Commit d3bf6045 authored by Andreas Klinger's avatar Andreas Klinger Committed by Greg Kroah-Hartman
Browse files

iio: hx711: add triggered buffer support 



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: default avatarAndreas Klinger <ak@it-klinger.de>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8bcf024f

drivers/iio/adc/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -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

drivers/iio/adc/hx711.c

+98 −23
Original line number Diff line number Diff line
@@ -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_read_raw(struct iio_dev *indio_dev,

				const struct iio_chan_spec *chan,

				int *val, int *val2, long mask)

static int hx711_reset_read(struct hx711_data *hx711_data, int chan)

{

	struct hx711_data *hx711_data = iio_priv(indio_dev);

	int ret;



	switch (mask) {

	case IIO_CHAN_INFO_RAW:

		mutex_lock(&hx711_data->lock);

	int val;



	/*

	 * 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);

	ret = hx711_set_gain_for_channel(hx711_data, chan);

	if (ret < 0)

		return ret;



	val = hx711_read(hx711_data);



	return val;

}



		*val = hx711_read(hx711_data);

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);



	switch (mask) {

	case IIO_CHAN_INFO_RAW:

		mutex_lock(&hx711_data->lock);



		*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;