iio: adc: adi-axi-adc: add support for AXI ADC IP core

This change adds support for the Analog Devices Generic AXI ADC IP core.
The IP core is used for interfacing with analog-to-digital (ADC) converters
that require either a high-speed serial interface (JESD204B/C) or a source
synchronous parallel interface (LVDS/CMOS).

Usually, some other interface type (i.e SPI) is used as a control interface
for the actual ADC, while the IP core (controlled via this driver), will
interface to the data-lines of the ADC and handle  the streaming of data
into memory via DMA.

Because of this, the AXI ADC driver needs the other SPI-ADC driver to
register with it. The SPI-ADC needs to be register via the SPI framework,
while the AXI ADC registers as a platform driver. The two cannot be ordered
in a hierarchy as both drivers have their own registers, and trying to
organize this [in a hierarchy becomes] problematic when trying to map
memory/registers.

There are some modes where the AXI ADC can operate as standalone ADC, but
those will be implemented at a later point in time.

DocLink: https://wiki.analog.com/resources/fpga/docs/axi_adc_ip

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/include/linux/iio/adc/adi-axi-adc.h b/include/linux/iio/adc/adi-axi-adc.h
new file mode 100644
index 000000000000..c5d48e1c2d36
--- /dev/null
+++ b/include/linux/iio/adc/adi-axi-adc.h
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Analog Devices Generic AXI ADC IP core driver/library
+ * Link: https://wiki.analog.com/resources/fpga/docs/axi_adc_ip
+ *
+ * Copyright 2012-2020 Analog Devices Inc.
+ */
+#ifndef __ADI_AXI_ADC_H__
+#define __ADI_AXI_ADC_H__
+
+struct device;
+struct iio_chan_spec;
+
+/**
+ * struct adi_axi_adc_chip_info - Chip specific information
+ * @name		Chip name
+ * @id			Chip ID (usually product ID)
+ * @channels		Channel specifications of type @struct axi_adc_chan_spec
+ * @num_channels	Number of @channels
+ * @scale_table		Supported scales by the chip; tuples of 2 ints
+ * @num_scales		Number of scales in the table
+ * @max_rate		Maximum sampling rate supported by the device
+ */
+struct adi_axi_adc_chip_info {
+	const char			*name;
+	unsigned int			id;
+
+	const struct iio_chan_spec	*channels;
+	unsigned int			num_channels;
+
+	const unsigned int		(*scale_table)[2];
+	int				num_scales;
+
+	unsigned long			max_rate;
+};
+
+/**
+ * struct adi_axi_adc_conv - data of the ADC attached to the AXI ADC
+ * @chip_info		chip info details for the client ADC
+ * @preenable_setup	op to run in the client before enabling the AXI ADC
+ * @reg_access		IIO debugfs_reg_access hook for the client ADC
+ * @read_raw		IIO read_raw hook for the client ADC
+ * @write_raw		IIO write_raw hook for the client ADC
+ */
+struct adi_axi_adc_conv {
+	const struct adi_axi_adc_chip_info		*chip_info;
+
+	int (*preenable_setup)(struct adi_axi_adc_conv *conv);
+	int (*reg_access)(struct adi_axi_adc_conv *conv, unsigned int reg,
+			  unsigned int writeval, unsigned int *readval);
+	int (*read_raw)(struct adi_axi_adc_conv *conv,
+			struct iio_chan_spec const *chan,
+			int *val, int *val2, long mask);
+	int (*write_raw)(struct adi_axi_adc_conv *conv,
+			 struct iio_chan_spec const *chan,
+			 int val, int val2, long mask);
+};
+
+struct adi_axi_adc_conv *devm_adi_axi_adc_conv_register(struct device *dev,
+							size_t sizeof_priv);
+
+void *adi_axi_adc_conv_priv(struct adi_axi_adc_conv *conv);
+
+#endif