diff options
| author |   Akinobu Mita <akinobu.mita@gmail.com> | 2016-01-08 00:40:30 +0900 |
|---|---|---|
| committer |   Jonathan Cameron <jic23@kernel.org> | 2016-01-16 13:04:05 +0000 |
| commit | 4ea71e5cee8ad52407ee95c3548d0887eedae301 (patch) | |
| tree | 4e5bb7df6d56631f15c27b53a992bfac6236b897 /drivers/iio/adc/mcp320x.c | |
| parent | MAINTAINERS: add entry for Atmel SAMA5D2 ADC driver (diff) | |
| download | linux-dev-4ea71e5cee8ad52407ee95c3548d0887eedae301.tar.xz linux-dev-4ea71e5cee8ad52407ee95c3548d0887eedae301.zip | |
iio: adc: mcp320x: support more differential voltage measurement
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@gmail.com>
Cc: Oskar Andero <oskar.andero@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: linux-iio@vger.kernel.org
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers/iio/adc/mcp320x.c')
| -rw-r--r-- | drivers/iio/adc/mcp320x.c | 31 |
1 files changed, 19 insertions, 12 deletions
diff --git a/drivers/iio/adc/mcp320x.c b/drivers/iio/adc/mcp320x.c index d1c05f6eed18..a850ca7d1eda 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 = { |