diff options
Diffstat (limited to 'drivers/staging/iio/adc/ad7887_ring.c')
-rw-r--r-- | drivers/staging/iio/adc/ad7887_ring.c | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/drivers/staging/iio/adc/ad7887_ring.c b/drivers/staging/iio/adc/ad7887_ring.c new file mode 100644 index 000000000000..6b9cb1f95a1e --- /dev/null +++ b/drivers/staging/iio/adc/ad7887_ring.c @@ -0,0 +1,266 @@ +/* + * Copyright 2010 Analog Devices Inc. + * Copyright (C) 2008 Jonathan Cameron + * + * Licensed under the GPL-2 or later. + * + * ad7887_ring.c + */ + +#include <linux/interrupt.h> +#include <linux/gpio.h> +#include <linux/workqueue.h> +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/sysfs.h> +#include <linux/list.h> +#include <linux/spi/spi.h> + +#include "../iio.h" +#include "../ring_generic.h" +#include "../ring_sw.h" +#include "../trigger.h" +#include "../sysfs.h" + +#include "ad7887.h" + +static IIO_SCAN_EL_C(in0, 0, 0, NULL); +static IIO_SCAN_EL_C(in1, 1, 0, NULL); + +static ssize_t ad7887_show_type(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_ring_buffer *ring = dev_get_drvdata(dev); + struct iio_dev *indio_dev = ring->indio_dev; + struct ad7887_state *st = indio_dev->dev_data; + + return sprintf(buf, "%c%d/%d>>%d\n", st->chip_info->sign, + st->chip_info->bits, st->chip_info->storagebits, + st->chip_info->left_shift); +} +static IIO_DEVICE_ATTR(in_type, S_IRUGO, ad7887_show_type, NULL, 0); + +static struct attribute *ad7887_scan_el_attrs[] = { + &iio_scan_el_in0.dev_attr.attr, + &iio_const_attr_in0_index.dev_attr.attr, + &iio_scan_el_in1.dev_attr.attr, + &iio_const_attr_in1_index.dev_attr.attr, + &iio_dev_attr_in_type.dev_attr.attr, + NULL, +}; + +static mode_t ad7887_scan_el_attr_is_visible(struct kobject *kobj, + struct attribute *attr, int n) +{ + struct device *dev = container_of(kobj, struct device, kobj); + struct iio_ring_buffer *ring = dev_get_drvdata(dev); + struct iio_dev *indio_dev = ring->indio_dev; + struct ad7887_state *st = indio_dev->dev_data; + + mode_t mode = attr->mode; + + if ((attr == &iio_scan_el_in1.dev_attr.attr) || + (attr == &iio_const_attr_in1_index.dev_attr.attr)) + if (!st->en_dual) + mode = 0; + + return mode; +} + +static struct attribute_group ad7887_scan_el_group = { + .name = "scan_elements", + .attrs = ad7887_scan_el_attrs, + .is_visible = ad7887_scan_el_attr_is_visible, +}; + +int ad7887_scan_from_ring(struct ad7887_state *st, long mask) +{ + struct iio_ring_buffer *ring = st->indio_dev->ring; + int count = 0, ret; + u16 *ring_data; + + if (!(ring->scan_mask & mask)) { + ret = -EBUSY; + goto error_ret; + } + + ring_data = kmalloc(ring->access.get_bytes_per_datum(ring), GFP_KERNEL); + if (ring_data == NULL) { + ret = -ENOMEM; + goto error_ret; + } + ret = ring->access.read_last(ring, (u8 *) ring_data); + if (ret) + goto error_free_ring_data; + + /* for single channel scan the result is stored with zero offset */ + if ((ring->scan_mask == ((1 << 1) | (1 << 0))) && (mask == (1 << 1))) + count = 1; + + ret = be16_to_cpu(ring_data[count]); + +error_free_ring_data: + kfree(ring_data); +error_ret: + return ret; +} + +/** + * ad7887_ring_preenable() setup the parameters of the ring before enabling + * + * The complex nature of the setting of the nuber of bytes per datum is due + * to this driver currently ensuring that the timestamp is stored at an 8 + * byte boundary. + **/ +static int ad7887_ring_preenable(struct iio_dev *indio_dev) +{ + struct ad7887_state *st = indio_dev->dev_data; + struct iio_ring_buffer *ring = indio_dev->ring; + size_t d_size; + + if (indio_dev->ring->access.set_bytes_per_datum) { + d_size = st->chip_info->storagebits / 8 + sizeof(s64); + if (d_size % 8) + d_size += 8 - (d_size % 8); + indio_dev->ring->access.set_bytes_per_datum(indio_dev->ring, + d_size); + } + + switch (ring->scan_mask) { + case (1 << 0): + st->ring_msg = &st->msg[AD7887_CH0]; + break; + case (1 << 1): + st->ring_msg = &st->msg[AD7887_CH1]; + /* Dummy read: push CH1 setting down to hardware */ + spi_sync(st->spi, st->ring_msg); + break; + case ((1 << 1) | (1 << 0)): + st->ring_msg = &st->msg[AD7887_CH0_CH1]; + break; + } + + return 0; +} + +static int ad7887_ring_postdisable(struct iio_dev *indio_dev) +{ + struct ad7887_state *st = indio_dev->dev_data; + + /* dummy read: restore default CH0 settin */ + return spi_sync(st->spi, &st->msg[AD7887_CH0]); +} + +/** + * ad7887_poll_func_th() th of trigger launched polling to ring buffer + * + * As sampling only occurs on spi comms occuring, leave timestamping until + * then. Some triggers will generate their own time stamp. Currently + * there is no way of notifying them when no one cares. + **/ +static void ad7887_poll_func_th(struct iio_dev *indio_dev, s64 time) +{ + struct ad7887_state *st = indio_dev->dev_data; + + schedule_work(&st->poll_work); + return; +} +/** + * ad7887_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 ad7887_poll_bh_to_ring(struct work_struct *work_s) +{ + struct ad7887_state *st = container_of(work_s, struct ad7887_state, + poll_work); + struct iio_dev *indio_dev = st->indio_dev; + struct iio_sw_ring_buffer *sw_ring = iio_to_sw_ring(indio_dev->ring); + struct iio_ring_buffer *ring = indio_dev->ring; + s64 time_ns; + __u8 *buf; + int b_sent; + size_t d_size; + + unsigned int bytes = ring->scan_count * st->chip_info->storagebits / 8; + + /* Ensure the timestamp is 8 byte aligned */ + d_size = bytes + sizeof(s64); + if (d_size % sizeof(s64)) + d_size += sizeof(s64) - (d_size % sizeof(s64)); + + /* Ensure only one copy of this function running at a time */ + if (atomic_inc_return(&st->protect_ring) > 1) + return; + + buf = kzalloc(d_size, GFP_KERNEL); + if (buf == NULL) + return; + + b_sent = spi_sync(st->spi, st->ring_msg); + if (b_sent) + goto done; + + time_ns = iio_get_time_ns(); + + memcpy(buf, st->data, bytes); + memcpy(buf + d_size - sizeof(s64), &time_ns, sizeof(time_ns)); + + indio_dev->ring->access.store_to(&sw_ring->buf, buf, time_ns); +done: + kfree(buf); + atomic_dec(&st->protect_ring); +} + +int ad7887_register_ring_funcs_and_init(struct iio_dev *indio_dev) +{ + struct ad7887_state *st = indio_dev->dev_data; + int ret; + + indio_dev->ring = iio_sw_rb_allocate(indio_dev); + if (!indio_dev->ring) { + ret = -ENOMEM; + goto error_ret; + } + /* Effectively select the ring buffer implementation */ + iio_ring_sw_register_funcs(&indio_dev->ring->access); + ret = iio_alloc_pollfunc(indio_dev, NULL, &ad7887_poll_func_th); + if (ret) + goto error_deallocate_sw_rb; + + /* Ring buffer functions - here trigger setup related */ + + indio_dev->ring->preenable = &ad7887_ring_preenable; + indio_dev->ring->postenable = &iio_triggered_ring_postenable; + indio_dev->ring->predisable = &iio_triggered_ring_predisable; + indio_dev->ring->postdisable = &ad7887_ring_postdisable; + indio_dev->ring->scan_el_attrs = &ad7887_scan_el_group; + + INIT_WORK(&st->poll_work, &ad7887_poll_bh_to_ring); + + /* Flag that polled ring buffering is possible */ + indio_dev->modes |= INDIO_RING_TRIGGERED; + return 0; +error_deallocate_sw_rb: + iio_sw_rb_free(indio_dev->ring); +error_ret: + return ret; +} + +void ad7887_ring_cleanup(struct iio_dev *indio_dev) +{ + /* ensure that the trigger has been detached */ + if (indio_dev->trig) { + iio_put_trigger(indio_dev->trig); + iio_trigger_dettach_poll_func(indio_dev->trig, + indio_dev->pollfunc); + } + kfree(indio_dev->pollfunc); + iio_sw_rb_free(indio_dev->ring); +} |