iio: adc: hx711: Add IIO driver for AVIA HX711

This is the IIO driver for AVIA HX711 ADC which is mostly used in weighting
cells.

The protocol is quite simple and using GPIOs:
One GPIO is used as clock (SCK) while another GPIO is read (DOUT)

The raw value read from the chip is delivered.
To get a weight one needs to subtract the zero offset and scale it.

Signed-off-by: Andreas Klinger <ak@it-klinger.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index be81ba3efd61..817693a14eb9 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -247,6 +247,25 @@ config HI8435
 	  This driver can also be built as a module. If so, the module will be
 	  called hi8435.
 
+config HX711
+	tristate "AVIA HX711 ADC for weight cells"
+	depends on GPIOLIB
+	help
+	  If you say yes here you get support for AVIA HX711 ADC which is used
+	  for weigh cells
+
+	  This driver uses two GPIOs, one acts as the clock and controls the
+	  channel selection and gain, the other one is used for the measurement
+          data
+
+	  Currently the raw value is read from the chip and delivered.
+	  To get an actual weight one needs to subtract the
+	  zero offset and multiply by a scale factor.
+	  This should be done in userspace.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called hx711.
+
 config INA2XX_ADC
 	tristate "Texas Instruments INA2xx Power Monitors IIO driver"
 	depends on I2C && !SENSORS_INA2XX