Re: [PATCH v4 1/2] hwmon: tmp513: Add max_channels variable to struct tmp51x_data

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Tue, Sep 05, 2023 at 07:42:51PM +0100, Biju Das wrote:
> The tmp512 chip has 3 channels whereas tmp513 has 4 channels. Avoid
> using tmp51x_ids for this HW difference by replacing OF/ID table
> data with maximum channels supported by the device.
> 
> Replace id->max_channels variable from struct tmp51x_data and drop the
> macros TMP51{2,3}_TEMP_CONFIG_DEFAULT as it can be derived from the macro
> TMP51X_TEMP_CONFIG_DEFAULT and update the logic in tmp51x_is_visible(),
> tmp51x_read_properties() and tmp51x_init() using max_channels.
> 
> While at it, drop enum tmp51x_ids as there is no user and remove
> trailing comma in the terminator entry for OF table.

...

> +#define TMP51X_TEMP_CONFIG_CONV_RATE	FIELD_PREP(GENMASK(9, 7), 0x7)
> +#define TMP51X_TEMP_CONFIG_RC		BIT(10)
> +#define TMP51X_TEMP_CHANNEL_MASK(n)	FIELD_PREP(GENMASK(14, 11), \
> +						   GENMASK((n) - 1, 0))

Why do you need FIELD_PREP() for the pure constants here? Why can you simply
define the constants in the proper place?

...

> +#define TMP51X_TEMP_CONFIG_DEFAULT(n)	(TMP51X_TEMP_CONFIG_CONT | \
> +			TMP51X_TEMP_CHANNEL_MASK(n) | \
> +			TMP51X_TEMP_CONFIG_CONV_RATE | TMP51X_TEMP_CONFIG_RC)

This is better to read in a form of

#define TMP51X_TEMP_CONFIG_DEFAULT(n)					\
	(TMP51X_TEMP_CHANNEL_MASK(n) | TMP51X_TEMP_CONFIG_CONT |	\
	 TMP51X_TEMP_CONFIG_CONV_RATE | TMP51X_TEMP_CONFIG_RC)

-- 
With Best Regards,
Andy Shevchenko