linux-kernel - Re: [PATCH v6 1/2] media: imx274: use regmap_bulk

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Message-ID: <20180828090300.GA23579@frolo.macqel>
Date:   Tue, 28 Aug 2018 11:03:00 +0200
From:   Philippe De Muyter <phdm@...q.eu>
To:     Luca Ceresoli <luca@...aceresoli.net>
Cc:     linux-media@...r.kernel.org,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Leon Luo <leonl@...pardimaging.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 1/2] media: imx274: use regmap_bulk_write to write
        multybyte registers

On Wed, Jul 25, 2018 at 06:24:54PM +0200, Luca Ceresoli wrote:
> Currently 2-bytes and 3-bytes registers are set by very similar
> functions doing the needed shift & mask manipulation, followed by very
> similar for loops setting one byte at a time over I2C.
> 
> Replace all of this code by a unique helper function that calls
> regmap_bulk_write(), which has two advantages:
>  - sets all the bytes in a unique I2C transaction
>  - removes lots of now unused code.
> 
> Signed-off-by: Luca Ceresoli <luca@...aceresoli.net>
> Cc: Sakari Ailus <sakari.ailus@...ux.intel.com>
> 
...
> +/**
> + * Write a multibyte register.
> + *
> + * Uses a bulk write where possible.
> + *
> + * @priv: Pointer to device structure
> + * @addr: Address of the LSB register.  Other registers must be
> + *        consecutive, least-to-most significant.
> + * @val: Value to be written to the register (cpu endianness)
> + * @nbytes: Number of bits to write (range: [1..3])
> + */
> +static int imx274_write_mbreg(struct stimx274 *priv, u16 addr, u32 val,
> +			      size_t nbytes)

Should nbytes be called nbits, or is nbytes a 'Number of bytes' ?

Philippe
-- 
Philippe De Muyter +32 2 6101532 Macq SA rue de l'Aeronef 2 B-1140 Bruxelles