Hi Andy,
> Am 10.04.2018 um 20:06 schrieb Andy Shevchenko <andy.shevchenko@xxxxxxxxx>:
>
> On Tue, Apr 10, 2018 at 7:07 PM, H. Nikolaus Schaller <hns@xxxxxxxxxxxxx> wrote:
>> PCAL chips ("L" seems to stand for "latched") have additional
>> registers starting at address 0x40 to control the latches,
>> interrupt mask, pull-up and pull down etc.
>>
>> The constants are so far defined in a way that they fit for
>> the pcal9555a when shifted by the number of banks, i.e. multiplied
>> by 2.
>>
>> Now the pcal6524 has 3 banks which means the relative offset
>> must be multiplied by 4 which gives a wrong result if not done
>> carefully, since the base offset is already included in the offset.
>>
>> For the basic registers shared with all pca93xx/tca64xx chips
>> there is no such offset.
>>
>> Therefore, we add code to adjust the register number for exended
>> registers to the 24 bit accessor functions.
>>
>> And we add additional register offset constants (not yet used by
>> the driver code) which are specific to the pcal6524.
>>
>
> First of all, as I said, please split this to two patches. Don't mix the things.
Ok. Queued for v4.
>
>
>> + /* adjust register address for pcal6524 */
>> + if (reg >= PCAL953X_OUT_STRENGTH)
>> + reg -= PCAL953X_OUT_STRENGTH >> 1;
>> +
>
> Give me some days to think about it.
No problem. I'll wait with v4.
The only alternative I would see is to add new accessor function
pointers for the extended registers and have 0x00 based offsets,
but that is IMHO more ugly.
BR and thanks,
Nikolaus
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
