On Fri, Feb 13, 2009 at 3:40 AM, Henk Stegeman <henk.stege...@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 output
> to the CPU.
> My idea is to add it as a gpios property in the slave device's
> configuration:
>
> s...@2400 { // PSC3 (SPI IF to the IO-controller )
> device_type = "spi";
> #address-cells = <1>;
> #size-cells = <0>;
> compatible = "fsl,mpc5200-psc-spi","fsl,mpc5200b-psc-spi";
> cell-index = <2>;
> reg = <0x2400 0x100>;
> interrupts = <2 3 0>;
> interrupt-parent = <&mpc5200_pic>;
> gpios = <&gpt4 0 0>;
>
> io-control...@0 {
> compatible = "microkey,smc4000io";
> spi-max-frequency = <1000000>;
> reg = <0>;
> // gpios: first is IRQ to cpu
> gpios = <&gpt6 0 0>;
> };
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:
io-control...@0 {
compatible = "microkey,smc4000io";
spi-max-frequency = <1000000>;
reg = <0>;
interrupt-controller = < &gpt6 >; // Use GPT6 as
the IRQ controller
interrupts = < 1 >; // And make it rising edge.
};
Then add these two properties to the GPT node:
interrupt-controller;
#interrupt-cells = <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 function
> gets called correctly by of_spi support but when I register as follows:
>
> static struct spi_driver smc4000io_driver = {
> .driver = {
> .name = "smc4000io",
> .bus = &spi_bus_type,
> .owner = THIS_MODULE,
> },
> .probe = smc4000io_probe,
> .remove = __devexit_p(smc4000io_remove),
> };
>
> static int __init smc4000io_init(void)
> {
> return spi_register_driver(&smc4000io_driver);
> }
>
> static void __exit smc4000io_exit(void)
> {
> spi_unregister_driver(&smc4000io_driver);
> }
>
> module_init(smc4000io_init);
Yes, this is right. The 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 = {
> .name = "smc4000io",
> .match_table = smc4000io_of_match,
> .probe = smc4000io_of_probe,
> .remove = __devexit_p(smc4000io_of_remove),
> };
>
> static int __init smc4000io_init(void)
> {
> return of_register_platform_driver(&smc4000_spi_of_driver);
> }
> module_init(smc4000io_init);
>
> Then my smc4000io_of_probe function never gets called.
Correct. of_platform_driver isn't useful in this case because the
device cannot exist independently of the SPI bus. Plus 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.
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