iio: Add AS3935 lightning sensor support
authorMatt Ranostay <mranostay@gmail.com>
Wed, 3 Dec 2014 12:53:00 +0000 (12:53 +0000)
committerJonathan Cameron <jic23@kernel.org>
Sun, 16 Mar 2014 18:00:32 +0000 (18:00 +0000)
AS3935 chipset can detect lightning strikes and reports those back as
events and the estimated distance to the storm.

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Documentation/ABI/testing/sysfs-bus-iio-proximity-as3935 [new file with mode: 0644]
drivers/iio/Kconfig
drivers/iio/Makefile
drivers/iio/proximity/Kconfig [new file with mode: 0644]
drivers/iio/proximity/Makefile [new file with mode: 0644]
drivers/iio/proximity/as3935.c [new file with mode: 0644]

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-proximity-as3935 b/Documentation/ABI/testing/sysfs-bus-iio-proximity-as3935
new file mode 100644 (file)
index 0000000..6708c5e
--- /dev/null
@@ -0,0 +1,16 @@
+What           /sys/bus/iio/devices/iio:deviceX/in_proximity_raw
+Date:          March 2014
+KernelVersion: 3.15
+Contact:       Matt Ranostay <mranostay@gmail.com>
+Description:
+               Get the current distance in meters of storm (1km steps)
+               1000-40000 = distance in meters
+
+What           /sys/bus/iio/devices/iio:deviceX/sensor_sensitivity
+Date:          March 2014
+KernelVersion: 3.15
+Contact:       Matt Ranostay <mranostay@gmail.com>
+Description:
+               Show or set the gain boost of the amp, from 0-31 range.
+               18 = indoors (default)
+               14 = outdoors
index 5dd0e120a504cd68cf096c1304512af112c97862..743485e4d6f83c28de0729509b8951b9f112a4eb 100644 (file)
@@ -74,6 +74,7 @@ if IIO_TRIGGER
    source "drivers/iio/trigger/Kconfig"
 endif #IIO_TRIGGER
 source "drivers/iio/pressure/Kconfig"
+source "drivers/iio/proximity/Kconfig"
 source "drivers/iio/temperature/Kconfig"
 
 endif # IIO
index 887d39090d7568391d059bdf9f30902a6123cd25..698afc2d17ce84c62e8e7fea4473558505d11808 100644 (file)
@@ -24,5 +24,6 @@ obj-y += light/
 obj-y += magnetometer/
 obj-y += orientation/
 obj-y += pressure/
+obj-y += proximity/
 obj-y += temperature/
 obj-y += trigger/
diff --git a/drivers/iio/proximity/Kconfig b/drivers/iio/proximity/Kconfig
new file mode 100644 (file)
index 0000000..0c8cdf5
--- /dev/null
@@ -0,0 +1,19 @@
+#
+# Proximity sensors
+#
+
+menu "Lightning sensors"
+
+config AS3935
+       tristate "AS3935 Franklin lightning sensor"
+       select IIO_BUFFER
+       select IIO_TRIGGERED_BUFFER
+       depends on SPI
+       help
+         Say Y here to build SPI interface support for the Austrian
+         Microsystems AS3935 lightning detection sensor.
+
+         To compile this driver as a module, choose M here: the
+         module will be called as3935
+
+endmenu
diff --git a/drivers/iio/proximity/Makefile b/drivers/iio/proximity/Makefile
new file mode 100644 (file)
index 0000000..743adee
--- /dev/null
@@ -0,0 +1,6 @@
+#
+# Makefile for IIO proximity sensors
+#
+
+# When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_AS3935)           += as3935.o
diff --git a/drivers/iio/proximity/as3935.c b/drivers/iio/proximity/as3935.c
new file mode 100644 (file)
index 0000000..bf677bf
--- /dev/null
@@ -0,0 +1,456 @@
+/*
+ * 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");