[PATCH 3/4] iio: adc: mcp3422: add hardware gain attribute

[Mitja Spes <mitja@lxnav.com>]

Allows setting gain separately from scale.

Signed-off-by: Mitja Spes <mitja@lxnav.com>
---
 drivers/iio/adc/mcp3422.c | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/mcp3422.c b/drivers/iio/adc/mcp3422.c
index cfb629b964af..eef35fb2fc22 100644
--- a/drivers/iio/adc/mcp3422.c
+++ b/drivers/iio/adc/mcp3422.c
@@ -58,7 +58,8 @@
 		.channel = _index, \
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \
 				| BIT(IIO_CHAN_INFO_SCALE) \
-				| BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+				| BIT(IIO_CHAN_INFO_SAMP_FREQ) \
+				| BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
 	}
 
 static const int mcp3422_scales[MCP3422_SRATE_COUNT][MCP3422_PGA_COUNT] = {
@@ -184,6 +185,10 @@ static int mcp3422_read_raw(struct iio_dev *iio,
 		*val1 = mcp3422_sample_rates[sample_rate];
 		return IIO_VAL_INT;
 
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		*val1 = (1 << pga);
+		return IIO_VAL_INT;
+
 	default:
 		break;
 	}
@@ -245,6 +250,29 @@ static int mcp3422_write_raw(struct iio_dev *iio,
 		adc->ch_config[req_channel] = config;
 		return 0;
 
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		switch (val1) {
+		case 1:
+			temp = MCP3422_PGA_1;
+			break;
+		case 2:
+			temp = MCP3422_PGA_2;
+			break;
+		case 4:
+			temp = MCP3422_PGA_4;
+			break;
+		case 8:
+			temp = MCP3422_PGA_8;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		config &= ~MCP3422_PGA_MASK;
+		config |= MCP3422_PGA_VALUE(temp);
+		adc->ch_config[req_channel] = config;
+		return 0;
+
 	default:
 		break;
 	}
@@ -260,6 +288,8 @@ static int mcp3422_write_raw_get_fmt(struct iio_dev *indio_dev,
 		return IIO_VAL_INT_PLUS_NANO;
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		return IIO_VAL_INT_PLUS_MICRO;
 	default:
 		return -EINVAL;
 	}
-- 
2.34.1