Re: [PATCH v6 2/2] Driver for ON Semi AR0521 camera sensor

[Joe Perches <joe@perches.com>]

On Thu, 2021-12-23 at 08:06 +0100, Krzysztof Hałasa wrote:
> The driver has been extensively tested in an i.MX6-based system.
> AR0521 is a 5.7 mm x 4.3 mm, 5 MPix RGGB MIPI/HiSPi BSI CMOS sensor
> from On Semiconductor.

trivial notes:

> diff --git a/drivers/media/i2c/ar0521.c b/drivers/media/i2c/ar0521.c
[]
> +/* External clock (extclk) frequencies */
> +#define AR0521_EXTCLK_MIN	  (10 * 1000 * 1000)

Generally, adding a prefix like AR0521_ to defines that are
locally defined in a single file unnecessarily increases
identifier length.

It makes using short line lengths difficult.

e.g. Using this identifier anywhere

> +#define AR0521_REG_HISPI_CONTROL_STATUS_FRAMER_TEST_MODE_ENABLE 0x80

Many of the 80 column line lengths and line wrapping used in this
file are not really nice to read.  I believe you don't have to be
strict about 80 column lines.

> +#define be		cpu_to_be16

It's a pity there's no way to declare an array with all members
having a specific endianness.  Making sure all elements in these
arrays are declared with be() is tedious.

> +#define AR0521_NUM_SUPPLIES ARRAY_SIZE(ar0521_supply_names)

It's almost always better to use ARRAY_SIZE directly and not
use a #define for the array size.

> +static int ar0521_set_gains(struct ar0521_dev *sensor)
> +{
[]
> +	dev_dbg(&sensor->i2c_client->dev, "%s()\n", __func__);

ftrace works and perhaps all the similar debug logging uses aren't
really necessary.