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iio: st_sensors: support active-low interrupts

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Most ST MEMS Sensors that support interrupts can also handle sending
an active low interrupt, i.e. going from high to low on data ready
(or other interrupt) and thus triggering on a falling edge to the
interrupt controller.

Set up logic to inspect the interrupt line we get for a sensor: if
it is triggering on rising edge, leave everything alone, but if it
triggers on falling edges, set up active low, and if unsupported
configurations appear: warn with errors and reconfigure the interrupt
to a rising edge, which all interrupt generating sensors support.

Create a local header for st_sensors_core.h to share functions
between the sensor core and the trigger setup code.

Cc: Giuseppe Barba <giuseppe.barba@st.com>
Cc: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Linus Walleij
2015-11-19 10:15:17 +01:00
committed by Jonathan Cameron
parent c4f0ebd914
commit a9fd053b56
8 changed files with 101 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/iio/common/st_sensors/st_sensors_core.c
View File

@@ -18,13 +18,15 @@
#include <asm/unaligned.h>
#include <linux/iio/common/st_sensors.h>
#include "st_sensors_core.h"
static inline u32 st_sensors_get_unaligned_le24(const u8 *p)
{
return (s32)((p[0] | p[1] << 8 | p[2] << 16) << 8) >> 8;
}
static int st_sensors_write_data_with_mask(struct iio_dev *indio_dev,
u8 reg_addr, u8 mask, u8 data)
int st_sensors_write_data_with_mask(struct iio_dev *indio_dev,
u8 reg_addr, u8 mask, u8 data)
{
int err;
u8 new_data;

8
drivers/iio/common/st_sensors/st_sensors_core.h Normal file
View File

@@ -0,0 +1,8 @@
/*
* Local functions in the ST Sensors core
*/
#ifndef __ST_SENSORS_CORE_H
#define __ST_SENSORS_CORE_H
int st_sensors_write_data_with_mask(struct iio_dev *indio_dev,
u8 reg_addr, u8 mask, u8 data);
#endif

52
drivers/iio/common/st_sensors/st_sensors_trigger.c
View File

@@ -14,32 +14,65 @@
#include <linux/iio/iio.h>
#include <linux/iio/trigger.h>
#include <linux/interrupt.h>
#include <linux/iio/common/st_sensors.h>
#include "st_sensors_core.h"
int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
const struct iio_trigger_ops *trigger_ops)
{
int err;
int err, irq;
struct st_sensor_data *sdata = iio_priv(indio_dev);
unsigned long irq_trig;
sdata->trig = iio_trigger_alloc("%s-trigger", indio_dev->name);
if (sdata->trig == NULL) {
err = -ENOMEM;
dev_err(&indio_dev->dev, "failed to allocate iio trigger.\n");
goto iio_trigger_alloc_error;
return -ENOMEM;
}
err = request_threaded_irq(sdata->get_irq_data_ready(indio_dev),
irq = sdata->get_irq_data_ready(indio_dev);
irq_trig = irqd_get_trigger_type(irq_get_irq_data(irq));
/*
* If the IRQ is triggered on falling edge, we need to mark the
* interrupt as active low, if the hardware supports this.
*/
if (irq_trig == IRQF_TRIGGER_FALLING) {
if (!sdata->sensor_settings->drdy_irq.addr_ihl) {
dev_err(&indio_dev->dev,
"falling edge specified for IRQ but hardware "
"only support rising edge, will request "
"rising edge\n");
irq_trig = IRQF_TRIGGER_RISING;
} 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)
goto iio_trigger_free;
dev_info(&indio_dev->dev,
"interrupts on the falling edge\n");
}
} else if (irq_trig == IRQF_TRIGGER_RISING) {
dev_info(&indio_dev->dev,
"interrupts on the rising edge\n");
} else {
dev_err(&indio_dev->dev,
"unsupported IRQ trigger specified (%lx), only "
"rising and falling edges supported, enforce "
"rising edge\n", irq_trig);
irq_trig = IRQF_TRIGGER_RISING;
}
err = request_threaded_irq(irq,
iio_trigger_generic_data_rdy_poll,
NULL,
IRQF_TRIGGER_RISING,
irq_trig,
sdata->trig->name,
sdata->trig);
if (err) {
dev_err(&indio_dev->dev, "failed to request trigger IRQ.\n");
goto request_irq_error;
goto iio_trigger_free;
}
iio_trigger_set_drvdata(sdata->trig, indio_dev);
@@ -57,9 +90,8 @@ int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
iio_trigger_register_error:
free_irq(sdata->get_irq_data_ready(indio_dev), sdata->trig);
request_irq_error:
iio_trigger_free:
iio_trigger_free(sdata->trig);
iio_trigger_alloc_error:
return err;
}
EXPORT_SYMBOL(st_sensors_allocate_trigger);