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-rw-r--r--drivers/w1/w1_io.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c
index 97b338a16abc..f4f82f1f486e 100644
--- a/drivers/w1/w1_io.c
+++ b/drivers/w1/w1_io.c
@@ -293,12 +293,24 @@ int w1_reset_bus(struct w1_master *dev)
293 result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1; 293 result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1;
294 else { 294 else {
295 dev->bus_master->write_bit(dev->bus_master->data, 0); 295 dev->bus_master->write_bit(dev->bus_master->data, 0);
296 /* minimum 480, max ? us
297 * be nice and sleep, except 18b20 spec lists 960us maximum,
298 * so until we can sleep with microsecond accuracy, spin.
299 * Feel free to come up with some other way to give up the
300 * cpu for such a short amount of time AND get it back in
301 * the maximum amount of time.
302 */
296 w1_delay(480); 303 w1_delay(480);
297 dev->bus_master->write_bit(dev->bus_master->data, 1); 304 dev->bus_master->write_bit(dev->bus_master->data, 1);
298 w1_delay(70); 305 w1_delay(70);
299 306
300 result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1; 307 result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1;
301 w1_delay(410); 308 /* minmum 70 (above) + 410 = 480 us
309 * There aren't any timing requirements between a reset and
310 * the following transactions. Sleeping is safe here.
311 */
312 /* w1_delay(410); min required time */
313 msleep(1);
302 } 314 }
303 315
304 return result; 316 return result;