Re: AM335x board with disabled RTC crashes

[Stefan Roese <mail@roese.nl>]

Thanks Nishanth!

On 11/21/2013 06:30 AM, Nishanth Menon wrote:
>> This (hacky) patch works, but I'm not sure if this is acceptable upstream:
>>
>> am335x-board_foo.dts:
>>
>> ...
>>
>> &rtc {
>> 	reg = <0x0 0x0>;
>> };
>>
> You should be able to achieve the same effect as following (example from
> BBB) - though I dont see this defined in
> Documentation/devicetree/bindings/arm/omap/omap.txt
> 
> I will allow the wisdom of others to comment better here :)
> diff --git a/arch/arm/boot/dts/am335x-boneblack.dts b/arch/arm/boot/dts/am335x-boneblack.dts
> index 6b71ad9..a734ef4 100644
> --- a/arch/arm/boot/dts/am335x-boneblack.dts
> +++ b/arch/arm/boot/dts/am335x-boneblack.dts
> @@ -66,6 +66,11 @@
>  	status = "okay";
>  };
>  
> +&am335xrtc {
> +	status = "disabled";
> +	ti,hwmods="disabled";
> +};

Yes, this works too. Thanks.

Which leaves only the quite ugly WARN() resulting from Suman's patch:

[    0.230270] omap_hwmod: rtc: Could not ioremap
[    0.234962] ------------[ cut here ]------------
[    0.239936] WARNING: CPU: 0 PID: 1 at arch/arm/mach-omap2/omap_hwmod.c:2434 _init+0x144/0x310()
[    0.249054] omap_hwmod: rtc: doesn't have mpu register target base
[    0.255526] Modules linked in:
[    0.258845] CPU: 0 PID: 1 Comm: swapper Not tainted 3.12.0-00004-gfcb6c2c-dirty #31
[    0.266938] [<c00197f4>] (unwind_backtrace+0x0/0xf0) from [<c0016ee8>] (show_stack+0x10/0x14)
[    0.275916] [<c0016ee8>] (show_stack+0x10/0x14) from [<c003be68>] (warn_slowpath_common+0x6c/0x8c)
[    0.285284] [<c003be68>] (warn_slowpath_common+0x6c/0x8c) from [<c003bf1c>] (warn_slowpath_fmt+0x30/0x40)
[    0.295323] [<c003bf1c>] (warn_slowpath_fmt+0x30/0x40) from [<c06fdac8>] (_init+0x144/0x310)
[    0.304200] [<c06fdac8>] (_init+0x144/0x310) from [<c0029e40>] (omap_hwmod_for_each+0x34/0x5c)
[    0.313250] [<c0029e40>] (omap_hwmod_for_each+0x34/0x5c) from [<c06fe1fc>] (__omap_hwmod_setup_all+0x24/0x40)
[    0.323643] [<c06fe1fc>] (__omap_hwmod_setup_all+0x24/0x40) from [<c00087e8>] (do_one_initcall+0x34/0x160)
[    0.333774] [<c00087e8>] (do_one_initcall+0x34/0x160) from [<c06f3af0>] (kernel_init_freeable+0xe8/0x1b4)
[    0.343824] [<c06f3af0>] (kernel_init_freeable+0xe8/0x1b4) from [<c04d0ff4>] (kernel_init+0x8/0xe4)
[    0.353338] [<c04d0ff4>] (kernel_init+0x8/0xe4) from [<c00139e8>] (ret_from_fork+0x14/0x2c)
[    0.362428] ---[ end trace 1b75b31a2719ed1c ]---

Do we really need this WARN() here? Or is the "Could not ioremap" line
enough?

Thanks,
Stefan