--- /dev/null
+/**
+ * Copyright (C) 2017 Axis Communications AB
+ *
+ * Driver for Texas Instruments' ADC084S021 ADC chip.
+ * Datasheets can be found here:
+ * http://www.ti.com/lit/ds/symlink/adc084s021.pdf
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/err.h>
+#include <linux/spi/spi.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/regulator/consumer.h>
+
+#define ADC084S021_DRIVER_NAME "adc084s021"
+
+struct adc084s021 {
+ struct spi_device *spi;
+ struct spi_message message;
+ struct spi_transfer spi_trans;
+ struct regulator *reg;
+ struct mutex lock;
+ /*
+ * DMA (thus cache coherency maintenance) requires the
+ * transfer buffers to live in their own cache line.
+ */
+ u16 tx_buf[4] ____cacheline_aligned;
+ __be16 rx_buf[5]; /* First 16-bits are trash */
+};
+
+#define ADC084S021_VOLTAGE_CHANNEL(num) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .channel = (num), \
+ .indexed = 1, \
+ .scan_index = (num), \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = 8, \
+ .storagebits = 16, \
+ .shift = 4, \
+ .endianness = IIO_BE, \
+ }, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
+ }
+
+static const struct iio_chan_spec adc084s021_channels[] = {
+ ADC084S021_VOLTAGE_CHANNEL(0),
+ ADC084S021_VOLTAGE_CHANNEL(1),
+ ADC084S021_VOLTAGE_CHANNEL(2),
+ ADC084S021_VOLTAGE_CHANNEL(3),
+ IIO_CHAN_SOFT_TIMESTAMP(4),
+};
+
+/**
+ * Read an ADC channel and return its value.
+ *
+ * @adc: The ADC SPI data.
+ * @data: Buffer for converted data.
+ */
+static int adc084s021_adc_conversion(struct adc084s021 *adc, void *data)
+{
+ int n_words = (adc->spi_trans.len >> 1) - 1; /* Discard first word */
+ int ret, i = 0;
+ u16 *p = data;
+
+ /* Do the transfer */
+ ret = spi_sync(adc->spi, &adc->message);
+ if (ret < 0)
+ return ret;
+
+ for (; i < n_words; i++)
+ *(p + i) = adc->rx_buf[i + 1];
+
+ return ret;
+}
+
+static int adc084s021_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *channel, int *val,
+ int *val2, long mask)
+{
+ struct adc084s021 *adc = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = iio_device_claim_direct_mode(indio_dev);
+ if (ret < 0)
+ return ret;
+
+ ret = regulator_enable(adc->reg);
+ if (ret) {
+ iio_device_release_direct_mode(indio_dev);
+ return ret;
+ }
+
+ adc->tx_buf[0] = channel->channel << 3;
+ ret = adc084s021_adc_conversion(adc, val);
+ iio_device_release_direct_mode(indio_dev);
+ regulator_disable(adc->reg);
+ if (ret < 0)
+ return ret;
+
+ *val = be16_to_cpu(*val);
+ *val = (*val >> channel->scan_type.shift) & 0xff;
+
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ ret = regulator_enable(adc->reg);
+ if (ret)
+ return ret;
+
+ ret = regulator_get_voltage(adc->reg);
+ regulator_disable(adc->reg);
+ if (ret < 0)
+ return ret;
+
+ *val = ret / 1000;
+
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+/**
+ * Read enabled ADC channels and push data to the buffer.
+ *
+ * @irq: The interrupt number (not used).
+ * @pollfunc: Pointer to the poll func.
+ */
+static irqreturn_t adc084s021_buffer_trigger_handler(int irq, void *pollfunc)
+{
+ struct iio_poll_func *pf = pollfunc;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct adc084s021 *adc = iio_priv(indio_dev);
+ __be16 data[8] = {0}; /* 4 * 16-bit words of data + 8 bytes timestamp */
+
+ mutex_lock(&adc->lock);
+
+ if (adc084s021_adc_conversion(adc, &data) < 0)
+ dev_err(&adc->spi->dev, "Failed to read data\n");
+
+ iio_push_to_buffers_with_timestamp(indio_dev, data,
+ iio_get_time_ns(indio_dev));
+ mutex_unlock(&adc->lock);
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static int adc084s021_buffer_preenable(struct iio_dev *indio_dev)
+{
+ struct adc084s021 *adc = iio_priv(indio_dev);
+ int scan_index;
+ int i = 0;
+
+ for_each_set_bit(scan_index, indio_dev->active_scan_mask,
+ indio_dev->masklength) {
+ const struct iio_chan_spec *channel =
+ &indio_dev->channels[scan_index];
+ adc->tx_buf[i++] = channel->channel << 3;
+ }
+ adc->spi_trans.len = 2 + (i * sizeof(__be16)); /* Trash + channels */
+
+ return regulator_enable(adc->reg);
+}
+
+static int adc084s021_buffer_postdisable(struct iio_dev *indio_dev)
+{
+ struct adc084s021 *adc = iio_priv(indio_dev);
+
+ adc->spi_trans.len = 4; /* Trash + single channel */
+
+ return regulator_disable(adc->reg);
+}
+
+static const struct iio_info adc084s021_info = {
+ .read_raw = adc084s021_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static const struct iio_buffer_setup_ops adc084s021_buffer_setup_ops = {
+ .preenable = adc084s021_buffer_preenable,
+ .postenable = iio_triggered_buffer_postenable,
+ .predisable = iio_triggered_buffer_predisable,
+ .postdisable = adc084s021_buffer_postdisable,
+};
+
+static int adc084s021_probe(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev;
+ struct adc084s021 *adc;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
+ if (!indio_dev) {
+ dev_err(&spi->dev, "Failed to allocate IIO device\n");
+ return -ENOMEM;
+ }
+
+ adc = iio_priv(indio_dev);
+ adc->spi = spi;
+
+ /* Connect the SPI device and the iio dev */
+ spi_set_drvdata(spi, indio_dev);
+
+ /* Initiate the Industrial I/O device */
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->dev.of_node = spi->dev.of_node;
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &adc084s021_info;
+ indio_dev->channels = adc084s021_channels;
+ indio_dev->num_channels = ARRAY_SIZE(adc084s021_channels);
+
+ /* Create SPI transfer for channel reads */
+ adc->spi_trans.tx_buf = adc->tx_buf;
+ adc->spi_trans.rx_buf = adc->rx_buf;
+ adc->spi_trans.len = 4; /* Trash + single channel */
+ spi_message_init_with_transfers(&adc->message, &adc->spi_trans, 1);
+
+ adc->reg = devm_regulator_get(&spi->dev, "vref");
+ if (IS_ERR(adc->reg))
+ return PTR_ERR(adc->reg);
+
+ mutex_init(&adc->lock);
+
+ /* Setup triggered buffer with pollfunction */
+ ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
+ adc084s021_buffer_trigger_handler,
+ &adc084s021_buffer_setup_ops);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to setup triggered buffer\n");
+ return ret;
+ }
+
+ return devm_iio_device_register(&spi->dev, indio_dev);
+}
+
+static const struct of_device_id adc084s021_of_match[] = {
+ { .compatible = "ti,adc084s021", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, adc084s021_of_match);
+
+static const struct spi_device_id adc084s021_id[] = {
+ { ADC084S021_DRIVER_NAME, 0},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, adc084s021_id);
+
+static struct spi_driver adc084s021_driver = {
+ .driver = {
+ .name = ADC084S021_DRIVER_NAME,
+ .of_match_table = of_match_ptr(adc084s021_of_match),
+ },
+ .probe = adc084s021_probe,
+ .id_table = adc084s021_id,
+};
+module_spi_driver(adc084s021_driver);
+
+MODULE_AUTHOR("Mårten Lindahl <martenli@axis.com>");
+MODULE_DESCRIPTION("Texas Instruments ADC084S021");
+MODULE_LICENSE("GPL v2");
+MODULE_VERSION("1.0");
projects / platform / kernel / linux-exynos.git / commitdiff