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iio: adc: Add driver for the TI ADS8344 A/DC chips
This adds support for the Texas Instruments ADS8344 ADC chip. This chip has a 16-bit 8-Channel ADC and is access directly through SPI. Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Gregory CLEMENT
Jonathan Cameron
parent
65c7a3d2cf
commit
8dd2d7c0fe
@ -979,6 +979,16 @@ config TI_ADS7950
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To compile this driver as a module, choose M here: the
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module will be called ti-ads7950.
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config TI_ADS8344
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tristate "Texas Instruments ADS8344"
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depends on SPI && OF
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help
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If you say yes here you get support for Texas Instruments ADS8344
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ADC chips
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This driver can also be built as a module. If so, the module will be
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called ti-ads8344.
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config TI_ADS8688
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tristate "Texas Instruments ADS8688"
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depends on SPI && OF
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@ -88,6 +88,7 @@ obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
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obj-$(CONFIG_TI_ADC161S626) += ti-adc161s626.o
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obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
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obj-$(CONFIG_TI_ADS7950) += ti-ads7950.o
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obj-$(CONFIG_TI_ADS8344) += ti-ads8344.o
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obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
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obj-$(CONFIG_TI_ADS124S08) += ti-ads124s08.o
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obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
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204
drivers/iio/adc/ti-ads8344.c
Normal file
204
drivers/iio/adc/ti-ads8344.c
Normal file
@ -0,0 +1,204 @@
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// SPDX-License-Identifier: GPL-2.0+
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/*
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* ADS8344 16-bit 8-Channel ADC driver
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*
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* Author: Gregory CLEMENT <gregory.clement@bootlin.com>
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*
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* Datasheet: http://www.ti.com/lit/ds/symlink/ads8344.pdf
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*/
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#include <linux/delay.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/iio.h>
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#include <linux/module.h>
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#include <linux/regulator/consumer.h>
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#include <linux/spi/spi.h>
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#define ADS8344_START BIT(7)
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#define ADS8344_SINGLE_END BIT(2)
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#define ADS8344_CHANNEL(channel) ((channel) << 4)
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#define ADS8344_CLOCK_INTERNAL 0x2 /* PD1 = 1 and PD0 = 0 */
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struct ads8344 {
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struct spi_device *spi;
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struct regulator *reg;
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/*
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* Lock protecting access to adc->tx_buff and rx_buff,
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* especially from concurrent read on sysfs file.
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*/
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struct mutex lock;
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u8 tx_buf ____cacheline_aligned;
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u16 rx_buf;
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};
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#define ADS8344_VOLTAGE_CHANNEL(chan, si) \
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{ \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.channel = chan, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
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}
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#define ADS8344_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si) \
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{ \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.channel = (chan1), \
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.channel2 = (chan2), \
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.differential = 1, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
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}
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static const struct iio_chan_spec ads8344_channels[] = {
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ADS8344_VOLTAGE_CHANNEL(0, 0),
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ADS8344_VOLTAGE_CHANNEL(1, 4),
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ADS8344_VOLTAGE_CHANNEL(2, 1),
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ADS8344_VOLTAGE_CHANNEL(3, 5),
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ADS8344_VOLTAGE_CHANNEL(4, 2),
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ADS8344_VOLTAGE_CHANNEL(5, 6),
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ADS8344_VOLTAGE_CHANNEL(6, 3),
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ADS8344_VOLTAGE_CHANNEL(7, 7),
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ADS8344_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
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ADS8344_VOLTAGE_CHANNEL_DIFF(2, 3, 9),
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ADS8344_VOLTAGE_CHANNEL_DIFF(4, 5, 10),
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ADS8344_VOLTAGE_CHANNEL_DIFF(6, 7, 11),
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ADS8344_VOLTAGE_CHANNEL_DIFF(1, 0, 12),
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ADS8344_VOLTAGE_CHANNEL_DIFF(3, 2, 13),
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ADS8344_VOLTAGE_CHANNEL_DIFF(5, 4, 14),
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ADS8344_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
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};
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static int ads8344_adc_conversion(struct ads8344 *adc, int channel,
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bool differential)
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{
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struct spi_device *spi = adc->spi;
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int ret;
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adc->tx_buf = ADS8344_START;
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if (!differential)
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adc->tx_buf |= ADS8344_SINGLE_END;
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adc->tx_buf |= ADS8344_CHANNEL(channel);
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adc->tx_buf |= ADS8344_CLOCK_INTERNAL;
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ret = spi_write(spi, &adc->tx_buf, 1);
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if (ret)
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return ret;
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udelay(9);
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ret = spi_read(spi, &adc->rx_buf, 2);
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if (ret)
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return ret;
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return adc->rx_buf;
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}
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static int ads8344_read_raw(struct iio_dev *iio,
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struct iio_chan_spec const *channel, int *value,
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int *shift, long mask)
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{
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struct ads8344 *adc = iio_priv(iio);
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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mutex_lock(&adc->lock);
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*value = ads8344_adc_conversion(adc, channel->scan_index,
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channel->differential);
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mutex_unlock(&adc->lock);
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if (*value < 0)
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return *value;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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*value = regulator_get_voltage(adc->reg);
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if (*value < 0)
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return *value;
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/* convert regulator output voltage to mV */
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*value /= 1000;
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*shift = 16;
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return IIO_VAL_FRACTIONAL_LOG2;
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default:
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return -EINVAL;
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}
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}
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static const struct iio_info ads8344_info = {
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.read_raw = ads8344_read_raw,
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};
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static int ads8344_probe(struct spi_device *spi)
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{
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struct iio_dev *indio_dev;
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struct ads8344 *adc;
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int ret;
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indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
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if (!indio_dev)
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return -ENOMEM;
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adc = iio_priv(indio_dev);
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adc->spi = spi;
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mutex_init(&adc->lock);
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indio_dev->name = dev_name(&spi->dev);
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indio_dev->dev.parent = &spi->dev;
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indio_dev->dev.of_node = spi->dev.of_node;
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indio_dev->info = &ads8344_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = ads8344_channels;
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indio_dev->num_channels = ARRAY_SIZE(ads8344_channels);
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adc->reg = devm_regulator_get(&spi->dev, "vref");
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if (IS_ERR(adc->reg))
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return PTR_ERR(adc->reg);
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ret = regulator_enable(adc->reg);
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if (ret)
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return ret;
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spi_set_drvdata(spi, indio_dev);
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ret = iio_device_register(indio_dev);
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if (ret) {
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regulator_disable(adc->reg);
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return ret;
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}
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return 0;
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}
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static int ads8344_remove(struct spi_device *spi)
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{
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struct iio_dev *indio_dev = spi_get_drvdata(spi);
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struct ads8344 *adc = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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regulator_disable(adc->reg);
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return 0;
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}
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static const struct of_device_id ads8344_of_match[] = {
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{ .compatible = "ti,ads8344", },
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{}
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};
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MODULE_DEVICE_TABLE(of, ads8344_of_match);
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static struct spi_driver ads8344_driver = {
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.driver = {
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.name = "ads8344",
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.of_match_table = ads8344_of_match,
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},
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.probe = ads8344_probe,
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.remove = ads8344_remove,
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};
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module_spi_driver(ads8344_driver);
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MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@bootlin.com>");
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MODULE_DESCRIPTION("ADS8344 driver");
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MODULE_LICENSE("GPL");
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