| /* |
| * Copyright 2010 Analog Devices Inc. |
| * Copyright (C) 2008 Jonathan Cameron |
| * |
| * Licensed under the GPL-2 or later. |
| * |
| * ad7476_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 "ad7476.h" |
| |
| static IIO_SCAN_EL_C(in0, 0, 0, NULL); |
| |
| static ssize_t ad7476_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 ad7476_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->res_shift); |
| } |
| static IIO_DEVICE_ATTR(in_type, S_IRUGO, ad7476_show_type, NULL, 0); |
| |
| static struct attribute *ad7476_scan_el_attrs[] = { |
| &iio_scan_el_in0.dev_attr.attr, |
| &iio_const_attr_in0_index.dev_attr.attr, |
| &iio_dev_attr_in_type.dev_attr.attr, |
| NULL, |
| }; |
| |
| static struct attribute_group ad7476_scan_el_group = { |
| .name = "scan_elements", |
| .attrs = ad7476_scan_el_attrs, |
| }; |
| |
| int ad7476_scan_from_ring(struct ad7476_state *st) |
| { |
| struct iio_ring_buffer *ring = st->indio_dev->ring; |
| int ret; |
| u8 *ring_data; |
| |
| 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, ring_data); |
| if (ret) |
| goto error_free_ring_data; |
| |
| ret = (ring_data[0] << 8) | ring_data[1]; |
| |
| error_free_ring_data: |
| kfree(ring_data); |
| error_ret: |
| return ret; |
| } |
| |
| /** |
| * ad7476_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 ad7476_ring_preenable(struct iio_dev *indio_dev) |
| { |
| struct ad7476_state *st = indio_dev->dev_data; |
| 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); |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * ad7476_poll_func_th() th of trigger launched polling to ring buffer |
| * |
| * As sampling only occurs on i2c 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 ad7476_poll_func_th(struct iio_dev *indio_dev, s64 time) |
| { |
| struct ad7476_state *st = indio_dev->dev_data; |
| |
| schedule_work(&st->poll_work); |
| return; |
| } |
| /** |
| * ad7476_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 ad7476_poll_bh_to_ring(struct work_struct *work_s) |
| { |
| struct ad7476_state *st = container_of(work_s, struct ad7476_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); |
| s64 time_ns; |
| __u8 *rxbuf; |
| int b_sent; |
| size_t d_size; |
| |
| /* Ensure the timestamp is 8 byte aligned */ |
| d_size = st->chip_info->storagebits / 8 + 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; |
| |
| rxbuf = kzalloc(d_size, GFP_KERNEL); |
| if (rxbuf == NULL) |
| return; |
| |
| b_sent = spi_read(st->spi, rxbuf, st->chip_info->storagebits / 8); |
| if (b_sent < 0) |
| goto done; |
| |
| time_ns = iio_get_time_ns(); |
| |
| memcpy(rxbuf + d_size - sizeof(s64), &time_ns, sizeof(time_ns)); |
| |
| indio_dev->ring->access.store_to(&sw_ring->buf, rxbuf, time_ns); |
| done: |
| kfree(rxbuf); |
| atomic_dec(&st->protect_ring); |
| } |
| |
| int ad7476_register_ring_funcs_and_init(struct iio_dev *indio_dev) |
| { |
| struct ad7476_state *st = indio_dev->dev_data; |
| int ret = 0; |
| |
| 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, &ad7476_poll_func_th); |
| if (ret) |
| goto error_deallocate_sw_rb; |
| |
| /* Ring buffer functions - here trigger setup related */ |
| |
| indio_dev->ring->preenable = &ad7476_ring_preenable; |
| indio_dev->ring->postenable = &iio_triggered_ring_postenable; |
| indio_dev->ring->predisable = &iio_triggered_ring_predisable; |
| indio_dev->ring->scan_el_attrs = &ad7476_scan_el_group; |
| |
| INIT_WORK(&st->poll_work, &ad7476_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 ad7476_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); |
| } |