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linux-next/drivers/iio/dac/ad5686-spi.c
Stefan Popa 1dbae4c6cd iio:dac:ad5686: Add AD5681R/AD5682R/AD5683/AD5683R support
The AD5681R/AD5682R/AD5683/AD5683R are a family of one channel DACs with
12-bit, 14-bit and 16-bit precision respectively. The devices have either
no built-in reference, or built-in 2.5V reference.

These devices are similar to AD5691R/AD5692R/AD5693/AD5693R except
with a few notable differences:
 * they use the SPI interface instead of I2C
 * in the write control register, DB18 and DB17 are used for setting the
   power mode, while DB16 is the REF bit. This is why a new regmap type
   was defined and checked accordingly.
 * the shift register is 24 bits wide, the first four bits are the command
   bits followed by the data bits. As the data comprises of 20-bit, 18-bit
   or 16-bit input code, this means that 4 LSB bits are don't care. This is
   why the data needs to be shifted on the left with four bits. Therefore,
   AD5683_REGMAP is checked inside a switch case in the ad5686_spi_write()
   function. On the other hand, similar devices such as AD5693R family,
   have the 4 MSB command bits followed by 4 don't care bits.

Datasheet:
http://www.analog.com/media/en/technical-documentation/data-sheets/AD5683R_5682R_5681R_5683.pdf

Signed-off-by: Stefan Popa <stefan.popa@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2018-05-20 11:45:45 +01:00

120 lines
2.7 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* AD5672R, AD5676, AD5676R, AD5681R, AD5682R, AD5683, AD5683R,
* AD5684, AD5684R, AD5685R, AD5686, AD5686R
* Digital to analog converters driver
*
* Copyright 2018 Analog Devices Inc.
*/
#include "ad5686.h"
#include <linux/module.h>
#include <linux/spi/spi.h>
static int ad5686_spi_write(struct ad5686_state *st,
u8 cmd, u8 addr, u16 val)
{
struct spi_device *spi = to_spi_device(st->dev);
u8 tx_len, *buf;
switch (st->chip_info->regmap_type) {
case AD5683_REGMAP:
st->data[0].d32 = cpu_to_be32(AD5686_CMD(cmd) |
AD5683_DATA(val));
buf = &st->data[0].d8[1];
tx_len = 3;
break;
case AD5686_REGMAP:
st->data[0].d32 = cpu_to_be32(AD5686_CMD(cmd) |
AD5686_ADDR(addr) |
val);
buf = &st->data[0].d8[1];
tx_len = 3;
break;
default:
return -EINVAL;
}
return spi_write(spi, buf, tx_len);
}
static int ad5686_spi_read(struct ad5686_state *st, u8 addr)
{
struct spi_transfer t[] = {
{
.tx_buf = &st->data[0].d8[1],
.len = 3,
.cs_change = 1,
}, {
.tx_buf = &st->data[1].d8[1],
.rx_buf = &st->data[2].d8[1],
.len = 3,
},
};
struct spi_device *spi = to_spi_device(st->dev);
u8 cmd = 0;
int ret;
if (st->chip_info->regmap_type == AD5686_REGMAP)
cmd = AD5686_CMD_READBACK_ENABLE;
else if (st->chip_info->regmap_type == AD5683_REGMAP)
cmd = AD5686_CMD_READBACK_ENABLE_V2;
st->data[0].d32 = cpu_to_be32(AD5686_CMD(cmd) |
AD5686_ADDR(addr));
st->data[1].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_NOOP));
ret = spi_sync_transfer(spi, t, ARRAY_SIZE(t));
if (ret < 0)
return ret;
return be32_to_cpu(st->data[2].d32);
}
static int ad5686_spi_probe(struct spi_device *spi)
{
const struct spi_device_id *id = spi_get_device_id(spi);
return ad5686_probe(&spi->dev, id->driver_data, id->name,
ad5686_spi_write, ad5686_spi_read);
}
static int ad5686_spi_remove(struct spi_device *spi)
{
return ad5686_remove(&spi->dev);
}
static const struct spi_device_id ad5686_spi_id[] = {
{"ad5672r", ID_AD5672R},
{"ad5676", ID_AD5676},
{"ad5676r", ID_AD5676R},
{"ad5681r", ID_AD5681R},
{"ad5682r", ID_AD5682R},
{"ad5683", ID_AD5683},
{"ad5683r", ID_AD5683R},
{"ad5684", ID_AD5684},
{"ad5684r", ID_AD5684R},
{"ad5685", ID_AD5685R}, /* Does not exist */
{"ad5685r", ID_AD5685R},
{"ad5686", ID_AD5686},
{"ad5686r", ID_AD5686R},
{}
};
MODULE_DEVICE_TABLE(spi, ad5686_spi_id);
static struct spi_driver ad5686_spi_driver = {
.driver = {
.name = "ad5686",
},
.probe = ad5686_spi_probe,
.remove = ad5686_spi_remove,
.id_table = ad5686_spi_id,
};
module_spi_driver(ad5686_spi_driver);
MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD5686 and similar multi-channel DACs");
MODULE_LICENSE("GPL v2");