Re: [PATCH] mfd: Add support for CPLD chip on Mikrotik RB4xx boards
From: Bert Vermeulen
Date: Tue Apr 07 2015 - 11:48:16 EST
On 07/04/15 08:52, Lee Jones wrote:
> On Mon, 06 Apr 2015, Bert Vermeulen wrote:
>> The SPI-connected CPLD chip controls access to the main NAND flash
>> chip and five LEDs.
>> Signed-off-by: Bert Vermeulen <bert@xxxxxxxx>
>> arch/mips/include/asm/mach-ath79/rb4xx_cpld.h | 49 +++++
>> drivers/mfd/Kconfig | 7 +
>> drivers/mfd/Makefile | 1 +
>> drivers/mfd/rb4xx-cpld.c | 279 ++++++++++++++++++++++++++
>> 4 files changed, 336 insertions(+)
>> create mode 100644 arch/mips/include/asm/mach-ath79/rb4xx_cpld.h
>> create mode 100644 drivers/mfd/rb4xx-cpld.c
> This device doesn't look like an MFD, it rather looks like a CPLD
> driver. We had a recent submission like this , perhaps this will
> provide another argument for drivers/programmables or something.
>  https://lkml.org/lkml/2015/2/17/42
Yup, got bounced into drivers/mfd after initially submitting it as an SPI
protocol driver (where it lives in openwrt). Indeed it's not a great fit
anywhere -- not even programmables: this thing has its firmware on board,
nothing ever feeds it on startup.
Drivers for CPLDs don't necessarily have anything in common -- these are
customized chips basically. In this case it's a NAND controller and GPIO/LED
expander rolled into one.
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