[U-Boot] [PATCH 4/9] w1: Add 1-Wire gpio driver

[Maxime Ripard]

Hi Simon,

On Fri, Nov 11, 2016 at 09:17:20AM -0700, Simon Glass wrote:
> Hi Maxime,
> 
> On 8 November 2016 at 03:06, Maxime Ripard
> <maxime.ripard at free-electrons.com> wrote:
> > Add a bus driver for bitbanging a 1-Wire bus over a GPIO.
> >
> > Signed-off-by: Maxime Ripard <maxime.ripard at free-electrons.com>
> > ---
> >  drivers/w1/Kconfig   |   6 ++-
> >  drivers/w1/Makefile  |   1 +-
> >  drivers/w1/w1-gpio.c | 160 ++++++++++++++++++++++++++++++++++++++++++++-
> >  3 files changed, 167 insertions(+), 0 deletions(-)
> >  create mode 100644 drivers/w1/w1-gpio.c
> >
> > diff --git a/drivers/w1/Kconfig b/drivers/w1/Kconfig
> > index 0c056b4c06a9..ccc3ae15db86 100644
> > --- a/drivers/w1/Kconfig
> > +++ b/drivers/w1/Kconfig
> > @@ -12,6 +12,12 @@ config W1
> >
> >  if W1
> >
> > +config W1_GPIO
> > +       bool "Enable 1-Wire GPIO bitbanging"
> > +       depends on DM_GPIO
> > +       help
> > +         Emulate a 1-Wire bus using a GPIO.
> 
> Any more details? How many GPIOs? Any particular chips that are
> supported?

1-Wire works on a single line, hence it's name. You usually have
either a controller (which is quite rare, but some SoCs have one) or
you can bitbang the bus. It's low bandwidth enough that it doesn't
really matter.

I'm not sure if it answers your question. I'll address your other
comments.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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