/*
* ADC12130/ADC12132/ADC12138 12-bit plus sign ADC driver
*
* Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*
* Datasheet: http://www.ti.com/lit/ds/symlink/adc12138.pdf
*/
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/clk.h>
#include <linux/spi/spi.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/regulator/consumer.h>
#define ADC12138_MODE_AUTO_CAL 0x08
#define ADC12138_MODE_READ_STATUS 0x0c
#define ADC12138_MODE_ACQUISITION_TIME_6 0x0e
#define ADC12138_MODE_ACQUISITION_TIME_10 0x4e
#define ADC12138_MODE_ACQUISITION_TIME_18 0x8e
#define ADC12138_MODE_ACQUISITION_TIME_34 0xce
#define ADC12138_STATUS_CAL BIT(6)
enum {
adc12130,
adc12132,
adc12138,
};
struct adc12138 {
struct spi_device *spi;
unsigned int id;
/* conversion clock */
struct clk *cclk;
/* positive analog voltage reference */
struct regulator *vref_p;
/* negative analog voltage reference */
struct regulator *vref_n;
struct mutex lock;
struct completion complete;
/* The number of cclk periods for the S/H's acquisition time */
unsigned int acquisition_time;
u8 tx_buf[2] ____cacheline_aligned;
u8 rx_buf[2];
};
#define ADC12138_VOLTAGE_CHANNEL(chan) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = chan, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
| BIT(IIO_CHAN_INFO_OFFSET), \
.scan_index = chan, \
.scan_type = { \
.sign = 's', \
.realbits = 13, \
.storagebits = 16, \
.shift = 3, \
.endianness = IIO_BE, \
}, \
}
#define ADC12138_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (chan1), \
.channel2 = (chan2), \
.differential = 1, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
| BIT(IIO_CHAN_INFO_OFFSET), \
.scan_index = si, \
.scan_type = { \
.sign = 's', \
.realbits = 13, \
.storagebits = 16, \
.shift = 3, \
.endianness = IIO_BE, \
}, \
}
static const struct iio_chan_spec adc12132_channels[] = {
ADC12138_VOLTAGE_CHANNEL(0),
ADC12138_VOLTAGE_CHANNEL(1),
ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 2),
ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 3),
IIO_CHAN_SOFT_TIMESTAMP(4),
};
static const struct iio_chan_spec adc12138_channels[] = {
ADC12138_VOLTAGE_CHANNEL(0),
ADC12138_VOLTAGE_CHANNEL(1),
ADC12138_VOLTAGE_CHANNEL(2),
ADC12138_VOLTAGE_CHANNEL(3),
ADC12138_VOLTAGE_CHANNEL(4),
ADC12138_VOLTAGE_CHANNEL(5),
ADC12138_VOLTAGE_CHANNEL(6),
ADC12138_VOLTAGE_CHANNEL(7),
ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 9),
ADC12138_VOLTAGE_CHANNEL_DIFF(2, 3, 10),
ADC12138_VOLTAGE_CHANNEL_DIFF(3, 2, 11),
ADC12138_VOLTAGE_CHANNEL_DIFF(4, 5, 12),
ADC12138_VOLTAGE_CHANNEL_DIFF(5, 4, 13),
ADC12138_VOLTAGE_CHANNEL_DIFF(6, 7, 14),
ADC12138_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
IIO_CHAN_SOFT_TIMESTAMP(16),
};
static int adc12138_mode_programming(struct adc12138 *adc, u8 mode,
void *rx_buf, int len)
{
struct spi_transfer xfer = {
.tx_buf = adc->tx_buf,
.rx_buf = adc->rx_buf,
.len = len,
};
int ret;
/* Skip unused bits for ADC12130 and ADC12132 */
if (adc->id != adc12138)
mode = (mode & 0xc0) | ((mode & 0x0f) << 2);
adc->tx_buf[0] = mode;
ret = spi_sync_transfer(adc->spi, &xfer, 1);
if (ret)
return ret;
memcpy(rx_buf, adc->rx_buf, len);
return 0;
}
static int adc12138_read_status(struct adc12138 *adc)
{
u8 rx_buf[2];
int ret;
ret = adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
rx_buf, 2);
if (ret)
return ret;
return (rx_buf[0] << 1) | (rx_buf[1] >> 7);
}
static int __adc12138_start_conv(struct adc12138 *adc,
struct iio_chan_spec const *channel,
void *data, int len)
{
const u8 ch_to_mux[] = { 0, 4, 1, 5, 2, 6, 3, 7 };
u8 mode = (ch_to_mux[channel->channel] << 4) |
(channel->differential ? 0 : 0x80);
return adc12138_mode_programming(adc, mode, data, len);
}
static int adc12138_start_conv(struct adc12138 *adc,
struct iio_chan_spec const *channel)
{
u8 trash;
return __adc12138_start_conv(adc, channel, &trash, 1);
}
static int adc12138_start_and_read_conv(struct adc12138 *adc,
struct iio_chan_spec const *channel,
__be16 *data)
{
return __adc12138_start_conv(adc, channel, data, 2);
}
static int adc12138_read_conv_data(struct adc12138 *adc, __be16 *value)
{
/* Issue a read status instruction and read previous conversion data */
return adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
value, sizeof(*value));
}
static int adc12138_wait_eoc(struct adc12138 *adc, unsigned long timeout)
{
if (!wait_for_completion_timeout(&adc->complete, timeout))
return -ETIMEDOUT;
return 0;
}
static int adc12138_adc_conversion(struct adc12138 *adc,
struct iio_chan_spec const *channel,
__be16 *value)
{
int ret;
reinit_completion(&adc->complete);
ret = adc12138_start_conv(adc, channel);
if (ret)
return ret;
ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
if (ret)
return ret;
return adc12138_read_conv_data(adc, value);
}
static int adc12138_read_raw(struct iio_dev *iio,
struct iio_chan_spec const *channel, int *value,
int *shift, long mask)
{
struct adc12138 *adc = iio_priv(iio);
int ret;
__be16 data;
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&adc->lock);
ret = adc12138_adc_conversion(adc, channel, &data);
mutex_unlock(&adc->lock);
if (ret)
return ret;
*value = sign_extend32(be16_to_cpu(data) >> 3, 12);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
ret = regulator_get_voltage(adc->vref_p);
if (ret < 0)
return ret;
*value = ret;
if (!IS_ERR(adc->vref_n)) {
ret = regulator_get_voltage(adc->vref_n);
if (ret < 0)
return ret;
*value -= ret;
}
/* convert regulator output voltage to mV */
*value /= 1000;
*shift = channel->scan_type.realbits - 1;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_OFFSET:
if (!IS_ERR(adc->vref_n)) {
*value = regulator_get_voltage(adc->vref_n);
if (*value < 0)
return *value;
} else {
*value = 0;
}
/* convert regulator output voltage to mV */
*value /= 1000;
return IIO_VAL_INT;
}
return -EINVAL;
}
static const struct iio_info adc12138_info = {
.read_raw = adc12138_read_raw,
.driver_module = THIS_MODULE,
};
static int adc12138_init(struct adc12138 *adc)
{
int ret;
int status;
u8 mode;
u8 trash;
reinit_completion(&adc->complete);
ret = adc12138_mode_programming(adc, ADC12138_MODE_AUTO_CAL, &trash, 1);
if (ret)
return ret;
/* data output at this time has no significance */
status = adc12138_read_status(adc);
if (status < 0)
return status;
adc12138_wait_eoc(adc, msecs_to_jiffies(100));
status = adc12138_read_status(adc);
if (status & ADC12138_STATUS_CAL) {
dev_warn(&adc->spi->dev,
"Auto Cal sequence is still in progress: %#x\n",
status);
return -EIO;
}
switch (adc->acquisition_time) {
case 6:
mode = ADC12138_MODE_ACQUISITION_TIME_6;
break;
case 10:
mode = ADC12138_MODE_ACQUISITION_TIME_10;
break;
case 18:
mode = ADC12138_MODE_ACQUISITION_TIME_18;
break;
case 34:
mode = ADC12138_MODE_ACQUISITION_TIME_34;
break;
default:
return -EINVAL;
}
return adc12138_mode_programming(adc, mode, &trash, 1);
}
static irqreturn_t adc12138_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct adc12138 *adc = iio_priv(indio_dev);
__be16 data[20] = { }; /* 16x 2 bytes ADC data + 8 bytes timestamp */
__be16 trash;
int ret;
int scan_index;
int i = 0;
mutex_lock(&adc->lock);
for_each_set_bit(scan_index, indio_dev->active_scan_mask,
indio_dev->masklength) {
const struct iio_chan_spec *scan_chan =
&indio_dev->channels[scan_index];
reinit_completion(&adc->complete);
ret = adc12138_start_and_read_conv(adc, scan_chan,
i ? &data[i - 1] : &trash);
if (ret) {
dev_warn(&adc->spi->dev,
"failed to start conversion\n");
goto out;
}
ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
if (ret) {
dev_warn(&adc->spi->dev, "wait eoc timeout\n");
goto out;
}
i++;
}
if (i) {
ret = adc12138_read_conv_data(adc, &data[i - 1]);
if (ret) {
dev_warn(&adc->spi->dev,
"failed to get conversion data\n");
goto out;
}
}
iio_push_to_buffers_with_timestamp(indio_dev, data,
iio_get_time_ns(indio_dev));
out:
mutex_unlock(&adc->lock);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static irqreturn_t adc12138_eoc_handler(int irq, void *p)
{
struct iio_dev *indio_dev = p;
struct adc12138 *adc = iio_priv(indio_dev);
complete(&adc->complete);
return IRQ_HANDLED;
}
static int adc12138_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct adc12138 *adc;
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
if (!indio_dev)
return -ENOMEM;
adc = iio_priv(indio_dev);
adc->spi = spi;
adc->id = spi_get_device_id(spi)->driver_data;
mutex_init(&adc->lock);
init_completion(&adc->complete);
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->dev.parent = &spi->dev;
indio_dev->info = &adc12138_info;
indio_dev->modes = INDIO_DIRECT_MODE;
switch (adc->id) {
case adc12130:
case adc12132:
indio_dev->channels = adc12132_channels;
indio_dev->num_channels = ARRAY_SIZE(adc12132_channels);
break;
case adc12138:
indio_dev->channels = adc12138_channels;
indio_dev->num_channels = ARRAY_SIZE(adc12138_channels);
break;
default:
return -EINVAL;
}
ret = of_property_read_u32(spi->dev.of_node, "ti,acquisition-time",
&adc->acquisition_time);
if (ret)
adc->acquisition_time = 10;
adc->cclk = devm_clk_get(&spi->dev, NULL);
if (IS_ERR(adc->cclk))
return PTR_ERR(adc->cclk);
adc->vref_p = devm_regulator_get(&spi->dev, "vref-p");
if (IS_ERR(adc->vref_p))
return PTR_ERR(adc->vref_p);
adc->vref_n = devm_regulator_get_optional(&spi->dev, "vref-n");
if (IS_ERR(adc->vref_n)) {
/*
* Assume vref_n is 0V if an optional regulator is not
* specified, otherwise return the error code.
*/
ret = PTR_ERR(adc->vref_n);
if (ret != -ENODEV)
return ret;
}
ret = devm_request_irq(&spi->dev, spi->irq, adc12138_eoc_handler,
IRQF_TRIGGER_RISING, indio_dev->name, indio_dev);
if (ret)
return ret;
ret = clk_prepare_enable(adc->cclk);
if (ret)
return ret;
ret = regulator_enable(adc->vref_p);
if (ret)
goto err_clk_disable;
if (!IS_ERR(adc->vref_n)) {
ret = regulator_enable(adc->vref_n);
if (ret)
goto err_vref_p_disable;
}
ret = adc12138_init(adc);
if (ret)
goto err_vref_n_disable;
spi_set_drvdata(spi, indio_dev);
ret = iio_triggered_buffer_setup(indio_dev, NULL,
adc12138_trigger_handler, NULL);
if (ret)
goto err_vref_n_disable;
ret = iio_device_register(indio_dev);
if (ret)
goto err_buffer_cleanup;
return 0;
err_buffer_cleanup:
iio_triggered_buffer_cleanup(indio_dev);
err_vref_n_disable:
if (!IS_ERR(adc->vref_n))
regulator_disable(adc->vref_n);
err_vref_p_disable:
regulator_disable(adc->vref_p);
err_clk_disable:
clk_disable_unprepare(adc->cclk);
return ret;
}
static int adc12138_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct adc12138 *adc = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
if (!IS_ERR(adc->vref_n))
regulator_disable(adc->vref_n);
regulator_disable(adc->vref_p);
clk_disable_unprepare(adc->cclk);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id adc12138_dt_ids[] = {
{ .compatible = "ti,adc12130", },
{ .compatible = "ti,adc12132", },
{ .compatible = "ti,adc12138", },
{}
};
MODULE_DEVICE_TABLE(of, adc12138_dt_ids);
#endif
static const struct spi_device_id adc12138_id[] = {
{ "adc12130", adc12130 },
{ "adc12132", adc12132 },
{ "adc12138", adc12138 },
{}
};
MODULE_DEVICE_TABLE(spi, adc12138_id);
static struct spi_driver adc12138_driver = {
.driver = {
.name = "adc12138",
.of_match_table = of_match_ptr(adc12138_dt_ids),
},
.probe = adc12138_probe,
.remove = adc12138_remove,
.id_table = adc12138_id,
};
module_spi_driver(adc12138_driver);
MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
MODULE_DESCRIPTION("ADC12130/ADC12132/ADC12138 driver");
MODULE_LICENSE("GPL v2");