Re: [PATCH] SPI: SSP SPI Controller driver

[chao bi <chao.bi-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>]

On Thu, 2012-12-06 at 12:38 +0000, Grant Likely wrote:
> On Wed, 21 Nov 2012 10:16:43 +0800, chao bi <chao.bi-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> wrote:

> > +	master->mode_bits = SPI_CPOL | SPI_CPHA;
> > +	master->bus_num = SSP_CFG_GET_SPI_BUS_NB(ssp_cfg);
> > +	master->num_chipselect = 1;
> > +	master->cleanup = cleanup;
> > +	master->setup = setup;
> > +	master->transfer = transfer;
> > +	drv_context->dma_wq = create_workqueue("intel_mid_ssp_spi");
> > +	INIT_WORK(&drv_context->complete_work, int_transfer_complete_work);
> 
> Workqueue management is integrated into the core spi infrastructure now.
> SPI drivers should no longer be creating their own workqueues.
> 
> Instead, replace the ->transfer hook with prepare_transfer_hardware(),
> unprepare_transfer_hardware() and transfer_one_message(). See
> Documentation/spi/spi-summary for details.

Hi Grant,
I'd like to talk about my understanding here, please correct me if I was wrong:

1. I understand the workqueue in spi core is for driving message
transfer, so SPI driver should not create new workqueue for this usage.
However, the workqueue created here is not for this usage it's to call
back to SPI protocol driver (ifx6x60.c) when DMA data transfer is
finished, so it seems not conflict with spi core. Am I right?

2. Currently our Medfield Platform SW is based on linux-3.0, transfer_one_message() 
is not implemented, so in SPI driver, we're still use ->transfer(), this 
is with long-term validation. If we change to ->transfer_one_message() now, 
it's hardly to do thorough validation on our platform, so shall we complete 
this part by 2 steps, firstly we implement with ->transfer() hoot which can be 
validation on our hardware platform, next step, when our internal SW version 
is upgraded to latest Linux version, then we raise a patch to adapt new spi core.
what's your opinion?

chao


------------------------------------------------------------------------------
LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial
Remotely access PCs and mobile devices and provide instant support
Improve your efficiency, and focus on delivering more value-add services
Discover what IT Professionals Know. Rescue delivers
http://p.sf.net/sfu/logmein_12329d2d