Re: [PATCH V3 2/5] spi: s3c64xx: added support for polling mode

From: Girish KS
Date: Thu Apr 04 2013 - 01:45:51 EST


On Wed, Apr 3, 2013 at 5:19 PM, Mark Brown
<broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> On Wed, Apr 03, 2013 at 05:00:04PM +0530, Girish KS wrote:
>> On Mon, Apr 1, 2013 at 6:42 PM, Mark Brown
>
>> >> - if (!sdd->pdev->dev.of_node) {
>> >> + if (!sdd->pdev->dev.of_node && !is_polling(sdd)) {
>> >> res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
>> >> if (!res) {
>> >> dev_err(&pdev->dev, "Unable to get SPI tx dma "
>
>> > It seems like it'd be sensible to also handle failure to get the DMA
>> > resource by going into polling mode.
>
>> There are 2 cases currently i have identified and handled,
>> 1. The SoC's dont have DMA support for spi controller. For such SoC's we
>> would not add the dma resource in the spi dts node. In this case the probe
>> would return error if failure for DMA resuorce is handled.
>
> That's not what the code currently does...
>
>> 2. The SoC has a DMA support for SPI controller, but due to some x
>> reason(H/W bug),
>> the driver would force polling mode by enabling
>> S3C64XX_SPI_QUIRK_POLL in driver
>> data. For such SoC's there would be a dma entry in the spi controller
>> dts node, and
>> probe can handle failure for DMA resource successfully.
>
>> To handle above both situations successfully if
>> (!sdd->pdev->dev.of_node && !is_polling(sdd)) is used.
>
> Right, that's what the code currently does but what I'm suggesting is
> that this isn't the most helpful thing to do and that printing a big
> warning then soldiering on in polling mode might be more useful.

Ok I got it. will do it.

Thanks Mark
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