--- /dev/null
+/*
+ * ADC0831/ADC0832/ADC0834/ADC0838 8-bit 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/adc0832-n.pdf
+ */
+
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/iio/iio.h>
+#include <linux/regulator/consumer.h>
+
+enum {
+ adc0831,
+ adc0832,
+ adc0834,
+ adc0838,
+};
+
+struct adc0832 {
+ struct spi_device *spi;
+ struct regulator *reg;
+ struct mutex lock;
+ u8 mux_bits;
+
+ u8 tx_buf[2] ____cacheline_aligned;
+ u8 rx_buf[2];
+};
+
+#define ADC0832_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) \
+ }
+
+#define ADC0832_VOLTAGE_CHANNEL_DIFF(chan1, chan2) \
+ { \
+ .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) \
+ }
+
+static const struct iio_chan_spec adc0831_channels[] = {
+ ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1),
+};
+
+static const struct iio_chan_spec adc0832_channels[] = {
+ ADC0832_VOLTAGE_CHANNEL(0),
+ ADC0832_VOLTAGE_CHANNEL(1),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0),
+};
+
+static const struct iio_chan_spec adc0834_channels[] = {
+ ADC0832_VOLTAGE_CHANNEL(0),
+ ADC0832_VOLTAGE_CHANNEL(1),
+ ADC0832_VOLTAGE_CHANNEL(2),
+ ADC0832_VOLTAGE_CHANNEL(3),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2),
+};
+
+static const struct iio_chan_spec adc0838_channels[] = {
+ ADC0832_VOLTAGE_CHANNEL(0),
+ ADC0832_VOLTAGE_CHANNEL(1),
+ ADC0832_VOLTAGE_CHANNEL(2),
+ ADC0832_VOLTAGE_CHANNEL(3),
+ ADC0832_VOLTAGE_CHANNEL(4),
+ ADC0832_VOLTAGE_CHANNEL(5),
+ ADC0832_VOLTAGE_CHANNEL(6),
+ ADC0832_VOLTAGE_CHANNEL(7),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(4, 5),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(5, 4),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(6, 7),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(7, 6),
+};
+
+static int adc0831_adc_conversion(struct adc0832 *adc)
+{
+ struct spi_device *spi = adc->spi;
+ int ret;
+
+ ret = spi_read(spi, &adc->rx_buf, 2);
+ if (ret)
+ return ret;
+
+ /*
+ * Skip TRI-STATE and a leading zero
+ */
+ return (adc->rx_buf[0] << 2 & 0xff) | (adc->rx_buf[1] >> 6);
+}
+
+static int adc0832_adc_conversion(struct adc0832 *adc, int channel,
+ bool differential)
+{
+ struct spi_device *spi = adc->spi;
+ struct spi_transfer xfer = {
+ .tx_buf = adc->tx_buf,
+ .rx_buf = adc->rx_buf,
+ .len = 2,
+ };
+ int ret;
+
+ if (!adc->mux_bits)
+ return adc0831_adc_conversion(adc);
+
+ /* start bit */
+ adc->tx_buf[0] = 1 << (adc->mux_bits + 1);
+ /* single-ended or differential */
+ adc->tx_buf[0] |= differential ? 0 : (1 << adc->mux_bits);
+ /* odd / sign */
+ adc->tx_buf[0] |= (channel % 2) << (adc->mux_bits - 1);
+ /* select */
+ if (adc->mux_bits > 1)
+ adc->tx_buf[0] |= channel / 2;
+
+ /* align Data output BIT7 (MSB) to 8-bit boundary */
+ adc->tx_buf[0] <<= 1;
+
+ ret = spi_sync_transfer(spi, &xfer, 1);
+ if (ret)
+ return ret;
+
+ return adc->rx_buf[1];
+}
+
+static int adc0832_read_raw(struct iio_dev *iio,
+ struct iio_chan_spec const *channel, int *value,
+ int *shift, long mask)
+{
+ struct adc0832 *adc = iio_priv(iio);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&adc->lock);
+ *value = adc0832_adc_conversion(adc, channel->channel,
+ 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 = 8;
+
+ return IIO_VAL_FRACTIONAL_LOG2;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_info adc0832_info = {
+ .read_raw = adc0832_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static int adc0832_probe(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev;
+ struct adc0832 *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 = spi_get_device_id(spi)->name;
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->info = &adc0832_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ switch (spi_get_device_id(spi)->driver_data) {
+ case adc0831:
+ adc->mux_bits = 0;
+ indio_dev->channels = adc0831_channels;
+ indio_dev->num_channels = ARRAY_SIZE(adc0831_channels);
+ break;
+ case adc0832:
+ adc->mux_bits = 1;
+ indio_dev->channels = adc0832_channels;
+ indio_dev->num_channels = ARRAY_SIZE(adc0832_channels);
+ break;
+ case adc0834:
+ adc->mux_bits = 2;
+ indio_dev->channels = adc0834_channels;
+ indio_dev->num_channels = ARRAY_SIZE(adc0834_channels);
+ break;
+ case adc0838:
+ adc->mux_bits = 3;
+ indio_dev->channels = adc0838_channels;
+ indio_dev->num_channels = ARRAY_SIZE(adc0838_channels);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ 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;
+
+ spi_set_drvdata(spi, indio_dev);
+
+ ret = iio_device_register(indio_dev);
+ if (ret)
+ regulator_disable(adc->reg);
+
+ return ret;
+}
+
+static int adc0832_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+ struct adc0832 *adc = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ regulator_disable(adc->reg);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+
+static const struct of_device_id adc0832_dt_ids[] = {
+ { .compatible = "ti,adc0831", },
+ { .compatible = "ti,adc0832", },
+ { .compatible = "ti,adc0834", },
+ { .compatible = "ti,adc0838", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, adc0832_dt_ids);
+
+#endif
+
+static const struct spi_device_id adc0832_id[] = {
+ { "adc0831", adc0831 },
+ { "adc0832", adc0832 },
+ { "adc0834", adc0834 },
+ { "adc0838", adc0838 },
+ {}
+};
+MODULE_DEVICE_TABLE(spi, adc0832_id);
+
+static struct spi_driver adc0832_driver = {
+ .driver = {
+ .name = "adc0832",
+ .of_match_table = of_match_ptr(adc0832_dt_ids),
+ },
+ .probe = adc0832_probe,
+ .remove = adc0832_remove,
+ .id_table = adc0832_id,
+};
+module_spi_driver(adc0832_driver);
+
+MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
+MODULE_DESCRIPTION("ADC0831/ADC0832/ADC0834/ADC0838 driver");
+MODULE_LICENSE("GPL v2");
git.samba.org / sfrench / cifs-2.6.git / commitdiff