xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

drivers/w1/masters/w1-gpio.c: add strong pullup emulation

Browse Source 
Strong pullup is emulated by driving pin logic high after write command
when using tri-state push-pull GPIO.

Signed-off-by: Evgeny Boger <boger@contactless.ru>
Cc: Greg KH <greg@kroah.com>
Acked-by: David Fries <david@fries.net>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Evgeny Boger
2014-01-23 15:56:18 -08:00
committed by Linus Torvalds
parent 63509beaf7
commit 3089a4c8d3
3 changed files with 23 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/w1/w1_int.c
View File

@@ -117,18 +117,6 @@ int w1_add_master_device(struct w1_bus_master *master)
printk(KERN_ERR "w1_add_master_device: invalid function set\n");
return(-EINVAL);
}
/* While it would be electrically possible to make a device that
* generated a strong pullup in bit bang mode, only hardware that
* controls 1-wire time frames are even expected to support a strong
* pullup. w1_io.c would need to support calling set_pullup before
* the last write_bit operation of a w1_write_8 which it currently
* doesn't.
*/
if (!master->write_byte && !master->touch_bit && master->set_pullup) {
printk(KERN_ERR "w1_add_master_device: set_pullup requires "
"write_byte or touch_bit, disabling\n");
master->set_pullup = NULL;
}
/* Lock until the device is added (or not) to w1_masters. */
mutex_lock(&w1_mlock);