Re: [PATCH 1/1] spi: pxa2xx: add driver enabling message

[Jarkko Nikula]

On 4/9/19 5:11 PM, Flavio Suligoi wrote:
> Hi Jarkko,
>
> > Hi
> >
> > On 4/8/19 6:22 PM, Flavio Suligoi wrote:
> > > Add an info message for the PXA2xx device driver start-up,
> > > with the indication of the transfer mode used (DMA or GPIO).
> > >
> > > This info is useful to individuate the timing when
> > > the module starts.
> > >
> > > Signed-off-by: Flavio Suligoi <f.suligoi@xxxxxxx>
> > > ---
> > >    drivers/spi/spi-pxa2xx.c | 3 +++
> > >    1 file changed, 3 insertions(+)
> > >
> > > diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
> > > index f7068cc..d449501 100644
> > > --- a/drivers/spi/spi-pxa2xx.c
> > > +++ b/drivers/spi/spi-pxa2xx.c
> > > @@ -1826,6 +1826,9 @@ static int pxa2xx_spi_probe(struct platform_device
> > *pdev)
> > >    		goto out_error_clock_enabled;
> > >    	}
> > >
> > > +	dev_info(dev, "PXA2xx SPI master controller (%s mode)\n",
> > > +		 platform_info->enable_dma ? "DMA" : "PIO");
> > > +
> > >    	return status;
> > Would this look better if moved before devm_spi_register_controller()
> > call?
>
> Ok, so in case of SPI registering failure, we have two messages, as:
>
> pxa2xx-spi 80860F0E:00: PXA2xx SPI master controller (DMA mode)
> pxa2xx-spi 80860F0E:00: problem registering spi controller
>
> Do you think that it is more explicative?
I think yes and it should not cause confusion since the error message is 
the last one.

I was thinking the successful registration case when DMA is not 
available. First there is a warning, followed by a debug message from 
SPI core (if CONFIG_SPI_DEBUG) and then info message.

[    9.506895] pxa2xx-spi pxa2xx-spi.13: no DMA channels available, 
using PIO
[    9.516770] pxa2xx-spi pxa2xx-spi.13: registered master spi2
[    9.518527] pxa2xx-spi pxa2xx-spi.13: PXA2xx SPI master controller 
(PIO mode)

Actually this info message doesn't necessarily tell will the driver end 
up using DMA for transfers. See pxa2xx_spi_can_dma() and 
pxa2xx_spi_transfer_one().

How about replacing "no DMA channels available, using PIO" and have 
instead single info message telling is the DMA available or does the 
driver use PIO only?

--
Jarkko