[U-Boot] [PATCH v4 05/29] dm: spi: Add a uclass for SPI

[Simon Glass]

Hi Stefan,

On 29 October 2014 22:38, Stefan Roese <sr at denx.de> wrote:
> Hi Simon,
>
> On 30.10.2014 02:43, Simon Glass wrote:
>>>
>>> In my case I'm implementing the Designware master SPI driver for the
>>> SoCFPGA. And since its a new driver it really makes sense to use DM
>>> directly. I'm starting to get an overview now. One thing though that I
>>> noticed is, that the SPI DM implementation seems to be a bit FDT centric.
>>> Please see below.
>>>
>>> <snip>
>>>
>>>> diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c
>>>
>>>
>>> <snip>
>>>
>>>> +int spi_post_bind(struct udevice *dev)
>>>> +{
>>>> +       /* Scan the bus for devices */
>>>> +       return dm_scan_fdt_node(dev, gd->fdt_blob, dev->of_offset,
>>>> false);
>>>> +}
>>>
>>>
>>>
>>> SoCFPGA currently does not support CONFIG_OF_CONTROL (no dtb supplied).
>>> So
>>
>>
>> In the kernel I see these files - are you sure it is not supported?
>>
>> arch/arm/boot/dts/socfpga_arria5.dtsi
>> arch/arm/boot/dts/socfpga_arria5_socdk.dts
>> arch/arm/boot/dts/socfpga_cyclone5.dtsi
>> arch/arm/boot/dts/socfpga_cyclone5_socdk.dts
>> arch/arm/boot/dts/socfpga_cyclone5_sockit.dts
>> arch/arm/boot/dts/socfpga_cyclone5_socrates.dts
>> arch/arm/boot/dts/socfpga.dtsi
>> arch/arm/boot/dts/socfpga_vt.dts
>
>
> Sure. In the kernel dts is supported. Only U-Boot for SoCFPGA has no DT
> support (right now).
>
>>> I'm planning to use platform_data to instantiate the device. Something
>>> like
>>> this in the board file:
>>>
>>> static const struct dw_spi_platdata spi_platdata = {
>>>          .base = SOCFPGA_SPIM0_ADDRESS,
>>> };
>>>
>>> U_BOOT_DEVICE(dw_spi) = {
>>>          .name = "dw_spi",
>>>          .platdata = &spi_platdata,
>>> };
>>>
>>> What would the non-fdt method have to be to bind the device in
>>> spi_post_bind() above?
>>
>>
>> We would have to create a new platform data structure that holds the
>> bus number, CS number and any other information. Then it will need to
>> cause spi_get_bus_and_cs() to locate it and do the right.
>>
>> But first let's make sure that you really do have the platform that
>> doesn't use device tree... If it is ARM my understanding is that it
>> should.
>
>
> It does. In the kernel. I think I'll dive into adding DT support for SoCFPGA
> for a few hours. Perhaps thats even easier than adding platform-data support
> to the SPI DM. Lets see how this goes...

Good luck. If you use CONFIG_OF_SEPARATE you will get u-boot-dtb.bin
and hopefully it will just work. For CONFIG_OF_EMBED I see a bug was
introduced so I need to do a patch for that.

>
>> Also see the SPI driver spi-howto.txt.
>
>
> Thanks,
> Stefan
>

Regards,
Simon