iio: adc: adi-axi-adc: add oversampling

Add support for enabling/disabling oversampling.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Link: https://patch.msgid.link/20250214131955.31973-8-antoniu.miclaus@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
index ed6a46bdbd8088f498f41815ec15807352373935..61ab7dce43be66868f09c41df18d09259db0cee3 100644 (file)
--- a/drivers/iio/adc/adi-axi-adc.c
+++ b/drivers/iio/adc/adi-axi-adc.c
@@ -47,6 +47,7 @@
 #define    ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK   BIT(1)
 
 #define ADI_AXI_ADC_REG_CNTRL_3                        0x004c
+#define   AXI_AD485X_CNTRL_3_OS_EN_MSK         BIT(2)
 #define   AXI_AD485X_CNTRL_3_PACKET_FORMAT_MSK GENMASK(1, 0)
 #define   AXI_AD485X_PACKET_FORMAT_20BIT       0x0
 #define   AXI_AD485X_PACKET_FORMAT_24BIT       0x1
@@ -379,6 +380,28 @@ static int axi_adc_ad485x_data_size_set(struct iio_backend *back,
                                  FIELD_PREP(AXI_AD485X_CNTRL_3_PACKET_FORMAT_MSK, val));
 }
 
+static int axi_adc_ad485x_oversampling_ratio_set(struct iio_backend *back,
+                                         unsigned int ratio)
+{
+       struct adi_axi_adc_state *st = iio_backend_get_priv(back);
+
+       /* The current state of the function enables or disables the
+        * oversampling in REG_CNTRL_3 register. A ratio equal to 1 implies no
+        * oversampling, while a value greater than 1 implies oversampling being
+        * enabled.
+        */
+       switch (ratio) {
+       case 0:
+               return -EINVAL;
+       case 1:
+               return regmap_clear_bits(st->regmap, ADI_AXI_ADC_REG_CNTRL_3,
+                                        AXI_AD485X_CNTRL_3_OS_EN_MSK);
+       default:
+               return regmap_set_bits(st->regmap, ADI_AXI_ADC_REG_CNTRL_3,
+                                      AXI_AD485X_CNTRL_3_OS_EN_MSK);
+       }
+}
+
 static struct iio_buffer *axi_adc_request_buffer(struct iio_backend *back,
                                                 struct iio_dev *indio_dev)
 {
@@ -548,6 +571,7 @@ static const struct iio_backend_ops adi_ad485x_ops = {
        .chan_status = axi_adc_chan_status,
        .interface_type_get = axi_adc_interface_type_get,
        .data_size_set = axi_adc_ad485x_data_size_set,
+       .oversampling_ratio_set = axi_adc_ad485x_oversampling_ratio_set,
        .debugfs_reg_access = iio_backend_debugfs_ptr(axi_adc_reg_access),
        .debugfs_print_chan_status =
                iio_backend_debugfs_ptr(axi_adc_debugfs_print_chan_status),