Re: [PATCH v3 3/6] regmap: Add regmap_noinc_read API

[Charles Keepax <ckeepax@opensource.cirrus.com>]

On Fri, Aug 03, 2018 at 04:02:18PM +0300, Stefan Popa wrote:
> From: Crestez Dan Leonard <leonard.crestez@intel.com>
> 
> The regmap API usually assumes that bulk read operations will read a
> range of registers but some I2C/SPI devices have certain registers for
> which a such a read operation will return data from an internal FIFO
> instead. Add an explicit API to support bulk read without range semantics.
> 
> Some linux drivers use regmap_bulk_read or regmap_raw_read for such
> registers, for example mpu6050 or bmi150 from IIO. This only happens to
> work because when caching is disabled a single regmap read op will map
> to a single bus read op (as desired). This breaks if caching is enabled and
> reg+1 happens to be a cacheable register.
> 
> Without regmap support refactoring a driver to enable regmap caching
> requires separate I2C and SPI paths. This is exactly what regmap is
> supposed to help avoid.
> 
> Suggested-by: Jonathan Cameron <jic23@kernel.org>
> Signed-off-by: Crestez Dan Leonard <leonard.crestez@intel.com>
> Signed-off-by: Stefan Popa <stefan.popa@analog.com>
> ---
> diff --git a/include/linux/regmap.h b/include/linux/regmap.h
> index 4f38068..b6e6040 100644
> --- a/include/linux/regmap.h
> +++ b/include/linux/regmap.h
> @@ -946,6 +946,8 @@ int regmap_raw_write_async(struct regmap *map, unsigned int reg,
>  int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val);
>  int regmap_raw_read(struct regmap *map, unsigned int reg,
>  		    void *val, size_t val_len);
> +int regmap_noinc_read(struct regmap *map, unsigned int reg,
> +		      void *val, size_t val_len);
>  int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
>  		     size_t val_count);
>  int regmap_update_bits_base(struct regmap *map, unsigned int reg,
> @@ -1196,6 +1198,13 @@ static inline int regmap_raw_read(struct regmap *map, unsigned int reg,
>  	return -EINVAL;
>  }
>  
> +static inline int regmap_pipe_read(struct regmap *map, unsigned int reg,
> +				   void *val, size_t val_len)
> +{
> +	WARN_ONCE(1, "regmap API is disabled");
> +	return -EINVAL;
> +}
> +

This is presumably supposed to be regmap_noinc_read.

Thanks,
Charles