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linux/drivers/iio/adc/ad7606_spi.c
Stefan Popa d2a415c86c iio: adc: ad7606: Add support for AD7606B ADC 
The AD7606B is a 16-bit ADC that supports simultaneous sampling of 8
channels. It is pin compatible to AD7606, but adds extra modes by
writing to the register map.

The AD7606B can be configured to work in software mode by setting all
oversampling pins to high. This mode is selected by default.
The oversampling ratio is configured from the OS_MODE register (address
0x08) with the addition of OS=128 and OS=256 that were not available in
hardware mode.

The device is configured to output data on a single spi channel, but this
configuration must be done right after restart. That is why the delay was
removed for devices which doesn't require it.

Moreover, in software mode, the range gpio has no longer its function.
Instead, the scale can be configured individually for each channel from
the RANGE_CH registers (address 0x03 to 0x06). Besides the already
supported ±10 V and ±5 V ranges, software mode can also accommodate the
±2.5 V range.

Signed-off-by: Stefan Popa <stefan.popa@analog.com>
Co-developed-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2019-08-25 16:11:00 +01:00

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// SPDX-License-Identifier: GPL-2.0
/*
* AD7606 SPI ADC driver
*
* Copyright 2011 Analog Devices Inc.
*/
#include <linux/module.h>
#include <linux/spi/spi.h>
#include <linux/types.h>
#include <linux/err.h>
#include <linux/iio/iio.h>
#include "ad7606.h"
#define MAX_SPI_FREQ_HZ 23500000 /* VDRIVE above 4.75 V */
#define AD7616_CONFIGURATION_REGISTER 0x02
#define AD7616_OS_MASK GENMASK(4, 2)
#define AD7616_BURST_MODE BIT(6)
#define AD7616_SEQEN_MODE BIT(5)
#define AD7616_RANGE_CH_A_ADDR_OFF 0x04
#define AD7616_RANGE_CH_B_ADDR_OFF 0x06
/*
* Range of channels from a group are stored in 2 registers.
* 0, 1, 2, 3 in a register followed by 4, 5, 6, 7 in second register.
* For channels from second group(8-15) the order is the same, only with
* an offset of 2 for register address.
*/
#define AD7616_RANGE_CH_ADDR(ch) ((ch) >> 2)
/* The range of the channel is stored in 2 bits */
#define AD7616_RANGE_CH_MSK(ch) (0b11 << (((ch) & 0b11) * 2))
#define AD7616_RANGE_CH_MODE(ch, mode) ((mode) << ((((ch) & 0b11)) * 2))
#define AD7606_CONFIGURATION_REGISTER 0x02
#define AD7606_SINGLE_DOUT 0x00
/*
* Range for AD7606B channels are stored in registers starting with address 0x3.
* Each register stores range for 2 channels(4 bits per channel).
*/
#define AD7606_RANGE_CH_MSK(ch) (GENMASK(3, 0) << (4 * ((ch) & 0x1)))
#define AD7606_RANGE_CH_MODE(ch, mode) \
((GENMASK(3, 0) & mode) << (4 * ((ch) & 0x1)))
#define AD7606_RANGE_CH_ADDR(ch) (0x03 + ((ch) >> 1))
#define AD7606_OS_MODE 0x08
static const struct iio_chan_spec ad7616_sw_channels[] = {
IIO_CHAN_SOFT_TIMESTAMP(16),
AD7616_CHANNEL(0),
AD7616_CHANNEL(1),
AD7616_CHANNEL(2),
AD7616_CHANNEL(3),
AD7616_CHANNEL(4),
AD7616_CHANNEL(5),
AD7616_CHANNEL(6),
AD7616_CHANNEL(7),
AD7616_CHANNEL(8),
AD7616_CHANNEL(9),
AD7616_CHANNEL(10),
AD7616_CHANNEL(11),
AD7616_CHANNEL(12),
AD7616_CHANNEL(13),
AD7616_CHANNEL(14),
AD7616_CHANNEL(15),
};
static const struct iio_chan_spec ad7606b_sw_channels[] = {
IIO_CHAN_SOFT_TIMESTAMP(8),
AD7616_CHANNEL(0),
AD7616_CHANNEL(1),
AD7616_CHANNEL(2),
AD7616_CHANNEL(3),
AD7616_CHANNEL(4),
AD7616_CHANNEL(5),
AD7616_CHANNEL(6),
AD7616_CHANNEL(7),
};
static const unsigned int ad7606B_oversampling_avail[9] = {
1, 2, 4, 8, 16, 32, 64, 128, 256
};
static u16 ad7616_spi_rd_wr_cmd(int addr, char isWriteOp)
{
/*
* The address of register consist of one w/r bit
* 6 bits of address followed by one reserved bit.
*/
return ((addr & 0x7F) << 1) | ((isWriteOp & 0x1) << 7);
}
static u16 ad7606B_spi_rd_wr_cmd(int addr, char is_write_op)
{
/*
* The address of register consists of one bit which
* specifies a read command placed in bit 6, followed by
* 6 bits of address.
*/
return (addr & 0x3F) | (((~is_write_op) & 0x1) << 6);
}
static int ad7606_spi_read_block(struct device *dev,
int count, void *buf)
{
struct spi_device *spi = to_spi_device(dev);
int i, ret;
unsigned short *data = buf;
__be16 *bdata = buf;
ret = spi_read(spi, buf, count * 2);
if (ret < 0) {
dev_err(&spi->dev, "SPI read error\n");
return ret;
}
for (i = 0; i < count; i++)
data[i] = be16_to_cpu(bdata[i]);
return 0;
}
static int ad7606_spi_reg_read(struct ad7606_state *st, unsigned int addr)
{
struct spi_device *spi = to_spi_device(st->dev);
struct spi_transfer t[] = {
{
.tx_buf = &st->d16[0],
.len = 2,
.cs_change = 0,
}, {
.rx_buf = &st->d16[1],
.len = 2,
},
};
int ret;
st->d16[0] = cpu_to_be16(st->bops->rd_wr_cmd(addr, 0) << 8);
ret = spi_sync_transfer(spi, t, ARRAY_SIZE(t));
if (ret < 0)
return ret;
return be16_to_cpu(st->d16[1]);
}
static int ad7606_spi_reg_write(struct ad7606_state *st,
unsigned int addr,
unsigned int val)
{
struct spi_device *spi = to_spi_device(st->dev);
st->d16[0] = cpu_to_be16((st->bops->rd_wr_cmd(addr, 1) << 8) |
(val & 0x1FF));
return spi_write(spi, &st->d16[0], sizeof(st->d16[0]));
}
static int ad7606_spi_write_mask(struct ad7606_state *st,
unsigned int addr,
unsigned long mask,
unsigned int val)
{
int readval;
readval = st->bops->reg_read(st, addr);
if (readval < 0)
return readval;
readval &= ~mask;
readval |= val;
return st->bops->reg_write(st, addr, readval);
}
static int ad7616_write_scale_sw(struct iio_dev *indio_dev, int ch, int val)
{
struct ad7606_state *st = iio_priv(indio_dev);
unsigned int ch_addr, mode, ch_index;
/*
* Ad7616 has 16 channels divided in group A and group B.
* The range of channels from A are stored in registers with address 4
* while channels from B are stored in register with address 6.
* The last bit from channels determines if it is from group A or B
* because the order of channels in iio is 0A, 0B, 1A, 1B...
*/
ch_index = ch >> 1;
ch_addr = AD7616_RANGE_CH_ADDR(ch_index);
if ((ch & 0x1) == 0) /* channel A */
ch_addr += AD7616_RANGE_CH_A_ADDR_OFF;
else /* channel B */
ch_addr += AD7616_RANGE_CH_B_ADDR_OFF;
/* 0b01 for 2.5v, 0b10 for 5v and 0b11 for 10v */
mode = AD7616_RANGE_CH_MODE(ch_index, ((val + 1) & 0b11));
return st->bops->write_mask(st, ch_addr, AD7616_RANGE_CH_MSK(ch_index),
mode);
}
static int ad7616_write_os_sw(struct iio_dev *indio_dev, int val)
{
struct ad7606_state *st = iio_priv(indio_dev);
return st->bops->write_mask(st, AD7616_CONFIGURATION_REGISTER,
AD7616_OS_MASK, val << 2);
}
static int ad7606_write_scale_sw(struct iio_dev *indio_dev, int ch, int val)
{
struct ad7606_state *st = iio_priv(indio_dev);
return ad7606_spi_write_mask(st,
AD7606_RANGE_CH_ADDR(ch),
AD7606_RANGE_CH_MSK(ch),
AD7606_RANGE_CH_MODE(ch, val));
}
static int ad7606_write_os_sw(struct iio_dev *indio_dev, int val)
{
struct ad7606_state *st = iio_priv(indio_dev);
return ad7606_spi_reg_write(st, AD7606_OS_MODE, val);
}
static int ad7616_sw_mode_config(struct iio_dev *indio_dev)
{
struct ad7606_state *st = iio_priv(indio_dev);
/*
* Scale can be configured individually for each channel
* in software mode.
*/
indio_dev->channels = ad7616_sw_channels;
st->write_scale = ad7616_write_scale_sw;
st->write_os = &ad7616_write_os_sw;
/* Activate Burst mode and SEQEN MODE */
return st->bops->write_mask(st,
AD7616_CONFIGURATION_REGISTER,
AD7616_BURST_MODE | AD7616_SEQEN_MODE,
AD7616_BURST_MODE | AD7616_SEQEN_MODE);
}
static int ad7606B_sw_mode_config(struct iio_dev *indio_dev)
{
struct ad7606_state *st = iio_priv(indio_dev);
unsigned long os[3] = {1};
/*
* Software mode is enabled when all three oversampling
* pins are set to high. If oversampling gpios are defined
* in the device tree, then they need to be set to high,
* otherwise, they must be hardwired to VDD
*/
if (st->gpio_os) {
gpiod_set_array_value(ARRAY_SIZE(os),
st->gpio_os->desc, st->gpio_os->info, os);
}
/* OS of 128 and 256 are available only in software mode */
st->oversampling_avail = ad7606B_oversampling_avail;
st->num_os_ratios = ARRAY_SIZE(ad7606B_oversampling_avail);
st->write_scale = ad7606_write_scale_sw;
st->write_os = &ad7606_write_os_sw;
/* Configure device spi to output on a single channel */
st->bops->reg_write(st,
AD7606_CONFIGURATION_REGISTER,
AD7606_SINGLE_DOUT);
/*
* Scale can be configured individually for each channel
* in software mode.
*/
indio_dev->channels = ad7606b_sw_channels;
return 0;
}
static const struct ad7606_bus_ops ad7606_spi_bops = {
.read_block = ad7606_spi_read_block,
};
static const struct ad7606_bus_ops ad7616_spi_bops = {
.read_block = ad7606_spi_read_block,
.reg_read = ad7606_spi_reg_read,
.reg_write = ad7606_spi_reg_write,
.write_mask = ad7606_spi_write_mask,
.rd_wr_cmd = ad7616_spi_rd_wr_cmd,
.sw_mode_config = ad7616_sw_mode_config,
};
static const struct ad7606_bus_ops ad7606B_spi_bops = {
.read_block = ad7606_spi_read_block,
.reg_read = ad7606_spi_reg_read,
.reg_write = ad7606_spi_reg_write,
.write_mask = ad7606_spi_write_mask,
.rd_wr_cmd = ad7606B_spi_rd_wr_cmd,
.sw_mode_config = ad7606B_sw_mode_config,
};
static int ad7606_spi_probe(struct spi_device *spi)
{
const struct spi_device_id *id = spi_get_device_id(spi);
const struct ad7606_bus_ops *bops;
switch (id->driver_data) {
case ID_AD7616:
bops = &ad7616_spi_bops;
break;
case ID_AD7606B:
bops = &ad7606B_spi_bops;
break;
default:
bops = &ad7606_spi_bops;
break;
}
return ad7606_probe(&spi->dev, spi->irq, NULL,
id->name, id->driver_data,
bops);
}
static const struct spi_device_id ad7606_id_table[] = {
{ "ad7605-4", ID_AD7605_4 },
{ "ad7606-4", ID_AD7606_4 },
{ "ad7606-6", ID_AD7606_6 },
{ "ad7606-8", ID_AD7606_8 },
{ "ad7606b", ID_AD7606B },
{ "ad7616", ID_AD7616 },
{}
};
MODULE_DEVICE_TABLE(spi, ad7606_id_table);
static const struct of_device_id ad7606_of_match[] = {
{ .compatible = "adi,ad7605-4" },
{ .compatible = "adi,ad7606-4" },
{ .compatible = "adi,ad7606-6" },
{ .compatible = "adi,ad7606-8" },
{ .compatible = "adi,ad7606b" },
{ .compatible = "adi,ad7616" },
{ },
};
MODULE_DEVICE_TABLE(of, ad7606_of_match);
static struct spi_driver ad7606_driver = {
.driver = {
.name = "ad7606",
.of_match_table = ad7606_of_match,
.pm = AD7606_PM_OPS,
},
.probe = ad7606_spi_probe,
.id_table = ad7606_id_table,
};
module_spi_driver(ad7606_driver);
MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
MODULE_LICENSE("GPL v2");
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