Re: Chipselect in SPI binding with mpc5200-psc-spi

[Henk Stegeman <henk.stegeman@gmail.com>]

I tried to make use of the irq-controller mode of the GPT as
suggested, however I'm not getting the IRQ.
Does anyone have an idea what I could be missing? (I've been testing
with 2.6.30).


The driver reports from it's probe:
[    1.502853] spi_master spi32766.0 Unable to get sample IRQ from of

My driver has:
	pdata->sample_irq =3D irq_of_parse_and_map(np, 0);
	if (pdata->sample_irq =3D=3D NO_IRQ) {
		ret =3D pdata->sample_irq;
		dev_err(dev, "Unable to get sample IRQ from of\n");
                ..
                }


My dts has:
	gpt6: timer@660 {	// General Purpose Timer GPT6 in GPIO mode for
SMC4000IO sample irq.
		interrupt-controller;
		#interrupt-cells =3D <1>;
		compatible =3D "fsl,mpc5200b-gpt","fsl,mpc5200-gpt";
		reg =3D <0x660 0x10>;
		interrupts =3D <1 15 0>;
		interrupt-parent =3D <&mpc5200_pic>;
	};


	io-controller@0 {
		compatible =3D "microkey,smc4000io";
		linux,modalias =3D "of_smc4000io";
		spi-max-frequency =3D <800000>;
		spi-cpha;
		reg =3D <0>;
		word-delay-us =3D <30>;
		interrupt-controller =3D <&gpt6>; // Use GPT6 as the IRQ controller
		interrupts =3D <2>; // And make it edge falling
	};


Thanks in advance,

Henk.

On Fri, Feb 13, 2009 at 5:19 PM, Grant Likely<grant.likely@secretlab.ca> wr=
ote:
> On Fri, Feb 13, 2009 at 3:40 AM, Henk Stegeman <henk.stegeman@gmail.com> =
wrote:
>> I'm busy adding support for slave deviced behind mpc52xx-psc-spi.
>> One complication I have is that my SPI slave device has an interrupt out=
put
>> to the CPU.
>> My idea is to add it as a gpios property in the slave device's
>> configuration:
>>
>> =A0 =A0 =A0 =A0 spi@2400 { =A0 =A0 =A0 =A0// PSC3 (SPI IF to the IO-cont=
roller )
>> =A0 =A0 =A0 =A0 =A0 =A0 device_type =3D "spi";
>> =A0 =A0 =A0 =A0 =A0 =A0 #address-cells =3D <1>;
>> =A0 =A0 =A0 =A0 =A0 =A0 #size-cells =3D <0>;
>> =A0 =A0 =A0 =A0 =A0 =A0 compatible =3D "fsl,mpc5200-psc-spi","fsl,mpc520=
0b-psc-spi";
>> =A0 =A0 =A0 =A0 =A0 =A0 cell-index =3D <2>;
>> =A0 =A0 =A0 =A0 =A0 =A0 reg =3D <0x2400 0x100>;
>> =A0 =A0 =A0 =A0 =A0 =A0 interrupts =3D <2 3 0>;
>> =A0 =A0 =A0 =A0 =A0 =A0 interrupt-parent =3D <&mpc5200_pic>;
>> =A0 =A0 =A0 =A0 =A0 =A0 gpios =3D <&gpt4 0 0>;
>>
>> =A0 =A0 =A0 =A0 =A0 =A0 io-controller@0 {
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 compatible =3D "microkey,smc4000io";
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 spi-max-frequency =3D <1000000>;
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 reg =3D <0>;
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 // gpios: first is IRQ to cpu
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 gpios =3D <&gpt6 0 0>;
>> =A0 =A0 =A0 =A0 =A0 =A0 };
>
> There is a better way to do this, and driver support for it is
> currently merged into Ben Herrenschmidt's -next tree.
>
> Do this instead:
> =A0 =A0 =A0 =A0io-controller@0 {
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0compatible =3D "microkey,smc4000io";
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0spi-max-frequency =3D <1000000>;
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0reg =3D <0>;
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0interrupt-controller =3D < &gpt6 >; =A0 =
=A0 // Use GPT6 as
> the IRQ controller
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0interrupts =3D < 1 >; =A0 =A0// And make i=
t rising edge.
> =A0 =A0 =A0 =A0};
>
> Then add these two properties to the GPT node:
>
> =A0 =A0 =A0 =A0interrupt-controller;
> =A0 =A0 =A0 =A0#interrupt-cells =3D <1>;
>
> Then you can use normal irq_of_parse_and_map() to set up your handler.
>
>> How should I then register my spi slave driver? My smc4000io_probe funct=
ion
>> gets called correctly by of_spi support but when I register as follows:
>>
>> static struct spi_driver smc4000io_driver =3D {
>> =A0 =A0 .driver =3D {
>> =A0 =A0 =A0 =A0 .name =A0 =A0=3D "smc4000io",
>> =A0 =A0 =A0 =A0 .bus =A0 =A0=3D &spi_bus_type,
>> =A0 =A0 =A0 =A0 .owner =A0 =A0=3D THIS_MODULE,
>> =A0 =A0 },
>> =A0 =A0 .probe =A0 =A0 =A0 =A0=3D smc4000io_probe,
>> =A0 =A0 .remove =A0 =A0 =A0 =A0=3D __devexit_p(smc4000io_remove),
>> };
>>
>> static int __init smc4000io_init(void)
>> {
>> =A0 =A0 return spi_register_driver(&smc4000io_driver);
>> }
>>
>> static void __exit smc4000io_exit(void)
>> {
>> =A0 =A0 spi_unregister_driver(&smc4000io_driver);
>> }
>>
>> module_init(smc4000io_init);
>
> Yes, this is right. =A0The psc_spi driver automatically registers all
> spi children that it finds in the device tree onto the SPI bus.
> Therefore registering an spi_driver() is the right thing to do.
>
>> But when I do:
>>
>> static struct of_platform_driver smc4000_spi_of_driver =3D {
>> =A0 =A0 .name =3D "smc4000io",
>> =A0 =A0 .match_table =3D smc4000io_of_match,
>> =A0 =A0 .probe =3D smc4000io_of_probe,
>> =A0 =A0 .remove =A0 =A0 =A0 =A0=3D __devexit_p(smc4000io_of_remove),
>> };
>>
>> static int __init smc4000io_init(void)
>> {
>> =A0 =A0 return of_register_platform_driver(&smc4000_spi_of_driver);
>> }
>> module_init(smc4000io_init);
>>
>> Then my smc4000io_of_probe function never gets called.
>
> Correct. =A0of_platform_driver isn't useful in this case because the
> device cannot exist independently of the SPI bus. =A0Plus an
> of_platform_device doesn't provide any information about the SPI bus
> itself.
>
> g.
>
> --
> Grant Likely, B.Sc., P.Eng.
> Secret Lab Technologies Ltd.
>