iio: dac: add support for AXI DAC IP core

Support the Analog Devices Generic AXI DAC IP core. The IP core is used
for interfacing with digital-to-analog (DAC) converters that require either
a high-speed serial interface (JESD204B/C) or a source synchronous parallel
interface (LVDS/CMOS). Typically (for such devices) SPI will be used for
configuration only, while this IP core handles the streaming of data into
memory via DMA.

Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240419-iio-backend-axi-dac-v4-9-5ca45b4de294@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

MAINTAINERS

@@ -1413,6 +1413,7 @@ L:	linux-iio@vger.kernel.org
 S:	Supported
 W:	https://ez.analog.com/linux-software-drivers
 F:	Documentation/devicetree/bindings/iio/dac/adi,axi-dac.yaml
+F:	drivers/iio/dac/adi-axi-dac.c
 
 ANALOG DEVICES INC DMA DRIVERS
 M:	Lars-Peter Clausen <lars@metafoo.de>

drivers/iio/dac/Kconfig

@@ -131,6 +131,27 @@ config AD5624R_SPI
 	  Say yes here to build support for Analog Devices AD5624R, AD5644R and
 	  AD5664R converters (DAC). This driver uses the common SPI interface.
 
+config ADI_AXI_DAC
+	tristate "Analog Devices Generic AXI DAC IP core driver"
+	select IIO_BUFFER
+	select IIO_BUFFER_DMAENGINE
+	select REGMAP_MMIO
+	select IIO_BACKEND
+	help
+	  Say yes here to build support for Analog Devices Generic
+	  AXI DAC IP core. The IP core is used for interfacing with
+	  digital-to-analog (DAC) converters that require either a high-speed
+	  serial interface (JESD204B/C) or a source synchronous parallel
+	  interface (LVDS/CMOS).
+	  Typically (for such devices) SPI will be used for configuration only,
+	  while this IP core handles the streaming of data into memory via DMA.
+
+	  Link: https://wiki.analog.com/resources/fpga/docs/axi_dac_ip
+	  If unsure, say N (but it's safe to say "Y").
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called adi-axi-dac.
+
 config LTC2688
 	tristate "Analog Devices LTC2688 DAC spi driver"
 	depends on SPI

drivers/iio/dac/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_AD5696_I2C) += ad5696-i2c.o
 obj-$(CONFIG_AD7293) += ad7293.o
 obj-$(CONFIG_AD7303) += ad7303.o
 obj-$(CONFIG_AD8801) += ad8801.o
+obj-$(CONFIG_ADI_AXI_DAC) += adi-axi-dac.o
 obj-$(CONFIG_CIO_DAC) += cio-dac.o
 obj-$(CONFIG_DPOT_DAC) += dpot-dac.o
 obj-$(CONFIG_DS4424) += ds4424.o