diff options
Diffstat (limited to 'drivers/staging/iio/adc/ad7298_ring.c')
-rw-r--r-- | drivers/staging/iio/adc/ad7298_ring.c | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/drivers/staging/iio/adc/ad7298_ring.c b/drivers/staging/iio/adc/ad7298_ring.c new file mode 100644 index 000000000000..19d1aced1e6c --- /dev/null +++ b/drivers/staging/iio/adc/ad7298_ring.c @@ -0,0 +1,258 @@ +/* + * AD7298 SPI ADC driver + * + * Copyright 2011 Analog Devices Inc. + * + * Licensed under the GPL-2. + */ + +#include <linux/interrupt.h> +#include <linux/workqueue.h> +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/sysfs.h> +#include <linux/spi/spi.h> + +#include "../iio.h" +#include "../ring_generic.h" +#include "../ring_sw.h" +#include "../trigger.h" +#include "../sysfs.h" + +#include "ad7298.h" + +static IIO_SCAN_EL_C(in0, 0, 0, NULL); +static IIO_SCAN_EL_C(in1, 1, 0, NULL); +static IIO_SCAN_EL_C(in2, 2, 0, NULL); +static IIO_SCAN_EL_C(in3, 3, 0, NULL); +static IIO_SCAN_EL_C(in4, 4, 0, NULL); +static IIO_SCAN_EL_C(in5, 5, 0, NULL); +static IIO_SCAN_EL_C(in6, 6, 0, NULL); +static IIO_SCAN_EL_C(in7, 7, 0, NULL); + +static IIO_SCAN_EL_TIMESTAMP(8); +static IIO_CONST_ATTR_SCAN_EL_TYPE(timestamp, s, 64, 64); + +static IIO_CONST_ATTR(in_type, "u12/16") ; + +static struct attribute *ad7298_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_scan_el_in2.dev_attr.attr, + &iio_const_attr_in2_index.dev_attr.attr, + &iio_scan_el_in3.dev_attr.attr, + &iio_const_attr_in3_index.dev_attr.attr, + &iio_scan_el_in4.dev_attr.attr, + &iio_const_attr_in4_index.dev_attr.attr, + &iio_scan_el_in5.dev_attr.attr, + &iio_const_attr_in5_index.dev_attr.attr, + &iio_scan_el_in6.dev_attr.attr, + &iio_const_attr_in6_index.dev_attr.attr, + &iio_scan_el_in7.dev_attr.attr, + &iio_const_attr_in7_index.dev_attr.attr, + &iio_const_attr_timestamp_index.dev_attr.attr, + &iio_scan_el_timestamp.dev_attr.attr, + &iio_const_attr_timestamp_type.dev_attr.attr, + &iio_const_attr_in_type.dev_attr.attr, + NULL, +}; + +static struct attribute_group ad7298_scan_el_group = { + .name = "scan_elements", + .attrs = ad7298_scan_el_attrs, +}; + +int ad7298_scan_from_ring(struct ad7298_state *st, long ch) +{ + struct iio_ring_buffer *ring = st->indio_dev->ring; + int ret; + u16 *ring_data; + + if (!(ring->scan_mask & (1 << ch))) { + 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; + + ret = be16_to_cpu(ring_data[ch]); + +error_free_ring_data: + kfree(ring_data); +error_ret: + return ret; +} + +/** + * ad7298_ring_preenable() setup the parameters of the ring before enabling + * + * The complex nature of the setting of the number of bytes per datum is due + * to this driver currently ensuring that the timestamp is stored at an 8 + * byte boundary. + **/ +static int ad7298_ring_preenable(struct iio_dev *indio_dev) +{ + struct ad7298_state *st = indio_dev->dev_data; + struct iio_ring_buffer *ring = indio_dev->ring; + size_t d_size; + int i, m; + unsigned short command; + + d_size = ring->scan_count * (AD7298_STORAGE_BITS / 8); + + if (ring->scan_timestamp) { + d_size += sizeof(s64); + + if (d_size % sizeof(s64)) + d_size += sizeof(s64) - (d_size % sizeof(s64)); + } + + if (ring->access.set_bytes_per_datum) + ring->access.set_bytes_per_datum(ring, d_size); + + st->d_size = d_size; + + command = AD7298_WRITE | st->ext_ref; + + for (i = 0, m = AD7298_CH(0); i < AD7298_MAX_CHAN; i++, m >>= 1) + if (ring->scan_mask & (1 << i)) + command |= m; + + st->tx_buf[0] = cpu_to_be16(command); + + /* build spi ring message */ + st->ring_xfer[0].tx_buf = &st->tx_buf[0]; + st->ring_xfer[0].len = 2; + st->ring_xfer[0].cs_change = 1; + st->ring_xfer[1].tx_buf = &st->tx_buf[1]; + st->ring_xfer[1].len = 2; + st->ring_xfer[1].cs_change = 1; + + spi_message_init(&st->ring_msg); + spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg); + spi_message_add_tail(&st->ring_xfer[1], &st->ring_msg); + + for (i = 0; i < ring->scan_count; i++) { + st->ring_xfer[i + 2].rx_buf = &st->rx_buf[i]; + st->ring_xfer[i + 2].len = 2; + st->ring_xfer[i + 2].cs_change = 1; + spi_message_add_tail(&st->ring_xfer[i + 2], &st->ring_msg); + } + /* make sure last transfer cs_change is not set */ + st->ring_xfer[i + 1].cs_change = 0; + + return 0; +} + +/** + * ad7298_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 ad7298_poll_func_th(struct iio_dev *indio_dev, s64 time) +{ + struct ad7298_state *st = indio_dev->dev_data; + + schedule_work(&st->poll_work); + return; +} + +/** + * ad7298_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 ad7298_poll_bh_to_ring(struct work_struct *work_s) +{ + struct ad7298_state *st = container_of(work_s, struct ad7298_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; + __u16 buf[16]; + int b_sent, i; + + /* Ensure only one copy of this function running at a time */ + if (atomic_inc_return(&st->protect_ring) > 1) + return; + + b_sent = spi_sync(st->spi, &st->ring_msg); + if (b_sent) + goto done; + + if (ring->scan_timestamp) { + time_ns = iio_get_time_ns(); + memcpy((u8 *)buf + st->d_size - sizeof(s64), + &time_ns, sizeof(time_ns)); + } + + for (i = 0; i < ring->scan_count; i++) + buf[i] = be16_to_cpu(st->rx_buf[i]); + + indio_dev->ring->access.store_to(&sw_ring->buf, (u8 *)buf, time_ns); +done: + atomic_dec(&st->protect_ring); +} + +int ad7298_register_ring_funcs_and_init(struct iio_dev *indio_dev) +{ + struct ad7298_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, &ad7298_poll_func_th); + if (ret) + goto error_deallocate_sw_rb; + + /* Ring buffer functions - here trigger setup related */ + + indio_dev->ring->preenable = &ad7298_ring_preenable; + indio_dev->ring->postenable = &iio_triggered_ring_postenable; + indio_dev->ring->predisable = &iio_triggered_ring_predisable; + indio_dev->ring->scan_el_attrs = &ad7298_scan_el_group; + indio_dev->ring->scan_timestamp = true; + + INIT_WORK(&st->poll_work, &ad7298_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 ad7298_ring_cleanup(struct iio_dev *indio_dev) +{ + 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); +} |