diff options
Diffstat (limited to 'drivers/iio/adc/dln2-adc.c')
| -rw-r--r-- | drivers/iio/adc/dln2-adc.c | 714 |
1 files changed, 714 insertions, 0 deletions
diff --git a/drivers/iio/adc/dln2-adc.c b/drivers/iio/adc/dln2-adc.c new file mode 100644 index 000000000..97d162a3c --- /dev/null +++ b/drivers/iio/adc/dln2-adc.c @@ -0,0 +1,714 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Driver for the Diolan DLN-2 USB-ADC adapter + * + * Copyright (c) 2017 Jack Andersen + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/platform_device.h> +#include <linux/mfd/dln2.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/iio/trigger.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> +#include <linux/iio/buffer.h> +#include <linux/iio/kfifo_buf.h> + +#define DLN2_ADC_MOD_NAME "dln2-adc" + +#define DLN2_ADC_ID 0x06 + +#define DLN2_ADC_GET_CHANNEL_COUNT DLN2_CMD(0x01, DLN2_ADC_ID) +#define DLN2_ADC_ENABLE DLN2_CMD(0x02, DLN2_ADC_ID) +#define DLN2_ADC_DISABLE DLN2_CMD(0x03, DLN2_ADC_ID) +#define DLN2_ADC_CHANNEL_ENABLE DLN2_CMD(0x05, DLN2_ADC_ID) +#define DLN2_ADC_CHANNEL_DISABLE DLN2_CMD(0x06, DLN2_ADC_ID) +#define DLN2_ADC_SET_RESOLUTION DLN2_CMD(0x08, DLN2_ADC_ID) +#define DLN2_ADC_CHANNEL_GET_VAL DLN2_CMD(0x0A, DLN2_ADC_ID) +#define DLN2_ADC_CHANNEL_GET_ALL_VAL DLN2_CMD(0x0B, DLN2_ADC_ID) +#define DLN2_ADC_CHANNEL_SET_CFG DLN2_CMD(0x0C, DLN2_ADC_ID) +#define DLN2_ADC_CHANNEL_GET_CFG DLN2_CMD(0x0D, DLN2_ADC_ID) +#define DLN2_ADC_CONDITION_MET_EV DLN2_CMD(0x10, DLN2_ADC_ID) + +#define DLN2_ADC_EVENT_NONE 0 +#define DLN2_ADC_EVENT_BELOW 1 +#define DLN2_ADC_EVENT_LEVEL_ABOVE 2 +#define DLN2_ADC_EVENT_OUTSIDE 3 +#define DLN2_ADC_EVENT_INSIDE 4 +#define DLN2_ADC_EVENT_ALWAYS 5 + +#define DLN2_ADC_MAX_CHANNELS 8 +#define DLN2_ADC_DATA_BITS 10 + +/* + * Plays similar role to iio_demux_table in subsystem core; except allocated + * in a fixed 8-element array. + */ +struct dln2_adc_demux_table { + unsigned int from; + unsigned int to; + unsigned int length; +}; + +struct dln2_adc { + struct platform_device *pdev; + struct iio_chan_spec iio_channels[DLN2_ADC_MAX_CHANNELS + 1]; + int port, trigger_chan; + struct iio_trigger *trig; + struct mutex mutex; + /* Cached sample period in milliseconds */ + unsigned int sample_period; + /* Demux table */ + unsigned int demux_count; + struct dln2_adc_demux_table demux[DLN2_ADC_MAX_CHANNELS]; + /* Precomputed timestamp padding offset and length */ + unsigned int ts_pad_offset, ts_pad_length; +}; + +struct dln2_adc_port_chan { + u8 port; + u8 chan; +}; + +struct dln2_adc_get_all_vals { + __le16 channel_mask; + __le16 values[DLN2_ADC_MAX_CHANNELS]; +}; + +static void dln2_adc_add_demux(struct dln2_adc *dln2, + unsigned int in_loc, unsigned int out_loc, + unsigned int length) +{ + struct dln2_adc_demux_table *p = dln2->demux_count ? + &dln2->demux[dln2->demux_count - 1] : NULL; + + if (p && p->from + p->length == in_loc && + p->to + p->length == out_loc) { + p->length += length; + } else if (dln2->demux_count < DLN2_ADC_MAX_CHANNELS) { + p = &dln2->demux[dln2->demux_count++]; + p->from = in_loc; + p->to = out_loc; + p->length = length; + } +} + +static void dln2_adc_update_demux(struct dln2_adc *dln2) +{ + int in_ind = -1, out_ind; + unsigned int in_loc = 0, out_loc = 0; + struct iio_dev *indio_dev = platform_get_drvdata(dln2->pdev); + + /* Clear out any old demux */ + dln2->demux_count = 0; + + /* Optimize all 8-channels case */ + if (indio_dev->masklength && + (*indio_dev->active_scan_mask & 0xff) == 0xff) { + dln2_adc_add_demux(dln2, 0, 0, 16); + dln2->ts_pad_offset = 0; + dln2->ts_pad_length = 0; + return; + } + + /* Build demux table from fixed 8-channels to active_scan_mask */ + for_each_set_bit(out_ind, + indio_dev->active_scan_mask, + indio_dev->masklength) { + /* Handle timestamp separately */ + if (out_ind == DLN2_ADC_MAX_CHANNELS) + break; + for (++in_ind; in_ind != out_ind; ++in_ind) + in_loc += 2; + dln2_adc_add_demux(dln2, in_loc, out_loc, 2); + out_loc += 2; + in_loc += 2; + } + + if (indio_dev->scan_timestamp) { + size_t ts_offset = indio_dev->scan_bytes / sizeof(int64_t) - 1; + + dln2->ts_pad_offset = out_loc; + dln2->ts_pad_length = ts_offset * sizeof(int64_t) - out_loc; + } else { + dln2->ts_pad_offset = 0; + dln2->ts_pad_length = 0; + } +} + +static int dln2_adc_get_chan_count(struct dln2_adc *dln2) +{ + int ret; + u8 port = dln2->port; + u8 count; + int olen = sizeof(count); + + ret = dln2_transfer(dln2->pdev, DLN2_ADC_GET_CHANNEL_COUNT, + &port, sizeof(port), &count, &olen); + if (ret < 0) { + dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__); + return ret; + } + if (olen < sizeof(count)) + return -EPROTO; + + return count; +} + +static int dln2_adc_set_port_resolution(struct dln2_adc *dln2) +{ + int ret; + struct dln2_adc_port_chan port_chan = { + .port = dln2->port, + .chan = DLN2_ADC_DATA_BITS, + }; + + ret = dln2_transfer_tx(dln2->pdev, DLN2_ADC_SET_RESOLUTION, + &port_chan, sizeof(port_chan)); + if (ret < 0) + dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__); + + return ret; +} + +static int dln2_adc_set_chan_enabled(struct dln2_adc *dln2, + int channel, bool enable) +{ + int ret; + struct dln2_adc_port_chan port_chan = { + .port = dln2->port, + .chan = channel, + }; + u16 cmd = enable ? DLN2_ADC_CHANNEL_ENABLE : DLN2_ADC_CHANNEL_DISABLE; + + ret = dln2_transfer_tx(dln2->pdev, cmd, &port_chan, sizeof(port_chan)); + if (ret < 0) + dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__); + + return ret; +} + +static int dln2_adc_set_port_enabled(struct dln2_adc *dln2, bool enable, + u16 *conflict_out) +{ + int ret; + u8 port = dln2->port; + __le16 conflict; + int olen = sizeof(conflict); + u16 cmd = enable ? DLN2_ADC_ENABLE : DLN2_ADC_DISABLE; + + if (conflict_out) + *conflict_out = 0; + + ret = dln2_transfer(dln2->pdev, cmd, &port, sizeof(port), + &conflict, &olen); + if (ret < 0) { + dev_dbg(&dln2->pdev->dev, "Problem in %s(%d)\n", + __func__, (int)enable); + if (conflict_out && enable && olen >= sizeof(conflict)) + *conflict_out = le16_to_cpu(conflict); + return ret; + } + if (enable && olen < sizeof(conflict)) + return -EPROTO; + + return ret; +} + +static int dln2_adc_set_chan_period(struct dln2_adc *dln2, + unsigned int channel, unsigned int period) +{ + int ret; + struct { + struct dln2_adc_port_chan port_chan; + __u8 type; + __le16 period; + __le16 low; + __le16 high; + } __packed set_cfg = { + .port_chan.port = dln2->port, + .port_chan.chan = channel, + .type = period ? DLN2_ADC_EVENT_ALWAYS : DLN2_ADC_EVENT_NONE, + .period = cpu_to_le16(period) + }; + + ret = dln2_transfer_tx(dln2->pdev, DLN2_ADC_CHANNEL_SET_CFG, + &set_cfg, sizeof(set_cfg)); + if (ret < 0) + dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__); + + return ret; +} + +static int dln2_adc_read(struct dln2_adc *dln2, unsigned int channel) +{ + int ret, i; + u16 conflict; + __le16 value; + int olen = sizeof(value); + struct dln2_adc_port_chan port_chan = { + .port = dln2->port, + .chan = channel, + }; + + ret = dln2_adc_set_chan_enabled(dln2, channel, true); + if (ret < 0) + return ret; + + ret = dln2_adc_set_port_enabled(dln2, true, &conflict); + if (ret < 0) { + if (conflict) { + dev_err(&dln2->pdev->dev, + "ADC pins conflict with mask %04X\n", + (int)conflict); + ret = -EBUSY; + } + goto disable_chan; + } + + /* + * Call GET_VAL twice due to initial zero-return immediately after + * enabling channel. + */ + for (i = 0; i < 2; ++i) { + ret = dln2_transfer(dln2->pdev, DLN2_ADC_CHANNEL_GET_VAL, + &port_chan, sizeof(port_chan), + &value, &olen); + if (ret < 0) { + dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__); + goto disable_port; + } + if (olen < sizeof(value)) { + ret = -EPROTO; + goto disable_port; + } + } + + ret = le16_to_cpu(value); + +disable_port: + dln2_adc_set_port_enabled(dln2, false, NULL); +disable_chan: + dln2_adc_set_chan_enabled(dln2, channel, false); + + return ret; +} + +static int dln2_adc_read_all(struct dln2_adc *dln2, + struct dln2_adc_get_all_vals *get_all_vals) +{ + int ret; + __u8 port = dln2->port; + int olen = sizeof(*get_all_vals); + + ret = dln2_transfer(dln2->pdev, DLN2_ADC_CHANNEL_GET_ALL_VAL, + &port, sizeof(port), get_all_vals, &olen); + if (ret < 0) { + dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__); + return ret; + } + if (olen < sizeof(*get_all_vals)) + return -EPROTO; + + return ret; +} + +static int dln2_adc_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, + int *val2, + long mask) +{ + int ret; + unsigned int microhertz; + struct dln2_adc *dln2 = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = iio_device_claim_direct_mode(indio_dev); + if (ret < 0) + return ret; + + mutex_lock(&dln2->mutex); + ret = dln2_adc_read(dln2, chan->channel); + mutex_unlock(&dln2->mutex); + + iio_device_release_direct_mode(indio_dev); + + if (ret < 0) + return ret; + + *val = ret; + return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + /* + * Voltage reference is fixed at 3.3v + * 3.3 / (1 << 10) * 1000000000 + */ + *val = 0; + *val2 = 3222656; + return IIO_VAL_INT_PLUS_NANO; + + case IIO_CHAN_INFO_SAMP_FREQ: + if (dln2->sample_period) { + microhertz = 1000000000 / dln2->sample_period; + *val = microhertz / 1000000; + *val2 = microhertz % 1000000; + } else { + *val = 0; + *val2 = 0; + } + + return IIO_VAL_INT_PLUS_MICRO; + + default: + return -EINVAL; + } +} + +static int dln2_adc_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, + int val2, + long mask) +{ + int ret; + unsigned int microhertz; + struct dln2_adc *dln2 = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_SAMP_FREQ: + microhertz = 1000000 * val + val2; + + mutex_lock(&dln2->mutex); + + dln2->sample_period = + microhertz ? 1000000000 / microhertz : UINT_MAX; + if (dln2->sample_period > 65535) { + dln2->sample_period = 65535; + dev_warn(&dln2->pdev->dev, + "clamping period to 65535ms\n"); + } + + /* + * The first requested channel is arbitrated as a shared + * trigger source, so only one event is registered with the + * DLN. The event handler will then read all enabled channel + * values using DLN2_ADC_CHANNEL_GET_ALL_VAL to maintain + * synchronization between ADC readings. + */ + if (dln2->trigger_chan != -1) + ret = dln2_adc_set_chan_period(dln2, + dln2->trigger_chan, dln2->sample_period); + else + ret = 0; + + mutex_unlock(&dln2->mutex); + + return ret; + + default: + return -EINVAL; + } +} + +static int dln2_update_scan_mode(struct iio_dev *indio_dev, + const unsigned long *scan_mask) +{ + struct dln2_adc *dln2 = iio_priv(indio_dev); + int chan_count = indio_dev->num_channels - 1; + int ret, i, j; + + mutex_lock(&dln2->mutex); + + for (i = 0; i < chan_count; ++i) { + ret = dln2_adc_set_chan_enabled(dln2, i, + test_bit(i, scan_mask)); + if (ret < 0) { + for (j = 0; j < i; ++j) + dln2_adc_set_chan_enabled(dln2, j, false); + mutex_unlock(&dln2->mutex); + dev_err(&dln2->pdev->dev, + "Unable to enable ADC channel %d\n", i); + return -EBUSY; + } + } + + dln2_adc_update_demux(dln2); + + mutex_unlock(&dln2->mutex); + + return 0; +} + +#define DLN2_ADC_CHAN(lval, idx) { \ + lval.type = IIO_VOLTAGE; \ + lval.channel = idx; \ + lval.indexed = 1; \ + lval.info_mask_separate = BIT(IIO_CHAN_INFO_RAW); \ + lval.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE) | \ + BIT(IIO_CHAN_INFO_SAMP_FREQ); \ + lval.scan_index = idx; \ + lval.scan_type.sign = 'u'; \ + lval.scan_type.realbits = DLN2_ADC_DATA_BITS; \ + lval.scan_type.storagebits = 16; \ + lval.scan_type.endianness = IIO_LE; \ +} + +/* Assignment version of IIO_CHAN_SOFT_TIMESTAMP */ +#define IIO_CHAN_SOFT_TIMESTAMP_ASSIGN(lval, _si) { \ + lval.type = IIO_TIMESTAMP; \ + lval.channel = -1; \ + lval.scan_index = _si; \ + lval.scan_type.sign = 's'; \ + lval.scan_type.realbits = 64; \ + lval.scan_type.storagebits = 64; \ +} + +static const struct iio_info dln2_adc_info = { + .read_raw = dln2_adc_read_raw, + .write_raw = dln2_adc_write_raw, + .update_scan_mode = dln2_update_scan_mode, +}; + +static irqreturn_t dln2_adc_trigger_h(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct { + __le16 values[DLN2_ADC_MAX_CHANNELS]; + int64_t timestamp_space; + } data; + struct dln2_adc_get_all_vals dev_data; + struct dln2_adc *dln2 = iio_priv(indio_dev); + const struct dln2_adc_demux_table *t; + int ret, i; + + mutex_lock(&dln2->mutex); + ret = dln2_adc_read_all(dln2, &dev_data); + mutex_unlock(&dln2->mutex); + if (ret < 0) + goto done; + + /* Demux operation */ + for (i = 0; i < dln2->demux_count; ++i) { + t = &dln2->demux[i]; + memcpy((void *)data.values + t->to, + (void *)dev_data.values + t->from, t->length); + } + + /* Zero padding space between values and timestamp */ + if (dln2->ts_pad_length) + memset((void *)data.values + dln2->ts_pad_offset, + 0, dln2->ts_pad_length); + + iio_push_to_buffers_with_timestamp(indio_dev, &data, + iio_get_time_ns(indio_dev)); + +done: + iio_trigger_notify_done(indio_dev->trig); + return IRQ_HANDLED; +} + +static int dln2_adc_triggered_buffer_postenable(struct iio_dev *indio_dev) +{ + int ret; + struct dln2_adc *dln2 = iio_priv(indio_dev); + u16 conflict; + unsigned int trigger_chan; + + mutex_lock(&dln2->mutex); + + /* Enable ADC */ + ret = dln2_adc_set_port_enabled(dln2, true, &conflict); + if (ret < 0) { + mutex_unlock(&dln2->mutex); + dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__); + if (conflict) { + dev_err(&dln2->pdev->dev, + "ADC pins conflict with mask %04X\n", + (int)conflict); + ret = -EBUSY; + } + return ret; + } + + /* Assign trigger channel based on first enabled channel */ + trigger_chan = find_first_bit(indio_dev->active_scan_mask, + indio_dev->masklength); + if (trigger_chan < DLN2_ADC_MAX_CHANNELS) { + dln2->trigger_chan = trigger_chan; + ret = dln2_adc_set_chan_period(dln2, dln2->trigger_chan, + dln2->sample_period); + mutex_unlock(&dln2->mutex); + if (ret < 0) { + dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__); + return ret; + } + } else { + dln2->trigger_chan = -1; + mutex_unlock(&dln2->mutex); + } + + return 0; +} + +static int dln2_adc_triggered_buffer_predisable(struct iio_dev *indio_dev) +{ + int ret; + struct dln2_adc *dln2 = iio_priv(indio_dev); + + mutex_lock(&dln2->mutex); + + /* Disable trigger channel */ + if (dln2->trigger_chan != -1) { + dln2_adc_set_chan_period(dln2, dln2->trigger_chan, 0); + dln2->trigger_chan = -1; + } + + /* Disable ADC */ + ret = dln2_adc_set_port_enabled(dln2, false, NULL); + + mutex_unlock(&dln2->mutex); + if (ret < 0) + dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__); + + return ret; +} + +static const struct iio_buffer_setup_ops dln2_adc_buffer_setup_ops = { + .postenable = dln2_adc_triggered_buffer_postenable, + .predisable = dln2_adc_triggered_buffer_predisable, +}; + +static void dln2_adc_event(struct platform_device *pdev, u16 echo, + const void *data, int len) +{ + struct iio_dev *indio_dev = platform_get_drvdata(pdev); + struct dln2_adc *dln2 = iio_priv(indio_dev); + + /* Called via URB completion handler */ + iio_trigger_poll(dln2->trig); +} + +static int dln2_adc_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct dln2_adc *dln2; + struct dln2_platform_data *pdata = dev_get_platdata(&pdev->dev); + struct iio_dev *indio_dev; + int i, ret, chans; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*dln2)); + if (!indio_dev) { + dev_err(dev, "failed allocating iio device\n"); + return -ENOMEM; + } + + dln2 = iio_priv(indio_dev); + dln2->pdev = pdev; + dln2->port = pdata->port; + dln2->trigger_chan = -1; + mutex_init(&dln2->mutex); + + platform_set_drvdata(pdev, indio_dev); + + ret = dln2_adc_set_port_resolution(dln2); + if (ret < 0) { + dev_err(dev, "failed to set ADC resolution to 10 bits\n"); + return ret; + } + + chans = dln2_adc_get_chan_count(dln2); + if (chans < 0) { + dev_err(dev, "failed to get channel count: %d\n", chans); + return chans; + } + if (chans > DLN2_ADC_MAX_CHANNELS) { + chans = DLN2_ADC_MAX_CHANNELS; + dev_warn(dev, "clamping channels to %d\n", + DLN2_ADC_MAX_CHANNELS); + } + + for (i = 0; i < chans; ++i) + DLN2_ADC_CHAN(dln2->iio_channels[i], i) + IIO_CHAN_SOFT_TIMESTAMP_ASSIGN(dln2->iio_channels[i], i); + + indio_dev->name = DLN2_ADC_MOD_NAME; + indio_dev->info = &dln2_adc_info; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = dln2->iio_channels; + indio_dev->num_channels = chans + 1; + indio_dev->setup_ops = &dln2_adc_buffer_setup_ops; + + dln2->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", + indio_dev->name, + iio_device_id(indio_dev)); + if (!dln2->trig) { + dev_err(dev, "failed to allocate trigger\n"); + return -ENOMEM; + } + iio_trigger_set_drvdata(dln2->trig, dln2); + ret = devm_iio_trigger_register(dev, dln2->trig); + if (ret) { + dev_err(dev, "failed to register trigger: %d\n", ret); + return ret; + } + iio_trigger_set_immutable(indio_dev, dln2->trig); + + ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL, + dln2_adc_trigger_h, + &dln2_adc_buffer_setup_ops); + if (ret) { + dev_err(dev, "failed to allocate triggered buffer: %d\n", ret); + return ret; + } + + ret = dln2_register_event_cb(pdev, DLN2_ADC_CONDITION_MET_EV, + dln2_adc_event); + if (ret) { + dev_err(dev, "failed to setup DLN2 periodic event: %d\n", ret); + return ret; + } + + ret = iio_device_register(indio_dev); + if (ret) { + dev_err(dev, "failed to register iio device: %d\n", ret); + goto unregister_event; + } + + return ret; + +unregister_event: + dln2_unregister_event_cb(pdev, DLN2_ADC_CONDITION_MET_EV); + + return ret; +} + +static int dln2_adc_remove(struct platform_device *pdev) +{ + struct iio_dev *indio_dev = platform_get_drvdata(pdev); + + iio_device_unregister(indio_dev); + dln2_unregister_event_cb(pdev, DLN2_ADC_CONDITION_MET_EV); + return 0; +} + +static struct platform_driver dln2_adc_driver = { + .driver.name = DLN2_ADC_MOD_NAME, + .probe = dln2_adc_probe, + .remove = dln2_adc_remove, +}; + +module_platform_driver(dln2_adc_driver); + +MODULE_AUTHOR("Jack Andersen <jackoalan@gmail.com"); +MODULE_DESCRIPTION("Driver for the Diolan DLN2 ADC interface"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:dln2-adc"); |