diff options
Diffstat (limited to 'drivers/iio/proximity/as3935.c')
| -rw-r--r-- | drivers/iio/proximity/as3935.c | 470 |
1 files changed, 470 insertions, 0 deletions
diff --git a/drivers/iio/proximity/as3935.c b/drivers/iio/proximity/as3935.c new file mode 100644 index 000000000..ebc95cf8f --- /dev/null +++ b/drivers/iio/proximity/as3935.c @@ -0,0 +1,470 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * as3935.c - Support for AS3935 Franklin lightning sensor + * + * Copyright (C) 2014, 2017-2018 + * Author: Matt Ranostay <matt.ranostay@konsulko.com> + */ + +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/workqueue.h> +#include <linux/devm-helpers.h> +#include <linux/mutex.h> +#include <linux/err.h> +#include <linux/irq.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> + +#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_NFLWDTH 0x01 +#define AS3935_NFLWDTH_MASK 0x7f + +#define AS3935_INT 0x03 +#define AS3935_INT_MASK 0x0f +#define AS3935_DISTURB_INT BIT(2) +#define AS3935_EVENT_INT BIT(3) +#define AS3935_NOISE_INT BIT(0) + +#define AS3935_DATA 0x07 +#define AS3935_DATA_MASK 0x3F + +#define AS3935_TUNE_CAP 0x08 +#define AS3935_DEFAULTS 0x3C +#define AS3935_CALIBRATE 0x3D + +#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; + + unsigned long noise_tripped; + u32 tune_cap; + u32 nflwdth_reg; + /* Ensure timestamp is naturally aligned */ + struct { + u8 chan; + s64 timestamp __aligned(8); + } scan; + u8 buf[2] __aligned(IIO_DMA_MINALIGN); +}; + +static const struct iio_chan_spec as3935_channels[] = { + { + .type = IIO_PROXIMITY, + .info_mask_separate = + BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_PROCESSED) | + BIT(IIO_CHAN_INFO_SCALE), + .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_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 sysfs_emit(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(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 ssize_t as3935_noise_level_tripped_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct as3935_state *st = iio_priv(dev_to_iio_dev(dev)); + int ret; + + mutex_lock(&st->lock); + ret = sysfs_emit(buf, "%d\n", !time_after(jiffies, st->noise_tripped + HZ)); + mutex_unlock(&st->lock); + + return ret; +} + +static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR, + as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0); + +static IIO_DEVICE_ATTR(noise_level_tripped, S_IRUGO, + as3935_noise_level_tripped_show, NULL, 0); + +static struct attribute *as3935_attributes[] = { + &iio_dev_attr_sensor_sensitivity.dev_attr.attr, + &iio_dev_attr_noise_level_tripped.dev_attr.attr, + NULL, +}; + +static const 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; + + /* storm out of range */ + if (*val == AS3935_DATA_MASK) + return -EINVAL; + + if (m == IIO_CHAN_INFO_RAW) + return IIO_VAL_INT; + + if (m == IIO_CHAN_INFO_PROCESSED) + *val *= 1000; + break; + case IIO_CHAN_INFO_SCALE: + *val = 1000; + break; + default: + return -EINVAL; + } + + return IIO_VAL_INT; +} + +static const struct iio_info as3935_info = { + .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; + + st->scan.chan = val & AS3935_DATA_MASK; + iio_push_to_buffers_with_timestamp(indio_dev, &st->scan, + iio_get_time_ns(indio_dev)); +err_read: + iio_trigger_notify_done(indio_dev->trig); + + return IRQ_HANDLED; +} + +static void as3935_event_work(struct work_struct *work) +{ + struct as3935_state *st; + int val; + int ret; + + st = container_of(work, struct as3935_state, work.work); + + ret = as3935_read(st, AS3935_INT, &val); + if (ret) { + dev_warn(&st->spi->dev, "read error\n"); + return; + } + + val &= AS3935_INT_MASK; + + switch (val) { + case AS3935_EVENT_INT: + iio_trigger_poll_chained(st->trig); + break; + case AS3935_DISTURB_INT: + case AS3935_NOISE_INT: + mutex_lock(&st->lock); + st->noise_tripped = jiffies; + mutex_unlock(&st->lock); + dev_warn(&st->spi->dev, "noise level is too high\n"); + 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) +{ + as3935_write(st, AS3935_DEFAULTS, 0x96); + 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)); + as3935_write(st, AS3935_NFLWDTH, st->nflwdth_reg); +} + +static int as3935_suspend(struct device *dev) +{ + struct iio_dev *indio_dev = dev_get_drvdata(dev); + 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 device *dev) +{ + struct iio_dev *indio_dev = dev_get_drvdata(dev); + 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); + + calibrate_as3935(st); + +err_resume: + mutex_unlock(&st->lock); + + return ret; +} + +static DEFINE_SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume); + +static int as3935_probe(struct spi_device *spi) +{ + struct device *dev = &spi->dev; + struct iio_dev *indio_dev; + struct iio_trigger *trig; + struct as3935_state *st; + int ret; + + /* Be sure lightning event interrupt is specified */ + if (!spi->irq) { + dev_err(dev, "unable to get event interrupt\n"); + return -EINVAL; + } + + indio_dev = devm_iio_device_alloc(dev, sizeof(*st)); + if (!indio_dev) + return -ENOMEM; + + st = iio_priv(indio_dev); + st->spi = spi; + + spi_set_drvdata(spi, indio_dev); + mutex_init(&st->lock); + + ret = device_property_read_u32(dev, + "ams,tuning-capacitor-pf", &st->tune_cap); + if (ret) { + st->tune_cap = 0; + dev_warn(dev, "no tuning-capacitor-pf set, defaulting to %d", + st->tune_cap); + } + + if (st->tune_cap > MAX_PF_CAP) { + dev_err(dev, "wrong tuning-capacitor-pf setting of %d\n", + st->tune_cap); + return -EINVAL; + } + + ret = device_property_read_u32(dev, + "ams,nflwdth", &st->nflwdth_reg); + if (!ret && st->nflwdth_reg > AS3935_NFLWDTH_MASK) { + dev_err(dev, "invalid nflwdth setting of %d\n", + st->nflwdth_reg); + return -EINVAL; + } + + 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(dev, "%s-dev%d", + indio_dev->name, + iio_device_id(indio_dev)); + + if (!trig) + return -ENOMEM; + + st->trig = trig; + st->noise_tripped = jiffies - HZ; + iio_trigger_set_drvdata(trig, indio_dev); + + ret = devm_iio_trigger_register(dev, trig); + if (ret) { + dev_err(dev, "failed to register trigger\n"); + return ret; + } + + ret = devm_iio_triggered_buffer_setup(dev, indio_dev, + iio_pollfunc_store_time, + as3935_trigger_handler, NULL); + + if (ret) { + dev_err(dev, "cannot setup iio trigger\n"); + return ret; + } + + calibrate_as3935(st); + + ret = devm_delayed_work_autocancel(dev, &st->work, as3935_event_work); + if (ret) + return ret; + + ret = devm_request_irq(dev, spi->irq, + &as3935_interrupt_handler, + IRQF_TRIGGER_RISING, + dev_name(dev), + indio_dev); + + if (ret) { + dev_err(dev, "unable to request irq\n"); + return ret; + } + + ret = devm_iio_device_register(dev, indio_dev); + if (ret < 0) { + dev_err(dev, "unable to register device\n"); + return ret; + } + return 0; +} + +static const struct of_device_id as3935_of_match[] = { + { .compatible = "ams,as3935", }, + { /* sentinel */ }, +}; +MODULE_DEVICE_TABLE(of, as3935_of_match); + +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", + .of_match_table = as3935_of_match, + .pm = pm_sleep_ptr(&as3935_pm_ops), + }, + .probe = as3935_probe, + .id_table = as3935_id, +}; +module_spi_driver(as3935_driver); + +MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>"); +MODULE_DESCRIPTION("AS3935 lightning sensor"); +MODULE_LICENSE("GPL"); |