diff options
Diffstat (limited to 'drivers/staging/iio/adc/ad7606.c')
| -rw-r--r-- | drivers/staging/iio/adc/ad7606.c | 543 |
1 files changed, 543 insertions, 0 deletions
diff --git a/drivers/staging/iio/adc/ad7606.c b/drivers/staging/iio/adc/ad7606.c new file mode 100644 index 000000000000..453190864b2f --- /dev/null +++ b/drivers/staging/iio/adc/ad7606.c @@ -0,0 +1,543 @@ +/* + * 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" + +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 = st->range * 2; + *val2 = st->chip_info->channels[0].scan_type.realbits; + return IIO_VAL_FRACTIONAL_LOG2; + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + *val = st->oversampling; + return IIO_VAL_INT; + } + return -EINVAL; +} + +static ssize_t ad7606_show_range(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct ad7606_state *st = iio_priv(indio_dev); + + return sprintf(buf, "%u\n", st->range); +} + +static ssize_t ad7606_store_range(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct ad7606_state *st = iio_priv(indio_dev); + unsigned long lval; + int ret; + + ret = kstrtoul(buf, 10, &lval); + if (ret) + return ret; + + if (!(lval == 5000 || lval == 10000)) + return -EINVAL; + + mutex_lock(&indio_dev->mlock); + gpiod_set_value(st->gpio_range, lval == 10000); + st->range = lval; + mutex_unlock(&indio_dev->mlock); + + return count; +} + +static IIO_DEVICE_ATTR(in_voltage_range, S_IRUGO | S_IWUSR, + ad7606_show_range, ad7606_store_range, 0); +static IIO_CONST_ATTR(in_voltage_range_available, "5000 10000"); + +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; + + switch (mask) { + 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(&indio_dev->mlock); + gpiod_set_array_value(ARRAY_SIZE(values), st->gpio_os->desc, + values); + st->oversampling = val; + mutex_unlock(&indio_dev->mlock); + + 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_range.dev_attr.attr, + &iio_const_attr_in_voltage_range_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_range.dev_attr.attr, + &iio_const_attr_in_voltage_range_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, + .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; + st->bops = bops; + st->base_address = base_address; + st->range = 5000; + 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; + else + indio_dev->info = &ad7606_info_os; + } else { + if (st->gpio_range) + indio_dev->info = &ad7606_info_range; + else + indio_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_SLEEP + +static 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 == 10000); + 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); + +#endif + +MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); +MODULE_DESCRIPTION("Analog Devices AD7606 ADC"); +MODULE_LICENSE("GPL v2"); |