// SPDX-License-Identifier: GPL-2.0-only
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/*
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* STMicroelectronics sensors trigger library driver
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*
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* Copyright 2012-2013 STMicroelectronics Inc.
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*
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* Denis Ciocca <denis.ciocca@st.com>
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/trigger.h>
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#include <linux/interrupt.h>
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#include <linux/regmap.h>
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#include <linux/iio/common/st_sensors.h>
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#include "st_sensors_core.h"
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/**
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* st_sensors_new_samples_available() - check if more samples came in
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* @indio_dev: IIO device reference.
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* @sdata: Sensor data.
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*
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* returns:
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* false - no new samples available or read error
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* true - new samples available
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*/
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static bool st_sensors_new_samples_available(struct iio_dev *indio_dev,
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struct st_sensor_data *sdata)
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{
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int ret, status;
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/* How would I know if I can't check it? */
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if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr)
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return true;
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/* No scan mask, no interrupt */
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if (!indio_dev->active_scan_mask)
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return false;
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ret = regmap_read(sdata->regmap,
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sdata->sensor_settings->drdy_irq.stat_drdy.addr,
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&status);
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if (ret < 0) {
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dev_err(sdata->dev, "error checking samples available\n");
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return false;
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}
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return !!(status & sdata->sensor_settings->drdy_irq.stat_drdy.mask);
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}
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/**
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* st_sensors_irq_handler() - top half of the IRQ-based triggers
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* @irq: irq number
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* @p: private handler data
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*/
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static irqreturn_t st_sensors_irq_handler(int irq, void *p)
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{
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struct iio_trigger *trig = p;
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struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
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struct st_sensor_data *sdata = iio_priv(indio_dev);
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/* Get the time stamp as close in time as possible */
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sdata->hw_timestamp = iio_get_time_ns(indio_dev);
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return IRQ_WAKE_THREAD;
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}
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/**
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* st_sensors_irq_thread() - bottom half of the IRQ-based triggers
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* @irq: irq number
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* @p: private handler data
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*/
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static irqreturn_t st_sensors_irq_thread(int irq, void *p)
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{
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struct iio_trigger *trig = p;
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struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
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struct st_sensor_data *sdata = iio_priv(indio_dev);
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/*
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* If this trigger is backed by a hardware interrupt and we have a
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* status register, check if this IRQ came from us. Notice that
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* we will process also if st_sensors_new_samples_available()
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* returns negative: if we can't check status, then poll
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* unconditionally.
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*/
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if (sdata->hw_irq_trigger &&
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st_sensors_new_samples_available(indio_dev, sdata)) {
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iio_trigger_poll_chained(p);
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} else {
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dev_dbg(sdata->dev, "spurious IRQ\n");
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return IRQ_NONE;
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}
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/*
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* If we have proper level IRQs the handler will be re-entered if
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* the line is still active, so return here and come back in through
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* the top half if need be.
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*/
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if (!sdata->edge_irq)
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return IRQ_HANDLED;
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/*
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* If we are using edge IRQs, new samples arrived while processing
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* the IRQ and those may be missed unless we pick them here, so poll
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* again. If the sensor delivery frequency is very high, this thread
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* turns into a polled loop handler.
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*/
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while (sdata->hw_irq_trigger &&
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st_sensors_new_samples_available(indio_dev, sdata)) {
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dev_dbg(sdata->dev, "more samples came in during polling\n");
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sdata->hw_timestamp = iio_get_time_ns(indio_dev);
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iio_trigger_poll_chained(p);
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}
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return IRQ_HANDLED;
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}
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int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
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const struct iio_trigger_ops *trigger_ops)
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{
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struct st_sensor_data *sdata = iio_priv(indio_dev);
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unsigned long irq_trig;
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int err;
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sdata->trig = iio_trigger_alloc("%s-trigger", indio_dev->name);
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if (sdata->trig == NULL) {
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dev_err(&indio_dev->dev, "failed to allocate iio trigger.\n");
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return -ENOMEM;
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}
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iio_trigger_set_drvdata(sdata->trig, indio_dev);
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sdata->trig->ops = trigger_ops;
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sdata->trig->dev.parent = sdata->dev;
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irq_trig = irqd_get_trigger_type(irq_get_irq_data(sdata->irq));
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/*
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* If the IRQ is triggered on falling edge, we need to mark the
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* interrupt as active low, if the hardware supports this.
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*/
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switch(irq_trig) {
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case IRQF_TRIGGER_FALLING:
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case IRQF_TRIGGER_LOW:
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if (!sdata->sensor_settings->drdy_irq.addr_ihl) {
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dev_err(&indio_dev->dev,
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"falling/low specified for IRQ but hardware supports only rising/high: will request rising/high\n");
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if (irq_trig == IRQF_TRIGGER_FALLING)
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irq_trig = IRQF_TRIGGER_RISING;
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if (irq_trig == IRQF_TRIGGER_LOW)
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irq_trig = IRQF_TRIGGER_HIGH;
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} else {
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/* Set up INT active low i.e. falling edge */
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err = st_sensors_write_data_with_mask(indio_dev,
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sdata->sensor_settings->drdy_irq.addr_ihl,
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sdata->sensor_settings->drdy_irq.mask_ihl, 1);
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if (err < 0)
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goto iio_trigger_free;
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dev_info(&indio_dev->dev,
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"interrupts on the falling edge or active low level\n");
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}
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break;
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case IRQF_TRIGGER_RISING:
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dev_info(&indio_dev->dev,
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"interrupts on the rising edge\n");
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break;
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case IRQF_TRIGGER_HIGH:
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dev_info(&indio_dev->dev,
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"interrupts active high level\n");
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break;
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default:
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/* This is the most preferred mode, if possible */
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dev_err(&indio_dev->dev,
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"unsupported IRQ trigger specified (%lx), enforce rising edge\n", irq_trig);
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irq_trig = IRQF_TRIGGER_RISING;
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}
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/* Tell the interrupt handler that we're dealing with edges */
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if (irq_trig == IRQF_TRIGGER_FALLING ||
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irq_trig == IRQF_TRIGGER_RISING) {
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if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr) {
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dev_err(&indio_dev->dev,
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"edge IRQ not supported w/o stat register.\n");
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err = -EOPNOTSUPP;
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goto iio_trigger_free;
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}
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sdata->edge_irq = true;
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} else {
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/*
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* If we're not using edges (i.e. level interrupts) we
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* just mask off the IRQ, handle one interrupt, then
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* if the line is still low, we return to the
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* interrupt handler top half again and start over.
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*/
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irq_trig |= IRQF_ONESHOT;
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}
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/*
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* If the interrupt pin is Open Drain, by definition this
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* means that the interrupt line may be shared with other
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* peripherals. But to do this we also need to have a status
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* register and mask to figure out if this sensor was firing
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* the IRQ or not, so we can tell the interrupt handle that
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* it was "our" interrupt.
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*/
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if (sdata->int_pin_open_drain &&
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sdata->sensor_settings->drdy_irq.stat_drdy.addr)
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irq_trig |= IRQF_SHARED;
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err = request_threaded_irq(sdata->irq,
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st_sensors_irq_handler,
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st_sensors_irq_thread,
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irq_trig,
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sdata->trig->name,
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sdata->trig);
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if (err) {
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dev_err(&indio_dev->dev, "failed to request trigger IRQ.\n");
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goto iio_trigger_free;
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}
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err = iio_trigger_register(sdata->trig);
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if (err < 0) {
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dev_err(&indio_dev->dev, "failed to register iio trigger.\n");
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goto iio_trigger_register_error;
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}
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indio_dev->trig = iio_trigger_get(sdata->trig);
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return 0;
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iio_trigger_register_error:
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free_irq(sdata->irq, sdata->trig);
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iio_trigger_free:
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iio_trigger_free(sdata->trig);
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return err;
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}
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EXPORT_SYMBOL(st_sensors_allocate_trigger);
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void st_sensors_deallocate_trigger(struct iio_dev *indio_dev)
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{
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struct st_sensor_data *sdata = iio_priv(indio_dev);
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iio_trigger_unregister(sdata->trig);
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free_irq(sdata->irq, sdata->trig);
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iio_trigger_free(sdata->trig);
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}
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EXPORT_SYMBOL(st_sensors_deallocate_trigger);
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int st_sensors_validate_device(struct iio_trigger *trig,
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struct iio_dev *indio_dev)
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{
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struct iio_dev *indio = iio_trigger_get_drvdata(trig);
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if (indio != indio_dev)
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return -EINVAL;
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return 0;
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}
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EXPORT_SYMBOL(st_sensors_validate_device);
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MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
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MODULE_DESCRIPTION("STMicroelectronics ST-sensors trigger");
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MODULE_LICENSE("GPL v2");
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