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

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>

1 files changed, 0 insertions, 12 deletions

diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index 5a98649f6abc..590bd8a7cd1b 100644
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -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);