[PATCH 2/2] iio: Add AS3935 lightning sensor support
From: Matt Ranostay
Date: Thu Jan 30 2014 - 05:11:35 EST
AS3935 chipset can detect lightning strikes and reports those
back as events and the esimated distance to the storm.
Signed-off-by: Matt Ranostay <mranostay@xxxxxxxxx>
---
.../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 <mranostay@xxxxxxxxx>
+ *
+ * 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,
+ },
+ IIO_CHAN_SOFT_TIMESTAMP(1),
+};
+
+static const unsigned long as3935_available_scan_masks[] = { 0x01, 0x0 };
+
+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,
+ 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);
+ 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);
+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);
+
+ return ret;
+};
+
+static int as3935_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+
+ 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 <mranostay@xxxxxxxxx>");
+MODULE_DESCRIPTION("AS3935 lightning sensor");
+MODULE_LICENSE("GPL");
--
1.8.3.2
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