[PATCH v5 02/10] iio: dac: mcp47feb02: Fix gain field initialization for active channels
From: Ariana Lazar
Date: Wed Sep 09 2026 - 10:32:18 EST
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 previous formula didn't initialize correctly all channels, being
replaced by the already defined macro used in write operations where needed
in the rest of the driver implementation. DAC_GAIN_MASK(i) extracts the
gain control bit for each active channel correctly ine one step.
Signed-off-by: Ariana Lazar <ariana.lazar@xxxxxxxxxxxxx>
---
drivers/iio/dac/mcp47feb02.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/iio/dac/mcp47feb02.c b/drivers/iio/dac/mcp47feb02.c
index 7502959d98eab27941d58b6b961e6e3dee4222e6..bf78618ac2c896b94e494a1ce76ef5b3e520f482 100644
--- a/drivers/iio/dac/mcp47feb02.c
+++ b/drivers/iio/dac/mcp47feb02.c
@@ -1017,7 +1017,6 @@ 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;
@@ -1028,7 +1027,7 @@ 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 = (gain_ch & DAC_GAIN_MASK(i)) ? 1 : 0;
/*
* Inform the user that the current voltage reference read from the volatile
--
2.43.0