linux-kernel - Re: [PATCH 2/3] iio: temperature: add max6675 thermocouple converter driver

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 3 Aug 2015 19:10:19 -0400
From:	Matt Porter <mporter@...sulko.com>
To:	Matt Ranostay <mranostay@...il.com>
Cc:	Linux IIO List <linux-iio@...r.kernel.org>,
	Devicetree List <devicetree@...r.kernel.org>,
	Jonathan Cameron <jic23@...nel.org>,
	Rob Herring <robh+dt@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/3] iio: temperature: add max6675 thermocouple converter
 driver

On Mon, Aug 03, 2015 at 03:39:00PM -0700, Matt Ranostay Matt Ranostay wrote:
> On Mon, Aug 3, 2015 at 1:56 PM, Matt Porter <mporter@...sulko.com> wrote:

...

> > +static int max6675_probe(struct spi_device *spi)
> > +{
> > +       struct iio_dev *indio_dev;
> > +       struct max6675_state *st;
> > +       int ret = 0;
> > +
> > +       indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> > +       if (!indio_dev)
> > +               return -ENOMEM;
> > +
> > +       st = iio_priv(indio_dev);
> > +       st->spi = spi;
> > +
> > +       spi->mode = SPI_MODE_1;
> > +       spi->bits_per_word = 16;
> 
> Have this error or display a warning when it doesn't match the passed
> DT binding settings. Otherwise it may get confusing why other SPI
> modes and word sizes don't work.

Ok, good point. The only thing here is that I've specified that spi-cpha
is required in the binding, indicating that Mode 1 will be used. I need
this driver to be instantiated via three methods: ACPI, DT, and "board
file" so for the latter I'm hardcoding in the driver the mode. The
device only works in Mode 1 so this seems sane, it's not configurable.
I don't parse that mode from either DT or ACPI data since it's not
needed. About the only thing I could do is pedantically check for
spi-cpha and if not present complain..but I think it's fine to simply
not parse at all given that we've hardcoded this for the allowed mode.

There's no property for bits_per_word, it's configured on a per-transfer
basis. In this case, this configures the default to do a 16-bit transfer
as required by the device. There is no way to modify this by a client of
this driver.

-Matt
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/