diff options
Diffstat (limited to 'drivers/iio/adc/hx711.c')
| -rw-r--r-- | drivers/iio/adc/hx711.c | 147 |
1 files changed, 40 insertions, 107 deletions
diff --git a/drivers/iio/adc/hx711.c b/drivers/iio/adc/hx711.c index 36b59d8957fb..1db8b68a8f64 100644 --- a/drivers/iio/adc/hx711.c +++ b/drivers/iio/adc/hx711.c @@ -1,22 +1,13 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * HX711: analog to digital converter for weight sensor module * * Copyright (c) 2016 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/kernel.h> #include <linux/module.h> -#include <linux/of.h> +#include <linux/mod_devicetable.h> #include <linux/platform_device.h> #include <linux/property.h> #include <linux/slab.h> @@ -32,6 +23,7 @@ /* gain to pulse and scale conversion */ #define HX711_GAIN_MAX 3 +#define HX711_RESET_GAIN 128 struct hx711_gain_to_scale { int gain; @@ -88,15 +80,17 @@ struct hx711_data { struct device *dev; struct gpio_desc *gpiod_pd_sck; struct gpio_desc *gpiod_dout; - struct regulator *reg_avdd; 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 + * 2x32-bit channel + 64-bit naturally aligned timestamp */ - u32 buffer[4]; + struct { + u32 channel[2]; + aligned_s64 timestamp; + } buffer; /* * delay after a rising edge on SCK until the data is ready DOUT * this is dependent on the hx711 where the datasheet tells a @@ -109,14 +103,14 @@ struct hx711_data { static int hx711_cycle(struct hx711_data *hx711_data) { - int val; + unsigned long flags; /* * if preempted for more then 60us while PD_SCK is high: * hx711 is going in reset * ==> measuring is false */ - preempt_disable(); + local_irq_save(flags); gpiod_set_value(hx711_data->gpiod_pd_sck, 1); /* @@ -126,7 +120,6 @@ static int hx711_cycle(struct hx711_data *hx711_data) */ ndelay(hx711_data->data_ready_delay_ns); - val = gpiod_get_value(hx711_data->gpiod_dout); /* * here we are not waiting for 0.2 us as suggested by the datasheet, * because the oscilloscope showed in a test scenario @@ -134,7 +127,7 @@ static int hx711_cycle(struct hx711_data *hx711_data) * and 0.56 us for PD_SCK low on TI Sitara with 800 MHz */ gpiod_set_value(hx711_data->gpiod_pd_sck, 0); - preempt_enable(); + local_irq_restore(flags); /* * make it a square wave for addressing cases with capacitance on @@ -142,7 +135,8 @@ static int hx711_cycle(struct hx711_data *hx711_data) */ ndelay(hx711_data->data_ready_delay_ns); - return val; + /* sample as late as possible */ + return gpiod_get_value(hx711_data->gpiod_dout); } static int hx711_read(struct hx711_data *hx711_data) @@ -194,8 +188,7 @@ static int hx711_wait_for_ready(struct hx711_data *hx711_data) static int hx711_reset(struct hx711_data *hx711_data) { - int ret; - int val = gpiod_get_value(hx711_data->gpiod_dout); + int val = hx711_wait_for_ready(hx711_data); if (val) { /* @@ -211,22 +204,10 @@ static int hx711_reset(struct hx711_data *hx711_data) msleep(10); gpiod_set_value(hx711_data->gpiod_pd_sck, 0); - ret = hx711_wait_for_ready(hx711_data); - if (ret) - return ret; - /* - * after a reset the gain is 128 so we do a dummy read - * to set the gain for the next read - */ - ret = hx711_read(hx711_data); - if (ret < 0) - return ret; - - /* - * after a dummy read we need to wait vor readiness - * for not mixing gain pulses with the clock - */ val = hx711_wait_for_ready(hx711_data); + + /* after a reset the gain is 128 */ + hx711_data->gain_set = HX711_RESET_GAIN; } return val; @@ -383,18 +364,15 @@ static irqreturn_t hx711_trigger(int irq, void *p) mutex_lock(&hx711_data->lock); - memset(hx711_data->buffer, 0, sizeof(hx711_data->buffer)); + 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, + iio_for_each_active_channel(indio_dev, i) { + hx711_data->buffer.channel[j] = hx711_reset_read(hx711_data, indio_dev->channels[i].channel); j++; } - iio_push_to_buffers_with_timestamp(indio_dev, hx711_data->buffer, + iio_push_to_buffers_with_timestamp(indio_dev, &hx711_data->buffer, pf->timestamp); mutex_unlock(&hx711_data->lock); @@ -480,17 +458,14 @@ static const struct iio_chan_spec hx711_chan_spec[] = { static int hx711_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; - struct device_node *np = dev->of_node; struct hx711_data *hx711_data; struct iio_dev *indio_dev; int ret; int i; indio_dev = devm_iio_device_alloc(dev, sizeof(struct hx711_data)); - if (!indio_dev) { - dev_err(dev, "failed to allocate IIO device\n"); + if (!indio_dev) return -ENOMEM; - } hx711_data = iio_priv(indio_dev); hx711_data->dev = dev; @@ -502,28 +477,20 @@ static int hx711_probe(struct platform_device *pdev) * in the driver it is an output */ hx711_data->gpiod_pd_sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_LOW); - if (IS_ERR(hx711_data->gpiod_pd_sck)) { - dev_err(dev, "failed to get sck-gpiod: err=%ld\n", - PTR_ERR(hx711_data->gpiod_pd_sck)); - return PTR_ERR(hx711_data->gpiod_pd_sck); - } + if (IS_ERR(hx711_data->gpiod_pd_sck)) + return dev_err_probe(dev, PTR_ERR(hx711_data->gpiod_pd_sck), + "failed to get sck-gpiod\n"); /* * DOUT stands for serial data output of HX711 * for the driver it is an input */ hx711_data->gpiod_dout = devm_gpiod_get(dev, "dout", GPIOD_IN); - if (IS_ERR(hx711_data->gpiod_dout)) { - dev_err(dev, "failed to get dout-gpiod: err=%ld\n", - PTR_ERR(hx711_data->gpiod_dout)); - return PTR_ERR(hx711_data->gpiod_dout); - } - - hx711_data->reg_avdd = devm_regulator_get(dev, "avdd"); - if (IS_ERR(hx711_data->reg_avdd)) - return PTR_ERR(hx711_data->reg_avdd); + if (IS_ERR(hx711_data->gpiod_dout)) + return dev_err_probe(dev, PTR_ERR(hx711_data->gpiod_dout), + "failed to get dout-gpiod\n"); - ret = regulator_enable(hx711_data->reg_avdd); + ret = devm_regulator_get_enable_read_voltage(dev, "avdd"); if (ret < 0) return ret; @@ -539,9 +506,6 @@ static int hx711_probe(struct platform_device *pdev) * approximately to fit into a 32 bit number: * 1 LSB = (AVDD * 100) / GAIN / 1678 [10^-9 mV] */ - ret = regulator_get_voltage(hx711_data->reg_avdd); - if (ret < 0) - goto error_regulator; /* we need 10^-9 mV */ ret *= 100; @@ -554,7 +518,7 @@ static int hx711_probe(struct platform_device *pdev) hx711_data->gain_chan_a = 128; hx711_data->clock_frequency = 400000; - ret = of_property_read_u32(np, "clock-frequency", + ret = device_property_read_u32(&pdev->dev, "clock-frequency", &hx711_data->clock_frequency); /* @@ -569,66 +533,35 @@ static int hx711_probe(struct platform_device *pdev) hx711_data->data_ready_delay_ns = 1000000000 / hx711_data->clock_frequency; - platform_set_drvdata(pdev, indio_dev); - indio_dev->name = "hx711"; - indio_dev->dev.parent = &pdev->dev; indio_dev->info = &hx711_iio_info; indio_dev->modes = INDIO_DIRECT_MODE; 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"); - goto error_buffer; - } - - return 0; - -error_buffer: - iio_triggered_buffer_cleanup(indio_dev); - -error_regulator: - regulator_disable(hx711_data->reg_avdd); - - return ret; -} - -static int hx711_remove(struct platform_device *pdev) -{ - struct hx711_data *hx711_data; - struct iio_dev *indio_dev; - - indio_dev = platform_get_drvdata(pdev); - hx711_data = iio_priv(indio_dev); - - iio_device_unregister(indio_dev); - - iio_triggered_buffer_cleanup(indio_dev); + ret = devm_iio_triggered_buffer_setup(dev, indio_dev, + iio_pollfunc_store_time, + hx711_trigger, NULL); + if (ret < 0) + return dev_err_probe(dev, ret, + "setup of iio triggered buffer failed\n"); - regulator_disable(hx711_data->reg_avdd); + ret = devm_iio_device_register(dev, indio_dev); + if (ret < 0) + return dev_err_probe(dev, ret, "Couldn't register the device\n"); return 0; } 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, - .remove = hx711_remove, .driver = { .name = "hx711-gpio", .of_match_table = of_hx711_match, |