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SubjectRe: [v2,2/4] Input: mt-matrix-keypad: Add Bosch mt matrix keypad driver
Date
From: Gireesh Hiremath <Gireesh.Hiremath@in.bosch.com>

Hi Krzysztof,

>>> You wrote pretty long message explaining how the device works, but I
>>> still do not see the answer to questions - why it cannot be part of
>>> matrix keypad?
>>
>> Following are the difference between matrix keypad and Bosch keypad
>> make us to add another keypad driver.
>>
>> matrix keypad:
>> - By hardware schematic, a column GPIO line will intersect only
>> with row GPIO lines, not with the other column GPIO lines
>> - so, row and column GPIO property are fixed, because of this
>> - key scanning work based on interrupt mode
>> - and key press is determined based on setting column as output,
>> row GPIO as input and set interrupt to monitor the changes in state,
>> serve the key pressed in ISR
>>
>> Bosch keypad:
>> - By hardware schematic column GPIO line can intersect with row GPIO line
>> as well as other column GPIO lines
>> - so, all GPIO act as row as well as column, because of this
>> - key scanning based on polling mode
>> - a key pressed is determined by setting one of GPIO line as output and
>> other as input and poll for change in the state of input GPIO lines.
>> Setting one of a GPIO line as output and remaining GPIO lines as input is on
>> round robin bases.
>
>Which is still not the answer "why it cannot be part of matrix keypad?".
>To me looks similar enough, although maybe not exactly superset of the
>other.

I have merged the Bosch keypad in to the matrix keypad
and sending version v3 patches to support that.

v3-0001-driver-input-matric-keypad-switch-to-gpiod.patch
v3-0002-driver-input-matric-keypad-add-reduced-matrix-sup.patch
v3-0003-dt-bindings-input-gpio-matrix-keypad-add-reduced-.patch

>
>>>
>>> "It looks like this driver has smaller number of features than
>>> matrix-keypad, so it should be integrated into the matrix-keypad.
>>> matrix-keypad features are superset to this one."
>>>
>>> "But anyway this should be just merged into matrix-keypad. It's a
>>> simpler set of that binding."
>>
>> This keypad driver specific to Bosch measuring tool or similar devices.
>> Please let me know to send latest patch which resolves build warning
>> and gpiod API support.
>
>That's a poor reason not to merge into existing driver... I am sorry,
>but our entire Linux kernel concept is to integrate, not duplicate. If
>each of vendors wanted their own feature, we would have unmanageable
>monstrosity with millions of drivers doing almost the same...
>
>
>Best regards,
>Krzysztof
>

Best regards,
Gireesh Hiremath

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