linux-kernel - Re: [PATCH 09/20] regmap: _regmap_raw_write fix for busses without write()

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Message-ID: <20150812122011.GE19600@pengutronix.de>
Date:	Wed, 12 Aug 2015 14:20:11 +0200
From:	Markus Pargmann <mpa@...gutronix.de>
To:	Mark Brown <broonie@...nel.org>
Cc:	linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
	Jonathan Cameron <jic23@...nel.org>, kernel@...gutronix.de,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 09/20] regmap: _regmap_raw_write fix for busses without
 write()

On Wed, Aug 12, 2015 at 12:20:35PM +0100, Mark Brown wrote:
> On Wed, Aug 12, 2015 at 12:12:34PM +0200, Markus Pargmann wrote:
> 
> > @@ -1229,6 +1229,11 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg,
> >  		}
> >  	}
> >  
> > +	if (!map->bus->write && val_len == map->format.val_bytes) {
> > +		ret = _regmap_bus_reg_write(map, reg, *(unsigned int *)val);
> > +		return ret;
> > +	}
> 
> This is broken - you can't use a raw value as a register value.  The

I am not sure what you mean here?

The register value given to _regmap_raw_write is the real register
value, not formatted differenty. This is given directly towards
bus->reg_write() which should handle the rest.

At least that's how I understood the code. For example regmap_read()
directly calls _regmap_read() which in turn calls directly
bus->reg_read() without any formating.

> endianness of the device may not be the same as the endianness of the
> system and you can't cast a value to unsigned int, the value may be of
> any size.

Yes right. On the other hand if bus->read() and bus->write() was not set
in the init method (before this patch series) no formatting functions at
all were assigned. So it was always ignored for bus->reg_read() and
bus->reg_write()?!

> 
> > @@ -1340,7 +1345,7 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg,
> >  	 * send the work_buf directly, otherwise try to do a gather
> >  	 * write.
> >  	 */
> > -	if (val == work_val) {
> > +	if (val == work_val && map->bus->write) {
> >  		ret = map->bus->write(map->bus_context, map->work_buf,
> >  				      map->format.reg_bytes +
> >  				      map->format.pad_bytes +
> 
> This appears to be another case of merging an unrelated change :(

Yes, will fix.

Thanks,

Markus

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