summaryrefslogtreecommitdiffstats
path: root/drivers/iio/adc/max1027.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/iio/adc/max1027.c')
-rw-r--r--drivers/iio/adc/max1027.c649
1 files changed, 649 insertions, 0 deletions
diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
new file mode 100644
index 0000000000..136fcf7538
--- /dev/null
+++ b/drivers/iio/adc/max1027.c
@@ -0,0 +1,649 @@
+// SPDX-License-Identifier: GPL-2.0-only
+ /*
+ * iio/adc/max1027.c
+ * Copyright (C) 2014 Philippe Reynes
+ *
+ * based on linux/drivers/iio/ad7923.c
+ * Copyright 2011 Analog Devices Inc (from AD7923 Driver)
+ * Copyright 2012 CS Systemes d'Information
+ *
+ * max1027.c
+ *
+ * Partial support for max1027 and similar chips.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/spi/spi.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#define MAX1027_CONV_REG BIT(7)
+#define MAX1027_SETUP_REG BIT(6)
+#define MAX1027_AVG_REG BIT(5)
+#define MAX1027_RST_REG BIT(4)
+
+/* conversion register */
+#define MAX1027_TEMP BIT(0)
+#define MAX1027_SCAN_0_N (0x00 << 1)
+#define MAX1027_SCAN_N_M (0x01 << 1)
+#define MAX1027_SCAN_N (0x02 << 1)
+#define MAX1027_NOSCAN (0x03 << 1)
+#define MAX1027_CHAN(n) ((n) << 3)
+
+/* setup register */
+#define MAX1027_UNIPOLAR 0x02
+#define MAX1027_BIPOLAR 0x03
+#define MAX1027_REF_MODE0 (0x00 << 2)
+#define MAX1027_REF_MODE1 (0x01 << 2)
+#define MAX1027_REF_MODE2 (0x02 << 2)
+#define MAX1027_REF_MODE3 (0x03 << 2)
+#define MAX1027_CKS_MODE0 (0x00 << 4)
+#define MAX1027_CKS_MODE1 (0x01 << 4)
+#define MAX1027_CKS_MODE2 (0x02 << 4)
+#define MAX1027_CKS_MODE3 (0x03 << 4)
+
+/* averaging register */
+#define MAX1027_NSCAN_4 0x00
+#define MAX1027_NSCAN_8 0x01
+#define MAX1027_NSCAN_12 0x02
+#define MAX1027_NSCAN_16 0x03
+#define MAX1027_NAVG_4 (0x00 << 2)
+#define MAX1027_NAVG_8 (0x01 << 2)
+#define MAX1027_NAVG_16 (0x02 << 2)
+#define MAX1027_NAVG_32 (0x03 << 2)
+#define MAX1027_AVG_EN BIT(4)
+
+/* Device can achieve 300ksps so we assume a 3.33us conversion delay */
+#define MAX1027_CONVERSION_UDELAY 4
+
+enum max1027_id {
+ max1027,
+ max1029,
+ max1031,
+ max1227,
+ max1229,
+ max1231,
+};
+
+static const struct spi_device_id max1027_id[] = {
+ {"max1027", max1027},
+ {"max1029", max1029},
+ {"max1031", max1031},
+ {"max1227", max1227},
+ {"max1229", max1229},
+ {"max1231", max1231},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, max1027_id);
+
+static const struct of_device_id max1027_adc_dt_ids[] = {
+ { .compatible = "maxim,max1027" },
+ { .compatible = "maxim,max1029" },
+ { .compatible = "maxim,max1031" },
+ { .compatible = "maxim,max1227" },
+ { .compatible = "maxim,max1229" },
+ { .compatible = "maxim,max1231" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, max1027_adc_dt_ids);
+
+#define MAX1027_V_CHAN(index, depth) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = index, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .scan_index = index + 1, \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = depth, \
+ .storagebits = 16, \
+ .shift = (depth == 10) ? 2 : 0, \
+ .endianness = IIO_BE, \
+ }, \
+ }
+
+#define MAX1027_T_CHAN \
+ { \
+ .type = IIO_TEMP, \
+ .channel = 0, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .scan_index = 0, \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = 12, \
+ .storagebits = 16, \
+ .endianness = IIO_BE, \
+ }, \
+ }
+
+#define MAX1X27_CHANNELS(depth) \
+ MAX1027_T_CHAN, \
+ MAX1027_V_CHAN(0, depth), \
+ MAX1027_V_CHAN(1, depth), \
+ MAX1027_V_CHAN(2, depth), \
+ MAX1027_V_CHAN(3, depth), \
+ MAX1027_V_CHAN(4, depth), \
+ MAX1027_V_CHAN(5, depth), \
+ MAX1027_V_CHAN(6, depth), \
+ MAX1027_V_CHAN(7, depth)
+
+#define MAX1X29_CHANNELS(depth) \
+ MAX1X27_CHANNELS(depth), \
+ MAX1027_V_CHAN(8, depth), \
+ MAX1027_V_CHAN(9, depth), \
+ MAX1027_V_CHAN(10, depth), \
+ MAX1027_V_CHAN(11, depth)
+
+#define MAX1X31_CHANNELS(depth) \
+ MAX1X29_CHANNELS(depth), \
+ MAX1027_V_CHAN(12, depth), \
+ MAX1027_V_CHAN(13, depth), \
+ MAX1027_V_CHAN(14, depth), \
+ MAX1027_V_CHAN(15, depth)
+
+static const struct iio_chan_spec max1027_channels[] = {
+ MAX1X27_CHANNELS(10),
+};
+
+static const struct iio_chan_spec max1029_channels[] = {
+ MAX1X29_CHANNELS(10),
+};
+
+static const struct iio_chan_spec max1031_channels[] = {
+ MAX1X31_CHANNELS(10),
+};
+
+static const struct iio_chan_spec max1227_channels[] = {
+ MAX1X27_CHANNELS(12),
+};
+
+static const struct iio_chan_spec max1229_channels[] = {
+ MAX1X29_CHANNELS(12),
+};
+
+static const struct iio_chan_spec max1231_channels[] = {
+ MAX1X31_CHANNELS(12),
+};
+
+/*
+ * These devices are able to scan from 0 to N, N being the highest voltage
+ * channel requested by the user. The temperature can be included or not,
+ * but cannot be retrieved alone. Based on the below
+ * ->available_scan_masks, the core will select the most appropriate
+ * ->active_scan_mask and the "minimum" number of channels will be
+ * scanned and pushed to the buffers.
+ *
+ * For example, if the user wants channels 1, 4 and 5, all channels from
+ * 0 to 5 will be scanned and pushed to the IIO buffers. The core will then
+ * filter out the unneeded samples based on the ->active_scan_mask that has
+ * been selected and only channels 1, 4 and 5 will be available to the user
+ * in the shared buffer.
+ */
+#define MAX1X27_SCAN_MASK_TEMP BIT(0)
+
+#define MAX1X27_SCAN_MASKS(temp) \
+ GENMASK(1, 1 - (temp)), GENMASK(2, 1 - (temp)), \
+ GENMASK(3, 1 - (temp)), GENMASK(4, 1 - (temp)), \
+ GENMASK(5, 1 - (temp)), GENMASK(6, 1 - (temp)), \
+ GENMASK(7, 1 - (temp)), GENMASK(8, 1 - (temp))
+
+#define MAX1X29_SCAN_MASKS(temp) \
+ MAX1X27_SCAN_MASKS(temp), \
+ GENMASK(9, 1 - (temp)), GENMASK(10, 1 - (temp)), \
+ GENMASK(11, 1 - (temp)), GENMASK(12, 1 - (temp))
+
+#define MAX1X31_SCAN_MASKS(temp) \
+ MAX1X29_SCAN_MASKS(temp), \
+ GENMASK(13, 1 - (temp)), GENMASK(14, 1 - (temp)), \
+ GENMASK(15, 1 - (temp)), GENMASK(16, 1 - (temp))
+
+static const unsigned long max1027_available_scan_masks[] = {
+ MAX1X27_SCAN_MASKS(0),
+ MAX1X27_SCAN_MASKS(1),
+ 0x00000000,
+};
+
+static const unsigned long max1029_available_scan_masks[] = {
+ MAX1X29_SCAN_MASKS(0),
+ MAX1X29_SCAN_MASKS(1),
+ 0x00000000,
+};
+
+static const unsigned long max1031_available_scan_masks[] = {
+ MAX1X31_SCAN_MASKS(0),
+ MAX1X31_SCAN_MASKS(1),
+ 0x00000000,
+};
+
+struct max1027_chip_info {
+ const struct iio_chan_spec *channels;
+ unsigned int num_channels;
+ const unsigned long *available_scan_masks;
+};
+
+static const struct max1027_chip_info max1027_chip_info_tbl[] = {
+ [max1027] = {
+ .channels = max1027_channels,
+ .num_channels = ARRAY_SIZE(max1027_channels),
+ .available_scan_masks = max1027_available_scan_masks,
+ },
+ [max1029] = {
+ .channels = max1029_channels,
+ .num_channels = ARRAY_SIZE(max1029_channels),
+ .available_scan_masks = max1029_available_scan_masks,
+ },
+ [max1031] = {
+ .channels = max1031_channels,
+ .num_channels = ARRAY_SIZE(max1031_channels),
+ .available_scan_masks = max1031_available_scan_masks,
+ },
+ [max1227] = {
+ .channels = max1227_channels,
+ .num_channels = ARRAY_SIZE(max1227_channels),
+ .available_scan_masks = max1027_available_scan_masks,
+ },
+ [max1229] = {
+ .channels = max1229_channels,
+ .num_channels = ARRAY_SIZE(max1229_channels),
+ .available_scan_masks = max1029_available_scan_masks,
+ },
+ [max1231] = {
+ .channels = max1231_channels,
+ .num_channels = ARRAY_SIZE(max1231_channels),
+ .available_scan_masks = max1031_available_scan_masks,
+ },
+};
+
+struct max1027_state {
+ const struct max1027_chip_info *info;
+ struct spi_device *spi;
+ struct iio_trigger *trig;
+ __be16 *buffer;
+ struct mutex lock;
+ struct completion complete;
+
+ u8 reg __aligned(IIO_DMA_MINALIGN);
+};
+
+static int max1027_wait_eoc(struct iio_dev *indio_dev)
+{
+ struct max1027_state *st = iio_priv(indio_dev);
+ unsigned int conversion_time = MAX1027_CONVERSION_UDELAY;
+ int ret;
+
+ if (st->spi->irq) {
+ ret = wait_for_completion_timeout(&st->complete,
+ msecs_to_jiffies(1000));
+ reinit_completion(&st->complete);
+ if (!ret)
+ return -ETIMEDOUT;
+ } else {
+ if (indio_dev->active_scan_mask)
+ conversion_time *= hweight32(*indio_dev->active_scan_mask);
+
+ usleep_range(conversion_time, conversion_time * 2);
+ }
+
+ return 0;
+}
+
+/* Scan from chan 0 to the highest requested channel. Include temperature on demand. */
+static int max1027_configure_chans_and_start(struct iio_dev *indio_dev)
+{
+ struct max1027_state *st = iio_priv(indio_dev);
+
+ st->reg = MAX1027_CONV_REG | MAX1027_SCAN_0_N;
+ st->reg |= MAX1027_CHAN(fls(*indio_dev->active_scan_mask) - 2);
+ if (*indio_dev->active_scan_mask & MAX1X27_SCAN_MASK_TEMP)
+ st->reg |= MAX1027_TEMP;
+
+ return spi_write(st->spi, &st->reg, 1);
+}
+
+static int max1027_enable_trigger(struct iio_dev *indio_dev, bool enable)
+{
+ struct max1027_state *st = iio_priv(indio_dev);
+
+ st->reg = MAX1027_SETUP_REG | MAX1027_REF_MODE2;
+
+ /*
+ * Start acquisition on:
+ * MODE0: external hardware trigger wired to the cnvst input pin
+ * MODE2: conversion register write
+ */
+ if (enable)
+ st->reg |= MAX1027_CKS_MODE0;
+ else
+ st->reg |= MAX1027_CKS_MODE2;
+
+ return spi_write(st->spi, &st->reg, 1);
+}
+
+static int max1027_read_single_value(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val)
+{
+ int ret;
+ struct max1027_state *st = iio_priv(indio_dev);
+
+ ret = iio_device_claim_direct_mode(indio_dev);
+ if (ret)
+ return ret;
+
+ /* Configure conversion register with the requested chan */
+ st->reg = MAX1027_CONV_REG | MAX1027_CHAN(chan->channel) |
+ MAX1027_NOSCAN;
+ if (chan->type == IIO_TEMP)
+ st->reg |= MAX1027_TEMP;
+ ret = spi_write(st->spi, &st->reg, 1);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev,
+ "Failed to configure conversion register\n");
+ goto release;
+ }
+
+ /*
+ * For an unknown reason, when we use the mode "10" (write
+ * conversion register), the interrupt doesn't occur every time.
+ * So we just wait the maximum conversion time and deliver the value.
+ */
+ ret = max1027_wait_eoc(indio_dev);
+ if (ret)
+ goto release;
+
+ /* Read result */
+ ret = spi_read(st->spi, st->buffer, (chan->type == IIO_TEMP) ? 4 : 2);
+
+release:
+ iio_device_release_direct_mode(indio_dev);
+
+ if (ret < 0)
+ return ret;
+
+ *val = be16_to_cpu(st->buffer[0]);
+
+ return IIO_VAL_INT;
+}
+
+static int max1027_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ int ret = 0;
+ struct max1027_state *st = iio_priv(indio_dev);
+
+ mutex_lock(&st->lock);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = max1027_read_single_value(indio_dev, chan, val);
+ break;
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_TEMP:
+ *val = 1;
+ *val2 = 8;
+ ret = IIO_VAL_FRACTIONAL;
+ break;
+ case IIO_VOLTAGE:
+ *val = 2500;
+ *val2 = chan->scan_type.realbits;
+ ret = IIO_VAL_FRACTIONAL_LOG2;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ mutex_unlock(&st->lock);
+
+ return ret;
+}
+
+static int max1027_debugfs_reg_access(struct iio_dev *indio_dev,
+ unsigned int reg, unsigned int writeval,
+ unsigned int *readval)
+{
+ struct max1027_state *st = iio_priv(indio_dev);
+ u8 *val = (u8 *)st->buffer;
+
+ if (readval) {
+ int ret = spi_read(st->spi, val, 2);
+ *readval = be16_to_cpu(st->buffer[0]);
+ return ret;
+ }
+
+ *val = (u8)writeval;
+ return spi_write(st->spi, val, 1);
+}
+
+static int max1027_set_cnvst_trigger_state(struct iio_trigger *trig, bool state)
+{
+ struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+ int ret;
+
+ /*
+ * In order to disable the convst trigger, start acquisition on
+ * conversion register write, which basically disables triggering
+ * conversions upon cnvst changes and thus has the effect of disabling
+ * the external hardware trigger.
+ */
+ ret = max1027_enable_trigger(indio_dev, state);
+ if (ret)
+ return ret;
+
+ if (state) {
+ ret = max1027_configure_chans_and_start(indio_dev);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int max1027_read_scan(struct iio_dev *indio_dev)
+{
+ struct max1027_state *st = iio_priv(indio_dev);
+ unsigned int scanned_chans;
+ int ret;
+
+ scanned_chans = fls(*indio_dev->active_scan_mask) - 1;
+ if (*indio_dev->active_scan_mask & MAX1X27_SCAN_MASK_TEMP)
+ scanned_chans++;
+
+ /* fill buffer with all channel */
+ ret = spi_read(st->spi, st->buffer, scanned_chans * 2);
+ if (ret < 0)
+ return ret;
+
+ iio_push_to_buffers(indio_dev, st->buffer);
+
+ return 0;
+}
+
+static irqreturn_t max1027_handler(int irq, void *private)
+{
+ struct iio_dev *indio_dev = private;
+ struct max1027_state *st = iio_priv(indio_dev);
+
+ /*
+ * If buffers are disabled (raw read) or when using external triggers,
+ * we just need to unlock the waiters which will then handle the data.
+ *
+ * When using the internal trigger, we must hand-off the choice of the
+ * handler to the core which will then lookup through the interrupt tree
+ * for the right handler registered with iio_triggered_buffer_setup()
+ * to execute, as this trigger might very well be used in conjunction
+ * with another device. The core will then call the relevant handler to
+ * perform the data processing step.
+ */
+ if (!iio_buffer_enabled(indio_dev))
+ complete(&st->complete);
+ else
+ iio_trigger_poll(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t max1027_trigger_handler(int irq, void *private)
+{
+ struct iio_poll_func *pf = private;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ int ret;
+
+ if (!iio_trigger_using_own(indio_dev)) {
+ ret = max1027_configure_chans_and_start(indio_dev);
+ if (ret)
+ goto out;
+
+ /* This is a threaded handler, it is fine to wait for an IRQ */
+ ret = max1027_wait_eoc(indio_dev);
+ if (ret)
+ goto out;
+ }
+
+ ret = max1027_read_scan(indio_dev);
+out:
+ if (ret)
+ dev_err(&indio_dev->dev,
+ "Cannot read scanned values (%d)\n", ret);
+
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static const struct iio_trigger_ops max1027_trigger_ops = {
+ .validate_device = &iio_trigger_validate_own_device,
+ .set_trigger_state = &max1027_set_cnvst_trigger_state,
+};
+
+static const struct iio_info max1027_info = {
+ .read_raw = &max1027_read_raw,
+ .debugfs_reg_access = &max1027_debugfs_reg_access,
+};
+
+static int max1027_probe(struct spi_device *spi)
+{
+ int ret;
+ struct iio_dev *indio_dev;
+ struct max1027_state *st;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+ if (!indio_dev) {
+ pr_err("Can't allocate iio device\n");
+ return -ENOMEM;
+ }
+
+ st = iio_priv(indio_dev);
+ st->spi = spi;
+ st->info = &max1027_chip_info_tbl[spi_get_device_id(spi)->driver_data];
+
+ mutex_init(&st->lock);
+ init_completion(&st->complete);
+
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->info = &max1027_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = st->info->channels;
+ indio_dev->num_channels = st->info->num_channels;
+ indio_dev->available_scan_masks = st->info->available_scan_masks;
+
+ st->buffer = devm_kmalloc_array(&indio_dev->dev,
+ indio_dev->num_channels, 2,
+ GFP_KERNEL);
+ if (!st->buffer)
+ return -ENOMEM;
+
+ /* Enable triggered buffers */
+ ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
+ &iio_pollfunc_store_time,
+ &max1027_trigger_handler,
+ NULL);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev, "Failed to setup buffer\n");
+ return ret;
+ }
+
+ /* If there is an EOC interrupt, register the cnvst hardware trigger */
+ if (spi->irq) {
+ st->trig = devm_iio_trigger_alloc(&spi->dev, "%s-trigger",
+ indio_dev->name);
+ if (!st->trig) {
+ ret = -ENOMEM;
+ dev_err(&indio_dev->dev,
+ "Failed to allocate iio trigger\n");
+ return ret;
+ }
+
+ st->trig->ops = &max1027_trigger_ops;
+ iio_trigger_set_drvdata(st->trig, indio_dev);
+ ret = devm_iio_trigger_register(&indio_dev->dev,
+ st->trig);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev,
+ "Failed to register iio trigger\n");
+ return ret;
+ }
+
+ ret = devm_request_irq(&spi->dev, spi->irq, max1027_handler,
+ IRQF_TRIGGER_FALLING,
+ spi->dev.driver->name, indio_dev);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev, "Failed to allocate IRQ.\n");
+ return ret;
+ }
+ }
+
+ /* Internal reset */
+ st->reg = MAX1027_RST_REG;
+ ret = spi_write(st->spi, &st->reg, 1);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev, "Failed to reset the ADC\n");
+ return ret;
+ }
+
+ /* Disable averaging */
+ st->reg = MAX1027_AVG_REG;
+ ret = spi_write(st->spi, &st->reg, 1);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev, "Failed to configure averaging register\n");
+ return ret;
+ }
+
+ /* Assume conversion on register write for now */
+ ret = max1027_enable_trigger(indio_dev, false);
+ if (ret)
+ return ret;
+
+ return devm_iio_device_register(&spi->dev, indio_dev);
+}
+
+static struct spi_driver max1027_driver = {
+ .driver = {
+ .name = "max1027",
+ .of_match_table = max1027_adc_dt_ids,
+ },
+ .probe = max1027_probe,
+ .id_table = max1027_id,
+};
+module_spi_driver(max1027_driver);
+
+MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
+MODULE_DESCRIPTION("MAX1X27/MAX1X29/MAX1X31 ADC");
+MODULE_LICENSE("GPL v2");
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-28 07:26:03 +0000