Hi Geert, > Hi Lukasz, > > On Thu, Sep 26, 2019 at 3:33 AM Lukasz Majewski <[email protected]> wrote: > > This change is necessary for spidev devices (e.g. /dev/spidev3.0) > > working in the slave mode (like NXP's dspi driver for Vybrid SoC). > > > > When SPI HW works in this mode - the master is responsible for > > providing CS and CLK signals. However, when some fault happens - > > like for example distortion on SPI lines - the SPI Linux driver > > needs a chance to recover from this abnormal situation and prepare > > itself for next (correct) transmission. > > > > This change doesn't pose any threat on drivers working in master > > mode as spi_slave_abort() function checks if SPI slave mode is > > supported. > > > > Signed-off-by: Lukasz Majewski <[email protected]> > > Thanks for your patch! > > Yesterday I saw this appear on spi/for-next, but I couldn't find the > email in my mbox. Today it has arrived. Looks like gmail had some > troubles ("Delivered after 138401 seconds", ugh).
I've already sent v2 of this patch, as Intel Linux test setup spot the
error with lack of #define guards.
>
> > --- a/drivers/spi/spidev.c
> > +++ b/drivers/spi/spidev.c
> > @@ -627,6 +627,7 @@ static int spidev_release(struct inode *inode,
> > struct file *filp) if (dofree)
> > kfree(spidev);
> > }
> > + spi_slave_abort(spidev->spi);
>
> Looks good to me. Just wondering if this should be done for the last
> user only, i.e. in the "if" block above, like resetting speed_hz?
I also thought about this. However, from my use case the user must end
the transmission with CTRL+C on his user space program, which in turn
communicate via SPI with /dev/spidev3.0.
There might be many (potential) programs using the /dev/spidev3.0 at the
same time, so the usage count may be not one.
For the above reason I've moved it outside the above if().
>
> > mutex_unlock(&device_list_lock);
> >
> > return 0;
>
> Gr{oetje,eeting}s,
>
> Geert
>
Best regards,
Lukasz Majewski
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