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iio: adc: Add TI ADS1100 and ADS1000

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The ADS1100 is a 16-bit ADC (at 8 samples per second).
The ADS1000 is similar, but has a fixed data rate.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230307065535.7927-2-mike.looijmans@topic.nl
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Mike Looijmans 2023-03-07 07:55:34 +01:00 committed by Jonathan Cameron
parent f8c64b146c
commit 541880542f
3 changed files with 456 additions and 0 deletions
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10
drivers/iio/adc/Kconfig
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@ -1229,6 +1229,16 @@ config TI_ADS7924
This driver can also be built as a module. If so, the module will be
called ti-ads7924.
config TI_ADS1100
tristate "Texas Instruments ADS1100 and ADS1000 ADC"
depends on I2C
help
If you say yes here you get support for Texas Instruments ADS1100 and
ADS1000 ADC chips.
This driver can also be built as a module. If so, the module will be
called ti-ads1100.
config TI_ADS7950
tristate "Texas Instruments ADS7950 ADC driver"
depends on SPI && GPIOLIB

1
drivers/iio/adc/Makefile
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@ -108,6 +108,7 @@ obj-$(CONFIG_TI_ADC108S102) += ti-adc108s102.o
obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
obj-$(CONFIG_TI_ADC161S626) += ti-adc161s626.o
obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
obj-$(CONFIG_TI_ADS1100) += ti-ads1100.o
obj-$(CONFIG_TI_ADS7924) += ti-ads7924.o
obj-$(CONFIG_TI_ADS7950) += ti-ads7950.o
obj-$(CONFIG_TI_ADS8344) += ti-ads8344.o

445
drivers/iio/adc/ti-ads1100.c Normal file
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@ -0,0 +1,445 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* ADS1100 - Texas Instruments Analog-to-Digital Converter
*
* Copyright (c) 2023, Topic Embedded Products
*
* Datasheet: https://www.ti.com/lit/gpn/ads1100
* IIO driver for ADS1100 and ADS1000 ADC 16-bit I2C
*/
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/property.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
#include <linux/units.h>
#include <linux/iio/iio.h>
#include <linux/iio/types.h>
/* The ADS1100 has a single byte config register */
/* Conversion in progress bit */
#define ADS1100_CFG_ST_BSY BIT(7)
/* Single conversion bit */
#define ADS1100_CFG_SC BIT(4)
/* Data rate */
#define ADS1100_DR_MASK GENMASK(3, 2)
/* Gain */
#define ADS1100_PGA_MASK GENMASK(1, 0)
#define ADS1100_CONTINUOUS 0
#define ADS1100_SINGLESHOT ADS1100_CFG_SC
#define ADS1100_SLEEP_DELAY_MS 2000
static const int ads1100_data_rate[] = { 128, 32, 16, 8 };
static const int ads1100_data_rate_bits[] = { 12, 14, 15, 16 };
struct ads1100_data {
struct i2c_client *client;
struct regulator *reg_vdd;
struct mutex lock;
int scale_avail[2 * 4]; /* 4 gain settings */
u8 config;
bool supports_data_rate; /* Only the ADS1100 can select the rate */
};
static const struct iio_chan_spec ads1100_channel = {
.type = IIO_VOLTAGE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_all =
BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
.info_mask_shared_by_all_available =
BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
.scan_type = {
.sign = 's',
.realbits = 16,
.storagebits = 16,
.endianness = IIO_CPU,
},
.datasheet_name = "AIN",
};
static int ads1100_set_config_bits(struct ads1100_data *data, u8 mask, u8 value)
{
int ret;
u8 config = (data->config & ~mask) | (value & mask);
if (data->config == config)
return 0; /* Already done */
ret = i2c_master_send(data->client, &config, 1);
if (ret < 0)
return ret;
data->config = config;
return 0;
};
static int ads1100_data_bits(struct ads1100_data *data)
{
return ads1100_data_rate_bits[FIELD_GET(ADS1100_DR_MASK, data->config)];
}
static int ads1100_get_adc_result(struct ads1100_data *data, int chan, int *val)
{
int ret;
__be16 buffer;
s16 value;
if (chan != 0)
return -EINVAL;
ret = pm_runtime_resume_and_get(&data->client->dev);
if (ret < 0)
return ret;
ret = i2c_master_recv(data->client, (char *)&buffer, sizeof(buffer));
pm_runtime_mark_last_busy(&data->client->dev);
pm_runtime_put_autosuspend(&data->client->dev);
if (ret < 0) {
dev_err(&data->client->dev, "I2C read fail: %d\n", ret);
return ret;
}
/* Value is always 16-bit 2's complement */
value = be16_to_cpu(buffer);
/* Shift result to compensate for bit resolution vs. sample rate */
value <<= 16 - ads1100_data_bits(data);
*val = sign_extend32(value, 15);
return 0;
}
static int ads1100_set_scale(struct ads1100_data *data, int val, int val2)
{
int microvolts;
int gain;
/* With Vdd between 2.7 and 5V, the scale is always below 1 */
if (val)
return -EINVAL;
if (!val2)
return -EINVAL;
microvolts = regulator_get_voltage(data->reg_vdd);
/*
* val2 is in 'micro' units, n = val2 / 1000000
* result must be millivolts, d = microvolts / 1000
* the full-scale value is d/n, corresponds to 2^15,
* hence the gain = (d / n) >> 15, factoring out the 1000 and moving the
* bitshift so everything fits in 32-bits yields this formula.
*/
gain = DIV_ROUND_CLOSEST(microvolts, BIT(15)) * MILLI / val2;
if (gain < BIT(0) || gain > BIT(3))
return -EINVAL;
ads1100_set_config_bits(data, ADS1100_PGA_MASK, ffs(gain) - 1);
return 0;
}
static int ads1100_set_data_rate(struct ads1100_data *data, int chan, int rate)
{
unsigned int i;
unsigned int size;
size = data->supports_data_rate ? ARRAY_SIZE(ads1100_data_rate) : 1;
for (i = 0; i < size; i++) {
if (ads1100_data_rate[i] == rate)
return ads1100_set_config_bits(data, ADS1100_DR_MASK,
FIELD_PREP(ADS1100_DR_MASK, i));
}
return -EINVAL;
}
static int ads1100_get_vdd_millivolts(struct ads1100_data *data)
{
return regulator_get_voltage(data->reg_vdd) / (MICRO / MILLI);
}
static void ads1100_calc_scale_avail(struct ads1100_data *data)
{
int millivolts = ads1100_get_vdd_millivolts(data);
unsigned int i;
for (i = 0; i < ARRAY_SIZE(data->scale_avail) / 2; i++) {
data->scale_avail[i * 2 + 0] = millivolts;
data->scale_avail[i * 2 + 1] = 15 + i;
}
}
static int ads1100_read_avail(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
const int **vals, int *type, int *length,
long mask)
{
struct ads1100_data *data = iio_priv(indio_dev);
if (chan->type != IIO_VOLTAGE)
return -EINVAL;
switch (mask) {
case IIO_CHAN_INFO_SAMP_FREQ:
*type = IIO_VAL_INT;
*vals = ads1100_data_rate;
if (data->supports_data_rate)
*length = ARRAY_SIZE(ads1100_data_rate);
else
*length = 1;
return IIO_AVAIL_LIST;
case IIO_CHAN_INFO_SCALE:
*type = IIO_VAL_FRACTIONAL_LOG2;
*vals = data->scale_avail;
*length = ARRAY_SIZE(data->scale_avail);
return IIO_AVAIL_LIST;
default:
return -EINVAL;
}
}
static int ads1100_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
{
int ret;
struct ads1100_data *data = iio_priv(indio_dev);
mutex_lock(&data->lock);
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
break;
ret = ads1100_get_adc_result(data, chan->address, val);
if (ret >= 0)
ret = IIO_VAL_INT;
iio_device_release_direct_mode(indio_dev);
break;
case IIO_CHAN_INFO_SCALE:
/* full-scale is the supply voltage in millivolts */
*val = ads1100_get_vdd_millivolts(data);
*val2 = 15 + FIELD_GET(ADS1100_PGA_MASK, data->config);
ret = IIO_VAL_FRACTIONAL_LOG2;
break;
case IIO_CHAN_INFO_SAMP_FREQ:
*val = ads1100_data_rate[FIELD_GET(ADS1100_DR_MASK,
data->config)];
ret = IIO_VAL_INT;
break;
default:
ret = -EINVAL;
break;
}
mutex_unlock(&data->lock);
return ret;
}
static int ads1100_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int val,
int val2, long mask)
{
struct ads1100_data *data = iio_priv(indio_dev);
int ret;
mutex_lock(&data->lock);
switch (mask) {
case IIO_CHAN_INFO_SCALE:
ret = ads1100_set_scale(data, val, val2);
break;
case IIO_CHAN_INFO_SAMP_FREQ:
ret = ads1100_set_data_rate(data, chan->address, val);
break;
default:
ret = -EINVAL;
break;
}
mutex_unlock(&data->lock);
return ret;
}
static const struct iio_info ads1100_info = {
.read_avail = ads1100_read_avail,
.read_raw = ads1100_read_raw,
.write_raw = ads1100_write_raw,
};
static int ads1100_setup(struct ads1100_data *data)
{
int ret;
u8 buffer[3];
/* Setup continuous sampling mode at 8sps */
buffer[0] = ADS1100_DR_MASK | ADS1100_CONTINUOUS;
ret = i2c_master_send(data->client, buffer, 1);
if (ret < 0)
return ret;
ret = i2c_master_recv(data->client, buffer, sizeof(buffer));
if (ret < 0)
return ret;
/* Config register returned in third byte, strip away the busy status */
data->config = buffer[2] & ~ADS1100_CFG_ST_BSY;
/* Detect the sample rate capability by checking the DR bits */
data->supports_data_rate = FIELD_GET(ADS1100_DR_MASK, buffer[2]) != 0;
return 0;
}
static void ads1100_reg_disable(void *reg)
{
regulator_disable(reg);
}
static void ads1100_disable_continuous(void *data)
{
ads1100_set_config_bits(data, ADS1100_CFG_SC, ADS1100_SINGLESHOT);
}
static int ads1100_probe(struct i2c_client *client)
{
struct iio_dev *indio_dev;
struct ads1100_data *data;
struct device *dev = &client->dev;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
dev_set_drvdata(dev, data);
data->client = client;
mutex_init(&data->lock);
indio_dev->name = "ads1100";
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = &ads1100_channel;
indio_dev->num_channels = 1;
indio_dev->info = &ads1100_info;
data->reg_vdd = devm_regulator_get(dev, "vdd");
if (IS_ERR(data->reg_vdd))
return dev_err_probe(dev, PTR_ERR(data->reg_vdd),
"Failed to get vdd regulator\n");
ret = regulator_enable(data->reg_vdd);
if (ret < 0)
return dev_err_probe(dev, PTR_ERR(data->reg_vdd),
"Failed to enable vdd regulator\n");
ret = devm_add_action_or_reset(dev, ads1100_reg_disable, data->reg_vdd);
if (ret)
return ret;
ret = ads1100_setup(data);
if (ret)
return dev_err_probe(dev, ret,
"Failed to communicate with device\n");
ret = devm_add_action_or_reset(dev, ads1100_disable_continuous, data);
if (ret)
return ret;
ads1100_calc_scale_avail(data);
pm_runtime_set_autosuspend_delay(dev, ADS1100_SLEEP_DELAY_MS);
pm_runtime_use_autosuspend(dev);
pm_runtime_set_active(dev);
ret = devm_pm_runtime_enable(dev);
if (ret)
return dev_err_probe(dev, ret, "Failed to enable pm_runtime\n");
ret = devm_iio_device_register(dev, indio_dev);
if (ret)
return dev_err_probe(dev, ret,
"Failed to register IIO device\n");
return 0;
}
static int ads1100_runtime_suspend(struct device *dev)
{
struct ads1100_data *data = dev_get_drvdata(dev);
ads1100_set_config_bits(data, ADS1100_CFG_SC, ADS1100_SINGLESHOT);
regulator_disable(data->reg_vdd);
return 0;
}
static int ads1100_runtime_resume(struct device *dev)
{
struct ads1100_data *data = dev_get_drvdata(dev);
int ret;
ret = regulator_enable(data->reg_vdd);
if (ret) {
dev_err(&data->client->dev, "Failed to enable Vdd\n");
return ret;
}
/*
* We'll always change the mode bit in the config register, so there is
* no need here to "force" a write to the config register. If the device
* has been power-cycled, we'll re-write its config register now.
*/
return ads1100_set_config_bits(data, ADS1100_CFG_SC,
ADS1100_CONTINUOUS);
}
static DEFINE_RUNTIME_DEV_PM_OPS(ads1100_pm_ops,
ads1100_runtime_suspend,
ads1100_runtime_resume,
NULL);
static const struct i2c_device_id ads1100_id[] = {
{ "ads1100" },
{ "ads1000" },
{ }
};
MODULE_DEVICE_TABLE(i2c, ads1100_id);
static const struct of_device_id ads1100_of_match[] = {
{.compatible = "ti,ads1100" },
{.compatible = "ti,ads1000" },
{ }
};
MODULE_DEVICE_TABLE(of, ads1100_of_match);
static struct i2c_driver ads1100_driver = {
.driver = {
.name = "ads1100",
.of_match_table = ads1100_of_match,
.pm = pm_ptr(&ads1100_pm_ops),
},
.probe_new = ads1100_probe,
.id_table = ads1100_id,
};
module_i2c_driver(ads1100_driver);
MODULE_AUTHOR("Mike Looijmans <mike.looijmans@topic.nl>");
MODULE_DESCRIPTION("Texas Instruments ADS1100 ADC driver");
MODULE_LICENSE("GPL");