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483 lines
10 KiB
483 lines
10 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* as3935.c - Support for AS3935 Franklin lightning sensor |
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* |
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* Copyright (C) 2014, 2017-2018 |
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* Author: Matt Ranostay <[email protected]> |
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*/ |
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#include <linux/module.h> |
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#include <linux/mod_devicetable.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/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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#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_NFLWDTH 0x01 |
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#define AS3935_NFLWDTH_MASK 0x7f |
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#define AS3935_INT 0x03 |
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#define AS3935_INT_MASK 0x0f |
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#define AS3935_DISTURB_INT BIT(2) |
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#define AS3935_EVENT_INT BIT(3) |
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#define AS3935_NOISE_INT BIT(0) |
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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_DEFAULTS 0x3C |
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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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unsigned long noise_tripped; |
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u32 tune_cap; |
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u32 nflwdth_reg; |
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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 ssize_t as3935_noise_level_tripped_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 ret; |
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mutex_lock(&st->lock); |
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ret = sprintf(buf, "%d\n", !time_after(jiffies, st->noise_tripped + HZ)); |
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mutex_unlock(&st->lock); |
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return ret; |
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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 IIO_DEVICE_ATTR(noise_level_tripped, S_IRUGO, |
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as3935_noise_level_tripped_show, NULL, 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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&iio_dev_attr_noise_level_tripped.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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/* 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_RAW) |
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return IIO_VAL_INT; |
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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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.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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iio_get_time_ns(indio_dev)); |
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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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}; |
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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_chained(st->trig); |
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break; |
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case AS3935_DISTURB_INT: |
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case AS3935_NOISE_INT: |
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mutex_lock(&st->lock); |
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st->noise_tripped = jiffies; |
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mutex_unlock(&st->lock); |
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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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as3935_write(st, AS3935_DEFAULTS, 0x96); |
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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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as3935_write(st, AS3935_NFLWDTH, st->nflwdth_reg); |
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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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calibrate_as3935(st); |
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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 void as3935_stop_work(void *data) |
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{ |
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struct iio_dev *indio_dev = data; |
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struct as3935_state *st = iio_priv(indio_dev); |
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cancel_delayed_work_sync(&st->work); |
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} |
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static int as3935_probe(struct spi_device *spi) |
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{ |
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struct device *dev = &spi->dev; |
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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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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(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(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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ret = device_property_read_u32(dev, |
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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(dev, "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(dev, "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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ret = device_property_read_u32(dev, |
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"ams,nflwdth", &st->nflwdth_reg); |
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if (!ret && st->nflwdth_reg > AS3935_NFLWDTH_MASK) { |
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dev_err(dev, "invalid nflwdth setting of %d\n", |
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st->nflwdth_reg); |
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return -EINVAL; |
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} |
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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(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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st->noise_tripped = jiffies - HZ; |
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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 = devm_iio_trigger_register(dev, trig); |
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if (ret) { |
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dev_err(dev, "failed to register trigger\n"); |
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return ret; |
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} |
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ret = devm_iio_triggered_buffer_setup(dev, indio_dev, |
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iio_pollfunc_store_time, |
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as3935_trigger_handler, NULL); |
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if (ret) { |
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dev_err(dev, "cannot setup iio trigger\n"); |
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return ret; |
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} |
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calibrate_as3935(st); |
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INIT_DELAYED_WORK(&st->work, as3935_event_work); |
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ret = devm_add_action(dev, as3935_stop_work, indio_dev); |
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if (ret) |
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return ret; |
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ret = devm_request_irq(dev, spi->irq, |
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&as3935_interrupt_handler, |
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IRQF_TRIGGER_RISING, |
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dev_name(dev), |
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indio_dev); |
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if (ret) { |
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dev_err(dev, "unable to request irq\n"); |
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return ret; |
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} |
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ret = devm_iio_device_register(dev, indio_dev); |
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if (ret < 0) { |
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dev_err(dev, "unable to register device\n"); |
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return ret; |
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} |
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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 = 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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.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 <[email protected]>"); |
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MODULE_DESCRIPTION("AS3935 lightning sensor"); |
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MODULE_LICENSE("GPL");
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