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* [PATCH 2/2] iio: adc: hx711: Add IIO driver for AVIA HX711
@ 2016-12-13 18:02 Andreas Klinger
  2016-12-13 20:22 ` Peter Meerwald-Stadler
  2016-12-17  8:53 ` Matt Ranostay
  0 siblings, 2 replies; 4+ messages in thread
From: Andreas Klinger @ 2016-12-13 18:02 UTC (permalink / raw)
  To: devicetree, linux-iio
  Cc: linux-kernel, robh+dt, pawel.moll, mark.rutland, ijc+devicetree,
	galak, jic23, knaack.h, lars, pmeerw, ak

This is the IIO driver for AVIA HX711 ADC which ist mostly used in weighting
cells.

The protocol is quite simple and using GPIO's:
One GPIO is used as clock (SCK) while another GPIO is read (DOUT)

Signed-off-by: Andreas Klinger <ak@it-klinger.de>
---
 drivers/iio/adc/Kconfig  |  13 +++
 drivers/iio/adc/Makefile |   1 +
 drivers/iio/adc/hx711.c  | 269 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 283 insertions(+)
 create mode 100644 drivers/iio/adc/hx711.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 932de1f9d1e7..7902b50fcf32 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -205,6 +205,19 @@ config HI8435
 	  This driver can also be built as a module. If so, the module will be
 	  called hi8435.
 
+config HX711
+	tristate "AVIA HX711 ADC for weight cells"
+	depends on GPIOLIB
+	help
+	  If you say yes here you get support for AVIA HX711 ADC which is used
+	  for weight cells
+
+	  This driver uses two GPIO's, one for setting the clock and the other
+	  one for getting the data
+
+	  This driver can also be built as a module. If so, the module will be
+	  called hx711.
+
 config INA2XX_ADC
 	tristate "Texas Instruments INA2xx Power Monitors IIO driver"
 	depends on I2C && !SENSORS_INA2XX
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index b1aa456e6af3..d46e289900ef 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
 obj-$(CONFIG_DA9150_GPADC) += da9150-gpadc.o
 obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
 obj-$(CONFIG_HI8435) += hi8435.o
+obj-$(CONFIG_HX711) += hx711.o
 obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
 obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
 obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
diff --git a/drivers/iio/adc/hx711.c b/drivers/iio/adc/hx711.c
new file mode 100644
index 000000000000..cbc89e467985
--- /dev/null
+++ b/drivers/iio/adc/hx711.c
@@ -0,0 +1,269 @@
+/*
+ * HX711: analog to digital converter for weight sensor module
+ *
+ * Copyright (c) Andreas Klinger <ak@it-klinger.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+
+#define HX711_GAIN_32		2	/* gain = 32 for channel B  */
+#define HX711_GAIN_64		3	/* gain = 64 for channel A  */
+#define HX711_GAIN_128		1	/* gain = 128 for channel A */
+
+
+struct hx711_data {
+	struct device		*dev;
+	dev_t			devt;
+	struct gpio_desc	*gpiod_sck;
+	struct gpio_desc	*gpiod_dout;
+	int			gain_pulse;
+	struct mutex		lock;
+};
+
+static void hx711_reset(struct hx711_data *hx711_data)
+{
+	int val;
+	int i;
+
+	val = gpiod_get_value(hx711_data->gpiod_dout);
+	if (val) {
+		dev_warn(hx711_data->dev, "RESET-HX711\n");
+
+		gpiod_set_value(hx711_data->gpiod_sck, 1);
+		udelay(80);
+		gpiod_set_value(hx711_data->gpiod_sck, 0);
+
+		for (i = 0; i < 1000; i++) {
+			val = gpiod_get_value(hx711_data->gpiod_dout);
+			if (!val)
+				break;
+			/* sleep at least 1 ms*/
+			msleep(1);
+		}
+	}
+}
+
+static int hx711_cycle(struct hx711_data *hx711_data)
+{
+	int val;
+
+	/* if preempted for more then 60us while SCK is high:
+	 * hx711 is going in reset
+	 * ==> measuring is false
+	 */
+	preempt_disable();
+	gpiod_set_value(hx711_data->gpiod_sck, 1);
+	val = gpiod_get_value(hx711_data->gpiod_dout);
+	gpiod_set_value(hx711_data->gpiod_sck, 0);
+	preempt_enable();
+
+	return val;
+}
+
+static unsigned int hx711_read(struct hx711_data *hx711_data)
+{
+	int i;
+	int ret;
+	int wert = 0;
+
+	hx711_reset(hx711_data);
+
+	for (i = 0; i < 24; i++) {
+		wert <<= 1;
+		ret = hx711_cycle(hx711_data);
+		if (ret)
+			wert++;
+	}
+
+	wert ^= 0x800000;
+
+	for (i = 0; i < hx711_data->gain_pulse; i++)
+		ret = hx711_cycle(hx711_data);
+
+	return wert;
+}
+
+
+static int hx711_read_raw(struct iio_dev *iio_dev,
+				const struct iio_chan_spec *chan,
+				int *val, int *val2, long mask)
+{
+	struct hx711_data *hx711_data = iio_priv(iio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			mutex_lock(&hx711_data->lock);
+			*val = (int)hx711_read(hx711_data);
+			mutex_unlock(&hx711_data->lock);
+			ret = IIO_VAL_INT;
+			break;
+		default:
+			return -EINVAL;
+		}
+		return ret;
+	default:
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static const struct iio_info hx711_iio_info = {
+	.driver_module		= THIS_MODULE,
+	.read_raw		= hx711_read_raw,
+};
+
+static const struct iio_chan_spec hx711_chan_spec[] = {
+	{ .type = IIO_VOLTAGE,
+		.channel = 0,
+		.info_mask_separate =
+			BIT(IIO_CHAN_INFO_RAW),
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 24,
+			.storagebits = 32,
+			.shift = 0,
+		}
+	},
+};
+
+static int hx711_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	struct hx711_data *hx711_data = NULL;
+	struct iio_dev *iio;
+	int ret = 0, ival;
+
+	iio = devm_iio_device_alloc(dev, sizeof(struct hx711_data));
+	if (!iio) {
+		dev_err(dev, "failed to allocate IIO device\n");
+		return -ENOMEM;
+	}
+
+	hx711_data = iio_priv(iio);
+	hx711_data->dev = dev;
+
+	mutex_init(&hx711_data->lock);
+
+	hx711_data->gpiod_sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_HIGH);
+	if (IS_ERR(hx711_data->gpiod_sck)) {
+		ret = PTR_ERR(hx711_data->gpiod_sck);
+		goto err;
+	}
+
+	hx711_data->gpiod_dout = devm_gpiod_get(dev, "dout", GPIOD_OUT_HIGH);
+	if (IS_ERR(hx711_data->gpiod_dout)) {
+		ret = PTR_ERR(hx711_data->gpiod_dout);
+		goto err;
+	}
+
+	ret = of_property_read_u32 (node, "gain", &ival);
+	if (!ret) {
+		switch (ival) {
+		case 32:
+			hx711_data->gain_pulse = HX711_GAIN_32;
+			break;
+		case 64:
+			hx711_data->gain_pulse = HX711_GAIN_64;
+			break;
+		case 128:
+			hx711_data->gain_pulse = HX711_GAIN_128;
+			break;
+		default:
+			hx711_data->gain_pulse = HX711_GAIN_128;
+		}
+	} else
+		hx711_data->gain_pulse = HX711_GAIN_128;
+	dev_dbg(hx711_data->dev, "gain: %d\n", hx711_data->gain_pulse);
+
+	ret = gpiod_direction_input(hx711_data->gpiod_dout);
+	if (ret < 0) {
+		dev_err(hx711_data->dev, "gpiod_direction_input: %d\n", ret);
+		goto err;
+	}
+
+	ret = gpiod_direction_output(hx711_data->gpiod_sck, 0);
+	if (ret < 0) {
+		dev_err(hx711_data->dev, "gpiod_direction_output: %d\n", ret);
+		goto err;
+	}
+
+	platform_set_drvdata(pdev, iio);
+
+	iio->name = pdev->name;
+	iio->dev.parent = &pdev->dev;
+	iio->info = &hx711_iio_info;
+	iio->modes = INDIO_DIRECT_MODE;
+	iio->channels = hx711_chan_spec;
+	iio->num_channels = ARRAY_SIZE(hx711_chan_spec);
+
+	dev_err(hx711_data->dev, "initialized\n");
+
+	return devm_iio_device_register(dev, iio);
+
+err:
+	return ret;
+}
+
+
+static int hx711_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int hx711_resume(struct device *dev)
+{
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(hx711_pm_ops, hx711_suspend, hx711_resume);
+
+
+static const struct of_device_id of_hx711_match[] = {
+	{ .compatible = "avia,hx711", },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, of_hx711_match);
+
+static struct platform_driver hx711_driver = {
+	.probe		= hx711_probe,
+	.driver		= {
+		.name		= "hx711-gpio",
+		.pm		= &hx711_pm_ops,
+		.of_match_table	= of_hx711_match,
+	},
+};
+
+module_platform_driver(hx711_driver);
+
+MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
+MODULE_DESCRIPTION("HX711 bitbanging driver - ADC for weight cells");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:hx711-gpio");
+
-- 
2.1.4

^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH 2/2] iio: adc: hx711: Add IIO driver for AVIA HX711
  2016-12-13 18:02 [PATCH 2/2] iio: adc: hx711: Add IIO driver for AVIA HX711 Andreas Klinger
@ 2016-12-13 20:22 ` Peter Meerwald-Stadler
  2016-12-17  8:53 ` Matt Ranostay
  1 sibling, 0 replies; 4+ messages in thread
From: Peter Meerwald-Stadler @ 2016-12-13 20:22 UTC (permalink / raw)
  To: Andreas Klinger
  Cc: devicetree, linux-iio, linux-kernel, robh+dt, pawel.moll,
	mark.rutland, ijc+devicetree, galak, jic23, knaack.h, lars


> This is the IIO driver for AVIA HX711 ADC which ist mostly used in weighting
> cells.

comments below
 
> The protocol is quite simple and using GPIO's:

GPIOs

> One GPIO is used as clock (SCK) while another GPIO is read (DOUT)
> 
> Signed-off-by: Andreas Klinger <ak@it-klinger.de>
> ---
>  drivers/iio/adc/Kconfig  |  13 +++
>  drivers/iio/adc/Makefile |   1 +
>  drivers/iio/adc/hx711.c  | 269 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 283 insertions(+)
>  create mode 100644 drivers/iio/adc/hx711.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 932de1f9d1e7..7902b50fcf32 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -205,6 +205,19 @@ config HI8435
>  	  This driver can also be built as a module. If so, the module will be
>  	  called hi8435.
>  
> +config HX711
> +	tristate "AVIA HX711 ADC for weight cells"
> +	depends on GPIOLIB
> +	help
> +	  If you say yes here you get support for AVIA HX711 ADC which is used
> +	  for weight cells
> +
> +	  This driver uses two GPIO's, one for setting the clock and the other

GPIOs

> +	  one for getting the data
> +
> +	  This driver can also be built as a module. If so, the module will be
> +	  called hx711.
> +
>  config INA2XX_ADC
>  	tristate "Texas Instruments INA2xx Power Monitors IIO driver"
>  	depends on I2C && !SENSORS_INA2XX
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index b1aa456e6af3..d46e289900ef 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -21,6 +21,7 @@ obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
>  obj-$(CONFIG_DA9150_GPADC) += da9150-gpadc.o
>  obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
>  obj-$(CONFIG_HI8435) += hi8435.o
> +obj-$(CONFIG_HX711) += hx711.o
>  obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
>  obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
>  obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
> diff --git a/drivers/iio/adc/hx711.c b/drivers/iio/adc/hx711.c
> new file mode 100644
> index 000000000000..cbc89e467985
> --- /dev/null
> +++ b/drivers/iio/adc/hx711.c
> @@ -0,0 +1,269 @@
> +/*
> + * HX711: analog to digital converter for weight sensor module
> + *
> + * Copyright (c) Andreas Klinger <ak@it-klinger.de>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + */
> +#include <linux/err.h>
> +#include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/slab.h>
> +#include <linux/sched.h>
> +#include <linux/delay.h>
> +#include <linux/iio/iio.h>
> +
> +#define HX711_GAIN_32		2	/* gain = 32 for channel B  */
> +#define HX711_GAIN_64		3	/* gain = 64 for channel A  */
> +#define HX711_GAIN_128		1	/* gain = 128 for channel A */
> +

only one newline here please

> +
> +struct hx711_data {
> +	struct device		*dev;
> +	dev_t			devt;

devt is not used, delete

> +	struct gpio_desc	*gpiod_sck;
> +	struct gpio_desc	*gpiod_dout;
> +	int			gain_pulse;
> +	struct mutex		lock;
> +};
> +
> +static void hx711_reset(struct hx711_data *hx711_data)
> +{
> +	int val;
> +	int i;
> +
> +	val = gpiod_get_value(hx711_data->gpiod_dout);
> +	if (val) {
> +		dev_warn(hx711_data->dev, "RESET-HX711\n");

message needed?

> +
> +		gpiod_set_value(hx711_data->gpiod_sck, 1);
> +		udelay(80);
> +		gpiod_set_value(hx711_data->gpiod_sck, 0);
> +
> +		for (i = 0; i < 1000; i++) {
> +			val = gpiod_get_value(hx711_data->gpiod_dout);
> +			if (!val)
> +				break;
> +			/* sleep at least 1 ms*/

add space before */

> +			msleep(1);
> +		}

can this fail? what is it takes longer than 1000 * 1ms?

> +	}
> +}
> +
> +static int hx711_cycle(struct hx711_data *hx711_data)
> +{
> +	int val;
> +
> +	/* if preempted for more then 60us while SCK is high:
> +	 * hx711 is going in reset
> +	 * ==> measuring is false
> +	 */
> +	preempt_disable();
> +	gpiod_set_value(hx711_data->gpiod_sck, 1);
> +	val = gpiod_get_value(hx711_data->gpiod_dout);
> +	gpiod_set_value(hx711_data->gpiod_sck, 0);
> +	preempt_enable();
> +
> +	return val;
> +}
> +
> +static unsigned int hx711_read(struct hx711_data *hx711_data)
> +{
> +	int i;
> +	int ret;
> +	int wert = 0;

val or value maybe?
should be unsigned int to match the return type of the function

> +
> +	hx711_reset(hx711_data);
> +
> +	for (i = 0; i < 24; i++) {
> +		wert <<= 1;
> +		ret = hx711_cycle(hx711_data);
> +		if (ret)
> +			wert++;
> +	}
> +
> +	wert ^= 0x800000;
> +
> +	for (i = 0; i < hx711_data->gain_pulse; i++)
> +		ret = hx711_cycle(hx711_data);
> +
> +	return wert;
> +}
> +

delete newline

> +
> +static int hx711_read_raw(struct iio_dev *iio_dev,
> +				const struct iio_chan_spec *chan,
> +				int *val, int *val2, long mask)
> +{
> +	struct hx711_data *hx711_data = iio_priv(iio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		switch (chan->type) {
> +		case IIO_VOLTAGE:
> +			mutex_lock(&hx711_data->lock);
> +			*val = (int)hx711_read(hx711_data);
> +			mutex_unlock(&hx711_data->lock);
> +			ret = IIO_VAL_INT;

return IIO_VAL_INT;

> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +		return ret;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return ret;

delete, dead code

> +}
> +
> +static const struct iio_info hx711_iio_info = {
> +	.driver_module		= THIS_MODULE,
> +	.read_raw		= hx711_read_raw,
> +};
> +
> +static const struct iio_chan_spec hx711_chan_spec[] = {
> +	{ .type = IIO_VOLTAGE,
> +		.channel = 0,

.channel = 0 not needed, there is only one channel

> +		.info_mask_separate =
> +			BIT(IIO_CHAN_INFO_RAW),
> +		.scan_type = {

scan_type not needed, driver does not support buffered reads

> +			.sign = 'u',
> +			.realbits = 24,
> +			.storagebits = 32,
> +			.shift = 0,
> +		}
> +	},
> +};
> +
> +static int hx711_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *node = dev->of_node;
> +	struct hx711_data *hx711_data = NULL;
> +	struct iio_dev *iio;
> +	int ret = 0, ival;
> +
> +	iio = devm_iio_device_alloc(dev, sizeof(struct hx711_data));
> +	if (!iio) {
> +		dev_err(dev, "failed to allocate IIO device\n");
> +		return -ENOMEM;
> +	}
> +
> +	hx711_data = iio_priv(iio);
> +	hx711_data->dev = dev;
> +
> +	mutex_init(&hx711_data->lock);
> +
> +	hx711_data->gpiod_sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_HIGH);
> +	if (IS_ERR(hx711_data->gpiod_sck)) {
> +		ret = PTR_ERR(hx711_data->gpiod_sck);
> +		goto err;
> +	}
> +
> +	hx711_data->gpiod_dout = devm_gpiod_get(dev, "dout", GPIOD_OUT_HIGH);
> +	if (IS_ERR(hx711_data->gpiod_dout)) {
> +		ret = PTR_ERR(hx711_data->gpiod_dout);
> +		goto err;
> +	}
> +
> +	ret = of_property_read_u32 (node, "gain", &ival);
> +	if (!ret) {
> +		switch (ival) {
> +		case 32:
> +			hx711_data->gain_pulse = HX711_GAIN_32;
> +			break;
> +		case 64:
> +			hx711_data->gain_pulse = HX711_GAIN_64;
> +			break;
> +		case 128:

merge default and case 128?

> +			hx711_data->gain_pulse = HX711_GAIN_128;
> +			break;
> +		default:
> +			hx711_data->gain_pulse = HX711_GAIN_128;
> +		}
> +	} else
> +		hx711_data->gain_pulse = HX711_GAIN_128;
> +	dev_dbg(hx711_data->dev, "gain: %d\n", hx711_data->gain_pulse);
> +
> +	ret = gpiod_direction_input(hx711_data->gpiod_dout);
> +	if (ret < 0) {
> +		dev_err(hx711_data->dev, "gpiod_direction_input: %d\n", ret);
> +		goto err;
> +	}
> +
> +	ret = gpiod_direction_output(hx711_data->gpiod_sck, 0);
> +	if (ret < 0) {
> +		dev_err(hx711_data->dev, "gpiod_direction_output: %d\n", ret);
> +		goto err;
> +	}
> +
> +	platform_set_drvdata(pdev, iio);
> +
> +	iio->name = pdev->name;
> +	iio->dev.parent = &pdev->dev;
> +	iio->info = &hx711_iio_info;
> +	iio->modes = INDIO_DIRECT_MODE;
> +	iio->channels = hx711_chan_spec;
> +	iio->num_channels = ARRAY_SIZE(hx711_chan_spec);
> +
> +	dev_err(hx711_data->dev, "initialized\n");

excessive logging, please remove

> +
> +	return devm_iio_device_register(dev, iio);
> +
> +err:
> +	return ret;

just return directly without goto?

> +}
> +
> +
> +static int hx711_suspend(struct device *dev)
> +{

pointless, just don't do PM support

> +	return 0;
> +}
> +
> +static int hx711_resume(struct device *dev)
> +{
> +	return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(hx711_pm_ops, hx711_suspend, hx711_resume);
> +
> +
> +static const struct of_device_id of_hx711_match[] = {
> +	{ .compatible = "avia,hx711", },
> +	{},
> +};
> +
> +MODULE_DEVICE_TABLE(of, of_hx711_match);
> +
> +static struct platform_driver hx711_driver = {
> +	.probe		= hx711_probe,
> +	.driver		= {
> +		.name		= "hx711-gpio",
> +		.pm		= &hx711_pm_ops,
> +		.of_match_table	= of_hx711_match,
> +	},
> +};
> +
> +module_platform_driver(hx711_driver);
> +
> +MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
> +MODULE_DESCRIPTION("HX711 bitbanging driver - ADC for weight cells");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:hx711-gpio");
> +
> 

-- 

Peter Meerwald-Stadler
+43-664-2444418 (mobile)

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH 2/2] iio: adc: hx711: Add IIO driver for AVIA HX711
  2016-12-13 18:02 [PATCH 2/2] iio: adc: hx711: Add IIO driver for AVIA HX711 Andreas Klinger
  2016-12-13 20:22 ` Peter Meerwald-Stadler
@ 2016-12-17  8:53 ` Matt Ranostay
  2016-12-19  9:26   ` Andreas Klinger
  1 sibling, 1 reply; 4+ messages in thread
From: Matt Ranostay @ 2016-12-17  8:53 UTC (permalink / raw)
  To: Andreas Klinger
  Cc: devicetree, linux-iio, linux-kernel, robh+dt, pawel.moll,
	mark.rutland, ijc+devicetree, galak, jic23, knaack.h, lars,
	pmeerw

On Tue, Dec 13, 2016 at 10:02 AM, Andreas Klinger <ak@it-klinger.de> wrote:
> This is the IIO driver for AVIA HX711 ADC which ist mostly used in weighting
> cells.

First off cool that this is finally getting a driver... I'll have to
get the SparkFun breakout and really cheap scale to test :).

>
> The protocol is quite simple and using GPIO's:
> One GPIO is used as clock (SCK) while another GPIO is read (DOUT)
>
> Signed-off-by: Andreas Klinger <ak@it-klinger.de>
> ---
>  drivers/iio/adc/Kconfig  |  13 +++
>  drivers/iio/adc/Makefile |   1 +
>  drivers/iio/adc/hx711.c  | 269 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 283 insertions(+)
>  create mode 100644 drivers/iio/adc/hx711.c
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 932de1f9d1e7..7902b50fcf32 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -205,6 +205,19 @@ config HI8435
>           This driver can also be built as a module. If so, the module will be
>           called hi8435.
>
> +config HX711
> +       tristate "AVIA HX711 ADC for weight cells"
> +       depends on GPIOLIB
> +       help
> +         If you say yes here you get support for AVIA HX711 ADC which is used
> +         for weight cells
> +
> +         This driver uses two GPIO's, one for setting the clock and the other
> +         one for getting the data
> +
> +         This driver can also be built as a module. If so, the module will be
> +         called hx711.
> +
>  config INA2XX_ADC
>         tristate "Texas Instruments INA2xx Power Monitors IIO driver"
>         depends on I2C && !SENSORS_INA2XX
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index b1aa456e6af3..d46e289900ef 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -21,6 +21,7 @@ obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
>  obj-$(CONFIG_DA9150_GPADC) += da9150-gpadc.o
>  obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
>  obj-$(CONFIG_HI8435) += hi8435.o
> +obj-$(CONFIG_HX711) += hx711.o
>  obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
>  obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
>  obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
> diff --git a/drivers/iio/adc/hx711.c b/drivers/iio/adc/hx711.c
> new file mode 100644
> index 000000000000..cbc89e467985
> --- /dev/null
> +++ b/drivers/iio/adc/hx711.c
> @@ -0,0 +1,269 @@
> +/*
> + * HX711: analog to digital converter for weight sensor module
> + *
> + * Copyright (c) Andreas Klinger <ak@it-klinger.de>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + */
> +#include <linux/err.h>
> +#include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/slab.h>
> +#include <linux/sched.h>
> +#include <linux/delay.h>
> +#include <linux/iio/iio.h>
> +
> +#define HX711_GAIN_32          2       /* gain = 32 for channel B  */
> +#define HX711_GAIN_64          3       /* gain = 64 for channel A  */
> +#define HX711_GAIN_128         1       /* gain = 128 for channel A */
> +
> +
> +struct hx711_data {
> +       struct device           *dev;
> +       dev_t                   devt;
> +       struct gpio_desc        *gpiod_sck;
> +       struct gpio_desc        *gpiod_dout;
> +       int                     gain_pulse;
> +       struct mutex            lock;
> +};
> +
> +static void hx711_reset(struct hx711_data *hx711_data)
> +{
> +       int val;
> +       int i;
> +
> +       val = gpiod_get_value(hx711_data->gpiod_dout);

could move the val assignment here to the initialization don't think
it will hit 80 chars

> +       if (val) {

move "int i" here to avoid compiler initialization warnings

> +               dev_warn(hx711_data->dev, "RESET-HX711\n");
> +
> +               gpiod_set_value(hx711_data->gpiod_sck, 1);
> +               udelay(80);

IIRC this chip has quite a bit of latency thresholds, can't use
usleep_range? Single core embedded systems could have an issue with
continuous  polling.

> +               gpiod_set_value(hx711_data->gpiod_sck, 0);
> +
> +               for (i = 0; i < 1000; i++) {
> +                       val = gpiod_get_value(hx711_data->gpiod_dout);
> +                       if (!val)
> +                               break;
> +                       /* sleep at least 1 ms*/
> +                       msleep(1);
> +               }
> +       }
> +}
> +
> +static int hx711_cycle(struct hx711_data *hx711_data)
> +{
> +       int val;
> +
> +       /* if preempted for more then 60us while SCK is high:
> +        * hx711 is going in reset
> +        * ==> measuring is false
> +        */
> +       preempt_disable();
> +       gpiod_set_value(hx711_data->gpiod_sck, 1);
> +       val = gpiod_get_value(hx711_data->gpiod_dout);
> +       gpiod_set_value(hx711_data->gpiod_sck, 0);
> +       preempt_enable();
> +
> +       return val;
> +}
> +
> +static unsigned int hx711_read(struct hx711_data *hx711_data)
> +{
> +       int i;
> +       int ret;
> +       int wert = 0;
> +
> +       hx711_reset(hx711_data);
> +
> +       for (i = 0; i < 24; i++) {
> +               wert <<= 1;
> +               ret = hx711_cycle(hx711_data);
> +               if (ret)
> +                       wert++;
> +       }
> +
> +       wert ^= 0x800000;
> +
> +       for (i = 0; i < hx711_data->gain_pulse; i++)
> +               ret = hx711_cycle(hx711_data);

What is ret used for here?
> +
> +       return wert;
> +}
> +
> +
> +static int hx711_read_raw(struct iio_dev *iio_dev,
> +                               const struct iio_chan_spec *chan,
> +                               int *val, int *val2, long mask)
> +{
> +       struct hx711_data *hx711_data = iio_priv(iio_dev);
> +       int ret;
> +
> +       switch (mask) {
> +       case IIO_CHAN_INFO_RAW:
> +               switch (chan->type) {
> +               case IIO_VOLTAGE:
> +                       mutex_lock(&hx711_data->lock);
> +                       *val = (int)hx711_read(hx711_data);
> +                       mutex_unlock(&hx711_data->lock);
> +                       ret = IIO_VAL_INT;
> +                       break;
> +               default:
> +                       return -EINVAL;
> +               }
> +               return ret;
> +       default:
> +               return -EINVAL;
> +       }
> +
> +       return ret;
> +}
> +
> +static const struct iio_info hx711_iio_info = {
> +       .driver_module          = THIS_MODULE,
> +       .read_raw               = hx711_read_raw,
> +};
> +
> +static const struct iio_chan_spec hx711_chan_spec[] = {
> +       { .type = IIO_VOLTAGE,
> +               .channel = 0,
> +               .info_mask_separate =
> +                       BIT(IIO_CHAN_INFO_RAW),
> +               .scan_type = {
> +                       .sign = 'u',
> +                       .realbits = 24,
> +                       .storagebits = 32,
> +                       .shift = 0,
> +               }
> +       },
> +};
> +
> +static int hx711_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct device_node *node = dev->of_node;
> +       struct hx711_data *hx711_data = NULL;
> +       struct iio_dev *iio;
> +       int ret = 0, ival;
> +
> +       iio = devm_iio_device_alloc(dev, sizeof(struct hx711_data));
> +       if (!iio) {
> +               dev_err(dev, "failed to allocate IIO device\n");
> +               return -ENOMEM;
> +       }
> +
> +       hx711_data = iio_priv(iio);
> +       hx711_data->dev = dev;
> +
> +       mutex_init(&hx711_data->lock);
> +
> +       hx711_data->gpiod_sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_HIGH);
> +       if (IS_ERR(hx711_data->gpiod_sck)) {
> +               ret = PTR_ERR(hx711_data->gpiod_sck);
> +               goto err;
> +       }
> +
> +       hx711_data->gpiod_dout = devm_gpiod_get(dev, "dout", GPIOD_OUT_HIGH);
> +       if (IS_ERR(hx711_data->gpiod_dout)) {
> +               ret = PTR_ERR(hx711_data->gpiod_dout);
> +               goto err;
> +       }
> +
> +       ret = of_property_read_u32 (node, "gain", &ival);
> +       if (!ret) {
> +               switch (ival) {
> +               case 32:
> +                       hx711_data->gain_pulse = HX711_GAIN_32;
> +                       break;
> +               case 64:
> +                       hx711_data->gain_pulse = HX711_GAIN_64;
> +                       break;
> +               case 128:
> +                       hx711_data->gain_pulse = HX711_GAIN_128;
> +                       break;
> +               default:
> +                       hx711_data->gain_pulse = HX711_GAIN_128;
> +               }
> +       } else
> +               hx711_data->gain_pulse = HX711_GAIN_128;
> +       dev_dbg(hx711_data->dev, "gain: %d\n", hx711_data->gain_pulse);
> +
> +       ret = gpiod_direction_input(hx711_data->gpiod_dout);
> +       if (ret < 0) {
> +               dev_err(hx711_data->dev, "gpiod_direction_input: %d\n", ret);
> +               goto err;
> +       }
> +
> +       ret = gpiod_direction_output(hx711_data->gpiod_sck, 0);
> +       if (ret < 0) {
> +               dev_err(hx711_data->dev, "gpiod_direction_output: %d\n", ret);
> +               goto err;
> +       }
> +
> +       platform_set_drvdata(pdev, iio);
> +
> +       iio->name = pdev->name;
> +       iio->dev.parent = &pdev->dev;
> +       iio->info = &hx711_iio_info;
> +       iio->modes = INDIO_DIRECT_MODE;
> +       iio->channels = hx711_chan_spec;
> +       iio->num_channels = ARRAY_SIZE(hx711_chan_spec);
> +
> +       dev_err(hx711_data->dev, "initialized\n");
> +
> +       return devm_iio_device_register(dev, iio);
> +
> +err:
> +       return ret;
> +}
> +
> +
> +static int hx711_suspend(struct device *dev)
> +{
> +       return 0;
> +}
> +
> +static int hx711_resume(struct device *dev)
> +{
> +       return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(hx711_pm_ops, hx711_suspend, hx711_resume);
> +
> +
> +static const struct of_device_id of_hx711_match[] = {
> +       { .compatible = "avia,hx711", },
> +       {},
> +};
> +
> +MODULE_DEVICE_TABLE(of, of_hx711_match);
> +
> +static struct platform_driver hx711_driver = {
> +       .probe          = hx711_probe,
> +       .driver         = {
> +               .name           = "hx711-gpio",
> +               .pm             = &hx711_pm_ops,
> +               .of_match_table = of_hx711_match,
> +       },
> +};
> +
> +module_platform_driver(hx711_driver);
> +
> +MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
> +MODULE_DESCRIPTION("HX711 bitbanging driver - ADC for weight cells");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:hx711-gpio");
> +
> --
> 2.1.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH 2/2] iio: adc: hx711: Add IIO driver for AVIA HX711
  2016-12-17  8:53 ` Matt Ranostay
@ 2016-12-19  9:26   ` Andreas Klinger
  0 siblings, 0 replies; 4+ messages in thread
From: Andreas Klinger @ 2016-12-19  9:26 UTC (permalink / raw)
  To: Matt Ranostay
  Cc: devicetree, linux-iio, linux-kernel, robh+dt, pawel.moll,
	mark.rutland, ijc+devicetree, galak, jic23, knaack.h, lars,
	pmeerw

Hello Matt,

thank you for your suggestions. See below.


Matt Ranostay <matt.ranostay@konsulko.com> schrieb am Sat, 17. Dec 00:53:
> On Tue, Dec 13, 2016 at 10:02 AM, Andreas Klinger <ak@it-klinger.de> wrote:
> > This is the IIO driver for AVIA HX711 ADC which ist mostly used in weighting
> > cells.
> 
> First off cool that this is finally getting a driver... I'll have to
> get the SparkFun breakout and really cheap scale to test :).
> 
> >
> > The protocol is quite simple and using GPIO's:
> > One GPIO is used as clock (SCK) while another GPIO is read (DOUT)
> >
> > Signed-off-by: Andreas Klinger <ak@it-klinger.de>
> > ---
> >  drivers/iio/adc/Kconfig  |  13 +++
> >  drivers/iio/adc/Makefile |   1 +
> >  drivers/iio/adc/hx711.c  | 269 +++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 283 insertions(+)
> >  create mode 100644 drivers/iio/adc/hx711.c
> >
> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > index 932de1f9d1e7..7902b50fcf32 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -205,6 +205,19 @@ config HI8435
> >           This driver can also be built as a module. If so, the module will be
> >           called hi8435.
> >
> > +config HX711
> > +       tristate "AVIA HX711 ADC for weight cells"
> > +       depends on GPIOLIB
> > +       help
> > +         If you say yes here you get support for AVIA HX711 ADC which is used
> > +         for weight cells
> > +
> > +         This driver uses two GPIO's, one for setting the clock and the other
> > +         one for getting the data
> > +
> > +         This driver can also be built as a module. If so, the module will be
> > +         called hx711.
> > +
> >  config INA2XX_ADC
> >         tristate "Texas Instruments INA2xx Power Monitors IIO driver"
> >         depends on I2C && !SENSORS_INA2XX
> > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > index b1aa456e6af3..d46e289900ef 100644
> > --- a/drivers/iio/adc/Makefile
> > +++ b/drivers/iio/adc/Makefile
> > @@ -21,6 +21,7 @@ obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
> >  obj-$(CONFIG_DA9150_GPADC) += da9150-gpadc.o
> >  obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
> >  obj-$(CONFIG_HI8435) += hi8435.o
> > +obj-$(CONFIG_HX711) += hx711.o
> >  obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
> >  obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
> >  obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
> > diff --git a/drivers/iio/adc/hx711.c b/drivers/iio/adc/hx711.c
> > new file mode 100644
> > index 000000000000..cbc89e467985
> > --- /dev/null
> > +++ b/drivers/iio/adc/hx711.c
> > @@ -0,0 +1,269 @@
> > +/*
> > + * HX711: analog to digital converter for weight sensor module
> > + *
> > + * Copyright (c) Andreas Klinger <ak@it-klinger.de>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + * GNU General Public License for more details.
> > + *
> > + */
> > +#include <linux/err.h>
> > +#include <linux/gpio.h>
> > +#include <linux/gpio/consumer.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/property.h>
> > +#include <linux/slab.h>
> > +#include <linux/sched.h>
> > +#include <linux/delay.h>
> > +#include <linux/iio/iio.h>
> > +
> > +#define HX711_GAIN_32          2       /* gain = 32 for channel B  */
> > +#define HX711_GAIN_64          3       /* gain = 64 for channel A  */
> > +#define HX711_GAIN_128         1       /* gain = 128 for channel A */
> > +
> > +
> > +struct hx711_data {
> > +       struct device           *dev;
> > +       dev_t                   devt;
> > +       struct gpio_desc        *gpiod_sck;
> > +       struct gpio_desc        *gpiod_dout;
> > +       int                     gain_pulse;
> > +       struct mutex            lock;
> > +};
> > +
> > +static void hx711_reset(struct hx711_data *hx711_data)
> > +{
> > +       int val;
> > +       int i;
> > +
> > +       val = gpiod_get_value(hx711_data->gpiod_dout);
> 
> could move the val assignment here to the initialization don't think
> it will hit 80 chars
> 

I'll change this.

> > +       if (val) {
> 
> move "int i" here to avoid compiler initialization warnings
> 
> > +               dev_warn(hx711_data->dev, "RESET-HX711\n");
> > +
> > +               gpiod_set_value(hx711_data->gpiod_sck, 1);
> > +               udelay(80);
> 
> IIRC this chip has quite a bit of latency thresholds, can't use
> usleep_range? Single core embedded systems could have an issue with
> continuous  polling.
>

That's a good suggestion. We don't need udelay so i'll change to usleep_range
for the next version

> > +               gpiod_set_value(hx711_data->gpiod_sck, 0);
> > +
> > +               for (i = 0; i < 1000; i++) {
> > +                       val = gpiod_get_value(hx711_data->gpiod_dout);
> > +                       if (!val)
> > +                               break;
> > +                       /* sleep at least 1 ms*/
> > +                       msleep(1);
> > +               }
> > +       }
> > +}
> > +
> > +static int hx711_cycle(struct hx711_data *hx711_data)
> > +{
> > +       int val;
> > +
> > +       /* if preempted for more then 60us while SCK is high:
> > +        * hx711 is going in reset
> > +        * ==> measuring is false
> > +        */
> > +       preempt_disable();
> > +       gpiod_set_value(hx711_data->gpiod_sck, 1);
> > +       val = gpiod_get_value(hx711_data->gpiod_dout);
> > +       gpiod_set_value(hx711_data->gpiod_sck, 0);
> > +       preempt_enable();
> > +
> > +       return val;
> > +}
> > +
> > +static unsigned int hx711_read(struct hx711_data *hx711_data)
> > +{
> > +       int i;
> > +       int ret;
> > +       int wert = 0;
> > +
> > +       hx711_reset(hx711_data);
> > +
> > +       for (i = 0; i < 24; i++) {
> > +               wert <<= 1;
> > +               ret = hx711_cycle(hx711_data);
> > +               if (ret)
> > +                       wert++;
> > +       }
> > +
> > +       wert ^= 0x800000;
> > +
> > +       for (i = 0; i < hx711_data->gain_pulse; i++)
> > +               ret = hx711_cycle(hx711_data);
> 
> What is ret used for here?
> > +
> > +       return wert;
> > +}
> > +
> > +
> > +static int hx711_read_raw(struct iio_dev *iio_dev,
> > +                               const struct iio_chan_spec *chan,
> > +                               int *val, int *val2, long mask)
> > +{
> > +       struct hx711_data *hx711_data = iio_priv(iio_dev);
> > +       int ret;
> > +
> > +       switch (mask) {
> > +       case IIO_CHAN_INFO_RAW:
> > +               switch (chan->type) {
> > +               case IIO_VOLTAGE:
> > +                       mutex_lock(&hx711_data->lock);
> > +                       *val = (int)hx711_read(hx711_data);
> > +                       mutex_unlock(&hx711_data->lock);
> > +                       ret = IIO_VAL_INT;
> > +                       break;
> > +               default:
> > +                       return -EINVAL;
> > +               }
> > +               return ret;
> > +       default:
> > +               return -EINVAL;
> > +       }
> > +
> > +       return ret;
> > +}
> > +
> > +static const struct iio_info hx711_iio_info = {
> > +       .driver_module          = THIS_MODULE,
> > +       .read_raw               = hx711_read_raw,
> > +};
> > +
> > +static const struct iio_chan_spec hx711_chan_spec[] = {
> > +       { .type = IIO_VOLTAGE,
> > +               .channel = 0,
> > +               .info_mask_separate =
> > +                       BIT(IIO_CHAN_INFO_RAW),
> > +               .scan_type = {
> > +                       .sign = 'u',
> > +                       .realbits = 24,
> > +                       .storagebits = 32,
> > +                       .shift = 0,
> > +               }
> > +       },
> > +};
> > +
> > +static int hx711_probe(struct platform_device *pdev)
> > +{
> > +       struct device *dev = &pdev->dev;
> > +       struct device_node *node = dev->of_node;
> > +       struct hx711_data *hx711_data = NULL;
> > +       struct iio_dev *iio;
> > +       int ret = 0, ival;
> > +
> > +       iio = devm_iio_device_alloc(dev, sizeof(struct hx711_data));
> > +       if (!iio) {
> > +               dev_err(dev, "failed to allocate IIO device\n");
> > +               return -ENOMEM;
> > +       }
> > +
> > +       hx711_data = iio_priv(iio);
> > +       hx711_data->dev = dev;
> > +
> > +       mutex_init(&hx711_data->lock);
> > +
> > +       hx711_data->gpiod_sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_HIGH);
> > +       if (IS_ERR(hx711_data->gpiod_sck)) {
> > +               ret = PTR_ERR(hx711_data->gpiod_sck);
> > +               goto err;
> > +       }
> > +
> > +       hx711_data->gpiod_dout = devm_gpiod_get(dev, "dout", GPIOD_OUT_HIGH);
> > +       if (IS_ERR(hx711_data->gpiod_dout)) {
> > +               ret = PTR_ERR(hx711_data->gpiod_dout);
> > +               goto err;
> > +       }
> > +
> > +       ret = of_property_read_u32 (node, "gain", &ival);
> > +       if (!ret) {
> > +               switch (ival) {
> > +               case 32:
> > +                       hx711_data->gain_pulse = HX711_GAIN_32;
> > +                       break;
> > +               case 64:
> > +                       hx711_data->gain_pulse = HX711_GAIN_64;
> > +                       break;
> > +               case 128:
> > +                       hx711_data->gain_pulse = HX711_GAIN_128;
> > +                       break;
> > +               default:
> > +                       hx711_data->gain_pulse = HX711_GAIN_128;
> > +               }
> > +       } else
> > +               hx711_data->gain_pulse = HX711_GAIN_128;
> > +       dev_dbg(hx711_data->dev, "gain: %d\n", hx711_data->gain_pulse);
> > +
> > +       ret = gpiod_direction_input(hx711_data->gpiod_dout);
> > +       if (ret < 0) {
> > +               dev_err(hx711_data->dev, "gpiod_direction_input: %d\n", ret);
> > +               goto err;
> > +       }
> > +
> > +       ret = gpiod_direction_output(hx711_data->gpiod_sck, 0);
> > +       if (ret < 0) {
> > +               dev_err(hx711_data->dev, "gpiod_direction_output: %d\n", ret);
> > +               goto err;
> > +       }
> > +
> > +       platform_set_drvdata(pdev, iio);
> > +
> > +       iio->name = pdev->name;
> > +       iio->dev.parent = &pdev->dev;
> > +       iio->info = &hx711_iio_info;
> > +       iio->modes = INDIO_DIRECT_MODE;
> > +       iio->channels = hx711_chan_spec;
> > +       iio->num_channels = ARRAY_SIZE(hx711_chan_spec);
> > +
> > +       dev_err(hx711_data->dev, "initialized\n");
> > +
> > +       return devm_iio_device_register(dev, iio);
> > +
> > +err:
> > +       return ret;
> > +}
> > +
> > +
> > +static int hx711_suspend(struct device *dev)
> > +{
> > +       return 0;
> > +}
> > +
> > +static int hx711_resume(struct device *dev)
> > +{
> > +       return 0;
> > +}
> > +
> > +static SIMPLE_DEV_PM_OPS(hx711_pm_ops, hx711_suspend, hx711_resume);
> > +
> > +
> > +static const struct of_device_id of_hx711_match[] = {
> > +       { .compatible = "avia,hx711", },
> > +       {},
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, of_hx711_match);
> > +
> > +static struct platform_driver hx711_driver = {
> > +       .probe          = hx711_probe,
> > +       .driver         = {
> > +               .name           = "hx711-gpio",
> > +               .pm             = &hx711_pm_ops,
> > +               .of_match_table = of_hx711_match,
> > +       },
> > +};
> > +
> > +module_platform_driver(hx711_driver);
> > +
> > +MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
> > +MODULE_DESCRIPTION("HX711 bitbanging driver - ADC for weight cells");
> > +MODULE_LICENSE("GPL");
> > +MODULE_ALIAS("platform:hx711-gpio");
> > +
> > --
> > 2.1.4
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2016-12-19  9:27 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-12-13 18:02 [PATCH 2/2] iio: adc: hx711: Add IIO driver for AVIA HX711 Andreas Klinger
2016-12-13 20:22 ` Peter Meerwald-Stadler
2016-12-17  8:53 ` Matt Ranostay
2016-12-19  9:26   ` Andreas Klinger

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