Re: [PATCH v2 2/3] iio: dac: Add AD5529R DAC driver support

[Janani Sunil <jan.sun97@gmail.com>]

On 5/16/26 21:35, David Lechner wrote:
> On 5/8/26 6:55 AM, Janani Sunil wrote:
>> Add support for AD5529R 16-channel, 12/16 bit Digital to Analog Converter
>>
> ...
>
>
>> +		.realbits = (bits),				\
>> +		.storagebits = 16,				\
>> +	},							\
>> +}
>> +static struct regmap *ad5529r_get_regmap(struct ad5529r_state *st, unsigned int reg)
>> +{
>> +	if (reg <= AD5529R_8BIT_REG_MAX)
>> +		return st->regmap_8bit;
>> +
>> +	return st->regmap_16bit;
>> +}
> Another way we have done this is make custom read/write functions for the
> regmap itself so that we don't have to have two regmaps.

Dual regmap approach was chosen here because:

1) It leverages regmap's val_bits validation and endianness for 16 bit registers, rather than
implementing them manually.

2) The two distinct register banks- 8 bit and 16 bit map naturally to the separate regmap configs

3) Each regmap has a focused rd_table/wr_table ranges matching the hardware, rather than a complex unified table

The routing overhead is just an address comparison, similar to what custom functions would need, but with automatic validation
and endianness handling

Best Regards,
Janani Sunil