| /* |
| * AD7298 SPI ADC driver |
| * |
| * Copyright 2011-2012 Analog Devices Inc. |
| * |
| * Licensed under the GPL-2. |
| */ |
| |
| #include <linux/interrupt.h> |
| #include <linux/kernel.h> |
| #include <linux/slab.h> |
| #include <linux/spi/spi.h> |
| |
| #include <linux/iio/iio.h> |
| #include <linux/iio/buffer.h> |
| #include <linux/iio/trigger_consumer.h> |
| #include <linux/iio/triggered_buffer.h> |
| |
| #include "ad7298.h" |
| |
| /** |
| * ad7298_update_scan_mode() setup the spi transfer buffer for the new scan mask |
| **/ |
| int ad7298_update_scan_mode(struct iio_dev *indio_dev, |
| const unsigned long *active_scan_mask) |
| { |
| struct ad7298_state *st = iio_priv(indio_dev); |
| int i, m; |
| unsigned short command; |
| int scan_count; |
| |
| /* Now compute overall size */ |
| scan_count = bitmap_weight(active_scan_mask, indio_dev->masklength); |
| |
| command = AD7298_WRITE | st->ext_ref; |
| |
| for (i = 0, m = AD7298_CH(0); i < AD7298_MAX_CHAN; i++, m >>= 1) |
| if (test_bit(i, active_scan_mask)) |
| 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 < 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_trigger_handler() bh of trigger launched polling to ring buffer |
| * |
| * Currently there is no option in this driver to disable the saving of |
| * timestamps within the ring. |
| **/ |
| static irqreturn_t ad7298_trigger_handler(int irq, void *p) |
| { |
| struct iio_poll_func *pf = p; |
| struct iio_dev *indio_dev = pf->indio_dev; |
| struct ad7298_state *st = iio_priv(indio_dev); |
| s64 time_ns = 0; |
| __u16 buf[16]; |
| int b_sent, i; |
| |
| b_sent = spi_sync(st->spi, &st->ring_msg); |
| if (b_sent) |
| goto done; |
| |
| if (indio_dev->scan_timestamp) { |
| time_ns = iio_get_time_ns(); |
| memcpy((u8 *)buf + indio_dev->scan_bytes - sizeof(s64), |
| &time_ns, sizeof(time_ns)); |
| } |
| |
| for (i = 0; i < bitmap_weight(indio_dev->active_scan_mask, |
| indio_dev->masklength); i++) |
| buf[i] = be16_to_cpu(st->rx_buf[i]); |
| |
| iio_push_to_buffer(indio_dev->buffer, (u8 *)buf); |
| |
| done: |
| iio_trigger_notify_done(indio_dev->trig); |
| |
| return IRQ_HANDLED; |
| } |
| |
| int ad7298_register_ring_funcs_and_init(struct iio_dev *indio_dev) |
| { |
| return iio_triggered_buffer_setup(indio_dev, NULL, |
| &ad7298_trigger_handler, NULL); |
| } |
| |
| void ad7298_ring_cleanup(struct iio_dev *indio_dev) |
| { |
| iio_triggered_buffer_cleanup(indio_dev); |
| } |