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linux-sg2042/drivers/iio/adc/dln2-adc.c

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/*
* Driver for the Diolan DLN-2 USB-ADC adapter
*
* Copyright (c) 2017 Jack Andersen
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2.
*/
#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;
struct iio_dev *indio_dev = platform_get_drvdata(dln2->pdev);
u16 conflict;
__le16 value;
int olen = sizeof(value);
struct dln2_adc_port_chan port_chan = {
.port = dln2->port,
.chan = channel,
};
ret = iio_device_claim_direct_mode(indio_dev);
if (ret < 0)
return ret;
ret = dln2_adc_set_chan_enabled(dln2, channel, true);
if (ret < 0)
goto release_direct;
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);
release_direct:
iio_device_release_direct_mode(indio_dev);
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:
mutex_lock(&dln2->mutex);
ret = dln2_adc_read(dln2, chan->channel);
mutex_unlock(&dln2->mutex);
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 iio_triggered_buffer_postenable(indio_dev);
}
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;
}
return iio_triggered_buffer_predisable(indio_dev);
}
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->dev.parent = dev;
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, indio_dev->id);
if (!dln2->trig) {
dev_err(dev, "failed to allocate trigger\n");
return -ENOMEM;
}
iio_trigger_set_drvdata(dln2->trig, dln2);
devm_iio_trigger_register(dev, dln2->trig);
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");
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