#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/workqueue.h>
#include <linux/devm-helpers.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/irq.h>
#include <linux/spi/spi.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/buffer.h>
#include <linux/iio/triggered_buffer.h>
#define AS3935_AFE_GAIN 0x00
#define AS3935_AFE_MASK 0x3F
#define AS3935_AFE_GAIN_MAX 0x1F
#define AS3935_AFE_PWR_BIT BIT(0)
#define AS3935_NFLWDTH 0x01
#define AS3935_NFLWDTH_MASK 0x7f
#define AS3935_INT 0x03
#define AS3935_INT_MASK 0x0f
#define AS3935_DISTURB_INT BIT(2)
#define AS3935_EVENT_INT BIT(3)
#define AS3935_NOISE_INT BIT(0)
#define AS3935_DATA 0x07
#define AS3935_DATA_MASK 0x3F
#define AS3935_TUNE_CAP 0x08
#define AS3935_DEFAULTS 0x3C
#define AS3935_CALIBRATE 0x3D
#define AS3935_READ_DATA BIT(14)
#define AS3935_ADDRESS(x) ((x) << 8)
#define MAX_PF_CAP 120
#define TUNE_CAP_DIV 8
struct as3935_state {
struct spi_device *spi;
struct iio_trigger *trig;
struct mutex lock;
struct delayed_work work;
unsigned long noise_tripped;
u32 tune_cap;
u32 nflwdth_reg;
struct {
u8 chan;
aligned_s64 timestamp;
} scan;
u8 buf[2] __aligned(IIO_DMA_MINALIGN);
};
static const struct iio_chan_spec as3935_channels[] = {
{
.type = IIO_PROXIMITY,
.info_mask_separate =
BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_PROCESSED) |
BIT(IIO_CHAN_INFO_SCALE),
.scan_index = 0,
.scan_type = {
.sign = 'u',
.realbits = 6,
.storagebits = 8,
},
},
IIO_CHAN_SOFT_TIMESTAMP(1),
};
static int as3935_read(struct as3935_state *st, unsigned int reg, int *val)
{
u8 cmd;
int ret;
cmd = (AS3935_READ_DATA | AS3935_ADDRESS(reg)) >> 8;
ret = spi_w8r8(st->spi, cmd);
if (ret < 0)
return ret;
*val = ret;
return 0;
}
static int as3935_write(struct as3935_state *st,
unsigned int reg,
unsigned int val)
{
u8 *buf = st->buf;
buf[0] = AS3935_ADDRESS(reg) >> 8;
buf[1] = val;
return spi_write(st->spi, buf, 2);
}
static ssize_t as3935_sensor_sensitivity_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
int val, ret;
ret = as3935_read(st, AS3935_AFE_GAIN, &val);
if (ret)
return ret;
val = (val & AS3935_AFE_MASK) >> 1;
return sysfs_emit(buf, "%d\n", val);
}
static ssize_t as3935_sensor_sensitivity_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
unsigned long val;
int ret;
ret = kstrtoul(buf, 10, &val);
if (ret)
return -EINVAL;
if (val > AS3935_AFE_GAIN_MAX)
return -EINVAL;
as3935_write(st, AS3935_AFE_GAIN, val << 1);
return len;
}
static ssize_t as3935_noise_level_tripped_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
int ret;
mutex_lock(&st->lock);
ret = sysfs_emit(buf, "%d\n", !time_after(jiffies, st->noise_tripped + HZ));
mutex_unlock(&st->lock);
return ret;
}
static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0);
static IIO_DEVICE_ATTR(noise_level_tripped, S_IRUGO,
as3935_noise_level_tripped_show, NULL, 0);
static struct attribute *as3935_attributes[] = {
&iio_dev_attr_sensor_sensitivity.dev_attr.attr,
&iio_dev_attr_noise_level_tripped.dev_attr.attr,
NULL,
};
static const struct attribute_group as3935_attribute_group = {
.attrs = as3935_attributes,
};
static int as3935_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long m)
{
struct as3935_state *st = iio_priv(indio_dev);
int ret;
switch (m) {
case IIO_CHAN_INFO_PROCESSED:
case IIO_CHAN_INFO_RAW:
*val2 = 0;
ret = as3935_read(st, AS3935_DATA, val);
if (ret)
return ret;
if (*val == AS3935_DATA_MASK)
return -EINVAL;
if (m == IIO_CHAN_INFO_RAW)
return IIO_VAL_INT;
if (m == IIO_CHAN_INFO_PROCESSED)
*val *= 1000;
break;
case IIO_CHAN_INFO_SCALE:
*val = 1000;
break;
default:
return -EINVAL;
}
return IIO_VAL_INT;
}
static const struct iio_info as3935_info = {
.attrs = &as3935_attribute_group,
.read_raw = &as3935_read_raw,
};
static irqreturn_t as3935_trigger_handler(int irq, void *private)
{
struct iio_poll_func *pf = private;
struct iio_dev *indio_dev = pf->indio_dev;
struct as3935_state *st = iio_priv(indio_dev);
int val, ret;
ret = as3935_read(st, AS3935_DATA, &val);
if (ret)
goto err_read;
st->scan.chan = val & AS3935_DATA_MASK;
iio_push_to_buffers_with_ts(indio_dev, &st->scan, sizeof(st->scan),
iio_get_time_ns(indio_dev));
err_read:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static void as3935_event_work(struct work_struct *work)
{
struct as3935_state *st;
int val;
int ret;
st = container_of(work, struct as3935_state, work.work);
ret = as3935_read(st, AS3935_INT, &val);
if (ret) {
dev_warn(&st->spi->dev, "read error\n");
return;
}
val &= AS3935_INT_MASK;
switch (val) {
case AS3935_EVENT_INT:
iio_trigger_poll_nested(st->trig);
break;
case AS3935_DISTURB_INT:
case AS3935_NOISE_INT:
mutex_lock(&st->lock);
st->noise_tripped = jiffies;
mutex_unlock(&st->lock);
dev_warn(&st->spi->dev, "noise level is too high\n");
break;
}
}
static irqreturn_t as3935_interrupt_handler(int irq, void *private)
{
struct iio_dev *indio_dev = private;
struct as3935_state *st = iio_priv(indio_dev);
schedule_delayed_work(&st->work, msecs_to_jiffies(3));
return IRQ_HANDLED;
}
static void calibrate_as3935(struct as3935_state *st)
{
as3935_write(st, AS3935_DEFAULTS, 0x96);
as3935_write(st, AS3935_CALIBRATE, 0x96);
as3935_write(st, AS3935_TUNE_CAP,
BIT(5) | (st->tune_cap / TUNE_CAP_DIV));
mdelay(2);
as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV));
as3935_write(st, AS3935_NFLWDTH, st->nflwdth_reg);
}
static int as3935_suspend(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct as3935_state *st = iio_priv(indio_dev);
int val, ret;
mutex_lock(&st->lock);
ret = as3935_read(st, AS3935_AFE_GAIN, &val);
if (ret)
goto err_suspend;
val |= AS3935_AFE_PWR_BIT;
ret = as3935_write(st, AS3935_AFE_GAIN, val);
err_suspend:
mutex_unlock(&st->lock);
return ret;
}
static int as3935_resume(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct as3935_state *st = iio_priv(indio_dev);
int val, ret;
mutex_lock(&st->lock);
ret = as3935_read(st, AS3935_AFE_GAIN, &val);
if (ret)
goto err_resume;
val &= ~AS3935_AFE_PWR_BIT;
ret = as3935_write(st, AS3935_AFE_GAIN, val);
calibrate_as3935(st);
err_resume:
mutex_unlock(&st->lock);
return ret;
}
static DEFINE_SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume);
static int as3935_probe(struct spi_device *spi)
{
struct device *dev = &spi->dev;
struct iio_dev *indio_dev;
struct iio_trigger *trig;
struct as3935_state *st;
int ret;
if (!spi->irq) {
dev_err(dev, "unable to get event interrupt\n");
return -EINVAL;
}
indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
st->spi = spi;
spi_set_drvdata(spi, indio_dev);
mutex_init(&st->lock);
ret = device_property_read_u32(dev,
"ams,tuning-capacitor-pf", &st->tune_cap);
if (ret) {
st->tune_cap = 0;
dev_warn(dev, "no tuning-capacitor-pf set, defaulting to %d",
st->tune_cap);
}
if (st->tune_cap > MAX_PF_CAP) {
dev_err(dev, "wrong tuning-capacitor-pf setting of %d\n",
st->tune_cap);
return -EINVAL;
}
ret = device_property_read_u32(dev,
"ams,nflwdth", &st->nflwdth_reg);
if (!ret && st->nflwdth_reg > AS3935_NFLWDTH_MASK) {
dev_err(dev, "invalid nflwdth setting of %d\n",
st->nflwdth_reg);
return -EINVAL;
}
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->channels = as3935_channels;
indio_dev->num_channels = ARRAY_SIZE(as3935_channels);
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &as3935_info;
trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
indio_dev->name,
iio_device_id(indio_dev));
if (!trig)
return -ENOMEM;
st->trig = trig;
st->noise_tripped = jiffies - HZ;
iio_trigger_set_drvdata(trig, indio_dev);
ret = devm_iio_trigger_register(dev, trig);
if (ret) {
dev_err(dev, "failed to register trigger\n");
return ret;
}
ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
iio_pollfunc_store_time,
as3935_trigger_handler, NULL);
if (ret) {
dev_err(dev, "cannot setup iio trigger\n");
return ret;
}
calibrate_as3935(st);
ret = devm_delayed_work_autocancel(dev, &st->work, as3935_event_work);
if (ret)
return ret;
ret = devm_request_irq(dev, spi->irq,
&as3935_interrupt_handler,
IRQF_TRIGGER_RISING,
dev_name(dev),
indio_dev);
if (ret) {
dev_err(dev, "unable to request irq\n");
return ret;
}
ret = devm_iio_device_register(dev, indio_dev);
if (ret < 0) {
dev_err(dev, "unable to register device\n");
return ret;
}
return 0;
}
static const struct of_device_id as3935_of_match[] = {
{ .compatible = "ams,as3935", },
{ }
};
MODULE_DEVICE_TABLE(of, as3935_of_match);
static const struct spi_device_id as3935_id[] = {
{"as3935", 0},
{ }
};
MODULE_DEVICE_TABLE(spi, as3935_id);
static struct spi_driver as3935_driver = {
.driver = {
.name = "as3935",
.of_match_table = as3935_of_match,
.pm = pm_sleep_ptr(&as3935_pm_ops),
},
.probe = as3935_probe,
.id_table = as3935_id,
};
module_spi_driver(as3935_driver);
MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
MODULE_DESCRIPTION("AS3935 lightning sensor");
MODULE_LICENSE("GPL");
