The patch titled
w1: w1_io.c reset comments and msleep
has been added to the -mm tree. Its filename is
w1-w1_ioc-reset-comments-and-msleep.patch
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------------------------------------------------------
Subject: w1: w1_io.c reset comments and msleep
From: David Fries <david@xxxxxxxxx>
w1_reset_bus, added some comments about the timing and switched to msleep
for the later delay. I don't have the hardware to test the sleep after
reset change. The one wire doesn't have a timing = requirement between
commands so it is fine. I do have the USB = hardware and it would be in
big trouble with 10ms interrupt trans= fers to find that the reset
completed.
Signed-off-by: David Fries <david@xxxxxxxxx>
Signed-off-by: Evgeniy Polyakov <johnpol@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/w1/w1_io.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff -puN drivers/w1/w1_io.c~w1-w1_ioc-reset-comments-and-msleep drivers/w1/w1_io.c
--- a/drivers/w1/w1_io.c~w1-w1_ioc-reset-comments-and-msleep
+++ a/drivers/w1/w1_io.c
@@ -293,12 +293,24 @@ int w1_reset_bus(struct w1_master *dev)
result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1;
else {
dev->bus_master->write_bit(dev->bus_master->data, 0);
+ /* minimum 480, max ? us
+ * be nice and sleep, except 18b20 spec lists 960us maximum,
+ * so until we can sleep with microsecond accuracy, spin.
+ * Feel free to come up with some other way to give up the
+ * cpu for such a short amount of time AND get it back in
+ * the maximum amount of time.
+ */
w1_delay(480);
dev->bus_master->write_bit(dev->bus_master->data, 1);
w1_delay(70);
result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1;
- w1_delay(410);
+ /* minmum 70 (above) + 410 = 480 us
+ * There aren't any timing requirements between a reset and
+ * the following transactions. Sleeping is safe here.
+ */
+ /* w1_delay(410); min required time */
+ msleep(1);
}
return result;
_
Patches currently in -mm which might be from david@xxxxxxxxx are
w1-fix-deadlocks-and-remove-w1_control_thread.patch
w1-abort-search-early-on-on-exit.patch
w1-dont-delay-search-start.patch
w1-w1_process-block-or-sleep.patch
w1-feature-enable-hardware-strong-pullup.patch
w1-feature-w1_thermc-use-strong-pullup-and-documentation.patch
w1-be-able-to-manually-add-and-remove-slaves.patch
w1-recode-w1_slave_found-logic.patch
w1-new-module-parameter-search_count.patch
w1-document-add-remove-search_count-and-pullup.patch
w1-w1_slave_read_id-read-bug-use-device_attribute.patch
w1-w1_therm-fix-user-buffer-overflow-and-cat.patch
w1-w1_family-remove-unused-variable-need_exit.patch
w1-w1_therm-consistent-mutex-access-code-cleanup.patch
w1-w1_intc-use-first-available-master-number.patch
w1-w1c-s-printk-dev_dbg.patch
w1-w1_ioc-reset-comments-and-msleep.patch
w1-ds1wmc-msleep-for-reset.patch
w1-ds2490c-correct-print-message.patch
w1-ds2490c-add-support-for-strong-pullup.patch
w1-ds2490c-ds_write_bit-grouping-error-disable-readback.patch
w1-ds2490c-disable-bit-read-and-write.patch
w1-ds2490c-simplify-and-fix-ds_touch_bit.patch
w1-ds2490c-ds_dump_status-rework.patch
w1-ds2490c-ds_reset-remove-ds_wait_status.patch
w1-ds2490c-reset-ds2490-in-init.patch
w1-ds2490c-magic-number-work.patch
w1-ds2490c-ds_write_block-remove-extra-ds_wait_status.patch
w1-documentation-w1-masters-ds2490-update.patch
w1-ds2490c-optimize-ds_set_pullup.patch
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