Some supported devices support burst read function. This provides a method
for reading a batch of data (status, temperature, gyroscopes,
accelerometers, time stamp/data counter, and CRC code), which does not
require a stall time between each 16-bit segment and only requires one
command on the DIN line to initiate. Devices supporting this mode
are:
* adis16495-1
* adis16495-2
* adis16495-3
* adis16497-1
* adis16497-2
* adis16497-3
Signed-off-by: Nuno Sa <nuno.sa@xxxxxxxxxx>
---
drivers/iio/imu/adis16480.c | 157 +++++++++++++++++++++++++++++++++---
1 file changed, 144 insertions(+), 13 deletions(-)
diff --git a/drivers/iio/imu/adis16480.c b/drivers/iio/imu/adis16480.c
index f81b86690b76..341945f8339e 100644
--- a/drivers/iio/imu/adis16480.c
+++ b/drivers/iio/imu/adis16480.c
@@ -5,6 +5,7 @@
* Copyright 2012 Analog Devices Inc.
*/
+#include <linux/crc32.h>
#include <linux/clk.h>
#include <linux/bitfield.h>
#include <linux/of_irq.h>
@@ -19,11 +20,14 @@
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/lcm.h>
+#include <linux/swab.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/imu/adis.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
#include <linux/debugfs.h>
@@ -103,6 +107,12 @@
* Available only for ADIS1649x devices
*/
#define ADIS16495_REG_SYNC_SCALE ADIS16480_REG(0x03, 0x10)
+#define ADIS16495_REG_BURST_CMD ADIS16480_REG(0x00, 0x7C)
+#define ADIS16495_BURST_ID 0xA5A5
+/* total number of segments in burst */
+#define ADIS16495_BURST_MAX_DATA 20
+/* spi max speed in burst mode */
+#define ADIS16495_BURST_MAX_SPEED 6000000
#define ADIS16480_REG_SERIAL_NUM ADIS16480_REG(0x04, 0x20)
@@ -163,6 +173,8 @@ struct adis16480 {
struct clk *ext_clk;
enum adis16480_clock_mode clk_mode;
unsigned int clk_freq;
+ /* Alignment needed for the timestamp */
+ __be16 data[ADIS16495_BURST_MAX_DATA] __aligned(8);
};
static const char * const adis16480_int_pin_names[4] = {
@@ -863,7 +875,7 @@ static const char * const adis16480_status_error_msgs[] = {
static int adis16480_enable_irq(struct adis *adis, bool enable);
-#define ADIS16480_DATA(_prod_id, _timeouts) \
+#define ADIS16480_DATA(_prod_id, _timeouts, _burst_len) \
{ \
.diag_stat_reg = ADIS16480_REG_DIAG_STS, \
.glob_cmd_reg = ADIS16480_REG_GLOB_CMD, \
@@ -887,6 +899,8 @@ static int adis16480_enable_irq(struct adis *adis, bool enable);
BIT(ADIS16480_DIAG_STAT_BARO_FAIL), \
.enable_irq = adis16480_enable_irq, \
.timeouts = (_timeouts), \
+ .burst_reg_cmd = ADIS16495_REG_BURST_CMD, \
+ .burst_len = (_burst_len), \
}
static const struct adis_timeout adis16485_timeouts = {
@@ -931,7 +945,7 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
.int_clk = 2460000,
.max_dec_rate = 2048,
.filter_freqs = adis16480_def_filter_freqs,
- .adis_data = ADIS16480_DATA(16375, &adis16485_timeouts),
+ .adis_data = ADIS16480_DATA(16375, &adis16485_timeouts, 0),
},
[ADIS16480] = {
.channels = adis16480_channels,
@@ -944,7 +958,7 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
.int_clk = 2460000,
.max_dec_rate = 2048,
.filter_freqs = adis16480_def_filter_freqs,
- .adis_data = ADIS16480_DATA(16480, &adis16480_timeouts),
+ .adis_data = ADIS16480_DATA(16480, &adis16480_timeouts, 0),
},
[ADIS16485] = {
.channels = adis16485_channels,
@@ -957,7 +971,7 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
.int_clk = 2460000,
.max_dec_rate = 2048,
.filter_freqs = adis16480_def_filter_freqs,
- .adis_data = ADIS16480_DATA(16485, &adis16485_timeouts),
+ .adis_data = ADIS16480_DATA(16485, &adis16485_timeouts, 0),
},
[ADIS16488] = {
.channels = adis16480_channels,
@@ -970,7 +984,7 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
.int_clk = 2460000,
.max_dec_rate = 2048,
.filter_freqs = adis16480_def_filter_freqs,
- .adis_data = ADIS16480_DATA(16488, &adis16485_timeouts),
+ .adis_data = ADIS16480_DATA(16488, &adis16485_timeouts, 0),
},
[ADIS16490] = {
.channels = adis16485_channels,
@@ -984,7 +998,7 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
.max_dec_rate = 4250,
.filter_freqs = adis16495_def_filter_freqs,
.has_pps_clk_mode = true,
- .adis_data = ADIS16480_DATA(16490, &adis16495_timeouts),
+ .adis_data = ADIS16480_DATA(16490, &adis16495_timeouts, 0),
},
[ADIS16495_1] = {
.channels = adis16485_channels,
@@ -998,7 +1012,9 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
.max_dec_rate = 4250,
.filter_freqs = adis16495_def_filter_freqs,
.has_pps_clk_mode = true,
- .adis_data = ADIS16480_DATA(16495, &adis16495_1_timeouts),
+ /* 20 elements of 16bits */
+ .adis_data = ADIS16480_DATA(16495, &adis16495_1_timeouts,
+ ADIS16495_BURST_MAX_DATA * 2),
},
[ADIS16495_2] = {
.channels = adis16485_channels,
@@ -1012,7 +1028,9 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
.max_dec_rate = 4250,
.filter_freqs = adis16495_def_filter_freqs,
.has_pps_clk_mode = true,
- .adis_data = ADIS16480_DATA(16495, &adis16495_1_timeouts),
+ /* 20 elements of 16bits */
+ .adis_data = ADIS16480_DATA(16495, &adis16495_1_timeouts,
+ ADIS16495_BURST_MAX_DATA * 2),
},
[ADIS16495_3] = {
.channels = adis16485_channels,
@@ -1026,7 +1044,9 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
.max_dec_rate = 4250,
.filter_freqs = adis16495_def_filter_freqs,
.has_pps_clk_mode = true,
- .adis_data = ADIS16480_DATA(16495, &adis16495_1_timeouts),
+ /* 20 elements of 16bits */
+ .adis_data = ADIS16480_DATA(16495, &adis16495_1_timeouts,
+ ADIS16495_BURST_MAX_DATA * 2),
},
[ADIS16497_1] = {
.channels = adis16485_channels,
@@ -1040,7 +1060,9 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
.max_dec_rate = 4250,
.filter_freqs = adis16495_def_filter_freqs,
.has_pps_clk_mode = true,
- .adis_data = ADIS16480_DATA(16497, &adis16495_1_timeouts),
+ /* 20 elements of 16bits */
+ .adis_data = ADIS16480_DATA(16497, &adis16495_1_timeouts,
+ ADIS16495_BURST_MAX_DATA * 2),
},
[ADIS16497_2] = {
.channels = adis16485_channels,
@@ -1054,7 +1076,9 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
.max_dec_rate = 4250,
.filter_freqs = adis16495_def_filter_freqs,
.has_pps_clk_mode = true,
- .adis_data = ADIS16480_DATA(16497, &adis16495_1_timeouts),
+ /* 20 elements of 16bits */
+ .adis_data = ADIS16480_DATA(16497, &adis16495_1_timeouts,
+ ADIS16495_BURST_MAX_DATA * 2),
},
[ADIS16497_3] = {
.channels = adis16485_channels,
@@ -1068,10 +1092,117 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
.max_dec_rate = 4250,
.filter_freqs = adis16495_def_filter_freqs,
.has_pps_clk_mode = true,
- .adis_data = ADIS16480_DATA(16497, &adis16495_1_timeouts),
+ /* 20 elements of 16bits */
+ .adis_data = ADIS16480_DATA(16497, &adis16495_1_timeouts,
+ ADIS16495_BURST_MAX_DATA * 2),
},
};
+static bool adis16480_validate_crc(const u16 *buf, const u8 n_elem, const u32 crc)
+{
+ u32 crc_calc;
+ u16 crc_buf[15];
+ int j;
+
+ for (j = 0; j < n_elem; j++)
+ crc_buf[j] = swab16(buf[j]);
+
+ crc_calc = crc32(~0, crc_buf, n_elem * 2);
+ crc_calc ^= ~0;
+
+ return (crc == crc_calc);
+}
+
+static irqreturn_t adis16480_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct adis16480 *st = iio_priv(indio_dev);
+ struct adis *adis = &st->adis;
+ int ret, bit, offset, i = 0;
+ __be16 *buffer;
+ u32 crc;
+ bool valid;
+ const u32 cached_spi_speed_hz = adis->spi->max_speed_hz;
+
+ adis_dev_lock(adis);
+ if (adis->current_page != 0) {
+ adis->tx[0] = ADIS_WRITE_REG(ADIS_REG_PAGE_ID);
+ adis->tx[1] = 0;
+ ret = spi_write(adis->spi, adis->tx, 2);
+ if (ret) {
+ dev_err(&adis->spi->dev, "Failed to change device page: %d\n", ret);
+ adis_dev_unlock(adis);
+ return ret;
+ }
+ }
+
+ adis->spi->max_speed_hz = ADIS16495_BURST_MAX_SPEED;
+
+ ret = spi_sync(adis->spi, &adis->msg);
+ if (ret) {
+ dev_err(&adis->spi->dev, "Failed to read data: %d\n", ret);
+ adis_dev_unlock(adis);
+ return ret;
+ }
+
+ adis->spi->max_speed_hz = cached_spi_speed_hz;
+ adis->current_page = 0;
+ adis_dev_unlock(adis);
+
+ /*
+ * After making the burst request, the response can have one or two
+ * 16-bit responses containing the BURST_ID depending on the sclk. If
+ * clk > 3.6MHz, then we will have two BURST_ID in a row. If clk < 3MHZ,
+ * we have only one. To manage that variation, we use the transition from the
+ * BURST_ID to the SYS_E_FLAG register, which will not be equal to 0xA5A5. If
+ * we not find this variation in the first 4 segments, then the data should
+ * not be valid. We don't return right away since the crc validation should
+ * fail anyways...
+ */
+ buffer = adis->buffer;
+ for (offset = 0; offset < 4; offset++) {
+ u16 curr = be16_to_cpu(buffer[offset]);
+ u16 next = be16_to_cpu(buffer[offset + 1]);
+
+ if (curr == ADIS16495_BURST_ID && next != ADIS16495_BURST_ID) {
+ offset++;
+ break;
+ }
+ }
+
+ crc = be16_to_cpu(buffer[offset + 16]) << 16 | be16_to_cpu(buffer[offset + 15]);
+ valid = adis16480_validate_crc((u16 *)&buffer[offset], 15, crc);
+ if (!valid) {
+ dev_err(&adis->spi->dev, "Invalid crc\n");
+ goto irq_done;
+ }
+
+ for_each_set_bit(bit, indio_dev->active_scan_mask, indio_dev->masklength) {
+ /*
+ * When burst mode is used, temperature is the first data
+ * channel in the sequence, but the temperature scan index
+ * is 10.
+ */
+ switch (bit) {
+ case ADIS16480_SCAN_TEMP:
+ st->data[i++] = buffer[offset + 1];
+ break;
+ case ADIS16480_SCAN_GYRO_X ... ADIS16480_SCAN_ACCEL_Z:
+ /* The lower register data is sequenced first */
+ st->data[i++] = buffer[2 * bit + offset + 3];
+ st->data[i++] = buffer[2 * bit + offset + 2];
+ break;
+ }
+ }
+
+ iio_push_to_buffers_with_timestamp(indio_dev, st->data, pf->timestamp);
+irq_done:
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
static const struct iio_info adis16480_info = {
.read_raw = &adis16480_read_raw,
.write_raw = &adis16480_write_raw,
@@ -1341,7 +1472,7 @@ static int adis16480_probe(struct spi_device *spi)
st->clk_freq = st->chip_info->int_clk;
}
- ret = devm_adis_setup_buffer_and_trigger(&st->adis, indio_dev, NULL);
+ ret = devm_adis_setup_buffer_and_trigger(&st->adis, indio_dev, adis16480_trigger_handler);
if (ret)
return ret;
--
2.31.1
