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iio: adc: Add TI ADS8688

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This patch adds support for the Texas Intruments ADS8688 ADC.

Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Reviewed-by: Martin Hundebøll <martin.hundeboll@prevas.dk>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Sean Nyekjaer 2015-11-09 13:52:59 +01:00 committed by Jonathan Cameron
parent f47dff3230
commit 3e87e78383
3 changed files with 497 additions and 0 deletions
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10
drivers/iio/adc/Kconfig
View file

@ -341,6 +341,16 @@ config TI_ADC128S052
This driver can also be built as a module. If so, the module will be
called ti-adc128s052.
config TI_ADS8688
tristate "Texas Instruments ADS8688"
depends on SPI && OF
help
If you say yes here you get support for Texas Instruments ADS8684 and
and ADS8688 ADC chips
This driver can also be built as a module. If so, the module will be
called ti-ads8688.
config TI_AM335X_ADC
tristate "TI's AM335X ADC driver"
depends on MFD_TI_AM335X_TSCADC

1
drivers/iio/adc/Makefile
View file

@ -33,6 +33,7 @@ obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o
obj-$(CONFIG_TWL6030_GPADC) += twl6030-gpadc.o

486
drivers/iio/adc/ti-ads8688.c Normal file
View file

@ -0,0 +1,486 @@
/*
* Copyright (C) 2015 Prevas A/S
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/spi/spi.h>
#include <linux/regulator/consumer.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define ADS8688_CMD_REG(x) (x << 8)
#define ADS8688_CMD_REG_NOOP 0x00
#define ADS8688_CMD_REG_RST 0x85
#define ADS8688_CMD_REG_MAN_CH(chan) (0xC0 | (4 * chan))
#define ADS8688_CMD_DONT_CARE_BITS 16
#define ADS8688_PROG_REG(x) (x << 9)
#define ADS8688_PROG_REG_RANGE_CH(chan) (0x05 + chan)
#define ADS8688_PROG_WR_BIT BIT(8)
#define ADS8688_PROG_DONT_CARE_BITS 8
#define ADS8688_REG_PLUSMINUS25VREF 0
#define ADS8688_REG_PLUSMINUS125VREF 1
#define ADS8688_REG_PLUSMINUS0625VREF 2
#define ADS8688_REG_PLUS25VREF 5
#define ADS8688_REG_PLUS125VREF 6
#define ADS8688_VREF_MV 4096
#define ADS8688_REALBITS 16
/*
* enum ads8688_range - ADS8688 reference voltage range
* @ADS8688_PLUSMINUS25VREF: Device is configured for input range ±2.5 * VREF
* @ADS8688_PLUSMINUS125VREF: Device is configured for input range ±1.25 * VREF
* @ADS8688_PLUSMINUS0625VREF: Device is configured for input range ±0.625 * VREF
* @ADS8688_PLUS25VREF: Device is configured for input range 0 - 2.5 * VREF
* @ADS8688_PLUS125VREF: Device is configured for input range 0 - 1.25 * VREF
*/
enum ads8688_range {
ADS8688_PLUSMINUS25VREF,
ADS8688_PLUSMINUS125VREF,
ADS8688_PLUSMINUS0625VREF,
ADS8688_PLUS25VREF,
ADS8688_PLUS125VREF,
};
struct ads8688_chip_info {
const struct iio_chan_spec *channels;
unsigned int num_channels;
};
struct ads8688_state {
struct mutex lock;
const struct ads8688_chip_info *chip_info;
struct spi_device *spi;
struct regulator *reg;
unsigned int vref_mv;
enum ads8688_range range[8];
union {
__be32 d32;
u8 d8[4];
} data[2] ____cacheline_aligned;
};
enum ads8688_id {
ID_ADS8684,
ID_ADS8688,
};
struct ads8688_ranges {
enum ads8688_range range;
unsigned int scale;
int offset;
u8 reg;
};
static const struct ads8688_ranges ads8688_range_def[5] = {
{
.range = ADS8688_PLUSMINUS25VREF,
.scale = 76295,
.offset = -(1 << (ADS8688_REALBITS - 1)),
.reg = ADS8688_REG_PLUSMINUS25VREF,
}, {
.range = ADS8688_PLUSMINUS125VREF,
.scale = 38148,
.offset = -(1 << (ADS8688_REALBITS - 1)),
.reg = ADS8688_REG_PLUSMINUS125VREF,
}, {
.range = ADS8688_PLUSMINUS0625VREF,
.scale = 19074,
.offset = -(1 << (ADS8688_REALBITS - 1)),
.reg = ADS8688_REG_PLUSMINUS0625VREF,
}, {
.range = ADS8688_PLUS25VREF,
.scale = 38148,
.offset = 0,
.reg = ADS8688_REG_PLUS25VREF,
}, {
.range = ADS8688_PLUS125VREF,
.scale = 19074,
.offset = 0,
.reg = ADS8688_REG_PLUS125VREF,
}
};
static ssize_t ads8688_show_scales(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct ads8688_state *st = iio_priv(dev_to_iio_dev(dev));
return sprintf(buf, "0.%09u 0.%09u 0.%09u\n",
ads8688_range_def[0].scale * st->vref_mv,
ads8688_range_def[1].scale * st->vref_mv,
ads8688_range_def[2].scale * st->vref_mv);
}
static ssize_t ads8688_show_offsets(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%d %d\n", ads8688_range_def[0].offset,
ads8688_range_def[3].offset);
}
static IIO_DEVICE_ATTR(in_voltage_scale_available, S_IRUGO,
ads8688_show_scales, NULL, 0);
static IIO_DEVICE_ATTR(in_voltage_offset_available, S_IRUGO,
ads8688_show_offsets, NULL, 0);
static struct attribute *ads8688_attributes[] = {
&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage_offset_available.dev_attr.attr,
NULL,
};
static const struct attribute_group ads8688_attribute_group = {
.attrs = ads8688_attributes,
};
#define ADS8688_CHAN(index) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = index, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \
| BIT(IIO_CHAN_INFO_SCALE) \
| BIT(IIO_CHAN_INFO_OFFSET), \
}
static const struct iio_chan_spec ads8684_channels[] = {
ADS8688_CHAN(0),
ADS8688_CHAN(1),
ADS8688_CHAN(2),
ADS8688_CHAN(3),
};
static const struct iio_chan_spec ads8688_channels[] = {
ADS8688_CHAN(0),
ADS8688_CHAN(1),
ADS8688_CHAN(2),
ADS8688_CHAN(3),
ADS8688_CHAN(4),
ADS8688_CHAN(5),
ADS8688_CHAN(6),
ADS8688_CHAN(7),
};
static int ads8688_prog_write(struct iio_dev *indio_dev, unsigned int addr,
unsigned int val)
{
struct ads8688_state *st = iio_priv(indio_dev);
u32 tmp;
tmp = ADS8688_PROG_REG(addr) | ADS8688_PROG_WR_BIT | val;
tmp <<= ADS8688_PROG_DONT_CARE_BITS;
st->data[0].d32 = cpu_to_be32(tmp);
return spi_write(st->spi, &st->data[0].d8[1], 3);
}
static int ads8688_reset(struct iio_dev *indio_dev)
{
struct ads8688_state *st = iio_priv(indio_dev);
u32 tmp;
tmp = ADS8688_CMD_REG(ADS8688_CMD_REG_RST);
tmp <<= ADS8688_CMD_DONT_CARE_BITS;
st->data[0].d32 = cpu_to_be32(tmp);
return spi_write(st->spi, &st->data[0].d8[0], 4);
}
static int ads8688_read(struct iio_dev *indio_dev, unsigned int chan)
{
struct ads8688_state *st = iio_priv(indio_dev);
int ret;
u32 tmp;
struct spi_transfer t[] = {
{
.tx_buf = &st->data[0].d8[0],
.len = 4,
.cs_change = 1,
}, {
.tx_buf = &st->data[1].d8[0],
.rx_buf = &st->data[1].d8[0],
.len = 4,
},
};
tmp = ADS8688_CMD_REG(ADS8688_CMD_REG_MAN_CH(chan));
tmp <<= ADS8688_CMD_DONT_CARE_BITS;
st->data[0].d32 = cpu_to_be32(tmp);
tmp = ADS8688_CMD_REG(ADS8688_CMD_REG_NOOP);
tmp <<= ADS8688_CMD_DONT_CARE_BITS;
st->data[1].d32 = cpu_to_be32(tmp);
ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
if (ret < 0)
return ret;
return be32_to_cpu(st->data[1].d32) & 0xffff;
}
static int ads8688_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long m)
{
int ret, offset;
unsigned long scale_mv;
struct ads8688_state *st = iio_priv(indio_dev);
mutex_lock(&st->lock);
switch (m) {
case IIO_CHAN_INFO_RAW:
ret = ads8688_read(indio_dev, chan->channel);
mutex_unlock(&st->lock);
if (ret < 0)
return ret;
*val = ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
scale_mv = st->vref_mv;
scale_mv *= ads8688_range_def[st->range[chan->channel]].scale;
*val = 0;
*val2 = scale_mv;
mutex_unlock(&st->lock);
return IIO_VAL_INT_PLUS_NANO;
case IIO_CHAN_INFO_OFFSET:
offset = ads8688_range_def[st->range[chan->channel]].offset;
*val = offset;
mutex_unlock(&st->lock);
return IIO_VAL_INT;
}
mutex_unlock(&st->lock);
return -EINVAL;
}
static int ads8688_write_reg_range(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
enum ads8688_range range)
{
unsigned int tmp;
int ret;
tmp = ADS8688_PROG_REG_RANGE_CH(chan->channel);
ret = ads8688_prog_write(indio_dev, tmp, range);
return ret;
}
static int ads8688_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct ads8688_state *st = iio_priv(indio_dev);
unsigned int scale = 0;
int ret = -EINVAL, i, offset = 0;
mutex_lock(&st->lock);
switch (mask) {
case IIO_CHAN_INFO_SCALE:
/* If the offset is 0 the ±2.5 * VREF mode is not available */
offset = ads8688_range_def[st->range[chan->channel]].offset;
if (offset == 0 && val2 == ads8688_range_def[0].scale * st->vref_mv) {
mutex_unlock(&st->lock);
return -EINVAL;
}
/* Lookup new mode */
for (i = 0; i < ARRAY_SIZE(ads8688_range_def); i++)
if (val2 == ads8688_range_def[i].scale * st->vref_mv &&
offset == ads8688_range_def[i].offset) {
ret = ads8688_write_reg_range(indio_dev, chan,
ads8688_range_def[i].reg);
break;
}
break;
case IIO_CHAN_INFO_OFFSET:
/*
* There are only two available offsets:
* 0 and -(1 << (ADS8688_REALBITS - 1))
*/
if (!(ads8688_range_def[0].offset == val ||
ads8688_range_def[3].offset == val)) {
mutex_unlock(&st->lock);
return -EINVAL;
}
/*
* If the device are in ±2.5 * VREF mode, it's not allowed to
* switch to a mode where the offset is 0
*/
if (val == 0 &&
st->range[chan->channel] == ADS8688_PLUSMINUS25VREF) {
mutex_unlock(&st->lock);
return -EINVAL;
}
scale = ads8688_range_def[st->range[chan->channel]].scale;
/* Lookup new mode */
for (i = 0; i < ARRAY_SIZE(ads8688_range_def); i++)
if (val == ads8688_range_def[i].offset &&
scale == ads8688_range_def[i].scale) {
ret = ads8688_write_reg_range(indio_dev, chan,
ads8688_range_def[i].reg);
break;
}
break;
}
if (!ret)
st->range[chan->channel] = ads8688_range_def[i].range;
mutex_unlock(&st->lock);
return ret;
}
static int ads8688_write_raw_get_fmt(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
long mask)
{
switch (mask) {
case IIO_CHAN_INFO_SCALE:
return IIO_VAL_INT_PLUS_NANO;
case IIO_CHAN_INFO_OFFSET:
return IIO_VAL_INT;
}
return -EINVAL;
}
static const struct iio_info ads8688_info = {
.read_raw = &ads8688_read_raw,
.write_raw = &ads8688_write_raw,
.write_raw_get_fmt = &ads8688_write_raw_get_fmt,
.attrs = &ads8688_attribute_group,
.driver_module = THIS_MODULE,
};
static const struct ads8688_chip_info ads8688_chip_info_tbl[] = {
[ID_ADS8684] = {
.channels = ads8684_channels,
.num_channels = ARRAY_SIZE(ads8684_channels),
},
[ID_ADS8688] = {
.channels = ads8688_channels,
.num_channels = ARRAY_SIZE(ads8688_channels),
},
};
static int ads8688_probe(struct spi_device *spi)
{
struct ads8688_state *st;
struct iio_dev *indio_dev;
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (indio_dev == NULL)
return -ENOMEM;
st = iio_priv(indio_dev);
st->reg = devm_regulator_get_optional(&spi->dev, "vref");
if (!IS_ERR(st->reg)) {
ret = regulator_enable(st->reg);
if (ret)
return ret;
ret = regulator_get_voltage(st->reg);
if (ret < 0)
goto error_out;
st->vref_mv = ret / 1000;
} else {
/* Use internal reference */
st->vref_mv = ADS8688_VREF_MV;
}
st->chip_info = &ads8688_chip_info_tbl[spi_get_device_id(spi)->driver_data];
spi->mode = SPI_MODE_1;
spi_set_drvdata(spi, indio_dev);
st->spi = spi;
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->dev.parent = &spi->dev;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = st->chip_info->channels;
indio_dev->num_channels = st->chip_info->num_channels;
indio_dev->info = &ads8688_info;
ads8688_reset(indio_dev);
mutex_init(&st->lock);
ret = iio_device_register(indio_dev);
if (ret)
goto error_out;
return 0;
error_out:
if (!IS_ERR_OR_NULL(st->reg))
regulator_disable(st->reg);
return ret;
}
static int ads8688_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct ads8688_state *st = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
if (!IS_ERR_OR_NULL(st->reg))
regulator_disable(st->reg);
return 0;
}
static const struct spi_device_id ads8688_id[] = {
{"ads8684", ID_ADS8684},
{"ads8688", ID_ADS8688},
{}
};
MODULE_DEVICE_TABLE(spi, ads8688_id);
static const struct of_device_id ads8688_of_match[] = {
{ .compatible = "ti,ads8684" },
{ .compatible = "ti,ads8688" },
{ }
};
MODULE_DEVICE_TABLE(of, ads8688_of_match);
static struct spi_driver ads8688_driver = {
.driver = {
.name = "ads8688",
.owner = THIS_MODULE,
},
.probe = ads8688_probe,
.remove = ads8688_remove,
.id_table = ads8688_id,
};
module_spi_driver(ads8688_driver);
MODULE_AUTHOR("Sean Nyekjaer <sean.nyekjaer@prevas.dk>");
MODULE_DESCRIPTION("Texas Instruments ADS8688 driver");
MODULE_LICENSE("GPL v2");