[PATCH 2/2] staging: iio: resolver: ad2s1210: add triggered buffer support

David Lechner
2023-09-21T20:27:36Z

This adds support for triggered buffers to the AD2S1210 resolver driver.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---
drivers/staging/iio/resolver/ad2s1210.c | 84 ++++++++++++++++++++++++-
1 file changed, 83 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
index f5b8b290e860..44a2ecaeeeff 100644
--- a/drivers/staging/iio/resolver/ad2s1210.c
+++ b/drivers/staging/iio/resolver/ad2s1210.c
@@ -19,8 +19,11 @@
#include <linux/sysfs.h>
#include <linux/types.h>

+#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>

#define DRV_NAME "ad2s1210"

@@ -85,6 +88,12 @@ struct ad2s1210_state {
unsigned long fclkin;
/** The selected resolution */
enum ad2s1210_resolution resolution;
+ /** Scan buffer */
+ struct {
+ __be16 chan[2];
+ /* Ensure timestamp is naturally aligned. */
+ s64 timestamp __aligned(8);
+ } scan;
u8 rx[2] __aligned(IIO_DMA_MINALIGN);
u8 tx[2];
};
@@ -592,18 +601,35 @@ static const struct iio_chan_spec ad2s1210_channels[] = {
.type = IIO_ANGL,
.indexed = 1,
.channel = 0,
+ .scan_index = 0,
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 16,
+ .storagebits = 16,
+ .endianness = IIO_BE,
+ },
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_HYSTERESIS),
.info_mask_separate_available =
BIT(IIO_CHAN_INFO_HYSTERESIS),
+ .datasheet_name = "position",
}, {
.type = IIO_ANGL_VEL,
.indexed = 1,
.channel = 0,
+ .scan_index = 1,
+ .scan_type = {
+ .sign = 's',
+ .realbits = 16,
+ .storagebits = 16,
+ .endianness = IIO_BE,
+ },
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
- }
+ .datasheet_name = "velocity",
+ },
+ IIO_CHAN_SOFT_TIMESTAMP(2),
};

static struct attribute *ad2s1210_attributes[] = {
@@ -665,6 +691,55 @@ static int ad2s1210_debugfs_reg_access(struct iio_dev *indio_dev,
return ret;
}

+static irqreturn_t ad2s1210_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct ad2s1210_state *st = iio_priv(indio_dev);
+ size_t chan = 0;
+ int ret;
+
+ mutex_lock(&st->lock);
+
+ memset(&st->scan, 0, sizeof(st->scan));
+ gpiod_set_value(st->sample_gpio, 1);
+
+ if (test_bit(0, indio_dev->active_scan_mask)) {
+ ret = ad2s1210_set_mode(st, MOD_POS);
+ if (ret < 0)
+ goto error_ret;
+
+ /* REVIST: we can read 3 bytes here and also get fault flags */
+ ret = spi_read(st->sdev, st->rx, 2);
+ if (ret < 0)
+ goto error_ret;
+
+ memcpy(&st->scan.chan[chan++], st->rx, 2);
+ }
+
+ if (test_bit(1, indio_dev->active_scan_mask)) {
+ ret = ad2s1210_set_mode(st, MOD_VEL);
+ if (ret < 0)
+ goto error_ret;
+
+ /* REVIST: we can read 3 bytes here and also get fault flags */
+ ret = spi_read(st->sdev, st->rx, 2);
+ if (ret < 0)
+ goto error_ret;
+
+ memcpy(&st->scan.chan[chan++], st->rx, 2);
+ }
+
+ iio_push_to_buffers_with_timestamp(indio_dev, &st->scan, pf->timestamp);
+
+error_ret:
+ gpiod_set_value(st->sample_gpio, 0);
+ mutex_unlock(&st->lock);
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
static const struct iio_info ad2s1210_info = {
.read_raw = ad2s1210_read_raw,
.read_avail = ad2s1210_read_avail,
@@ -850,6 +925,13 @@ static int ad2s1210_probe(struct spi_device *spi)
indio_dev->num_channels = ARRAY_SIZE(ad2s1210_channels);
indio_dev->name = spi_get_device_id(spi)->name;

+ ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
+ &iio_pollfunc_store_time,
+ &ad2s1210_trigger_handler, NULL);
+ if (ret < 0)
+ return dev_err_probe(&spi->dev, ret,
+ "iio triggered buffer setup failed\n");
+
return devm_iio_device_register(&spi->dev, indio_dev);
}

--
2.34.1