> AS3935 chipset can detect lightning strikes and reports those
> back as events and the esimated distance to the storm.
pretty cool :)
the distance thing should be documented in
Documentation/ABI/testing/sysfs-bus-iio -- which unit (meters?) for
example
sysfs attributes such as boost should be documented as well; or better use
a writable scale attribute if possible
nitpicking inline
> ---
> .../devicetree/bindings/iio/distance/as3935.txt | 25 ++
> drivers/iio/Kconfig | 1 +
> drivers/iio/Makefile | 1 +
> drivers/iio/distance/Kconfig | 19 +
> drivers/iio/distance/Makefile | 6 +
> drivers/iio/distance/as3935.c | 459
> +++++++++++++++++++++
> 6 files changed, 511 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/iio/distance/as3935.txt
> create mode 100644 drivers/iio/distance/Kconfig
> create mode 100644 drivers/iio/distance/Makefile
> create mode 100644 drivers/iio/distance/as3935.c
>
> diff --git a/Documentation/devicetree/bindings/iio/distance/as3935.txt
> b/Documentation/devicetree/bindings/iio/distance/as3935.txt
> new file mode 100644
> index 0000000..af35827
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/distance/as3935.txt
> @@ -0,0 +1,25 @@
> +Austrian Microsystems AS3935 Franklin lightning sensor device driver
> +
> +Required properties:
> + - compatible: must be "ams,as3935"
> + - reg: SPI chip select number for the device
> + - spi-max-frequency: Max SPI frequency to use
> + - spi-cpha: SPI Mode 1
> + - gpios: GPIO input of interrupt line from IRQ pin of AS3935 IC
> +
> +Optional properties:
> + - ams,tune-cap: Calibration tuning capacitor stepping value 0 - 15.
> + Range of 0 to 120 pF, 8pF steps. This will require using the
> calibration
> + data from the manufacturer.
> +
> +
> +Example:
> +
> + as3935@0 {
> + compatible = "ams,as3935";
> + reg = <0>;
> + spi-max-frequency = <100000>;
> + spi-cpha;
> + ams,tune-cap = /bits/ 8 <10>;
> + gpios = <&gpio1 16 10>;
> + };
> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
> index 5dd0e12..5164a68 100644
> --- a/drivers/iio/Kconfig
> +++ b/drivers/iio/Kconfig
> @@ -63,6 +63,7 @@ source "drivers/iio/adc/Kconfig"
> source "drivers/iio/amplifiers/Kconfig"
> source "drivers/iio/common/Kconfig"
> source "drivers/iio/dac/Kconfig"
> +source "drivers/iio/distance/Kconfig"
> source "drivers/iio/frequency/Kconfig"
> source "drivers/iio/gyro/Kconfig"
> source "drivers/iio/humidity/Kconfig"
> diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
> index 887d390..1574731 100644
> --- a/drivers/iio/Makefile
> +++ b/drivers/iio/Makefile
> @@ -16,6 +16,7 @@ obj-y += adc/
> obj-y += amplifiers/
> obj-y += common/
> obj-y += dac/
> +obj-y += distance/
> obj-y += gyro/
> obj-y += frequency/
> obj-y += humidity/
> diff --git a/drivers/iio/distance/Kconfig b/drivers/iio/distance/Kconfig
> new file mode 100644
> index 0000000..753352c
> --- /dev/null
> +++ b/drivers/iio/distance/Kconfig
> @@ -0,0 +1,19 @@
> +#
> +# Distance sensors
> +#
> +
> +menu "Lightning sensors"
> +
> +config AS3935
> + tristate "AS3935 Franklin lightning sensor"
> + select IIO_BUFFER
> + select IIO_TRIGGERED_BUFFER
> + depends on SPI
> + help
> + If you say yes here you get support for the Austrian Microsystems
> + AS3935 lightning detection sensor.
> +
> + This driver can also be built as a module. If so, the module
> + will be called as3935
> +
> +endmenu
> diff --git a/drivers/iio/distance/Makefile b/drivers/iio/distance/Makefile
> new file mode 100644
> index 0000000..f63b70d
> --- /dev/null
> +++ b/drivers/iio/distance/Makefile
> @@ -0,0 +1,6 @@
> +#
> +# Makefile for IIO distance sensors
> +#
> +
> +# When adding new entries keep the list in alphabetical order
> +obj-$(CONFIG_AS3935) += as3935.o
> diff --git a/drivers/iio/distance/as3935.c b/drivers/iio/distance/as3935.c
> new file mode 100644
> index 0000000..1a8f48d
> --- /dev/null
> +++ b/drivers/iio/distance/as3935.c
> @@ -0,0 +1,459 @@
> +/*
> + * as3935.c - Support for AS3935 Franklin lightning sensor
> + *
> + * Copyright (C) 2014 Matt Ranostay <[email protected]>
> + *
> + * 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/mutex.h>
> +#include <linux/workqueue.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/pinctrl/pinctrl.h>
> +#include <linux/pinctrl/pinmux.h>
> +#include <linux/pinctrl/consumer.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/of_gpio.h>
> +
> +
> +#define AS3935_AFE_GAIN 0x00
> +#define AS3935_AFE_MASK 0x3F
> +#define AS3935_AFE_GAIN_MAX 0x1F
> +
> +#define AS3935_INT 0x03
> +#define AS3935_INT_MASK 0x07
> +#define AS3935_DATA 0x07
> +#define AS3935_DATA_MASK 0x1F
> +
> +#define AS3935_TUNE_CAP 0x08
> +#define AS3935_CALIBRATE 0x3D
> +
> +#define AS3935_WRITE_DATA (0x1 << 15)
> +#define AS3935_READ_DATA (0x1 << 14)
> +#define AS3935_ADDRESS(x) (x << 8)
> +
> +#define AS3935_EVENT_INT (1<<3)
> +#define AS3935_NOISE_INT (1<<0)
> +
> +struct as3935_state {
> + struct spi_device *spi;
> + struct mutex lock;
> +
> + struct iio_trigger *trig;
> + struct delayed_work work;
> +
> + u8 tune_cap;
> +};
> +
> +static const struct iio_chan_spec as3935_channels[] = {
> + {
> + .type = IIO_DISTANCE,
> + .channel = 0,
> + .info_mask_separate =
> + BIT(IIO_CHAN_INFO_RAW),
> + .scan_index = 0,
> + .scan_type = {
> + .sign = 'u',
> + .realbits = 6,
> + .storagebits = 6,
> + },
> + .modified = 0,
channel and modified are not needed
storagebits should be a multiple of 8
> + },
> + IIO_CHAN_SOFT_TIMESTAMP(1),
> +};
> +
> +static const unsigned long as3935_available_scan_masks[] = { 0x01, 0x0 };
is this needed? there is just one channel
> +
> +static int as3935_read(struct as3935_state *st, unsigned int reg, int *val)
> +{
> + u8 tx, rx;
> + int ret;
> +
> + struct spi_transfer xfers[] = {
> + {
> + .tx_buf = &tx,
> + .bits_per_word = 8,
> + .len = 1,
> + }, {
> + .rx_buf = &rx,
> + .bits_per_word = 8,
> + .len = 1,
> + },
> + };
> +
> + mutex_lock(&st->lock);
> + tx = (AS3935_READ_DATA | AS3935_ADDRESS(reg)) >> 8;
> +
> + ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));
> + mutex_unlock(&st->lock);
> +
> + *val = rx;
> +
> + return ret;
> +};
> +
> +static int as3935_write(struct as3935_state *st,
> + unsigned int reg,
> + unsigned int val)
> +{
> + u8 buf[2];
> + int ret;
> +
> + mutex_lock(&st->lock);
> + buf[0] = AS3935_WRITE_DATA | AS3935_ADDRESS(reg) >> 8;
> + buf[1] = val;
> +
> + ret = spi_write(st->spi, (u8 *) &buf, 2);
> + mutex_unlock(&st->lock);
> +
> + return ret;
> +};
> +
> +static ssize_t gain_boost_show(struct device *dev,
not prefixed with as3935_
> + 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 gain_boost_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(gain_boost, S_IRUGO | S_IWUSR,
> + gain_boost_show, gain_boost_store, 0);
> +
> +
> +static struct attribute *as3935_attributes[] = {
> + &iio_dev_attr_gain_boost.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);
> +
> + if (m == IIO_CHAN_INFO_RAW) {
> + int ret;
> + *val = 0;
> + ret = as3935_read(st, AS3935_DATA, val2);
huh, this always returns 0?
only val is return if IIO_VAL_INT
> + if (ret)
> + return ret;
> + return IIO_VAL_INT;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static const struct iio_info as3935_info = {
> + .driver_module = THIS_MODULE,
> + .attrs = &as3935_attribute_group,
> + .read_raw = &as3935_read_raw,
> +};
> +
> +static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
> + .postenable = &iio_triggered_buffer_postenable,
> + .predisable = &iio_triggered_buffer_predisable,
> +};
> +
> +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;
> + iio_push_to_buffers_with_timestamp(indio_dev, &val, iio_get_time_ns());
> +
> + iio_trigger_notify_done(indio_dev->trig);
iio_trigger_notify_done() must always be called, most past err_read
> +err_read:
> +
> + 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;
> + struct spi_device *spi;
> + int val;
> +
> + st = container_of(work, struct as3935_state, work.work);
> + spi = st->spi;
> +
> + as3935_read(st, AS3935_INT, &val);
> + val &= AS3935_INT_MASK;
> +
> + switch (val) {
> + case AS3935_EVENT_INT:
> + iio_trigger_poll(st->trig, 0);
> + break;
> + case AS3935_NOISE_INT:
> + dev_warn(&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);
> +
> + cancel_delayed_work(&st->work);
> + schedule_delayed_work(&st->work, jiffies_to_msecs(3));
> + return IRQ_HANDLED;
> +}
> +
> +static void calibrate_as3935(struct as3935_state *st)
> +{
> + /* mask disturber interrupt bit */
> + as3935_write(st, AS3935_INT, 1 << 5);
> +
> + as3935_write(st, AS3935_CALIBRATE, 0x96);
> + as3935_write(st, AS3935_TUNE_CAP, 1 << 5 | st->tune_cap);
> +
> + mdelay(2);
> + as3935_write(st, AS3935_TUNE_CAP, st->tune_cap);
> +}
> +
> +#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;
> +
> + ret = as3935_read(st, AS3935_AFE_GAIN, &val);
> + if (ret)
> + return ret;
> + val |= 0x01;
> +
> + return as3935_write(st, AS3935_AFE_GAIN, val);
> +}
> +
> +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;
> +
> + ret = as3935_read(st, AS3935_AFE_GAIN, &val);
> + if (ret)
> + return ret;
> + val &= ~1;
> +
> + return as3935_write(st, AS3935_AFE_GAIN, val);
> +}
> +#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 gpio;
> + int irq;
> + int ret;
> +
> + /* Grab the GPIO to use for lightning event interrupt */
> + if (np)
> + gpio = of_get_gpio(spi->dev.of_node, 0);
> + else {
> + dev_err(&spi->dev, "unable to get interrupt gpio\n");
> + return -EINVAL;
> + }
> +
> + /* GPIO event setup */
> + ret = devm_gpio_request(&spi->dev, gpio, "as3935");
> + if (ret) {
> + dev_err(&spi->dev, "failed to request GPIO %u\n", gpio);
> + return ret;
> + }
> +
> + ret = gpio_direction_input(gpio);
> + if (ret) {
> + dev_err(&spi->dev, "failed to set pin direction\n");
> + return -EINVAL;
> + }
> +
> + /* IRQ setup */
> + irq = gpio_to_irq(gpio);
> + if (irq < 0) {
> + dev_err(&spi->dev, "failed to map GPIO to IRQ: %d\n", irq);
> + 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);
> +
> + of_property_read_u8(np, "ams,tune-cap", &st->tune_cap);
> + if (st->tune_cap > 15) {
> + dev_err(&spi->dev,
> + "wrong tune_cap 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->available_scan_masks = as3935_available_scan_masks;
> + 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,
> + &iio_triggered_buffer_setup_ops);
> +
> + if (ret) {
> + dev_err(&spi->dev, "cannot setup iio trigger\n");
> + return -EINVAL;
> + }
> +
> + calibrate_as3935(st);
> +
> + ret = devm_request_irq(&spi->dev, 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 uninit_buffer;
> + }
> +
> + ret = iio_device_register(indio_dev);
> + if (ret < 0) {
> + dev_err(&spi->dev, "unable to register device\n");
> + goto uninit_buffer;
> + }
> +
> + return 0;
> +
> +uninit_buffer:
> + iio_triggered_buffer_cleanup(indio_dev);
iio_trigger_unregister()?
> +
> + return ret;
> +};
> +
> +static int as3935_remove(struct spi_device *spi)
> +{
> + struct iio_dev *indio_dev = spi_get_drvdata(spi);
> +
iio_trigger_unregister()?
iio_triggered_buffer_cleanup()?
> + iio_device_unregister(indio_dev);
> + 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 <[email protected]>");
> +MODULE_DESCRIPTION("AS3935 lightning sensor");
> +MODULE_LICENSE("GPL");
>
--
Peter Meerwald
+43-664-2444418 (mobile)
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