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iio: hx711: add triggered buffer support

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Add buffer to device data struct and add trigger function

Data format is quite simple:
      voltage - channel 0   32 Bit
      voltage - channel 1   32 Bit
      timestamp             64 Bit

Using both channels at the same time is working quite slow because of
changing the channel which needs a dummy read.

Signed-off-by: Andreas Klinger <ak@it-klinger.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andreas Klinger 2017-12-13 18:10:11 +01:00 committed by Greg Kroah-Hartman
parent 8bcf024f06
commit d3bf60450d
2 changed files with 100 additions and 23 deletions
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2
drivers/iio/adc/Kconfig
View file

@ -319,6 +319,8 @@ config HI8435
config HX711
tristate "AVIA HX711 ADC for weight cells"
depends on GPIOLIB
select IIO_BUFFER
select IIO_TRIGGERED_BUFFER
help
If you say yes here you get support for AVIA HX711 ADC which is used
for weigh cells

121
drivers/iio/adc/hx711.c
View file

@ -24,6 +24,9 @@
#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/gpio/consumer.h>
#include <linux/regulator/consumer.h>
@ -89,6 +92,11 @@ struct hx711_data {
int gain_set; /* gain set on device */
int gain_chan_a; /* gain for channel A */
struct mutex lock;
/*
* triggered buffer
* 2x32-bit channel + 64-bit timestamp
*/
u32 buffer[4];
};
static int hx711_cycle(struct hx711_data *hx711_data)
@ -236,34 +244,40 @@ static int hx711_set_gain_for_channel(struct hx711_data *hx711_data, int chan)
return 0;
}
static int hx711_reset_read(struct hx711_data *hx711_data, int chan)
{
int ret;
int val;
/*
* hx711_reset() must be called from here
* because it could be calling hx711_read() by itself
*/
if (hx711_reset(hx711_data)) {
dev_err(hx711_data->dev, "reset failed!");
return -EIO;
}
ret = hx711_set_gain_for_channel(hx711_data, chan);
if (ret < 0)
return ret;
val = hx711_read(hx711_data);
return val;
}
static int hx711_read_raw(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
int *val, int *val2, long mask)
{
struct hx711_data *hx711_data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&hx711_data->lock);
/*
* hx711_reset() must be called from here
* because it could be calling hx711_read() by itself
*/
if (hx711_reset(hx711_data)) {
mutex_unlock(&hx711_data->lock);
dev_err(hx711_data->dev, "reset failed!");
return -EIO;
}
ret = hx711_set_gain_for_channel(hx711_data, chan->channel);
if (ret < 0) {
mutex_unlock(&hx711_data->lock);
return ret;
}
*val = hx711_read(hx711_data);
*val = hx711_reset_read(hx711_data, chan->channel);
mutex_unlock(&hx711_data->lock);
@ -339,6 +353,36 @@ static int hx711_write_raw_get_fmt(struct iio_dev *indio_dev,
return IIO_VAL_INT_PLUS_NANO;
}
static irqreturn_t hx711_trigger(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct hx711_data *hx711_data = iio_priv(indio_dev);
int i, j = 0;
mutex_lock(&hx711_data->lock);
memset(hx711_data->buffer, 0, sizeof(hx711_data->buffer));
for (i = 0; i < indio_dev->masklength; i++) {
if (!test_bit(i, indio_dev->active_scan_mask))
continue;
hx711_data->buffer[j] = hx711_reset_read(hx711_data,
indio_dev->channels[i].channel);
j++;
}
iio_push_to_buffers_with_timestamp(indio_dev, hx711_data->buffer,
pf->timestamp);
mutex_unlock(&hx711_data->lock);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static ssize_t hx711_scale_available_show(struct device *dev,
struct device_attribute *attr,
char *buf)
@ -387,6 +431,13 @@ static const struct iio_chan_spec hx711_chan_spec[] = {
.indexed = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
.scan_index = 0,
.scan_type = {
.sign = 'u',
.realbits = 24,
.storagebits = 32,
.endianness = IIO_CPU,
},
},
{
.type = IIO_VOLTAGE,
@ -394,7 +445,15 @@ static const struct iio_chan_spec hx711_chan_spec[] = {
.indexed = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
.scan_index = 1,
.scan_type = {
.sign = 'u',
.realbits = 24,
.storagebits = 32,
.endianness = IIO_CPU,
},
},
IIO_CHAN_SOFT_TIMESTAMP(2),
};
static int hx711_probe(struct platform_device *pdev)
@ -459,10 +518,9 @@ static int hx711_probe(struct platform_device *pdev)
* 1 LSB = (AVDD * 100) / GAIN / 1678 [10^-9 mV]
*/
ret = regulator_get_voltage(hx711_data->reg_avdd);
if (ret < 0) {
regulator_disable(hx711_data->reg_avdd);
return ret;
}
if (ret < 0)
goto error_regulator;
/* we need 10^-9 mV */
ret *= 100;
@ -482,12 +540,27 @@ static int hx711_probe(struct platform_device *pdev)
indio_dev->channels = hx711_chan_spec;
indio_dev->num_channels = ARRAY_SIZE(hx711_chan_spec);
ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
hx711_trigger, NULL);
if (ret < 0) {
dev_err(dev, "setup of iio triggered buffer failed\n");
goto error_regulator;
}
ret = iio_device_register(indio_dev);
if (ret < 0) {
dev_err(dev, "Couldn't register the device\n");
regulator_disable(hx711_data->reg_avdd);
goto error_buffer;
}
return 0;
error_buffer:
iio_triggered_buffer_cleanup(indio_dev);
error_regulator:
regulator_disable(hx711_data->reg_avdd);
return ret;
}
@ -501,6 +574,8 @@ static int hx711_remove(struct platform_device *pdev)
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
regulator_disable(hx711_data->reg_avdd);
return 0;