Re: [PATCH v6 02/11] iio: dac: mcp47feb02: Fix gain field initialization for active channels

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] iio: dac: unused macro MCP47FEB02_GAIN_BIT_MASK
--

commit 9156f8c32ec03099abf89f1f0f71cf04b9870e24
Author: Ariana Lazar <ariana.lazar@microchip.com>

iio: dac: mcp47feb02: Fix gain field initialization for active channels

As per MCP47FXBX48 Datasheet, in the format of the Gain Control and System
Status Register each DAC channel has one bit to control its gain,
starting at bit 8, while bits 0-7 contain status or unimplemented bits.
The patch updates the driver to use field_get() for correctly extracting 
the gain control bit for each active channel.

Link: https://lore.kernel.org/all/20260804134616.1D8A21F00A3E@smtp.kernel.org/

> diff --git a/drivers/iio/dac/mcp47feb02.c b/drivers/iio/dac/mcp47feb02.c
> index 6a3875e1d6a2c..fa4bd1df95484 100644
> --- a/drivers/iio/dac/mcp47feb02.c
> +++ b/drivers/iio/dac/mcp47feb02.c
> @@ -1016,7 +1016,6 @@ static int mcp47feb02_init_ctrl_regs(struct mcp47feb02_data *data)
>  	if (ret)
>  		return ret;
>  
> -	gain_ch = gain_ch & MCP47FEB02_GAIN_BITS_MASK;
>  	for_each_set_bit(i, &data->active_channels_mask, data->phys_channels) {
>  		struct device *dev = regmap_get_device(data->regmap);
>  		unsigned int pd_tmp, dac_val;
> @@ -1027,7 +1026,7 @@ static int mcp47feb02_init_ctrl_regs(struct mcp47feb02_data *data)
>  		data->chdata[i].dac_data = dac_val;
>  
>  		data->chdata[i].ref_mode = (vref_ch >> (2 * i)) & MCP47FEB02_DAC_CTRL_MASK;
> -		data->chdata[i].use_2x_gain = (gain_ch >> i)  & MCP47FEB02_GAIN_BIT_MASK;
> +		data->chdata[i].use_2x_gain = field_get(DAC_GAIN_MASK(i), gain_ch);

[Severity: Low]
Does this leave the MCP47FEB02_GAIN_BIT_MASK macro defined but unused?

Since this was its only usage in mcp47feb02_init_ctrl_regs(), should the
definition also be removed from drivers/iio/dac/mcp47feb02.c?

>  		/*
>  		 * Inform the user that the current voltage reference read from the volatile

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260916-mcp47feb02_refactor-v6-0-285464651f89@microchip.com?part=2