On 07/02/2022 13:00, Jonathan Neuschäfer wrote:
> Hello,
>
> On Mon, Feb 07, 2022 at 02:33:38PM +0800, Tyrone Ting wrote:
>> From: Tyrone Ting <kfting@xxxxxxxxxxx>
>>
>> NPCM8XX uses a similar i2c module as NPCM7XX.
>> The only difference is that the internal HW FIFO
>> is larger.
>>
>> Related Makefile and Kconfig files are modified
>> to support as well.
>>
>> Fixes: 56a1485b102e ("i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver")
>
> It's not really a bug fix, but rather an additional feature.
> Therefore, I suggest removing the Fixes tag from this patch.
>
>> Signed-off-by: Tyrone Ting <kfting@xxxxxxxxxxx>
>> Signed-off-by: Tali Perry <tali.perry1@xxxxxxxxx>
>> ---
> [...]
>> /* init register and default value required to enable module */
>> #define NPCM_I2CSEGCTL 0xE4
>> +#ifdef CONFIG_ARCH_NPCM7XX
>> #define NPCM_I2CSEGCTL_INIT_VAL 0x0333F000
>> +#else
>> +#define NPCM_I2CSEGCTL_INIT_VAL 0x9333F000
>> +#endif
>
> This is going to cause problems when someone tries to compile a kernel
> that runs on both NPCM7xx and NPCM8xx (because the driver will then only
> work on NPCM7xx).
Yes, good catch.
The NPCM7XX is multiplatform, I guess NPCM8xx will be as well, so this
looks like an invalid code. How such code is supposed to work on
multiplatform kernel?
>
> And every time another platform is added, this approach will make the
> code less readable.
>
> A more future-proof approach is probably to have a struct with chip-
> specific data (such as the I2CSECCTL initialization value), which is
> then selected via the .data field in of_device_id.
Best regards,
Krzysztof
