Hello Matt, thank you for your suggestions. See below. Matt Ranostay <matt.ranostay@xxxxxxxxxxxx> schrieb am Sat, 17. Dec 00:53: > On Tue, Dec 13, 2016 at 10:02 AM, Andreas Klinger <ak@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx> > > --- > > 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@xxxxxxxxxxxxx> > > + * > > + * 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@xxxxxxxxxxxxx>"); > > +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@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html