iio:dac:ad5686: Refactor the driver

In this patch restructures the existing ad5686 driver by adding a module
for SPI and a header file, while the baseline module deals with the
chip-logic.

This is a necessary step, as this driver should support in the future
similar devices which differ only in the type of interface used (I2C
instead of SPI).

Signed-off-by: Stefan Popa <stefan.popa@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 114 insertions, 0 deletions

diff --git a/drivers/iio/dac/ad5686.h b/drivers/iio/dac/ad5686.h
new file mode 100644
index 000000000000..c8e1565391ca
--- /dev/null
+++ b/drivers/iio/dac/ad5686.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * This file is part of AD5686 DAC driver
+ *
+ * Copyright 2018 Analog Devices Inc.
+ */
+
+#ifndef __DRIVERS_IIO_DAC_AD5686_H__
+#define __DRIVERS_IIO_DAC_AD5686_H__
+
+#include <linux/types.h>
+#include <linux/cache.h>
+#include <linux/mutex.h>
+#include <linux/kernel.h>
+
+#define AD5686_ADDR(x)				((x) << 16)
+#define AD5686_CMD(x)				((x) << 20)
+
+#define AD5686_ADDR_DAC(chan)			(0x1 << (chan))
+#define AD5686_ADDR_ALL_DAC			0xF
+
+#define AD5686_CMD_NOOP				0x0
+#define AD5686_CMD_WRITE_INPUT_N		0x1
+#define AD5686_CMD_UPDATE_DAC_N			0x2
+#define AD5686_CMD_WRITE_INPUT_N_UPDATE_N	0x3
+#define AD5686_CMD_POWERDOWN_DAC		0x4
+#define AD5686_CMD_LDAC_MASK			0x5
+#define AD5686_CMD_RESET			0x6
+#define AD5686_CMD_INTERNAL_REFER_SETUP		0x7
+#define AD5686_CMD_DAISY_CHAIN_ENABLE		0x8
+#define AD5686_CMD_READBACK_ENABLE		0x9
+
+#define AD5686_LDAC_PWRDN_NONE			0x0
+#define AD5686_LDAC_PWRDN_1K			0x1
+#define AD5686_LDAC_PWRDN_100K			0x2
+#define AD5686_LDAC_PWRDN_3STATE		0x3
+
+/**
+ * ad5686_supported_device_ids:
+ */
+enum ad5686_supported_device_ids {
+	ID_AD5672R,
+	ID_AD5676,
+	ID_AD5676R,
+	ID_AD5684,
+	ID_AD5684R,
+	ID_AD5685R,
+	ID_AD5686,
+	ID_AD5686R,
+};
+
+struct ad5686_state;
+
+typedef int (*ad5686_write_func)(struct ad5686_state *st,
+				 u8 cmd, u8 addr, u16 val);
+
+typedef int (*ad5686_read_func)(struct ad5686_state *st, u8 addr);
+
+/**
+ * struct ad5686_chip_info - chip specific information
+ * @int_vref_mv:	AD5620/40/60: the internal reference voltage
+ * @num_channels:	number of channels
+ * @channel:		channel specification
+ */
+
+struct ad5686_chip_info {
+	u16				int_vref_mv;
+	unsigned int			num_channels;
+	struct iio_chan_spec		*channels;
+};
+
+/**
+ * struct ad5446_state - driver instance specific data
+ * @spi:		spi_device
+ * @chip_info:		chip model specific constants, available modes etc
+ * @reg:		supply regulator
+ * @vref_mv:		actual reference voltage used
+ * @pwr_down_mask:	power down mask
+ * @pwr_down_mode:	current power down mode
+ * @data:		spi transfer buffers
+ */
+
+struct ad5686_state {
+	struct device			*dev;
+	const struct ad5686_chip_info	*chip_info;
+	struct regulator		*reg;
+	unsigned short			vref_mv;
+	unsigned int			pwr_down_mask;
+	unsigned int			pwr_down_mode;
+	ad5686_write_func		write;
+	ad5686_read_func		read;
+
+	/*
+	 * DMA (thus cache coherency maintenance) requires the
+	 * transfer buffers to live in their own cache lines.
+	 */
+
+	union {
+		__be32 d32;
+		__be16 d16;
+		u8 d8[4];
+	} data[3] ____cacheline_aligned;
+};
+
+
+int ad5686_probe(struct device *dev,
+		 enum ad5686_supported_device_ids chip_type,
+		 const char *name, ad5686_write_func write,
+		 ad5686_read_func read);
+
+int ad5686_remove(struct device *dev);
+
+
+#endif /* __DRIVERS_IIO_DAC_AD5686_H__ */