From mboxrd@z Thu Jan  1 00:00:00 1970
From: nsekhar@ti.com (Sekhar Nori)
Date: Mon, 2 Jan 2017 13:34:29 +0530
Subject: [v2, 1/4] ARM: davinci: da8xx-dt: Add ti-aemif lookup for clock
 matching
In-Reply-To: <33cf2e96-6551-df6a-8a30-bf2c3aeabfee@lechnology.com>
References: <20160810110032.29295-2-kbeldan@baylibre.com>
 <33cf2e96-6551-df6a-8a30-bf2c3aeabfee@lechnology.com>
Message-ID: <72eb6441-6463-abd8-65e6-06772b925999@ti.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Saturday 31 December 2016 06:22 AM, David Lechner wrote:
> On 08/10/2016 06:00 AM, Karl Beldan wrote:
>> Many davinci boards (da830 and da850 families) don't have their clocks
>> in DT yet and won't be successful in getting an unnamed aemif clock
>> without explicitly registering them via clk_lookups, failing the
>> ti-aemif memory driver probe.
>>
>> The current aemif lookup entry resolving to the same clock:
>>     'CLK(NULL,               "aemif",        &aemif_clk)'
>> remains, as it is currently used (davinci_nand is getting a named clock
>> "aemif").
>>
>> This change will allow to switch from the mach-davinci aemif code to
>> the ti-aemif memory driver.
>>
>> Signed-off-by: Karl Beldan <kbeldan@baylibre.com>
>> ---
> 
> FYI, I can't boot LEGO MINDSTORMS EV3 (AM1908) with a v4.9 mainline
> kernel. I did a git bisect and traced it down to this patch. I'm
> guessing that simply reverting it will break other things.
> 
> The problem is that &aemif_clk is a node in a linked list and points to
> itself, which creates an infinite loop when looking up the usb clocks
> that are later in the list.
> 
> I thought there was a patch to fix this properly from one of the Bay
> Libre guys to fix this already, but I can't seem to find it at the
> moment. When it is found, it would be good to have it applied to the 4.9
> stable and 4.10 mainline trees.

Yes, a patch was submitted. It is pending in my queue since I need to do
a few experiments myself to determine if its the best solution possible.
Thanks for the heads-up on need to mark it for v4.9 stable. Will do.

Thanks,
Sekhar