[RFC PATCH 00/10] arm: add support for SoC S5P4418

[Stefan B. <stefan_b@posteo.net>]

Hi Amit,

Am 22.02.20 um 14:06 schrieb Amit Tomer:
> Hi,
> 
> On Tue, Feb 4, 2020 at 1:12 AM Stefan Bosch <stefan_b@posteo.net> wrote:
>>
>>
>> This patch adds support for SAMSUNG's/NEXELL's ARM Cortex-A9 based
>> S5P4418 SoC, especially FriendlyARM's NanoPi2 and NanoPC-T2 boards.
>> It is based on the following FriendlyARM's U-Boot version:
>> https://github.com/friendlyarm/u-boot/tree/nanopi2-v2016.01.
>>
> I don't think this is the right approach, i.e. to take everything from
> BSP source as it is and put
> it into mainline U-BOOT. AFAIR,  Some of the peripherals present on
> these NEXELL SoC's are
> compatible with SAMSUNG IP (for instance the UART).
> So, are we sure that some of the already existing code in U-BOOT can't
> be re-used to drive those
> compatible peripherals at-least ?
> 
> Thanks
> -Amit
> 

You are right, already existing code in U-BOOT should be used where 
possible. So I have reviewed the code (and will review it further). Up 
to now, I have the following proposals for the peripherials indicated:

UART:
Actually the UARTs of the S5P4418 are Amba PrimeCell PL011 compatible, 
therefore the appropriate code is used. S5P6818 does have different 
UARTs which apparently arch/arm/mach-nexell/serial.c is for. Since 
S5P6818 is not supported (yet) I will remove this file.

TIMER:
Currently arch/arm/mach-nexell/timer.c is used. I will try to use 
arch/arm/cpu/armv7/s5p-common/timer.c instead. The timer-registers used 
seem to be the same, but the functions in timer.c are not which is a 
possible pitfall.

PWM:
Currently drivers/pwm/pwm-nexell.c is used. This is a extended version 
of arch/arm/cpu/armv7/s5p-common/pwm.c. I.e. pwm.c is adapted with
"#if defined(CONFIG_ARCH_NEXELL) ... #else" at some places. So my 
proposal is to change s5p-common/pwm.c appropriately to get rid of 
pwm-nexell.c.


Regards
Stefan