[PATCH 1/2] ARM: dts: armada388-clearfog: enable spi flash

[gregory.clement@bootlin.com (Gregory CLEMENT)]

Hi Russell King,
 
 On jeu., juin 28 2018, Russell King - ARM Linux <linux@armlinux.org.uk> wrote:

> On Thu, Jun 28, 2018 at 01:47:30PM +0300, Baruch Siach wrote:
>> Hi Russell,
>> 
>> On Thu, Jun 28, 2018 at 11:33:20AM +0100, Russell King - ARM Linux wrote:
>> > On Thu, Jun 28, 2018 at 01:07:59PM +0300, Baruch Siach wrote:
>> > > Thanks for reviewing.
>> > > 
>> > > On Thu, Jun 28, 2018 at 10:51:14AM +0100, Russell King - ARM Linux wrote:
>> > > > On Thu, Jun 28, 2018 at 10:13:35AM +0300, Baruch Siach wrote:
>> > > > > The SolidRun Armada 388 SOM has the SPI flash populated by default
>> > > > > unless the customer explicitly asks otherwise. Enable support by
>> > > > > default.
>> > > > 
>> > > > Are you sure about that - at least some of my boards do not have the
>> > > > SPI flash populated.
>> > > > 
>> > > > &spi1 {
>> > > >         /* The microsom has an optional W25Q32 on board, connected to CS0 */
>> > > > ...
>> > > > &spi1 {
>> > > >         /*
>> > > >          * Add SPI CS pins for clearfog:
>> > > >          * CS0: W25Q32 (not populated on uSOM)
>> > > 
>> > > I should update this line as well, I guess.
>> > > 
>> > > >          * CS1: PIC microcontroller (Pro models)
>> > > >          * CS2: mikrobus
>> > > >          */
>> > > > 
>> > > > I wouldn't have written "not populated on uSOM" without having first
>> > > > taken the uSOM off and physically checked.
>> > > 
>> > > Are these production SOMs or development/engineering samples?
>> > 
>> > I don't remember.
>> > 
>> > > Ilya Viten from the SolidRun commercial department told me that all production 
>> > > SOMs that were shipped to customers have the SPI flash populated.
>> > 
>> > Yes, Jon confirms that.
>> > 
>> > > This is just the default value for the common case.
>> > 
>> > Has it been tested with boards that don't have the SPI flash populated?
>> > That needs to happen to make sure that this doesn't cause a regression.
>> 
>> I don't have such a SOM handy. I can try to "produce" one next week.
>> 
>> I tested a modified DT with the 'reg' property set to 1 to simulate an 
>> unpopulated SPI flash. The driver probe seems to fail gracefully:
>> 
>>   m25p80 spi1.1: unrecognized JEDEC id bytes: ff, ff, ff
>> 
>> Is this test sufficient to ensure the safety of this patch?
>
> Yes, that's fine, thanks for checking.
>
> Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
>
> Gregory, please add my acked-by to your hasty commit, thanks.

Done!

Thanks,

Gregory

>
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-- 
Gregory Clement, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
http://bootlin.com