--- /dev/null
+/*
+ * 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");
projects / deliverable / linux.git / commitdiff
