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linux/drivers/iio/adc/ti-ads8344.c
Jonathan Cameron 09e3bdfe49 iio: adc: standardize on formatting for id match tables
This is a frequent minor comment in reviews, so start cleaning up
existing drivers in the hope we get fewer cases of cut and paste.

There are not kernel wide rules for these, but for IIO the style
that I prefer (and hence most common) is:

- Space after { and before }
- No comma after terminator { }

This may cause merge conflicts but they should be trivial to resolve
hence I have not broken this into per driver patches.

Link: https://patch.msgid.link/20240818180912.719399-1-jic23@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2024-09-05 19:27:13 +01:00

194 lines
4.6 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* ADS8344 16-bit 8-Channel ADC driver
*
* Author: Gregory CLEMENT <gregory.clement@bootlin.com>
*
* Datasheet: https://www.ti.com/lit/ds/symlink/ads8344.pdf
*/
#include <linux/delay.h>
#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#define ADS8344_START BIT(7)
#define ADS8344_SINGLE_END BIT(2)
#define ADS8344_CHANNEL(channel) ((channel) << 4)
#define ADS8344_CLOCK_INTERNAL 0x2 /* PD1 = 1 and PD0 = 0 */
struct ads8344 {
struct spi_device *spi;
struct regulator *reg;
/*
* Lock protecting access to adc->tx_buff and rx_buff,
* especially from concurrent read on sysfs file.
*/
struct mutex lock;
u8 tx_buf __aligned(IIO_DMA_MINALIGN);
u8 rx_buf[3];
};
#define ADS8344_VOLTAGE_CHANNEL(chan, addr) \
{ \
.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), \
.address = addr, \
}
#define ADS8344_VOLTAGE_CHANNEL_DIFF(chan1, chan2, addr) \
{ \
.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), \
.address = addr, \
}
static const struct iio_chan_spec ads8344_channels[] = {
ADS8344_VOLTAGE_CHANNEL(0, 0),
ADS8344_VOLTAGE_CHANNEL(1, 4),
ADS8344_VOLTAGE_CHANNEL(2, 1),
ADS8344_VOLTAGE_CHANNEL(3, 5),
ADS8344_VOLTAGE_CHANNEL(4, 2),
ADS8344_VOLTAGE_CHANNEL(5, 6),
ADS8344_VOLTAGE_CHANNEL(6, 3),
ADS8344_VOLTAGE_CHANNEL(7, 7),
ADS8344_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
ADS8344_VOLTAGE_CHANNEL_DIFF(2, 3, 9),
ADS8344_VOLTAGE_CHANNEL_DIFF(4, 5, 10),
ADS8344_VOLTAGE_CHANNEL_DIFF(6, 7, 11),
ADS8344_VOLTAGE_CHANNEL_DIFF(1, 0, 12),
ADS8344_VOLTAGE_CHANNEL_DIFF(3, 2, 13),
ADS8344_VOLTAGE_CHANNEL_DIFF(5, 4, 14),
ADS8344_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
};
static int ads8344_adc_conversion(struct ads8344 *adc, int channel,
bool differential)
{
struct spi_device *spi = adc->spi;
int ret;
adc->tx_buf = ADS8344_START;
if (!differential)
adc->tx_buf |= ADS8344_SINGLE_END;
adc->tx_buf |= ADS8344_CHANNEL(channel);
adc->tx_buf |= ADS8344_CLOCK_INTERNAL;
ret = spi_write(spi, &adc->tx_buf, 1);
if (ret)
return ret;
udelay(9);
ret = spi_read(spi, adc->rx_buf, sizeof(adc->rx_buf));
if (ret)
return ret;
return adc->rx_buf[0] << 9 | adc->rx_buf[1] << 1 | adc->rx_buf[2] >> 7;
}
static int ads8344_read_raw(struct iio_dev *iio,
struct iio_chan_spec const *channel, int *value,
int *shift, long mask)
{
struct ads8344 *adc = iio_priv(iio);
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&adc->lock);
*value = ads8344_adc_conversion(adc, channel->address,
channel->differential);
mutex_unlock(&adc->lock);
if (*value < 0)
return *value;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*value = regulator_get_voltage(adc->reg);
if (*value < 0)
return *value;
/* convert regulator output voltage to mV */
*value /= 1000;
*shift = 16;
return IIO_VAL_FRACTIONAL_LOG2;
default:
return -EINVAL;
}
}
static const struct iio_info ads8344_info = {
.read_raw = ads8344_read_raw,
};
static void ads8344_reg_disable(void *data)
{
regulator_disable(data);
}
static int ads8344_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct ads8344 *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;
mutex_init(&adc->lock);
indio_dev->name = dev_name(&spi->dev);
indio_dev->info = &ads8344_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = ads8344_channels;
indio_dev->num_channels = ARRAY_SIZE(ads8344_channels);
adc->reg = devm_regulator_get(&spi->dev, "vref");
if (IS_ERR(adc->reg))
return PTR_ERR(adc->reg);
ret = regulator_enable(adc->reg);
if (ret)
return ret;
ret = devm_add_action_or_reset(&spi->dev, ads8344_reg_disable, adc->reg);
if (ret)
return ret;
return devm_iio_device_register(&spi->dev, indio_dev);
}
static const struct of_device_id ads8344_of_match[] = {
{ .compatible = "ti,ads8344", },
{ }
};
MODULE_DEVICE_TABLE(of, ads8344_of_match);
static struct spi_driver ads8344_driver = {
.driver = {
.name = "ads8344",
.of_match_table = ads8344_of_match,
},
.probe = ads8344_probe,
};
module_spi_driver(ads8344_driver);
MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@bootlin.com>");
MODULE_DESCRIPTION("ADS8344 driver");
MODULE_LICENSE("GPL");