/*
* as3935.c - Support for AS3935 Franklin lightning sensor
*
* Copyright (C) 2014 Matt Ranostay <mranostay@gmail.com>
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that 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.
*
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/workqueue.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/irq.h>
#include <linux/gpio.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>
#include <linux/of_gpio.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_INT 0x03
#define AS3935_INT_MASK 0x07
#define AS3935_EVENT_INT BIT(3)
#define AS3935_NOISE_INT BIT(1)
#define AS3935_DATA 0x07
#define AS3935_DATA_MASK 0x3F
#define AS3935_TUNE_CAP 0x08
#define AS3935_CALIBRATE 0x3D
#define AS3935_WRITE_DATA BIT(15)
#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;
u32 tune_cap;
u8 buf[2] ____cacheline_aligned;
};
static const struct iio_chan_spec as3935_channels[] = {
{
.type = IIO_PROXIMITY,
.info_mask_separate =
BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_PROCESSED),
.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_WRITE_DATA | 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 sprintf(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((const char *) 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 IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0);
static struct attribute *as3935_attributes[] = {
&iio_dev_attr_sensor_sensitivity.dev_attr.attr,
NULL,
};
static 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 (m == IIO_CHAN_INFO_RAW)
return IIO_VAL_INT;
/* storm out of range */
if (*val == AS3935_DATA_MASK)
return -EINVAL;
*val *= 1000;
break;
default:
return -EINVAL;
}
return IIO_VAL_INT;
}
static const struct iio_info as3935_info = {
.driver_module = THIS_MODULE,
.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;
val &= AS3935_DATA_MASK;
val *= 1000;
iio_push_to_buffers_with_timestamp(indio_dev, &val, pf->timestamp);
err_read:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
};
static const struct iio_trigger_ops iio_interrupt_trigger_ops = {
.owner = THIS_MODULE,
};
static void as3935_event_work(struct work_struct *work)
{
struct as3935_state *st;
int val;
st = container_of(work, struct as3935_state, work.work);
as3935_read(st, AS3935_INT, &val);
val &= AS3935_INT_MASK;
switch (val) {
case AS3935_EVENT_INT:
iio_trigger_poll(st->trig, iio_get_time_ns());
break;
case AS3935_NOISE_INT:
dev_warn(&st->spi->dev, "noise level is too high");
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);
/*
* Delay work for >2 milliseconds after an interrupt to allow
* estimated distance to recalculated.
*/
schedule_delayed_work(&st->work, msecs_to_jiffies(3));
return IRQ_HANDLED;
}
static void calibrate_as3935(struct as3935_state *st)
{
mutex_lock(&st->lock);
/* mask disturber interrupt bit */
as3935_write(st, AS3935_INT, BIT(5));
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));
mutex_unlock(&st->lock);
}
#ifdef CONFIG_PM_SLEEP
static int as3935_suspend(struct spi_device *spi, pm_message_t msg)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
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 spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
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);
err_resume:
mutex_unlock(&st->lock);
return ret;
}
#else
#define as3935_suspend NULL
#define as3935_resume NULL
#endif
static int as3935_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct iio_trigger *trig;
struct as3935_state *st;
struct device_node *np = spi->dev.of_node;
int ret;
/* Be sure lightning event interrupt is specified */
if (!spi->irq) {
dev_err(&spi->dev, "unable to get event interrupt\n");
return -EINVAL;
}
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
st->spi = spi;
st->tune_cap = 0;
spi_set_drvdata(spi, indio_dev);
mutex_init(&st->lock);
INIT_DELAYED_WORK(&st->work, as3935_event_work);
ret = of_property_read_u32(np,
"ams,tuning-capacitor-pf", &st->tune_cap);
if (ret) {
st->tune_cap = 0;
dev_warn(&spi->dev,
"no tuning-capacitor-pf set, defaulting to %d",
st->tune_cap);
}
if (st->tune_cap > MAX_PF_CAP) {
dev_err(&spi->dev,
"wrong tuning-capacitor-pf setting of %d\n",
st->tune_cap);
return -EINVAL;
}
indio_dev->dev.parent = &spi->dev;
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(&spi->dev, "%s-dev%d",
indio_dev->name, indio_dev->id);
if (!trig)
return -ENOMEM;
st->trig = trig;
trig->dev.parent = indio_dev->dev.parent;
iio_trigger_set_drvdata(trig, indio_dev);
trig->ops = &iio_interrupt_trigger_ops;
ret = iio_trigger_register(trig);
if (ret) {
dev_err(&spi->dev, "failed to register trigger\n");
return ret;
}
ret = iio_triggered_buffer_setup(indio_dev, NULL,
&as3935_trigger_handler, NULL);
if (ret) {
dev_err(&spi->dev, "cannot setup iio trigger\n");
goto unregister_trigger;
}
calibrate_as3935(st);
ret = devm_request_irq(&spi->dev, spi->irq,
&as3935_interrupt_handler,
IRQF_TRIGGER_RISING,
dev_name(&spi->dev),
indio_dev);
if (ret) {
dev_err(&spi->dev, "unable to request irq\n");
goto unregister_buffer;
}
ret = iio_device_register(indio_dev);
if (ret < 0) {
dev_err(&spi->dev, "unable to register device\n");
goto unregister_buffer;
}
return 0;
unregister_buffer:
iio_triggered_buffer_cleanup(indio_dev);
unregister_trigger:
iio_trigger_unregister(st->trig);
return ret;
};
static int as3935_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct as3935_state *st = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
iio_trigger_unregister(st->trig);
return 0;
};
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",
.owner = THIS_MODULE,
},
.probe = as3935_probe,
.remove = as3935_remove,
.id_table = as3935_id,
.suspend = as3935_suspend,
.resume = as3935_resume,
};
module_spi_driver(as3935_driver);
MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
MODULE_DESCRIPTION("AS3935 lightning sensor");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:as3935");
