Messages in this thread | | | Date | Tue, 12 Nov 2013 05:07:14 +0400 | From | Evgeny Boger <> | Subject | Re: [PATCH 1/1] Add strong pullup emulation to w1-gpio master driver. |
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+David Fries <david@fries.net>
Hi David,
Would you please comment on this?
11/12/2013 05:03 AM, Evgeniy Polyakov: > Hi > > 12.11.2013, 03:32, "Evgeny Boger" <eugenyboger@gmail.com>: >>> Why did you drop this check? It has nothing with w1-gpio driver >> This check prevents master from implementing "set_pullup" provided it does support only "write_bit" method. >> The comment above states that >>> 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. >> which is kind of strange, since it describes what w1_io.c actually does support. >> >> w1_write_8 (w1_io.c:154, https://github.com/torvalds/linux/blob/master/drivers/w1/w1_io.c#L154): >>> for (i = 0; i < 8; ++i) { >>> if (i == 7) >>> w1_pre_write(dev); >>> w1_touch_bit(dev, (byte >> i) & 0x1); >>> } >> It seems like w1_write_8() calls w1_pre_write(), which in turn calls set_pullup() just before the last write_bit(). >> >> I'm not sure why this check was there in the first place. > Please add author of those lines to clarify things. > This doesn't look obvious to me
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