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 Reviewed-by: Lars-Peter Clausen <lars@xxxxxxxxxx> Signed-off-by: Nuno Sa <nuno.sa@xxxxxxxxxx> --- Changes in v2: * Return right away if offset == 4 (no valid transition found from brurst_id to sys_flags). Changes in v3: * Move crc32.h header; * Return proper 'irqreturn_t' types in all error paths; * Move 'adis->current_page = 0' to right after setting it; * Restore spi max transfer in case 'spi_sync()' fails; * Use 80 line chars for 'devm_adis_setup_buffer_and_trigger()'. Changes in v4: * Rebased this patch on top of the series in [1]. Thus, we do not need to directly change the spi max speed and avoid a potential race. [1]: https://marc.info/?l=linux-iio&m=161908662424639&w=2 drivers/iio/imu/adis16480.c | 160 +++++++++++++++++++++++++++++++++--- 1 file changed, 147 insertions(+), 13 deletions(-) diff --git a/drivers/iio/imu/adis16480.c b/drivers/iio/imu/adis16480.c index f81b86690b76..a9c21a5ae05a 100644 --- a/drivers/iio/imu/adis16480.c +++ b/drivers/iio/imu/adis16480.c @@ -19,11 +19,15 @@ #include <linux/sysfs.h> #include <linux/module.h> #include <linux/lcm.h> +#include <linux/swab.h> +#include <linux/crc32.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 +899,9 @@ 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), \ + .burst_max_speed_hz = ADIS16495_BURST_MAX_SPEED \ } static const struct adis_timeout adis16485_timeouts = { @@ -931,7 +946,7 @@ 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 +959,7 @@ 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 +972,7 @@ 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 +985,7 @@ 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 +999,7 @@ 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 +1013,9 @@ 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 +1029,9 @@ 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 +1045,9 @@ 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 +1061,9 @@ 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 +1077,9 @@ 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 +1093,118 @@ 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; + + 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); + goto irq_done; + } + + adis->current_page = 0; + } + + 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); + goto irq_done; + } + + 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. + */ + 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; + } + } + + if (offset == 4) { + dev_err(&adis->spi->dev, "Invalid burst data\n"); + goto irq_done; + } + + 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 +1474,8 @@ 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
