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-rw-r--r--drivers/iio/adc/ti-adc0832.c338
1 files changed, 338 insertions, 0 deletions
diff --git a/drivers/iio/adc/ti-adc0832.c b/drivers/iio/adc/ti-adc0832.c
new file mode 100644
index 000000000..b11ce555b
--- /dev/null
+++ b/drivers/iio/adc/ti-adc0832.c
@@ -0,0 +1,338 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ADC0831/ADC0832/ADC0834/ADC0838 8-bit ADC driver
+ *
+ * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
+ *
+ * Datasheet: https://www.ti.com/lit/ds/symlink/adc0832-n.pdf
+ */
+
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/spi/spi.h>
+#include <linux/iio/iio.h>
+#include <linux/regulator/consumer.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+
+enum {
+ adc0831,
+ adc0832,
+ adc0834,
+ adc0838,
+};
+
+struct adc0832 {
+ struct spi_device *spi;
+ struct regulator *reg;
+ struct mutex lock;
+ u8 mux_bits;
+ /*
+ * Max size needed: 16x 1 byte ADC data + 8 bytes timestamp
+ * May be shorter if not all channels are enabled subject
+ * to the timestamp remaining 8 byte aligned.
+ */
+ u8 data[24] __aligned(8);
+
+ u8 tx_buf[2] __aligned(IIO_DMA_MINALIGN);
+ 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), \
+ .scan_index = chan, \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = 8, \
+ .storagebits = 8, \
+ }, \
+ }
+
+#define ADC0832_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), \
+ .scan_index = si, \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = 8, \
+ .storagebits = 8, \
+ }, \
+ }
+
+static const struct iio_chan_spec adc0831_channels[] = {
+ ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 0),
+ IIO_CHAN_SOFT_TIMESTAMP(1),
+};
+
+static const struct iio_chan_spec adc0832_channels[] = {
+ ADC0832_VOLTAGE_CHANNEL(0),
+ ADC0832_VOLTAGE_CHANNEL(1),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 2),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 3),
+ IIO_CHAN_SOFT_TIMESTAMP(4),
+};
+
+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, 4),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 5),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 6),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 7),
+ IIO_CHAN_SOFT_TIMESTAMP(8),
+};
+
+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, 8),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 9),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 10),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 11),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(4, 5, 12),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(5, 4, 13),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(6, 7, 14),
+ ADC0832_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
+ IIO_CHAN_SOFT_TIMESTAMP(16),
+};
+
+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,
+};
+
+static irqreturn_t adc0832_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct adc0832 *adc = iio_priv(indio_dev);
+ 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];
+ int ret = adc0832_adc_conversion(adc, scan_chan->channel,
+ scan_chan->differential);
+ if (ret < 0) {
+ dev_warn(&adc->spi->dev,
+ "failed to get conversion data\n");
+ goto out;
+ }
+
+ adc->data[i] = ret;
+ i++;
+ }
+ iio_push_to_buffers_with_timestamp(indio_dev, adc->data,
+ iio_get_time_ns(indio_dev));
+out:
+ mutex_unlock(&adc->lock);
+
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static void adc0832_reg_disable(void *reg)
+{
+ regulator_disable(reg);
+}
+
+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->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;
+
+ ret = devm_add_action_or_reset(&spi->dev, adc0832_reg_disable,
+ adc->reg);
+ if (ret)
+ return ret;
+
+ ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
+ adc0832_trigger_handler, NULL);
+ if (ret)
+ return ret;
+
+ return devm_iio_device_register(&spi->dev, indio_dev);
+}
+
+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);
+
+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 = adc0832_dt_ids,
+ },
+ .probe = adc0832_probe,
+ .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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-24 07:27:35 +0000