Subject: Re: [PATCH v2 2/3] net: can: c_can: Add syscon/regmap RAMINIT mechanism

From: Roger Quadros <[email-masked]>
Date: Wed, 1 Oct 2014 12:06:55 +0300

On 10/01/2014 11:47 AM, Marc Kleine-Budde wrote:
> On 10/01/2014 10:45 AM, Roger Quadros wrote:
>> On 09/30/2014 07:04 PM, Marc Kleine-Budde wrote:
>>> On 09/30/2014 05:25 PM, Wolfram Sang wrote:
>>>>
>>>>> Yes, but syscon_regmap_lookup_by_phandle() doesn't need any support for
>>>>> additional parameters. Have a look at:
>>>>>
>>>>> drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
>>>>>
>>>>> First get the regmap, then the 1st argument is the offset in the regmap,
>>>>> the 2nd and 3rd could be the bits.
>>>>
>>>> So, for one driver the extra arguments are: <reg> <start_bit> <stop_bit>
>>>> For another driver (the stmmac example): <reg_offset> <reg_shift>
>>>
>>> The DCAN's "reg" is a "reg_offset" as in the stmmc.
>>>
>>> Roger, can we derive both start and done bit from a common reg_shift?
>>
>> I'm sorry I didn't understand what you meant.
>>
>> <&syscon_phandl> <reg offset> <start bit> <stop bit> should work well for us.
>> Even though reg offset is the same for both the DCAN instances.
> 
> What's start bit and stop bit for instance 0 and 1 on that SoC that has
> two instances??
> 

we have 3 SoCs at the moment, all have 2 DCAN instances.

AM33xx & AM43xx
instance	start	stop
1		0	8
2		1	9	

DRA7xx
instance	start	stop
1		3	1
2		5	2

cheers,
-roger