[RFC PATCH 2/2] board: ti: am65x: Move to using Extension framework

[Nishanth Menon]

On 15:29-20230711, Roger Quadros wrote:
> Hi Simon,
> 
> On 10/07/2023 22:45, Simon Glass wrote:
> > Hi Roger,
> > 
> > On Mon, 10 Jul 2023 at 08:51, Roger Quadros <rogerq at kernel.org> wrote:
> >>
> >> Support the Expansion cards via Extension framework.
> >> This should make 'expansion' command work to scan
> >> for expansion cards and apply DT overlays.
> >>
> >> Card detection code is moved to a library so
> >> other boards can benefit from it.
> >>
> >> Signed-off-by: Roger Quadros <rogerq at kernel.org>
> >> ---
> >>  board/ti/am65x/evm.c               | 264 ++++++++---------------------
> >>  board/ti/common/Kconfig            |   8 +
> >>  board/ti/common/Makefile           |   1 +
> >>  board/ti/common/ti_card_detect.c   | 155 +++++++++++++++++
> >>  board/ti/common/ti_card_detect.h   |  43 +++++
> >>  configs/am65x_evm_a53_defconfig    |   2 +
> >>  configs/am65x_hs_evm_a53_defconfig |   2 +
> >>  7 files changed, 280 insertions(+), 195 deletions(-)
> >>  create mode 100644 board/ti/common/ti_card_detect.c
> >>  create mode 100644 board/ti/common/ti_card_detect.h
> > 
> > Before this goes too far I think this should move to using a linker
> > list to declare the driver (or a driver-model driver if you prefer,
> > but that might be overkill).
> 
> ti_card_detect.c This is not a device driver but just a helper library
> which is ultimately going to be used directly by the board files.
> 
> e.g.
> see board/ti/am65x/evm.c
> 
> > 
> > What do people think?

I think the linker list idea is better that library approach. One of the
whack-a-mole we have been dealing with is with i2c eeprom detection
board/ti/common/board_detect.c

The linker list idea could potentially allows us to have a common
detect schemes with appropriate fall backs as pertinent to the
platform (e.g. mid production update from 2byte to 1 byte eeprom etc)
maybe the order indicated by defconfig? And adds capability to have
fall through down to board type detection (thinking cape_detect /
ti_card_detect etc..)..

Also boards that dont care for this can disable the configuration and
use the rest of the codebase (simplify evm.c)

Just my 2 cents..

-- 
Regards,
Nishanth Menon
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