Messages in this thread | | | From | Evgeniy Polyakov <> | Subject | Re: [PATCH 1/1] Add strong pullup emulation to w1-gpio master driver. | Date | Tue, 12 Nov 2013 05:03:24 +0400 |
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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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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