From mboxrd@z Thu Jan  1 00:00:00 1970
From: Felix Brack <fb@ltec.ch>
Date: Mon, 16 Jul 2018 14:48:32 +0200
Subject: [U-Boot] [PATCH] serial: ns16550: Add register shift variable
In-Reply-To: <20180716124248.1872E24015D@gemini.denx.de>
References: <1531492980-16543-1-git-send-email-fb@ltec.ch>
 <20180714104721.A8B69240175@gemini.denx.de>
 <20180714154933.GF2888@bill-the-cat>
 <1b0d33fa-adfb-9825-5ae8-8bded1678c0c@ltec.ch>
 <20180716124248.1872E24015D@gemini.denx.de>
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On 16.07.2018 14:42, Wolfgang Denk wrote:
> Dear Felix,
> 
> In message <1b0d33fa-adfb-9825-5ae8-8bded1678c0c@ltec.ch> you wrote:
>>
>>>> This needs to be rewritten.
>>>
>>> To try and help clarify, the property in question means "quantity to
>>> shift the register offsets by."  It should be clear in our Kconfig help
>>> entry as well that this is what we're looking for.
>>>
>> Thanks for this! The help text will be fixed in v2.
> 
> None of the places I could find in the Linux
> Documentation/devicetree/bindings directory actually explains what
> "shift the register offsets" means.   Only the code reveals that
> this means a LEFT shift of the register address (offset).
> 
> At least one place in Linux interprets <reg-shift> differently; here
> it operates on the _data_ (instead there they use <reg-spacing>):
> 
> "devicetree/bindings/ipmi/ipmi-smic.txt":
> 
> - reg-shift - The amount to shift the registers to the right to get the data
>         into bit zero.
> 
> (see ipmi_si_mem_io.c
> 
> 
> So can we please add an explanation what _exactly_ this means?
>
I will propose one with v2 post.

> Thanks.
> 
> 
> Wolfgang Denk
> 

regards, Felix