475 lines
10 KiB
C
475 lines
10 KiB
C
/*
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* as3935.c - Support for AS3935 Franklin lightning sensor
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*
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* Copyright (C) 2014 Matt Ranostay <mranostay@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/delay.h>
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#include <linux/workqueue.h>
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#include <linux/mutex.h>
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#include <linux/err.h>
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#include <linux/irq.h>
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#include <linux/gpio.h>
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#include <linux/spi/spi.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/sysfs.h>
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#include <linux/iio/trigger.h>
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#include <linux/iio/trigger_consumer.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/triggered_buffer.h>
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#include <linux/of_gpio.h>
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#define AS3935_AFE_GAIN 0x00
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#define AS3935_AFE_MASK 0x3F
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#define AS3935_AFE_GAIN_MAX 0x1F
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#define AS3935_AFE_PWR_BIT BIT(0)
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#define AS3935_INT 0x03
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#define AS3935_INT_MASK 0x07
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#define AS3935_EVENT_INT BIT(3)
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#define AS3935_NOISE_INT BIT(1)
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#define AS3935_DATA 0x07
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#define AS3935_DATA_MASK 0x3F
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#define AS3935_TUNE_CAP 0x08
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#define AS3935_CALIBRATE 0x3D
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#define AS3935_READ_DATA BIT(14)
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#define AS3935_ADDRESS(x) ((x) << 8)
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#define MAX_PF_CAP 120
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#define TUNE_CAP_DIV 8
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struct as3935_state {
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struct spi_device *spi;
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struct iio_trigger *trig;
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struct mutex lock;
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struct delayed_work work;
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u32 tune_cap;
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u8 buffer[16]; /* 8-bit data + 56-bit padding + 64-bit timestamp */
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u8 buf[2] ____cacheline_aligned;
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};
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static const struct iio_chan_spec as3935_channels[] = {
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{
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.type = IIO_PROXIMITY,
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.info_mask_separate =
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BIT(IIO_CHAN_INFO_RAW) |
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BIT(IIO_CHAN_INFO_PROCESSED) |
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BIT(IIO_CHAN_INFO_SCALE),
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.scan_index = 0,
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.scan_type = {
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.sign = 'u',
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.realbits = 6,
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.storagebits = 8,
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},
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},
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IIO_CHAN_SOFT_TIMESTAMP(1),
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};
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static int as3935_read(struct as3935_state *st, unsigned int reg, int *val)
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{
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u8 cmd;
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int ret;
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cmd = (AS3935_READ_DATA | AS3935_ADDRESS(reg)) >> 8;
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ret = spi_w8r8(st->spi, cmd);
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if (ret < 0)
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return ret;
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*val = ret;
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return 0;
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}
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static int as3935_write(struct as3935_state *st,
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unsigned int reg,
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unsigned int val)
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{
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u8 *buf = st->buf;
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buf[0] = AS3935_ADDRESS(reg) >> 8;
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buf[1] = val;
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return spi_write(st->spi, buf, 2);
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}
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static ssize_t as3935_sensor_sensitivity_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
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int val, ret;
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ret = as3935_read(st, AS3935_AFE_GAIN, &val);
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if (ret)
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return ret;
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val = (val & AS3935_AFE_MASK) >> 1;
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return sprintf(buf, "%d\n", val);
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}
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static ssize_t as3935_sensor_sensitivity_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t len)
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{
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struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
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unsigned long val;
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int ret;
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ret = kstrtoul((const char *) buf, 10, &val);
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if (ret)
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return -EINVAL;
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if (val > AS3935_AFE_GAIN_MAX)
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return -EINVAL;
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as3935_write(st, AS3935_AFE_GAIN, val << 1);
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return len;
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}
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static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
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as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0);
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static struct attribute *as3935_attributes[] = {
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&iio_dev_attr_sensor_sensitivity.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group as3935_attribute_group = {
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.attrs = as3935_attributes,
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};
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static int as3935_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val,
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int *val2,
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long m)
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{
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struct as3935_state *st = iio_priv(indio_dev);
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int ret;
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switch (m) {
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case IIO_CHAN_INFO_PROCESSED:
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case IIO_CHAN_INFO_RAW:
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*val2 = 0;
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ret = as3935_read(st, AS3935_DATA, val);
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if (ret)
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return ret;
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if (m == IIO_CHAN_INFO_RAW)
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return IIO_VAL_INT;
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/* storm out of range */
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if (*val == AS3935_DATA_MASK)
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return -EINVAL;
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if (m == IIO_CHAN_INFO_PROCESSED)
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*val *= 1000;
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break;
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case IIO_CHAN_INFO_SCALE:
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*val = 1000;
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break;
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default:
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return -EINVAL;
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}
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return IIO_VAL_INT;
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}
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static const struct iio_info as3935_info = {
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.driver_module = THIS_MODULE,
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.attrs = &as3935_attribute_group,
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.read_raw = &as3935_read_raw,
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};
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static irqreturn_t as3935_trigger_handler(int irq, void *private)
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{
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struct iio_poll_func *pf = private;
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struct iio_dev *indio_dev = pf->indio_dev;
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struct as3935_state *st = iio_priv(indio_dev);
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int val, ret;
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ret = as3935_read(st, AS3935_DATA, &val);
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if (ret)
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goto err_read;
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st->buffer[0] = val & AS3935_DATA_MASK;
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iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
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pf->timestamp);
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err_read:
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iio_trigger_notify_done(indio_dev->trig);
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return IRQ_HANDLED;
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}
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static const struct iio_trigger_ops iio_interrupt_trigger_ops = {
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.owner = THIS_MODULE,
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};
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static void as3935_event_work(struct work_struct *work)
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{
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struct as3935_state *st;
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int val;
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int ret;
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st = container_of(work, struct as3935_state, work.work);
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ret = as3935_read(st, AS3935_INT, &val);
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if (ret) {
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dev_warn(&st->spi->dev, "read error\n");
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return;
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}
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val &= AS3935_INT_MASK;
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switch (val) {
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case AS3935_EVENT_INT:
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iio_trigger_poll(st->trig);
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break;
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case AS3935_NOISE_INT:
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dev_warn(&st->spi->dev, "noise level is too high\n");
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break;
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}
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}
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static irqreturn_t as3935_interrupt_handler(int irq, void *private)
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{
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struct iio_dev *indio_dev = private;
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struct as3935_state *st = iio_priv(indio_dev);
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/*
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* Delay work for >2 milliseconds after an interrupt to allow
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* estimated distance to recalculated.
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*/
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schedule_delayed_work(&st->work, msecs_to_jiffies(3));
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return IRQ_HANDLED;
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}
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static void calibrate_as3935(struct as3935_state *st)
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{
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mutex_lock(&st->lock);
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/* mask disturber interrupt bit */
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as3935_write(st, AS3935_INT, BIT(5));
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as3935_write(st, AS3935_CALIBRATE, 0x96);
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as3935_write(st, AS3935_TUNE_CAP,
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BIT(5) | (st->tune_cap / TUNE_CAP_DIV));
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mdelay(2);
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as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV));
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mutex_unlock(&st->lock);
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}
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#ifdef CONFIG_PM_SLEEP
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static int as3935_suspend(struct device *dev)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct as3935_state *st = iio_priv(indio_dev);
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int val, ret;
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mutex_lock(&st->lock);
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ret = as3935_read(st, AS3935_AFE_GAIN, &val);
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if (ret)
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goto err_suspend;
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val |= AS3935_AFE_PWR_BIT;
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ret = as3935_write(st, AS3935_AFE_GAIN, val);
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err_suspend:
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mutex_unlock(&st->lock);
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return ret;
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}
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static int as3935_resume(struct device *dev)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct as3935_state *st = iio_priv(indio_dev);
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int val, ret;
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mutex_lock(&st->lock);
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ret = as3935_read(st, AS3935_AFE_GAIN, &val);
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if (ret)
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goto err_resume;
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val &= ~AS3935_AFE_PWR_BIT;
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ret = as3935_write(st, AS3935_AFE_GAIN, val);
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err_resume:
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mutex_unlock(&st->lock);
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return ret;
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}
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static SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume);
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#define AS3935_PM_OPS (&as3935_pm_ops)
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#else
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#define AS3935_PM_OPS NULL
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#endif
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static int as3935_probe(struct spi_device *spi)
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{
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struct iio_dev *indio_dev;
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struct iio_trigger *trig;
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struct as3935_state *st;
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struct device_node *np = spi->dev.of_node;
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int ret;
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/* Be sure lightning event interrupt is specified */
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if (!spi->irq) {
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dev_err(&spi->dev, "unable to get event interrupt\n");
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return -EINVAL;
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}
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indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
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if (!indio_dev)
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return -ENOMEM;
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st = iio_priv(indio_dev);
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st->spi = spi;
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spi_set_drvdata(spi, indio_dev);
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mutex_init(&st->lock);
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INIT_DELAYED_WORK(&st->work, as3935_event_work);
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ret = of_property_read_u32(np,
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"ams,tuning-capacitor-pf", &st->tune_cap);
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if (ret) {
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st->tune_cap = 0;
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dev_warn(&spi->dev,
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"no tuning-capacitor-pf set, defaulting to %d",
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st->tune_cap);
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}
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if (st->tune_cap > MAX_PF_CAP) {
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dev_err(&spi->dev,
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"wrong tuning-capacitor-pf setting of %d\n",
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st->tune_cap);
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return -EINVAL;
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}
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indio_dev->dev.parent = &spi->dev;
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indio_dev->name = spi_get_device_id(spi)->name;
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indio_dev->channels = as3935_channels;
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indio_dev->num_channels = ARRAY_SIZE(as3935_channels);
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->info = &as3935_info;
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trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
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indio_dev->name, indio_dev->id);
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if (!trig)
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return -ENOMEM;
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st->trig = trig;
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trig->dev.parent = indio_dev->dev.parent;
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iio_trigger_set_drvdata(trig, indio_dev);
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trig->ops = &iio_interrupt_trigger_ops;
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ret = iio_trigger_register(trig);
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if (ret) {
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dev_err(&spi->dev, "failed to register trigger\n");
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return ret;
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}
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ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
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&as3935_trigger_handler, NULL);
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if (ret) {
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dev_err(&spi->dev, "cannot setup iio trigger\n");
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goto unregister_trigger;
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}
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calibrate_as3935(st);
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ret = devm_request_irq(&spi->dev, spi->irq,
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&as3935_interrupt_handler,
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IRQF_TRIGGER_RISING,
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dev_name(&spi->dev),
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indio_dev);
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if (ret) {
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dev_err(&spi->dev, "unable to request irq\n");
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goto unregister_buffer;
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}
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ret = iio_device_register(indio_dev);
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if (ret < 0) {
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dev_err(&spi->dev, "unable to register device\n");
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goto unregister_buffer;
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}
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return 0;
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unregister_buffer:
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iio_triggered_buffer_cleanup(indio_dev);
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unregister_trigger:
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iio_trigger_unregister(st->trig);
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return ret;
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}
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static int as3935_remove(struct spi_device *spi)
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{
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struct iio_dev *indio_dev = spi_get_drvdata(spi);
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struct as3935_state *st = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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iio_triggered_buffer_cleanup(indio_dev);
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iio_trigger_unregister(st->trig);
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return 0;
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}
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static const struct of_device_id as3935_of_match[] = {
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{ .compatible = "ams,as3935", },
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{ /* sentinel */ },
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};
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MODULE_DEVICE_TABLE(of, as3935_of_match);
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static const struct spi_device_id as3935_id[] = {
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{"as3935", 0},
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{},
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};
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MODULE_DEVICE_TABLE(spi, as3935_id);
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static struct spi_driver as3935_driver = {
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.driver = {
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.name = "as3935",
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.of_match_table = of_match_ptr(as3935_of_match),
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.pm = AS3935_PM_OPS,
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},
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.probe = as3935_probe,
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.remove = as3935_remove,
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.id_table = as3935_id,
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};
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module_spi_driver(as3935_driver);
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MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
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MODULE_DESCRIPTION("AS3935 lightning sensor");
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MODULE_LICENSE("GPL");
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