mcp320x driver supports the pseudo-differential mode by
in_voltage'IN+'-voltage'IN-'_raw where (IN+, IN-) = (0, 1), (2, 3), ...
mcp320x chips except MCP3X01 can also select swapped IN+ and IN-
pairs in the pseudo-differential mode.
i.e. in_voltage'IN+'-voltage'IN-'_raw where (IN+, IN-) = (1, 0),
(3, 2), ...
If the voltage level of IN+ is equal to or less than IN-, the
resultant code will be 000h. So it is useful to provide these, too.
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Cc: Oskar Andero <oskar.andero@xxxxxxxxx>
Cc: Jonathan Cameron <jic23@xxxxxxxxxx>
Cc: Hartmut Knaack <knaack.h@xxxxxx>
Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>
Cc: Peter Meerwald <pmeerw@xxxxxxxxxx>
Cc: linux-iio@xxxxxxxxxxxxxxx
---
drivers/iio/adc/mcp320x.c | 31 +++++++++++++++++++------------
1 file changed, 19 insertions(+), 12 deletions(-)
diff --git a/drivers/iio/adc/mcp320x.c b/drivers/iio/adc/mcp320x.c
index 8569c8e..a9c4acd 100644
--- a/drivers/iio/adc/mcp320x.c
+++ b/drivers/iio/adc/mcp320x.c
@@ -187,26 +187,27 @@ out:
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
}
-#define MCP320X_VOLTAGE_CHANNEL_DIFF(num) \
+#define MCP320X_VOLTAGE_CHANNEL_DIFF(chan1, chan2) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
- .channel = (num * 2), \
- .channel2 = (num * 2 + 1), \
- .address = (num * 2), \
+ .channel = (chan1), \
+ .channel2 = (chan2), \
+ .address = (chan1), \
.differential = 1, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
}
static const struct iio_chan_spec mcp3201_channels[] = {
- MCP320X_VOLTAGE_CHANNEL_DIFF(0),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
};
static const struct iio_chan_spec mcp3202_channels[] = {
MCP320X_VOLTAGE_CHANNEL(0),
MCP320X_VOLTAGE_CHANNEL(1),
- MCP320X_VOLTAGE_CHANNEL_DIFF(0),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
};
static const struct iio_chan_spec mcp3204_channels[] = {
@@ -214,8 +215,10 @@ static const struct iio_chan_spec mcp3204_channels[] = {
MCP320X_VOLTAGE_CHANNEL(1),
MCP320X_VOLTAGE_CHANNEL(2),
MCP320X_VOLTAGE_CHANNEL(3),
- MCP320X_VOLTAGE_CHANNEL_DIFF(0),
- MCP320X_VOLTAGE_CHANNEL_DIFF(1),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
};
static const struct iio_chan_spec mcp3208_channels[] = {
@@ -227,10 +230,14 @@ static const struct iio_chan_spec mcp3208_channels[] = {
MCP320X_VOLTAGE_CHANNEL(5),
MCP320X_VOLTAGE_CHANNEL(6),
MCP320X_VOLTAGE_CHANNEL(7),
- MCP320X_VOLTAGE_CHANNEL_DIFF(0),
- MCP320X_VOLTAGE_CHANNEL_DIFF(1),
- MCP320X_VOLTAGE_CHANNEL_DIFF(2),
- MCP320X_VOLTAGE_CHANNEL_DIFF(3),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(4, 5),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(5, 4),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(6, 7),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(7, 6),
};
static const struct iio_info mcp320x_info = {
--
2.5.0
--
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