iio: adc: ad9467: check for backend capabilities

Add capability checks for operation with backends that do not necessarily
support full set of features, but are otherwise compatible with the device.
This ensures a fully functional device, but with limited capabilities.

Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Tomas Melin <tomas.melin@vaisala.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/ad9467.c b/drivers/iio/adc/ad9467.c
index ee0190e711af11f684dab1bcbb1a1d1cf97fde6a..d611ca813c0cb943e35982810dcfa9e03871927e 100644 (file)
--- a/drivers/iio/adc/ad9467.c
+++ b/drivers/iio/adc/ad9467.c
@@ -925,7 +925,11 @@ static int __ad9467_update_clock(struct ad9467_state *st, long r_clk)
                return ret;
 
        guard(mutex)(&st->lock);
-       return ad9467_calibrate(st);
+
+       if (iio_backend_has_caps(st->back, IIO_BACKEND_CAP_CALIBRATION))
+               return ad9467_calibrate(st);
+
+       return 0;
 }
 
 static int ad9467_write_raw(struct iio_dev *indio_dev,
@@ -1131,12 +1135,15 @@ static ssize_t ad9467_chan_test_mode_read(struct file *file,
                len = scnprintf(buf, sizeof(buf), "Running \"%s\" Test:\n\t",
                                ad9467_test_modes[chan->mode]);
 
-               ret = iio_backend_debugfs_print_chan_status(st->back, chan->idx,
-                                                           buf + len,
-                                                           sizeof(buf) - len);
-               if (ret < 0)
-                       return ret;
-               len += ret;
+               if (iio_backend_has_caps(st->back, IIO_BACKEND_CAP_CALIBRATION)) {
+                       ret = iio_backend_debugfs_print_chan_status(st->back,
+                                                                   chan->idx,
+                                                                   buf + len,
+                                                                   sizeof(buf) - len);
+                       if (ret < 0)
+                               return ret;
+                       len += ret;
+               }
        } else if (chan->mode == AN877_ADC_TESTMODE_OFF) {
                len = scnprintf(buf, sizeof(buf), "No test Running...\n");
        } else {
@@ -1175,11 +1182,13 @@ static ssize_t ad9467_chan_test_mode_write(struct file *file,
        if (mode == AN877_ADC_TESTMODE_OFF) {
                unsigned int out_mode;
 
-               if (chan->mode == AN877_ADC_TESTMODE_PN9_SEQ ||
-                   chan->mode == AN877_ADC_TESTMODE_PN23_SEQ) {
-                       ret = ad9467_backend_testmode_off(st, chan->idx);
-                       if (ret)
-                               return ret;
+               if (iio_backend_has_caps(st->back, IIO_BACKEND_CAP_CALIBRATION)) {
+                       if (chan->mode == AN877_ADC_TESTMODE_PN9_SEQ ||
+                           chan->mode == AN877_ADC_TESTMODE_PN23_SEQ) {
+                               ret = ad9467_backend_testmode_off(st, chan->idx);
+                               if (ret)
+                                       return ret;
+                       }
                }
 
                ret = ad9467_testmode_set(st, chan->idx, mode);
@@ -1205,16 +1214,18 @@ static ssize_t ad9467_chan_test_mode_write(struct file *file,
                        return ret;
 
                /*  some patterns have a backend matching monitoring block */
-               if (mode == AN877_ADC_TESTMODE_PN9_SEQ) {
-                       ret = ad9467_backend_testmode_on(st, chan->idx,
+               if (iio_backend_has_caps(st->back, IIO_BACKEND_CAP_CALIBRATION)) {
+                       if (mode == AN877_ADC_TESTMODE_PN9_SEQ) {
+                               ret = ad9467_backend_testmode_on(st, chan->idx,
                                                         IIO_BACKEND_ADI_PRBS_9A);
-                       if (ret)
-                               return ret;
-               } else if (mode == AN877_ADC_TESTMODE_PN23_SEQ) {
-                       ret = ad9467_backend_testmode_on(st, chan->idx,
+                               if (ret)
+                                       return ret;
+                       } else if (mode == AN877_ADC_TESTMODE_PN23_SEQ) {
+                               ret = ad9467_backend_testmode_on(st, chan->idx,
                                                         IIO_BACKEND_ADI_PRBS_23A);
-                       if (ret)
-                               return ret;
+                               if (ret)
+                                       return ret;
+                       }
                }
        }
 
@@ -1280,8 +1291,9 @@ static void ad9467_debugfs_init(struct iio_dev *indio_dev)
        if (!st->chan_test)
                return;
 
-       debugfs_create_file("calibration_table_dump", 0400, d, st,
-                           &ad9467_calib_table_fops);
+       if (iio_backend_has_caps(st->back, IIO_BACKEND_CAP_CALIBRATION))
+               debugfs_create_file("calibration_table_dump", 0400, d, st,
+                                   &ad9467_calib_table_fops);
 
        for (chan = 0; chan < st->info->num_channels; chan++) {
                snprintf(attr_name, sizeof(attr_name), "in_voltage%u_test_mode",
@@ -1356,17 +1368,23 @@ static int ad9467_probe(struct spi_device *spi)
        if (ret)
                return ret;
 
-       ret = devm_iio_backend_request_buffer(dev, st->back, indio_dev);
-       if (ret)
-               return ret;
+       if (iio_backend_has_caps(st->back, IIO_BACKEND_CAP_BUFFER)) {
+               ret = devm_iio_backend_request_buffer(dev, st->back, indio_dev);
+               if (ret)
+                       return ret;
+       }
 
-       ret = devm_iio_backend_enable(dev, st->back);
-       if (ret)
-               return ret;
+       if (iio_backend_has_caps(st->back, IIO_BACKEND_CAP_ENABLE)) {
+               ret = devm_iio_backend_enable(dev, st->back);
+               if (ret)
+                       return ret;
+       }
 
-       ret = ad9467_calibrate(st);
-       if (ret)
-               return ret;
+       if (iio_backend_has_caps(st->back, IIO_BACKEND_CAP_CALIBRATION)) {
+               ret = ad9467_calibrate(st);
+               if (ret)
+                       return ret;
+       }
 
        ret = devm_iio_device_register(dev, indio_dev);
        if (ret)