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// SPDX-License-Identifier: GPL-2.0-only
/*
* STMicroelectronics sensors trigger library driver
*
* Copyright 2012-2013 STMicroelectronics Inc.
*
* Denis Ciocca <denis.ciocca@st.com>
*/
#include <linux/kernel.h>
#include <linux/iio/iio.h>
#include <linux/iio/trigger.h>
#include <linux/interrupt.h>
#include <linux/regmap.h>
#include <linux/iio/common/st_sensors.h>
#include "st_sensors_core.h"
/**
* st_sensors_new_samples_available() - check if more samples came in
* @indio_dev: IIO device reference.
* @sdata: Sensor data.
*
* returns:
* false - no new samples available or read error
* true - new samples available
*/
static bool st_sensors_new_samples_available(struct iio_dev *indio_dev,
struct st_sensor_data *sdata)
{
int ret, status;
/* How would I know if I can't check it? */
if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr)
return true;
/* No scan mask, no interrupt */
if (!indio_dev->active_scan_mask)
return false;
ret = regmap_read(sdata->regmap,
sdata->sensor_settings->drdy_irq.stat_drdy.addr,
&status);
if (ret < 0) {
dev_err(indio_dev->dev.parent,
"error checking samples available\n");
return false;
}
return !!(status & sdata->sensor_settings->drdy_irq.stat_drdy.mask);
}
/**
* st_sensors_irq_handler() - top half of the IRQ-based triggers
* @irq: irq number
* @p: private handler data
*/
static irqreturn_t st_sensors_irq_handler(int irq, void *p)
{
struct iio_trigger *trig = p;
struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
struct st_sensor_data *sdata = iio_priv(indio_dev);
/* Get the time stamp as close in time as possible */
sdata->hw_timestamp = iio_get_time_ns(indio_dev);
return IRQ_WAKE_THREAD;
}
/**
* st_sensors_irq_thread() - bottom half of the IRQ-based triggers
* @irq: irq number
* @p: private handler data
*/
static irqreturn_t st_sensors_irq_thread(int irq, void *p)
{
struct iio_trigger *trig = p;
struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
struct st_sensor_data *sdata = iio_priv(indio_dev);
/*
* If this trigger is backed by a hardware interrupt and we have a
* status register, check if this IRQ came from us. Notice that
* we will process also if st_sensors_new_samples_available()
* returns negative: if we can't check status, then poll
* unconditionally.
*/
if (sdata->hw_irq_trigger &&
st_sensors_new_samples_available(indio_dev, sdata)) {
iio_trigger_poll_nested(p);
} else {
dev_dbg(indio_dev->dev.parent, "spurious IRQ\n");
return IRQ_NONE;
}
/*
* If we have proper level IRQs the handler will be re-entered if
* the line is still active, so return here and come back in through
* the top half if need be.
*/
if (!sdata->edge_irq)
return IRQ_HANDLED;
/*
* If we are using edge IRQs, new samples arrived while processing
* the IRQ and those may be missed unless we pick them here, so poll
* again. If the sensor delivery frequency is very high, this thread
* turns into a polled loop handler.
*/
while (sdata->hw_irq_trigger &&
st_sensors_new_samples_available(indio_dev, sdata)) {
dev_dbg(indio_dev->dev.parent,
"more samples came in during polling\n");
sdata->hw_timestamp = iio_get_time_ns(indio_dev);
iio_trigger_poll_nested(p);
}
return IRQ_HANDLED;
}
int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
const struct iio_trigger_ops *trigger_ops)
{
struct st_sensor_data *sdata = iio_priv(indio_dev);
struct device *parent = indio_dev->dev.parent;
unsigned long irq_trig;
int err;
sdata->trig = devm_iio_trigger_alloc(parent, "%s-trigger",
indio_dev->name);
if (sdata->trig == NULL) {
dev_err(&indio_dev->dev, "failed to allocate iio trigger.\n");
return -ENOMEM;
}
iio_trigger_set_drvdata(sdata->trig, indio_dev);
sdata->trig->ops = trigger_ops;
/*
* If the IRQ is triggered on falling edge, we need to mark the
* interrupt as active low, if the hardware supports this.
*/
irq_trig = irq_get_trigger_type(sdata->irq);
switch(irq_trig) {
case IRQF_TRIGGER_FALLING:
case IRQF_TRIGGER_LOW:
if (!sdata->sensor_settings->drdy_irq.addr_ihl) {
dev_err(&indio_dev->dev,
"falling/low specified for IRQ but hardware supports only rising/high: will request rising/high\n");
if (irq_trig == IRQF_TRIGGER_FALLING)
irq_trig = IRQF_TRIGGER_RISING;
if (irq_trig == IRQF_TRIGGER_LOW)
irq_trig = IRQF_TRIGGER_HIGH;
} else {
/* Set up INT active low i.e. falling edge */
err = st_sensors_write_data_with_mask(indio_dev,
sdata->sensor_settings->drdy_irq.addr_ihl,
sdata->sensor_settings->drdy_irq.mask_ihl, 1);
if (err < 0)
return err;
dev_info(&indio_dev->dev,
"interrupts on the falling edge or active low level\n");
}
break;
case IRQF_TRIGGER_RISING:
dev_info(&indio_dev->dev,
"interrupts on the rising edge\n");
break;
case IRQF_TRIGGER_HIGH:
dev_info(&indio_dev->dev,
"interrupts active high level\n");
break;
default:
/* This is the most preferred mode, if possible */
dev_err(&indio_dev->dev,
"unsupported IRQ trigger specified (%lx), enforce rising edge\n", irq_trig);
irq_trig = IRQF_TRIGGER_RISING;
}
/* Tell the interrupt handler that we're dealing with edges */
if (irq_trig == IRQF_TRIGGER_FALLING ||
irq_trig == IRQF_TRIGGER_RISING) {
if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr) {
dev_err(&indio_dev->dev,
"edge IRQ not supported w/o stat register.\n");
return -EOPNOTSUPP;
}
sdata->edge_irq = true;
} else {
/*
* If we're not using edges (i.e. level interrupts) we
* just mask off the IRQ, handle one interrupt, then
* if the line is still low, we return to the
* interrupt handler top half again and start over.
*/
irq_trig |= IRQF_ONESHOT;
}
/*
* If the interrupt pin is Open Drain, by definition this
* means that the interrupt line may be shared with other
* peripherals. But to do this we also need to have a status
* register and mask to figure out if this sensor was firing
* the IRQ or not, so we can tell the interrupt handle that
* it was "our" interrupt.
*/
if (sdata->int_pin_open_drain &&
sdata->sensor_settings->drdy_irq.stat_drdy.addr)
irq_trig |= IRQF_SHARED;
err = devm_request_threaded_irq(parent,
sdata->irq,
st_sensors_irq_handler,
st_sensors_irq_thread,
irq_trig,
sdata->trig->name,
sdata->trig);
if (err) {
dev_err(&indio_dev->dev, "failed to request trigger IRQ.\n");
return err;
}
err = devm_iio_trigger_register(parent, sdata->trig);
if (err < 0) {
dev_err(&indio_dev->dev, "failed to register iio trigger.\n");
return err;
}
indio_dev->trig = iio_trigger_get(sdata->trig);
return 0;
}
EXPORT_SYMBOL_NS(st_sensors_allocate_trigger, "IIO_ST_SENSORS");
int st_sensors_validate_device(struct iio_trigger *trig,
struct iio_dev *indio_dev)
{
struct iio_dev *indio = iio_trigger_get_drvdata(trig);
if (indio != indio_dev)
return -EINVAL;
return 0;
}
EXPORT_SYMBOL_NS(st_sensors_validate_device, "IIO_ST_SENSORS");
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