staging: iio: resolver: ad2s1210: add triggered buffer support

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

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231005-ad2s1210-mainline-v4-6-ec00746840fc@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
index 83f6ac890dbc8a6e75469a54b55511feb926dbfd..4d651a2d0f38886707a004c3414c11fa65a688b5 100644 (file)
--- a/drivers/staging/iio/resolver/ad2s1210.c
+++ b/drivers/staging/iio/resolver/ad2s1210.c
@@ -20,8 +20,11 @@
 #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"
 
@@ -94,6 +97,12 @@ struct ad2s1210_state {
        enum ad2s1210_resolution resolution;
        /** For reading raw sample value via SPI. */
        __be16 sample __aligned(IIO_DMA_MINALIGN);
+       /** Scan buffer */
+       struct {
+               __be16 chan[2];
+               /* Ensure timestamp is naturally aligned. */
+               s64 timestamp __aligned(8);
+       } scan;
        /** SPI transmit buffer. */
        u8 rx[2];
        /** SPI receive buffer. */
@@ -621,6 +630,13 @@ 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),
@@ -630,9 +646,18 @@ static const struct iio_chan_spec ad2s1210_channels[] = {
                .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),
-       }, {
+       },
+       IIO_CHAN_SOFT_TIMESTAMP(2),
+       {
                /* used to configure phase lock range and get phase lock error */
                .type = IIO_PHASE,
                .indexed = 1,
@@ -760,6 +785,55 @@ 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 = {
        .event_attrs = &ad2s1210_event_attribute_group,
        .read_raw = ad2s1210_read_raw,
@@ -957,6 +1031,13 @@ 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);
 }