Messages in this thread | | | Date | Tue, 27 Oct 2015 11:09:11 +0100 | Subject | Re: [PATCH] pinctrl: uniphier: set input-enable before pin-muxing | From | Linus Walleij <> |
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On Tue, Oct 20, 2015 at 10:25 AM, Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
> While IECTRL is disabled, input signals are pulled-down internally. > If pin-muxing is set up first, glitch signals (Low to High transition) > might be input to hardware blocks. > > Bad case scenario: > [1] The hardware block is already running before pinctrl is handled. > (the reset is de-asserted by default or by a firmware, for example) > [2] The pin-muxing is set up. The input signals to hardware block > are pulled-down by the chip-internal biasing. > [3] The pins are input-enabled. The signals from the board reach the > hardware block. > > Actually, one invalid character is input to the UART blocks for such > SoCs as PH1-LD4, PH1-sLD8, where UART devices start to run at the > power on reset. > > To avoid such problems, pins should be input-enabled before muxing. > > Fixes: 6e9088920258 ("pinctrl: UniPhier: add UniPhier pinctrl core support") > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > Reported-by: Dai Okamura <okamura.dai@socionext.com> > --- > > Hi Linus, > > If it is not too late, please apply this fix for Linux 4.3.
It's too late at this point.
Patch is applied for devel and will come into v4.4 and from there to -stable.
Yours, Linus Walleij
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