Re: [PATCH] staging: iio: ad7192: Use the dedicated reset function
From: Jonathan Cameron
Date: Sat Sep 16 2017 - 18:44:02 EST
On Sat, 16 Sep 2017 15:22:23 -0700
Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> On Thu, 14 Sep 2017 16:31:06 +0200
> Michael Hennerich <michael.hennerich@xxxxxxxxxx> wrote:
> > On 14.09.2017 15:50, Stefan Popa wrote:
> > > SPI host drivers can use DMA to transfer data, so the buffer should be properly allocated.
> > > Keeping it on the stack could cause an undefined behavior.
> > >
> > > The dedicated reset function solves this issue.
> > >
> > > Signed-off-by: Stefan Popa <stefan.popa@xxxxxxxxxx>
> > Acked-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
> Applied to the togreg branch of iio.git rather than staging
> branch as the reset functionality is reasonably recent and
> not going to be available in stable kernels etc..
> Good work. I was reading this on a plane the other day and
> noticed the same issue - always nice when someone else
> fixes something on your todo list ;)
Doh, I had forgotten the support was part of a fix for a different
driver so is only in the fixes-togreg branch of iio.git.
I'll take this one the same way with a bit of a tweak to the patch
title to make it clear it is fixing something.
> > Well done!
> > > ---
> > > drivers/staging/iio/adc/ad7192.c | 4 +---
> > > 1 file changed, 1 insertion(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/staging/iio/adc/ad7192.c b/drivers/staging/iio/adc/ad7192.c
> > > index d11c6de..6150d27 100644
> > > --- a/drivers/staging/iio/adc/ad7192.c
> > > +++ b/drivers/staging/iio/adc/ad7192.c
> > > @@ -223,11 +223,9 @@ static int ad7192_setup(struct ad7192_state *st,
> > > struct iio_dev *indio_dev = spi_get_drvdata(st->sd.spi);
> > > unsigned long long scale_uv;
> > > int i, ret, id;
> > > - u8 ones;
> > >
> > > /* reset the serial interface */
> > > - memset(&ones, 0xFF, 6);
> > > - ret = spi_write(st->sd.spi, &ones, 6);
> > > + ret = ad_sd_reset(&st->sd, 48);
> > > if (ret < 0)
> > > goto out;
> > > usleep_range(500, 1000); /* Wait for at least 500us */
> > >
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