--- /dev/null
+/*
+ * TI ADC108S102 SPI ADC driver
+ *
+ * Copyright (c) 2013-2015 Intel Corporation.
+ * Copyright (c) 2017 Siemens AG
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * This IIO device driver is designed to work with the following
+ * analog to digital converters from Texas Instruments:
+ * ADC108S102
+ * ADC128S102
+ * The communication with ADC chip is via the SPI bus (mode 3).
+ */
+
+#include <linux/acpi.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/types.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+/*
+ * In case of ACPI, we use the hard-wired 5000 mV of the Galileo and IOT2000
+ * boards as default for the reference pin VA. Device tree users encode that
+ * via the vref-supply regulator.
+ */
+#define ADC108S102_VA_MV_ACPI_DEFAULT 5000
+
+/*
+ * Defining the ADC resolution being 12 bits, we can use the same driver for
+ * both ADC108S102 (10 bits resolution) and ADC128S102 (12 bits resolution)
+ * chips. The ADC108S102 effectively returns a 12-bit result with the 2
+ * least-significant bits unset.
+ */
+#define ADC108S102_BITS 12
+#define ADC108S102_MAX_CHANNELS 8
+
+/*
+ * 16-bit SPI command format:
+ * [15:14] Ignored
+ * [13:11] 3-bit channel address
+ * [10:0] Ignored
+ */
+#define ADC108S102_CMD(ch) ((u16)(ch) << 11)
+
+/*
+ * 16-bit SPI response format:
+ * [15:12] Zeros
+ * [11:0] 12-bit ADC sample (for ADC108S102, [1:0] will always be 0).
+ */
+#define ADC108S102_RES_DATA(res) ((u16)res & GENMASK(11, 0))
+
+struct adc108s102_state {
+ struct spi_device *spi;
+ struct regulator *reg;
+ u32 va_millivolt;
+ /* SPI transfer used by triggered buffer handler*/
+ struct spi_transfer ring_xfer;
+ /* SPI transfer used by direct scan */
+ struct spi_transfer scan_single_xfer;
+ /* SPI message used by ring_xfer SPI transfer */
+ struct spi_message ring_msg;
+ /* SPI message used by scan_single_xfer SPI transfer */
+ struct spi_message scan_single_msg;
+
+ /*
+ * SPI message buffers:
+ * tx_buf: |C0|C1|C2|C3|C4|C5|C6|C7|XX|
+ * rx_buf: |XX|R0|R1|R2|R3|R4|R5|R6|R7|tt|tt|tt|tt|
+ *
+ * tx_buf: 8 channel read commands, plus 1 dummy command
+ * rx_buf: 1 dummy response, 8 channel responses, plus 64-bit timestamp
+ */
+ __be16 rx_buf[13] ____cacheline_aligned;
+ __be16 tx_buf[9] ____cacheline_aligned;
+};
+
+#define ADC108S102_V_CHAN(index) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = index, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_SCALE), \
+ .address = index, \
+ .scan_index = index, \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = ADC108S102_BITS, \
+ .storagebits = 16, \
+ .endianness = IIO_BE, \
+ }, \
+ }
+
+static const struct iio_chan_spec adc108s102_channels[] = {
+ ADC108S102_V_CHAN(0),
+ ADC108S102_V_CHAN(1),
+ ADC108S102_V_CHAN(2),
+ ADC108S102_V_CHAN(3),
+ ADC108S102_V_CHAN(4),
+ ADC108S102_V_CHAN(5),
+ ADC108S102_V_CHAN(6),
+ ADC108S102_V_CHAN(7),
+ IIO_CHAN_SOFT_TIMESTAMP(8),
+};
+
+static int adc108s102_update_scan_mode(struct iio_dev *indio_dev,
+ unsigned long const *active_scan_mask)
+{
+ struct adc108s102_state *st = iio_priv(indio_dev);
+ unsigned int bit, cmds;
+
+ /*
+ * Fill in the first x shorts of tx_buf with the number of channels
+ * enabled for sampling by the triggered buffer.
+ */
+ cmds = 0;
+ for_each_set_bit(bit, active_scan_mask, ADC108S102_MAX_CHANNELS)
+ st->tx_buf[cmds++] = cpu_to_be16(ADC108S102_CMD(bit));
+
+ /* One dummy command added, to clock in the last response */
+ st->tx_buf[cmds++] = 0x00;
+
+ /* build SPI ring message */
+ st->ring_xfer.tx_buf = &st->tx_buf[0];
+ st->ring_xfer.rx_buf = &st->rx_buf[0];
+ st->ring_xfer.len = cmds * sizeof(st->tx_buf[0]);
+
+ spi_message_init_with_transfers(&st->ring_msg, &st->ring_xfer, 1);
+
+ return 0;
+}
+
+static irqreturn_t adc108s102_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct adc108s102_state *st = iio_priv(indio_dev);
+ int ret;
+
+ ret = spi_sync(st->spi, &st->ring_msg);
+ if (ret < 0)
+ goto out_notify;
+
+ /* Skip the dummy response in the first slot */
+ iio_push_to_buffers_with_timestamp(indio_dev,
+ (u8 *)&st->rx_buf[1],
+ iio_get_time_ns(indio_dev));
+
+out_notify:
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static int adc108s102_scan_direct(struct adc108s102_state *st, unsigned int ch)
+{
+ int ret;
+
+ st->tx_buf[0] = cpu_to_be16(ADC108S102_CMD(ch));
+ ret = spi_sync(st->spi, &st->scan_single_msg);
+ if (ret)
+ return ret;
+
+ /* Skip the dummy response in the first slot */
+ return be16_to_cpu(st->rx_buf[1]);
+}
+
+static int adc108s102_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long m)
+{
+ struct adc108s102_state *st = iio_priv(indio_dev);
+ int ret;
+
+ switch (m) {
+ case IIO_CHAN_INFO_RAW:
+ ret = iio_device_claim_direct_mode(indio_dev);
+ if (ret)
+ return ret;
+
+ ret = adc108s102_scan_direct(st, chan->address);
+
+ iio_device_release_direct_mode(indio_dev);
+
+ if (ret < 0)
+ return ret;
+
+ *val = ADC108S102_RES_DATA(ret);
+
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ if (chan->type != IIO_VOLTAGE)
+ break;
+
+ *val = st->va_millivolt;
+ *val2 = chan->scan_type.realbits;
+
+ return IIO_VAL_FRACTIONAL_LOG2;
+ default:
+ break;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_info adc108s102_info = {
+ .read_raw = &adc108s102_read_raw,
+ .update_scan_mode = &adc108s102_update_scan_mode,
+ .driver_module = THIS_MODULE,
+};
+
+static int adc108s102_probe(struct spi_device *spi)
+{
+ struct adc108s102_state *st;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ st = iio_priv(indio_dev);
+
+ if (ACPI_COMPANION(&spi->dev)) {
+ st->va_millivolt = ADC108S102_VA_MV_ACPI_DEFAULT;
+ } else {
+ st->reg = devm_regulator_get(&spi->dev, "vref");
+ if (IS_ERR(st->reg))
+ return PTR_ERR(st->reg);
+
+ ret = regulator_enable(st->reg);
+ if (ret < 0) {
+ dev_err(&spi->dev, "Cannot enable vref regulator\n");
+ return ret;
+ }
+
+ ret = regulator_get_voltage(st->reg);
+ if (ret < 0) {
+ dev_err(&spi->dev, "vref get voltage failed\n");
+ return ret;
+ }
+
+ st->va_millivolt = ret / 1000;
+ }
+
+ spi_set_drvdata(spi, indio_dev);
+ st->spi = spi;
+
+ indio_dev->name = spi->modalias;
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = adc108s102_channels;
+ indio_dev->num_channels = ARRAY_SIZE(adc108s102_channels);
+ indio_dev->info = &adc108s102_info;
+
+ /* Setup default message */
+ st->scan_single_xfer.tx_buf = st->tx_buf;
+ st->scan_single_xfer.rx_buf = st->rx_buf;
+ st->scan_single_xfer.len = 2 * sizeof(st->tx_buf[0]);
+
+ spi_message_init_with_transfers(&st->scan_single_msg,
+ &st->scan_single_xfer, 1);
+
+ ret = iio_triggered_buffer_setup(indio_dev, NULL,
+ &adc108s102_trigger_handler, NULL);
+ if (ret)
+ goto error_disable_reg;
+
+ ret = iio_device_register(indio_dev);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to register IIO device\n");
+ goto error_cleanup_triggered_buffer;
+ }
+ return 0;
+
+error_cleanup_triggered_buffer:
+ iio_triggered_buffer_cleanup(indio_dev);
+
+error_disable_reg:
+ regulator_disable(st->reg);
+
+ return ret;
+}
+
+static int adc108s102_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+ struct adc108s102_state *st = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ iio_triggered_buffer_cleanup(indio_dev);
+
+ regulator_disable(st->reg);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id adc108s102_of_match[] = {
+ { .compatible = "ti,adc108s102" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, adc108s102_of_match);
+#endif
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id adc108s102_acpi_ids[] = {
+ { "INT3495", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(acpi, adc108s102_acpi_ids);
+#endif
+
+static const struct spi_device_id adc108s102_id[] = {
+ { "adc108s102", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(spi, adc108s102_id);
+
+static struct spi_driver adc108s102_driver = {
+ .driver = {
+ .name = "adc108s102",
+ .of_match_table = of_match_ptr(adc108s102_of_match),
+ .acpi_match_table = ACPI_PTR(adc108s102_acpi_ids),
+ },
+ .probe = adc108s102_probe,
+ .remove = adc108s102_remove,
+ .id_table = adc108s102_id,
+};
+module_spi_driver(adc108s102_driver);
+
+MODULE_AUTHOR("Bogdan Pricop <bogdan.pricop@emutex.com>");
+MODULE_DESCRIPTION("Texas Instruments ADC108S102 and ADC128S102 driver");
+MODULE_LICENSE("GPL v2");
projects / karo-tx-linux.git / commitdiff