staging: iio: adc: ad7192: Add system calibration support

This patch will add a system calibration attribute for each channel. Using
this option the user will have the ability to calibrate each channel for
zero scale and full scale. It uses the iio_chan_spec_ext_info and IIO_ENUM
to implement the functionality.

Signed-off-by: Mircea Caprioru <mircea.caprioru@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-adc-ad7192 b/Documentation/ABI/testing/sysfs-bus-iio-adc-ad7192
index 74a2873..7627d3b 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-iio-adc-ad7192
+++ b/Documentation/ABI/testing/sysfs-bus-iio-adc-ad7192
@@ -13,3 +13,27 @@ Description:
                need to minimize the system current consumption.
                Reading gives the state of the bridge switch.
                Writing '1' enables the bridge switch.
+
+What:          /sys/bus/iio/devices/iio:deviceX/in_voltagex_sys_calibration
+KernelVersion:
+Contact:       linux-iio@vger.kernel.org
+Description:
+               Initiates the system calibration procedure. This is done on a
+               single channel at a time. Write '1' to start the calibration.
+
+What:          /sys/bus/iio/devices/iio:deviceX/in_voltagex_sys_calibration_mode_available
+KernelVersion:
+Contact:       linux-iio@vger.kernel.org
+Description:
+               Reading returns a list with the possible calibration modes.
+               There are two available options:
+               "zero_scale" - calibrate to zero scale
+               "full_scale" - calibrate to full scale
+
+What:          /sys/bus/iio/devices/iio:deviceX/in_voltagex_sys_calibration_mode
+KernelVersion:
+Contact:       linux-iio@vger.kernel.org
+Description:
+               Sets up the calibration mode used in the system calibration
+               procedure. Reading returns the current calibration mode.
+               Writing sets the system calibration mode.

diff --git a/drivers/staging/iio/adc/ad7192.c b/drivers/staging/iio/adc/ad7192.c
index e6b6604..bf3e2a9 100644 (file)
--- a/drivers/staging/iio/adc/ad7192.c
+++ b/drivers/staging/iio/adc/ad7192.c
@@ -155,6 +155,11 @@
  * The DOUT/RDY output must also be wired to an interrupt capable GPIO.
  */
 
+enum {
+   AD7192_SYSCALIB_ZERO_SCALE,
+   AD7192_SYSCALIB_FULL_SCALE,
+};
+
 struct ad7192_state {
        struct regulator                *avdd;
        struct regulator                *dvdd;
@@ -169,10 +174,80 @@ struct ad7192_state {
        u8                              devid;
        u8                              clock_sel;
        struct mutex                    lock;   /* protect sensor state */
+       u8                              syscalib_mode[8];
 
        struct ad_sigma_delta           sd;
 };
 
+static const char * const ad7192_syscalib_modes[] = {
+       [AD7192_SYSCALIB_ZERO_SCALE] = "zero_scale",
+       [AD7192_SYSCALIB_FULL_SCALE] = "full_scale",
+};
+
+static int ad7192_set_syscalib_mode(struct iio_dev *indio_dev,
+                                   const struct iio_chan_spec *chan,
+                                   unsigned int mode)
+{
+       struct ad7192_state *st = iio_priv(indio_dev);
+
+       st->syscalib_mode[chan->channel] = mode;
+
+       return 0;
+}
+
+static int ad7192_get_syscalib_mode(struct iio_dev *indio_dev,
+                                   const struct iio_chan_spec *chan)
+{
+       struct ad7192_state *st = iio_priv(indio_dev);
+
+       return st->syscalib_mode[chan->channel];
+}
+
+static ssize_t ad7192_write_syscalib(struct iio_dev *indio_dev,
+                                    uintptr_t private,
+                                    const struct iio_chan_spec *chan,
+                                    const char *buf, size_t len)
+{
+       struct ad7192_state *st = iio_priv(indio_dev);
+       bool sys_calib;
+       int ret, temp;
+
+       ret = strtobool(buf, &sys_calib);
+       if (ret)
+               return ret;
+
+       temp = st->syscalib_mode[chan->channel];
+       if (sys_calib) {
+               if (temp == AD7192_SYSCALIB_ZERO_SCALE)
+                       ret = ad_sd_calibrate(&st->sd, AD7192_MODE_CAL_SYS_ZERO,
+                                             chan->address);
+               else
+                       ret = ad_sd_calibrate(&st->sd, AD7192_MODE_CAL_SYS_FULL,
+                                             chan->address);
+       }
+
+       return ret ? ret : len;
+}
+
+static const struct iio_enum ad7192_syscalib_mode_enum = {
+       .items = ad7192_syscalib_modes,
+       .num_items = ARRAY_SIZE(ad7192_syscalib_modes),
+       .set = ad7192_set_syscalib_mode,
+       .get = ad7192_get_syscalib_mode
+};
+
+static const struct iio_chan_spec_ext_info ad7192_calibsys_ext_info[] = {
+       {
+               .name = "sys_calibration",
+               .write = ad7192_write_syscalib,
+               .shared = IIO_SEPARATE,
+       },
+       IIO_ENUM("sys_calibration_mode", IIO_SEPARATE,
+                &ad7192_syscalib_mode_enum),
+       IIO_ENUM_AVAILABLE("sys_calibration_mode", &ad7192_syscalib_mode_enum),
+       {}
+};
+
 static struct ad7192_state *ad_sigma_delta_to_ad7192(struct ad_sigma_delta *sd)
 {
        return container_of(sd, struct ad7192_state, sd);
@@ -770,9 +845,11 @@ static int ad7192_channels_config(struct iio_dev *indio_dev)
                *chan = channels[i];
                chan->info_mask_shared_by_all |=
                        BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY);
-               if (chan->type != IIO_TEMP)
+               if (chan->type != IIO_TEMP) {
                        chan->info_mask_shared_by_type_available |=
                                BIT(IIO_CHAN_INFO_SCALE);
+                       chan->ext_info = ad7192_calibsys_ext_info;
+               }
                chan++;
        }