Thread (11 messages) 11 messages, 3 authors, 2009-07-08

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

From: Grant Likely <hidden>
Date: 2009-07-07 15:57:55

On Tue, Jul 7, 2009 at 8:31 AM, Henk Stegeman[off-list ref] wrot=
e:
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).
Make sure the 5200 general purpose timer driver is compiled in (not a modul=
e).

The driver reports from it's probe:
[ =A0 =A01.502853] spi_master spi32766.0 Unable to get sample IRQ from of

My driver has:
=A0 =A0 =A0 =A0pdata->sample_irq =3D irq_of_parse_and_map(np, 0);
=A0 =A0 =A0 =A0if (pdata->sample_irq =3D=3D NO_IRQ) {
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0ret =3D pdata->sample_irq;
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0dev_err(dev, "Unable to get sample IRQ fro=
m of\n");
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0..
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0}


My dts has:
=A0 =A0 =A0 =A0gpt6: timer@660 { =A0 =A0 =A0 // General Purpose Timer GPT=
6 in GPIO mode for
SMC4000IO sample irq.
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0interrupt-controller;
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0#interrupt-cells =3D <1>;
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0compatible =3D "fsl,mpc5200b-gpt","fsl,mpc=
5200-gpt";
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0reg =3D <0x660 0x10>;
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0interrupts =3D <1 15 0>;
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0interrupt-parent =3D <&mpc5200_pic>;
=A0 =A0 =A0 =A0};


=A0 =A0 =A0 =A0io-controller@0 {
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0compatible =3D "microkey,smc4000io";
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0linux,modalias =3D "of_smc4000io";
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0spi-max-frequency =3D <800000>;
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0spi-cpha;
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0reg =3D <0>;
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0word-delay-us =3D <30>;
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0interrupt-controller =3D <&gpt6>; // Use G=
PT6 as the IRQ controller
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0interrupts =3D <2>; // And make it edge fa=
lling
=A0 =A0 =A0 =A0};


Thanks in advance,

Henk.

On Fri, Feb 13, 2009 at 5:19 PM, Grant Likely[off-list ref] =
wrote:
quoted
On Fri, Feb 13, 2009 at 3:40 AM, Henk Stegeman [off-list ref]=
 wrote:
quoted
quoted
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 ou=
tput
quoted
quoted
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-con=
troller )
quoted
quoted
=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,mpc52=
00b-psc-spi";
quoted
quoted
=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
quoted
the IRQ controller
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0interrupts =3D < 1 >; =A0 =A0// And make =
it rising edge.
quoted
=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.
quoted
How should I then register my spi slave driver? My smc4000io_probe func=
tion
quoted
quoted
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.
quoted
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.


--=20
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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