GSoC PRU: AM35xx Clock driver

[Vijay Kumar Banerjee]

On Wed, Jul 24, 2019 at 6:36 PM Nils Hölscher <nilhoel1 at gmail.com> wrote:

> Hi again,
>
> Hi Nils

> I just decompiled my device tree and checked.
> The probe code of the prcm driver is as follows:
> "
> static int
> am335x_prcm_probe(device_t dev)
> {
>     printk("am335x_prcm_probe\n");
>
>     if (!ofw_bus_status_okay(dev)){
>         printk("ofw_bus_status_not_okay\n");
>         return (ENXIO);
>     }
>
> Do you get the "ofw_bus_status_not_okay" print ?

>     if (ofw_bus_is_compatible(dev, "ti,am3-prcm")) {
>         device_set_desc(dev, "AM335x Power and Clock Management");
>         printk("PROBE SUCESSFULL\n");
>         return(BUS_PROBE_DEFAULT);
>     }
>     printk("ofw_bus incompatible\n");
>     return (ENXIO);
> }
> "
> So it seems the prcm part in the device tree has to be compatible to
> "ti,am3-prcm".
> The thing is the decompiled device tree states just that:
> "
> prcm at 0 {
>                         compatible = "ti,am3-prcm\0simple-bus";
>
In my device tree, it runs successfully and the decompiled compatible looks
like  :
```
            prcm at 200000 {
                compatible = "ti,am3-prcm";
                reg = < 0x200000 0x4000 >;
                linux,phandle = < 0x4a >;
                phandle = < 0x4a >;
```

>                         reg = <0x00 0x2000>;
>                         #address-cells = <0x01>;
>                         #size-cells = <0x01>;
>                         ranges = <0x00 0x00 0x2000>;
>                         phandle = <0x5a>;
> [...]
> "
> Any ideas would help, cause I am currently not able to understand this
> behaviour.
> Also without this driver even the dev_usb_bbb driver shouldn't work.
> However it attaches because it doesn't check for the clocks error code.
>
I remember testing this a few days ago for my fb drivers and it was
attaching alright,
if I remember correctly. If changing the dtb doesn't work for you, I won't
mind checking
again, this will give me a hint for the display issue as well.

>
>
Best,
> Nils
>
>
>
> On Wed, 24 Jul 2019 at 14:43, Nils Hölscher <nilhoel1 at gmail.com> wrote:
>
>> Hi,
>>
>> I just found out that the prcm driver fails to probe on the simplebus and
>> therefore cannot apply itself.
>> Seems like I am back to checking dtb.
>>
>> Best,
>> Nils
>>
>> On Tue, 23 Jul 2019 at 14:26, Nils Hölscher <nilhoel1 at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> After debugging with printk, didn't get the module loading working as
>>> suggested by Sebastian.
>>> I just found out that my PRU driver can't be attached, cause the AM35xx
>>> clock driver isn't loaded.
>>> The driver can be found her:
>>>
>>> https://github.com/RTEMS/rtems-libbsd/blob/610349693dd31d8b0efd33776516b7187cc5cda2/freebsd/sys/arm/ti/am335x/am335x_prcm.c
>>>
>>> Can anyone tell me how to load this driver and obisouly before I
>>> initialize my BSD modules?
>>>
>>> FYI: The code line that fails is this one, cause the driver hasn't been
>>> initialized.
>>>
>>> https://github.com/RTEMS/rtems-libbsd/blob/610349693dd31d8b0efd33776516b7187cc5cda2/freebsd/sys/arm/ti/am335x/am335x_prcm.c#L854
>>>
>>> Thanks,
>>> Nils
>>>
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