iio: backend: extend features

Extend backend features with new calls needed later on this
patchset from axi version of ad3552r.

The follwoing calls are added:

iio_backend_ddr_enable()
	enable ddr bus transfer
iio_backend_ddr_disable()
	disable ddr bus transfer
iio_backend_data_stream_enable()
	enable data stream over bus interface
iio_backend_data_stream_disable()
	disable data stream over bus interface
iio_backend_data_transfer_addr()
	define the target register address where the DAC sample
	will be written.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20241028-wip-bl-ad3552r-axi-v0-iio-testing-v9-3-f6960b4f9719@kernel-space.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/industrialio-backend.c

@@ -718,6 +718,84 @@ static int __devm_iio_backend_get(struct device *dev, struct iio_backend *back)
 	return 0;
 }
 
+/**
+ * iio_backend_ddr_enable - Enable interface DDR (Double Data Rate) mode
+ * @back: Backend device
+ *
+ * Enable DDR, data is generated by the IP at each front (raising and falling)
+ * of the bus clock signal.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_ddr_enable(struct iio_backend *back)
+{
+	return iio_backend_op_call(back, ddr_enable);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_ddr_enable, IIO_BACKEND);
+
+/**
+ * iio_backend_ddr_disable - Disable interface DDR (Double Data Rate) mode
+ * @back: Backend device
+ *
+ * Disable DDR, setting into SDR mode (Single Data Rate).
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_ddr_disable(struct iio_backend *back)
+{
+	return iio_backend_op_call(back, ddr_disable);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_ddr_disable, IIO_BACKEND);
+
+/**
+ * iio_backend_data_stream_enable - Enable data stream
+ * @back: Backend device
+ *
+ * Enable data stream over the bus interface.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_data_stream_enable(struct iio_backend *back)
+{
+	return iio_backend_op_call(back, data_stream_enable);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_data_stream_enable, IIO_BACKEND);
+
+/**
+ * iio_backend_data_stream_disable - Disable data stream
+ * @back: Backend device
+ *
+ * Disable data stream over the bus interface.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_data_stream_disable(struct iio_backend *back)
+{
+	return iio_backend_op_call(back, data_stream_disable);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_data_stream_disable, IIO_BACKEND);
+
+/**
+ * iio_backend_data_transfer_addr - Set data address.
+ * @back: Backend device
+ * @address: Data register address
+ *
+ * Some devices may need to inform the backend about an address
+ * where to read or write the data.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_data_transfer_addr(struct iio_backend *back, u32 address)
+{
+	return iio_backend_op_call(back, data_transfer_addr, address);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_data_transfer_addr, IIO_BACKEND);
+
 static struct iio_backend *__devm_iio_backend_fwnode_get(struct device *dev, const char *name,
 							 struct fwnode_handle *fwnode)
 {

include/linux/iio/backend.h

@@ -14,12 +14,14 @@ struct iio_dev;
 enum iio_backend_data_type {
 	IIO_BACKEND_TWOS_COMPLEMENT,
 	IIO_BACKEND_OFFSET_BINARY,
+	IIO_BACKEND_DATA_UNSIGNED,
 	IIO_BACKEND_DATA_TYPE_MAX
 };
 
 enum iio_backend_data_source {
 	IIO_BACKEND_INTERNAL_CONTINUOUS_WAVE,
 	IIO_BACKEND_EXTERNAL,
+	IIO_BACKEND_INTERNAL_RAMP_16BIT,
 	IIO_BACKEND_DATA_SOURCE_MAX
 };
 
@@ -89,6 +91,11 @@ enum iio_backend_sample_trigger {
  * @read_raw: Read a channel attribute from a backend device
  * @debugfs_print_chan_status: Print channel status into a buffer.
  * @debugfs_reg_access: Read or write register value of backend.
+ * @ddr_enable: Enable interface DDR (Double Data Rate) mode.
+ * @ddr_disable: Disable interface DDR (Double Data Rate) mode.
+ * @data_stream_enable: Enable data stream.
+ * @data_stream_disable: Disable data stream.
+ * @data_transfer_addr: Set data address.
  **/
 struct iio_backend_ops {
 	int (*enable)(struct iio_backend *back);
@@ -129,6 +136,11 @@ struct iio_backend_ops {
 					 size_t len);
 	int (*debugfs_reg_access)(struct iio_backend *back, unsigned int reg,
 				  unsigned int writeval, unsigned int *readval);
+	int (*ddr_enable)(struct iio_backend *back);
+	int (*ddr_disable)(struct iio_backend *back);
+	int (*data_stream_enable)(struct iio_backend *back);
+	int (*data_stream_disable)(struct iio_backend *back);
+	int (*data_transfer_addr)(struct iio_backend *back, u32 address);
 };
 
 /**
@@ -164,6 +176,11 @@ int iio_backend_data_sample_trigger(struct iio_backend *back,
 int devm_iio_backend_request_buffer(struct device *dev,
 				    struct iio_backend *back,
 				    struct iio_dev *indio_dev);
+int iio_backend_ddr_enable(struct iio_backend *back);
+int iio_backend_ddr_disable(struct iio_backend *back);
+int iio_backend_data_stream_enable(struct iio_backend *back);
+int iio_backend_data_stream_disable(struct iio_backend *back);
+int iio_backend_data_transfer_addr(struct iio_backend *back, u32 address);
 ssize_t iio_backend_ext_info_set(struct iio_dev *indio_dev, uintptr_t private,
 				 const struct iio_chan_spec *chan,
 				 const char *buf, size_t len);