw) To: Evgeniy Polyakov; +Cc: Dmitry Khromov, linux-kernel@vger.kernel.org On Wed, May 13, 2015 at 06:00:55PM +0300, Evgeniy Polyakov wrote: > Hi > > 12.05.2015, 22:30, "Dmitry Khromov" <dk@icelogic.net>: > > 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 <dk@icelogic.net> > > Greg, please pull it upstream > Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Ok, will do. ^ permalink raw reply [flat|nested] 10+ messages in thread
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2015-04-14 7:40 ` [PATCH] Introduce an ability to specify microseconds bus scanning intervals in w1 core Dmitry Khromov
2015-04-14 17:15 ` Randy Dunlap
2015-04-22 21:55 ` [PATCH v2] w1: introduce an ability to specify microseconds bus scanning intervals Dmitry Khromov
2015-04-22 23:22 ` Evgeniy Polyakov
2015-04-23 9:20 ` Greg KH
2015-04-23 11:30 ` Dmitry Khromov
2015-04-23 11:33 ` [PATCH v3] " Dmitry Khromov
2015-05-12 19:29 ` Dmitry Khromov
2015-05-13 15:00 ` Evgeniy Polyakov
2015-05-13 15:31 ` gregkh
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