From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941226AbcLMSDr (ORCPT ); Tue, 13 Dec 2016 13:03:47 -0500 Received: from mout.kundenserver.de ([212.227.17.13]:62350 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S941105AbcLMSDV (ORCPT ); Tue, 13 Dec 2016 13:03:21 -0500 Date: Tue, 13 Dec 2016 19:02:55 +0100 From: Andreas Klinger To: devicetree@vger.kernel.org, linux-iio@vger.kernel.org Cc: linux-kernel@vger.kernel.org, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, jic23@kernel.org, knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net, ak@it-klinger.de Subject: [PATCH 2/2] iio: adc: hx711: Add IIO driver for AVIA HX711 Message-ID: <20161213180254.GA3185@andreas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) X-Provags-ID: V03:K0:pfsuJLuNmHNeXccWL5PotNMyRTlZ4vNz8rBWvdo2bmnPxNp9Chp laYY8AEVPhN/qFUad1yO1oespY/dlrR/drewrwPhsAAU8JFXLVdnq2Q1tLAdG9exUMv9dbq dNy0I4YIKujegRujZw0t7bQ5uU3wbRFCl/Vbgx1cFKt1ZNBiQBsazyEpTXYyqYbhT3eVOBJ aJw7WOjIzokKAUcYeXbog== X-UI-Out-Filterresults: notjunk:1;V01:K0:v9Xpqa6HHyg=:h722OdYLxWOowewgJ+Gcxh awVyEIpAY82zEoYkJUbWk9N2imOtCI/WcmY168vVdcC9crJ7oWvVoIevFZI4dBspu9hLmzqIZ KfVkkR0FQDdwWDyZZgmvSmLvtHGCEDmiIaOwYAcfu32uMPXhGp/0xDMRydo8nDmPMGgBDD4k/ eL/HlhrNleC3z12lV5XdqWq7lG+oPg+rIfHoUI9Fb6Wp6yBAT6sgI8ydrIspJv2SS/yQn3Qxz lxpW8fJheD1ibu36t4x53jDs+yA5/ZqcAGfjLd+cSWIcr4E6wufZIsNiEbiDv771xIm9I5qTu GN/F1CICmBpGJuU4mIPVgu4O+v5wqyefJQyumrdt4Jb60SaixhR9xDVnf0okgIsGq3NtefUlB bsRD8XtwFRbxNeToJ6KuQCgnU7ZZzukOX8jAVy3J6bsgImAe/yWAfhYynao4AMumw4FgtTaSB 7ZZuX7QMbgjt/QQ3o/0cv/yRHBCTDuITjMadSDseJpO7If6JFoUo0XkfbqEoCPIdf1FhOdbnl Gw+iZR7WM+A1N1oSUCMxeiVBmDVn49wfml6uRPIIbu72P1rEQ3QsjQuvOMwd2qBYAecy/OSeB 5hF/qwLz3G9NID2A6dl8nSysbCtI4r3i67BR+Wkp9gJrWupEWp19OEiLoGU/+Wnp0+YwL8Ci8 P4E5Uqvzlf/ZYTWAX/pWQIkUtfj/8WGz9GSXyAVGXCtEXUgNRP3uQdveVQKDAlG/o7gE= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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 + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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 "); +MODULE_DESCRIPTION("HX711 bitbanging driver - ADC for weight cells"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:hx711-gpio"); + -- 2.1.4