Re: [PATCH 06/15] mfd/ab8500: Remove confusing ab8500-i2c file and merge into ab8500-core

[Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>]

On Fri, May 4, 2012 at 8:23 PM, Lee Jones <lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:

> ab8500-i2c is used as core code to register the ab8500 device.
> After allocating ab8500 memory, it immediately calls into
> ab8500-core where the real initialisation takes place. This
> patch moves all core registration and memory allocation into
> the true ab8500-core file and removes ab8500-i2c completely.
>
> Signed-off-by: Lee Jones <lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

This code is in a separate file for a reason:

git checkout v2.6.37
$ ls drivers/mfd/
ab8500-core.c
ab8500-debugfs.c
ab8500-i2c.c
ab8500-spi.c

So the driver supports different backendsm and at one point
there was both the SPI and "I2C" (actually PRCMU) backend.

And the physical component has an SPI port as well.

However nowadays it's not used, since the component is design to
be used by the PRCMU I2C channel and nothing else, the SPI
mode was just for prototyping and testing. On newer boards
and the Snowball the SPI isn't even routed.

(...)
+static int ab8500_i2c_write(struct ab8500 *ab8500, u16 addr, u8 data)
+static int ab8500_i2c_read(struct ab8500 *ab8500, u16 addr)

As you might have noticed, many people have been confused by
the "i2c" naming of these things. Yes, there is physically an I2C
carrying these out but in Linux terms that's just confusing, it's mixing
hardware and software terminology. Take this opportunity to
rename them:

static int ab8500_prcmu_write(struct ab8500 *ab8500, u16 addr, u8 data)
static int ab8500_prcmu_read(struct ab8500 *ab8500, u16 addr)

etc, so they have a meaningful name.

Yours,
Linus Walleij