iio: dac: ad3552r-hs: add debugfs reg access

Add debugfs register access.

Reviewed-by: Nuno Sá <[e-mail]>
Signed-off-by: Angelo Dureghello <[e-mail]>
Reviewed-by: David Lechner <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/dac/ad3552r-common.c

···
 	.num_ranges = ARRAY_SIZE(ad3542r_ch_ranges),
 	.requires_output_range = true,
 	.num_spi_data_lanes = 2,
+	.max_reg_addr = 0x46,
 };
 EXPORT_SYMBOL_NS_GPL(ad3541r_model_data, "IIO_AD3552R");
 
···
 	.num_ranges = ARRAY_SIZE(ad3542r_ch_ranges),
 	.requires_output_range = true,
 	.num_spi_data_lanes = 2,
+	.max_reg_addr = 0x49,
 };
 EXPORT_SYMBOL_NS_GPL(ad3542r_model_data, "IIO_AD3552R");
 
···
 	.num_ranges = ARRAY_SIZE(ad3552r_ch_ranges),
 	.requires_output_range = false,
 	.num_spi_data_lanes = 4,
+	.max_reg_addr = 0x46,
 };
 EXPORT_SYMBOL_NS_GPL(ad3551r_model_data, "IIO_AD3552R");
 
···
 	.num_ranges = ARRAY_SIZE(ad3552r_ch_ranges),
 	.requires_output_range = false,
 	.num_spi_data_lanes = 4,
+	.max_reg_addr = 0x49,
 };
 EXPORT_SYMBOL_NS_GPL(ad3552r_model_data, "IIO_AD3552R");
 

drivers/iio/dac/ad3552r-hs.c

···
 				      gain, 1);
 }
 
+static int ad3552r_hs_reg_access(struct iio_dev *indio_dev, unsigned int reg,
+				 unsigned int writeval, unsigned int *readval)
+{
+	struct ad3552r_hs_state *st = iio_priv(indio_dev);
+
+	if (reg > st->model_data->max_reg_addr)
+		return -EINVAL;
+
+	/*
+	 * There are 8, 16 or 24 bit registers, but HDL supports only reading 8
+	 * or 16 bit data, not 24. So, also to avoid to check any proper read
+	 * alignment, supporting only 8-bit readings here.
+	 */
+	if (readval)
+		return ad3552r_hs_reg_read(st, reg, readval, 1);
+
+	return st->data->bus_reg_write(st->back, reg, writeval, 1);
+}
+
 static int ad3552r_hs_setup(struct ad3552r_hs_state *st)
 {
 	u16 id;
···
 static const struct iio_info ad3552r_hs_info = {
 	.read_raw = &ad3552r_hs_read_raw,
 	.write_raw = &ad3552r_hs_write_raw,
+	.debugfs_reg_access = &ad3552r_hs_reg_access,
 };
 
 static int ad3552r_hs_probe(struct platform_device *pdev)

drivers/iio/dac/ad3552r.h

···
 	int num_ranges;
 	bool requires_output_range;
 	int num_spi_data_lanes;
+	int max_reg_addr;
 };
 
 struct ad3552r_ch_data {