From: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
Some variants in the ADIS16400 family support burst mode. This mechanism is
implemented in the `adis16400_buffer.c` file.
Some variants in ADIS16480 are also adding burst mode, which is
functionally similar to ADIS16400, but with different parameters. To get
there, a `adis_burst` struct is added to parametrize certain bits of the
SPI communication to setup: the register that triggers burst-mode, and the
extra-data-length that needs be accounted for when building the bust-length
buffer.
The trigger handler cannot be made generic, since it's very specific to
each ADIS164XX family.
A future enhancement of this `adis_burst` mode will be the possibility to
enable/disable burst-mode. For the ADIS16400 family it's hard-coded to on
by default. But for ADIS16480 there will be a need to disable this.
When that will be implemented, both ADIS16400 & ADIS16480 will have the
burst-mode enable-able/disable-able.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
---
drivers/iio/imu/adis16400_buffer.c | 7 +++----
drivers/iio/imu/adis16400_core.c | 8 ++++++++
include/linux/iio/imu/adis.h | 14 ++++++++++++++
3 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/imu/adis16400_buffer.c b/drivers/iio/imu/adis16400_buffer.c
index 268349eb51c7..199bd72348eb 100644
--- a/drivers/iio/imu/adis16400_buffer.c
+++ b/drivers/iio/imu/adis16400_buffer.c
@@ -22,7 +22,7 @@ int adis16400_update_scan_mode(struct iio_dev *indio_dev,
unsigned int burst_length;
u8 *tx;
- if (st->variant->flags & ADIS16400_NO_BURST)
+ if (!adis->burst || !adis->burst->en)
return adis_update_scan_mode(indio_dev, scan_mask);
kfree(adis->xfer);
@@ -30,8 +30,7 @@ int adis16400_update_scan_mode(struct iio_dev *indio_dev,
/* All but the timestamp channel */
burst_length = (indio_dev->num_channels - 1) * sizeof(u16);
- if (st->variant->flags & ADIS16400_BURST_DIAG_STAT)
- burst_length += sizeof(u16);
+ burst_length += adis->burst->extra_len;
adis->xfer = kcalloc(2, sizeof(*adis->xfer), GFP_KERNEL);
if (!adis->xfer)
@@ -42,7 +41,7 @@ int adis16400_update_scan_mode(struct iio_dev *indio_dev,
return -ENOMEM;
tx = adis->buffer + burst_length;
- tx[0] = ADIS_READ_REG(ADIS16400_GLOB_CMD);
+ tx[0] = ADIS_READ_REG(adis->burst->reg_cmd);
tx[1] = 0;
adis->xfer[0].tx_buf = tx;
diff --git a/drivers/iio/imu/adis16400_core.c b/drivers/iio/imu/adis16400_core.c
index 34d52863377a..0d799e983d74 100644
--- a/drivers/iio/imu/adis16400_core.c
+++ b/drivers/iio/imu/adis16400_core.c
@@ -146,6 +146,11 @@ enum adis16400_chip_variant {
ADIS16448,
};
+static struct adis_burst adis16400_burst = {
+ .en = true,
+ .reg_cmd = ADIS16400_GLOB_CMD,
+};
+
static int adis16334_get_freq(struct adis16400_state *st)
{
int ret;
@@ -973,6 +978,9 @@ static int adis16400_probe(struct spi_device *spi)
if (!(st->variant->flags & ADIS16400_NO_BURST)) {
adis16400_setup_chan_mask(st);
indio_dev->available_scan_masks = st->avail_scan_mask;
+ st->adis.burst = &adis16400_burst;
+ if (st->variant->flags & ADIS16400_BURST_DIAG_STAT)
+ st->adis.burst->extra_len = sizeof(u16);
}
ret = adis_init(&st->adis, indio_dev, spi, &adis16400_data);
diff --git a/include/linux/iio/imu/adis.h b/include/linux/iio/imu/adis.h
index cb6c3ed13459..26141ee87cfb 100644
--- a/include/linux/iio/imu/adis.h
+++ b/include/linux/iio/imu/adis.h
@@ -21,6 +21,7 @@
#define ADIS_REG_PAGE_ID 0x00
struct adis;
+struct adis_burst;
/**
* struct adis_data - ADIS chip variant specific data
@@ -59,6 +60,7 @@ struct adis {
struct iio_trigger *trig;
const struct adis_data *data;
+ struct adis_burst *burst;
struct mutex txrx_lock;
struct spi_message msg;
@@ -234,6 +236,18 @@ int adis_single_conversion(struct iio_dev *indio_dev,
#ifdef CONFIG_IIO_ADIS_LIB_BUFFER
+/**
+ * struct adis_burst - ADIS data for burst transfers
+ * @en burst mode enabled
+ * @reg_cmd register command that triggers burst
+ * @extra_len extra length to account in the SPI RX buffer
+ */
+struct adis_burst {
+ bool en;
+ unsigned int reg_cmd;
+ unsigned int extra_len;
+};
+
int adis_setup_buffer_and_trigger(struct adis *adis,
struct iio_dev *indio_dev, irqreturn_t (*trigger_handler)(int, void *));
void adis_cleanup_buffer_and_trigger(struct adis *adis,
--
2.17.1
