Re: [PATCH 4/6] regmap: add MMIO bus support

[Mark Brown <broonie@opensource.wolfsonmicro.com>]

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On Wed, Apr 04, 2012 at 03:48:31PM -0600, Stephen Warren wrote:
> From: Stephen Warren <swarren@nvidia.com>
> 
> This is a basic memory-mapped-IO bus for regmap. It has the following
> features and limitations:

I applied these up to here but it was painful as patch 2 didn't apply
cleanly to -rc1 and git am couldn't find the blobs to use for
resolution.  Please check things worked out OK but I'm pretty sure they
did.

> * Registers themselves may be 8, 16, 32, or 64-bit. 64-bit is only
>   supported on 64-bit platforms.
> * Register offsets are limited to precisely 32-bit.
> * IO is performed using readl/writel, with no provision for using the
>   __raw_readl or readl_relaxed variants.

Also limited native endian register I/O.  It would have been much better
to fix this in the core - please consider producing followup patches to
push the code there, though it's far from essential.

> +static int regmap_mmio_gather_write(void *context,
> +				    const void *reg, size_t reg_size,
> +				    const void *val, size_t val_size)
> +{
> +	struct regmap_mmio_context *ctx = context;
> +	u32 offset;
> +
> +	if (reg_size != 4)
> +		return -EIO;

Given that you constrain on registration too this should be BUG_ON(),
we're seriously confused if we're specifying a different register size
here and -EIO is going to be a bit obscure.

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