linux下ADC驱动（AD7606）

/* * AD7606 ADC driver * * Copyright 2011 Analog Devices Inc. * * Licensed under the GPL-2. */#ifndef IIO_ADC_AD7606_H_#define IIO_ADC_AD7606_H_/** * struct ad7606_chip_info - chip specific information * @name:identification string for chip * @channels:channel specification * @num_channels:number of channels * @lockprotect sensor state */struct ad7606_chip_info {const struct iio_chan_spec*channels;unsigned intnum_channels;};/** * struct ad7606_state - driver instance specific data * @lockprotect sensor state */struct ad7606_state {struct device*dev;const struct ad7606_chip_info*chip_info;struct regulator*reg;struct work_structpoll_work;wait_queue_head_twq_data_avail;const struct ad7606_bus_ops*bops;unsigned intrange;unsigned intoversampling;booldone;void __iomem*base_address;struct mutexlock; /* protect sensor state */struct gpio_desc*gpio_convst;struct gpio_desc*gpio_reset;struct gpio_desc*gpio_range;struct gpio_desc*gpio_standby;struct gpio_desc*gpio_frstdata;struct gpio_descs*gpio_os;/* * DMA (thus cache coherency maintenance) requires the * transfer buffers to live in their own cache lines. * 8 * 16-bit samples + 64-bit timestamp */unsigned shortdata[12] ____cacheline_aligned;};struct ad7606_bus_ops {/* more methods added in future? */int (*read_block)(struct device *, int, void *);};int ad7606_probe(struct device *dev, int irq, void __iomem *base_address, const char *name, unsigned int id, const struct ad7606_bus_ops *bops);int ad7606_remove(struct device *dev, int irq);enum ad7606_supported_device_ids {ID_AD7606_8,ID_AD7606_6,ID_AD7606_4};#ifdef CONFIG_PM_SLEEPextern const struct dev_pm_ops ad7606_pm_ops;#define AD7606_PM_OPS (&ad7606_pm_ops)#else#define AD7606_PM_OPS NULL#endif#endif /* IIO_ADC_AD7606_H_ */

ad7606.h

/* * AD7606 SPI ADC driver * * Copyright 2011 Analog Devices Inc. * * Licensed under the GPL-2. */#include <linux/interrupt.h>#include <linux/device.h>#include <linux/kernel.h>#include <linux/slab.h>#include <linux/sysfs.h>#include <linux/regulator/consumer.h>#include <linux/err.h>#include <linux/gpio/consumer.h>#include <linux/delay.h>#include <linux/sched.h>#include <linux/module.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 "ad7606.h"/* Scales are computed as 2.5/2**16 and 5/2**16 respectively */static const unsigned int scale_avail[2][2] = {{0, 38147}, {0, 76294}};static int ad7606_reset(struct ad7606_state *st){if (st->gpio_reset) {gpiod_set_value(st->gpio_reset, 1);ndelay(100); /* t_reset >= 100ns */gpiod_set_value(st->gpio_reset, 0);return 0;}return -ENODEV;}static int ad7606_read_samples(struct ad7606_state *st){unsigned int num = st->chip_info->num_channels;u16 *data = st->data;int ret;/* * The frstdata signal is set to high while and after reading the sample * of the first channel and low for all other channels. This can be used * to check that the incoming data is correctly aligned. During normal * operation the data should never become unaligned, but some glitch or * electrostatic discharge might cause an extra read or clock cycle. * Monitoring the frstdata signal allows to recover from such failure * situations. */if (st->gpio_frstdata) {ret = st->bops->read_block(st->dev, 1, data);if (ret)return ret;if (!gpiod_get_value(st->gpio_frstdata)) {ad7606_reset(st);return -EIO;}data++;num--;}return st->bops->read_block(st->dev, num, data);}static irqreturn_t ad7606_trigger_handler(int irq, void *p){struct iio_poll_func *pf = p;struct ad7606_state *st = iio_priv(pf->indio_dev);gpiod_set_value(st->gpio_convst, 1);return IRQ_HANDLED;}/** * ad7606_poll_bh_to_ring() bh of trigger launched polling to ring buffer * @work_s:the work struct through which this was scheduled * * Currently there is no option in this driver to disable the saving of * timestamps within the ring. * I think the one copy of this at a time was to avoid problems if the * trigger was set far too high and the reads then locked up the computer. **/static void ad7606_poll_bh_to_ring(struct work_struct *work_s){struct ad7606_state *st = container_of(work_s, struct ad7606_state,poll_work);struct iio_dev *indio_dev = iio_priv_to_dev(st);int ret;ret = ad7606_read_samples(st);if (ret == 0)iio_push_to_buffers_with_timestamp(indio_dev, st->data,   iio_get_time_ns(indio_dev));gpiod_set_value(st->gpio_convst, 0);iio_trigger_notify_done(indio_dev->trig);}static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch){struct ad7606_state *st = iio_priv(indio_dev);int ret;st->done = false;gpiod_set_value(st->gpio_convst, 1);ret = wait_event_interruptible(st->wq_data_avail, st->done);if (ret)goto error_ret;ret = ad7606_read_samples(st);if (ret == 0)ret = st->data[ch];error_ret:gpiod_set_value(st->gpio_convst, 0);return ret;}static int ad7606_read_raw(struct iio_dev *indio_dev,   struct iio_chan_spec const *chan,   int *val,   int *val2,   long m){int ret;struct ad7606_state *st = iio_priv(indio_dev);switch (m) {case IIO_CHAN_INFO_RAW:ret = iio_device_claim_direct_mode(indio_dev);if (ret)return ret;ret = ad7606_scan_direct(indio_dev, chan->address);iio_device_release_direct_mode(indio_dev);if (ret < 0)return ret;*val = (short)ret;return IIO_VAL_INT;case IIO_CHAN_INFO_SCALE:*val = scale_avail[st->range][0];*val2 = scale_avail[st->range][1];return IIO_VAL_INT_PLUS_MICRO;case IIO_CHAN_INFO_OVERSAMPLING_RATIO:*val = st->oversampling;return IIO_VAL_INT;}return -EINVAL;}static ssize_t in_voltage_scale_available_show(struct device *dev,       struct device_attribute *attr,       char *buf){int i, len = 0;for (i = 0; i < ARRAY_SIZE(scale_avail); i++)len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06u ", scale_avail[i][0], scale_avail[i][1]);buf[len - 1] = '\n';return len;}static IIO_DEVICE_ATTR_RO(in_voltage_scale_available, 0);static int ad7606_oversampling_get_index(unsigned int val){unsigned char supported[] = {1, 2, 4, 8, 16, 32, 64};int i;for (i = 0; i < ARRAY_SIZE(supported); i++)if (val == supported[i])return i;return -EINVAL;}static int ad7606_write_raw(struct iio_dev *indio_dev,    struct iio_chan_spec const *chan,    int val,    int val2,    long mask){struct ad7606_state *st = iio_priv(indio_dev);int values[3];int ret, i;switch (mask) {case IIO_CHAN_INFO_SCALE:ret = -EINVAL;mutex_lock(&st->lock);for (i = 0; i < ARRAY_SIZE(scale_avail); i++)if (val2 == scale_avail[i][1]) {gpiod_set_value(st->gpio_range, i);st->range = i;ret = 0;break;}mutex_unlock(&st->lock);return ret;case IIO_CHAN_INFO_OVERSAMPLING_RATIO:if (val2)return -EINVAL;ret = ad7606_oversampling_get_index(val);if (ret < 0)return ret;values[0] = (ret >> 0) & 1;values[1] = (ret >> 1) & 1;values[2] = (ret >> 2) & 1;mutex_lock(&st->lock);gpiod_set_array_value(ARRAY_SIZE(values), st->gpio_os->desc,      values);st->oversampling = val;mutex_unlock(&st->lock);return 0;default:return -EINVAL;}}static IIO_CONST_ATTR(oversampling_ratio_available, "1 2 4 8 16 32 64");static struct attribute *ad7606_attributes_os_and_range[] = {&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,&iio_const_attr_oversampling_ratio_available.dev_attr.attr,NULL,};static const struct attribute_group ad7606_attribute_group_os_and_range = {.attrs = ad7606_attributes_os_and_range,};static struct attribute *ad7606_attributes_os[] = {&iio_const_attr_oversampling_ratio_available.dev_attr.attr,NULL,};static const struct attribute_group ad7606_attribute_group_os = {.attrs = ad7606_attributes_os,};static struct attribute *ad7606_attributes_range[] = {&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,NULL,};static const struct attribute_group ad7606_attribute_group_range = {.attrs = ad7606_attributes_range,};#define AD7606_CHANNEL(num)\{\.type = IIO_VOLTAGE,\.indexed = 1,\.channel = num,\.address = num,\.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),\.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\.info_mask_shared_by_all =\BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),\.scan_index = num,\.scan_type = {\.sign = 's',\.realbits = 16,\.storagebits = 16,\.endianness = IIO_CPU,\},\}static const struct iio_chan_spec ad7606_channels[] = {IIO_CHAN_SOFT_TIMESTAMP(8),AD7606_CHANNEL(0),AD7606_CHANNEL(1),AD7606_CHANNEL(2),AD7606_CHANNEL(3),AD7606_CHANNEL(4),AD7606_CHANNEL(5),AD7606_CHANNEL(6),AD7606_CHANNEL(7),};static const struct ad7606_chip_info ad7606_chip_info_tbl[] = {/* * More devices added in future */[ID_AD7606_8] = {.channels = ad7606_channels,.num_channels = 9,},[ID_AD7606_6] = {.channels = ad7606_channels,.num_channels = 7,},[ID_AD7606_4] = {.channels = ad7606_channels,.num_channels = 5,},};static int ad7606_request_gpios(struct ad7606_state *st){struct device *dev = st->dev;st->gpio_convst = devm_gpiod_get(dev, "conversion-start", GPIOD_OUT_LOW);if (IS_ERR(st->gpio_convst))return PTR_ERR(st->gpio_convst);st->gpio_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);if (IS_ERR(st->gpio_reset))return PTR_ERR(st->gpio_reset);st->gpio_range = devm_gpiod_get_optional(dev, "range", GPIOD_OUT_LOW);if (IS_ERR(st->gpio_range))return PTR_ERR(st->gpio_range);st->gpio_standby = devm_gpiod_get_optional(dev, "standby",   GPIOD_OUT_HIGH);if (IS_ERR(st->gpio_standby))return PTR_ERR(st->gpio_standby);st->gpio_frstdata = devm_gpiod_get_optional(dev, "first-data",    GPIOD_IN);if (IS_ERR(st->gpio_frstdata))return PTR_ERR(st->gpio_frstdata);st->gpio_os = devm_gpiod_get_array_optional(dev, "oversampling-ratio",GPIOD_OUT_LOW);return PTR_ERR_OR_ZERO(st->gpio_os);}/** *  Interrupt handler */static irqreturn_t ad7606_interrupt(int irq, void *dev_id){struct iio_dev *indio_dev = dev_id;struct ad7606_state *st = iio_priv(indio_dev);if (iio_buffer_enabled(indio_dev)) {schedule_work(&st->poll_work);} else {st->done = true;wake_up_interruptible(&st->wq_data_avail);}return IRQ_HANDLED;};static const struct iio_info ad7606_info_no_os_or_range = {.driver_module = THIS_MODULE,.read_raw = &ad7606_read_raw,};static const struct iio_info ad7606_info_os_and_range = {.driver_module = THIS_MODULE,.read_raw = &ad7606_read_raw,.write_raw = &ad7606_write_raw,.attrs = &ad7606_attribute_group_os_and_range,};static const struct iio_info ad7606_info_os = {.driver_module = THIS_MODULE,.read_raw = &ad7606_read_raw,.write_raw = &ad7606_write_raw,.attrs = &ad7606_attribute_group_os,};static const struct iio_info ad7606_info_range = {.driver_module = THIS_MODULE,.read_raw = &ad7606_read_raw,.write_raw = &ad7606_write_raw,.attrs = &ad7606_attribute_group_range,};int ad7606_probe(struct device *dev, int irq, void __iomem *base_address, const char *name, unsigned int id, const struct ad7606_bus_ops *bops){struct ad7606_state *st;int ret;struct iio_dev *indio_dev;indio_dev = devm_iio_device_alloc(dev, sizeof(*st));if (!indio_dev)return -ENOMEM;st = iio_priv(indio_dev);st->dev = dev;mutex_init(&st->lock);st->bops = bops;st->base_address = base_address;/* tied to logic low, analog input range is +/- 5V */st->range = 0;st->oversampling = 1;INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);st->reg = devm_regulator_get(dev, "avcc");if (IS_ERR(st->reg))return PTR_ERR(st->reg);ret = regulator_enable(st->reg);if (ret) {dev_err(dev, "Failed to enable specified AVcc supply\n");return ret;}ret = ad7606_request_gpios(st);if (ret)goto error_disable_reg;st->chip_info = &ad7606_chip_info_tbl[id];indio_dev->dev.parent = dev;if (st->gpio_os) {if (st->gpio_range)indio_dev->info = &ad7606_info_os_and_range;elseindio_dev->info = &ad7606_info_os;} else {if (st->gpio_range)indio_dev->info = &ad7606_info_range;elseindio_dev->info = &ad7606_info_no_os_or_range;}indio_dev->modes = INDIO_DIRECT_MODE;indio_dev->name = name;indio_dev->channels = st->chip_info->channels;indio_dev->num_channels = st->chip_info->num_channels;init_waitqueue_head(&st->wq_data_avail);ret = ad7606_reset(st);if (ret)dev_warn(st->dev, "failed to RESET: no RESET GPIO specified\n");ret = request_irq(irq, ad7606_interrupt, IRQF_TRIGGER_FALLING, name,  indio_dev);if (ret)goto error_disable_reg;ret = iio_triggered_buffer_setup(indio_dev, &ad7606_trigger_handler, NULL, NULL);if (ret)goto error_free_irq;ret = iio_device_register(indio_dev);if (ret)goto error_unregister_ring;dev_set_drvdata(dev, indio_dev);return 0;error_unregister_ring:iio_triggered_buffer_cleanup(indio_dev);error_free_irq:free_irq(irq, indio_dev);error_disable_reg:regulator_disable(st->reg);return ret;}EXPORT_SYMBOL_GPL(ad7606_probe);int ad7606_remove(struct device *dev, int irq){struct iio_dev *indio_dev = dev_get_drvdata(dev);struct ad7606_state *st = iio_priv(indio_dev);iio_device_unregister(indio_dev);iio_triggered_buffer_cleanup(indio_dev);free_irq(irq, indio_dev);regulator_disable(st->reg);return 0;}EXPORT_SYMBOL_GPL(ad7606_remove);#ifdef CONFIG_PM_SLEEPstatic int ad7606_suspend(struct device *dev){struct iio_dev *indio_dev = dev_get_drvdata(dev);struct ad7606_state *st = iio_priv(indio_dev);if (st->gpio_standby) {gpiod_set_value(st->gpio_range, 1);gpiod_set_value(st->gpio_standby, 0);}return 0;}static int ad7606_resume(struct device *dev){struct iio_dev *indio_dev = dev_get_drvdata(dev);struct ad7606_state *st = iio_priv(indio_dev);if (st->gpio_standby) {gpiod_set_value(st->gpio_range, st->range);gpiod_set_value(st->gpio_standby, 1);ad7606_reset(st);}return 0;}SIMPLE_DEV_PM_OPS(ad7606_pm_ops, ad7606_suspend, ad7606_resume);EXPORT_SYMBOL_GPL(ad7606_pm_ops);#endifMODULE_AUTHOR("Michael Hennerich <[e-mail]>");MODULE_DESCRIPTION("Analog Devices AD7606 ADC");MODULE_LICENSE("GPL v2");