[PATCH v2 2/2] iio: accel: Add driver for Murata SCA3300 accelerometer

From: Tomas Melin
Date: Fri Apr 16 2021 - 09:46:41 EST

Add initial support for Murata SCA3300 3-axis industrial
accelerometer with digital SPI interface. This device also
provides a temperature measurement.

Device product page including datasheet can be found at:
https://www.murata.com/en-global/products/sensor/accel/sca3300

Signed-off-by: Tomas Melin <tomas.melin@xxxxxxxxxxx>
---
drivers/iio/accel/Kconfig | 13 +
drivers/iio/accel/Makefile | 1 +
drivers/iio/accel/sca3300.c | 468 ++++++++++++++++++++++++++++++++++++
3 files changed, 482 insertions(+)
create mode 100644 drivers/iio/accel/sca3300.c

diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index cceda3cecbcf..0dbf7b648e8a 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -450,6 +450,19 @@ config SCA3000
To compile this driver as a module, say M here: the module will be
called sca3000.

+config SCA3300
+ tristate "Murata SCA3300 3-Axis Accelerometer Driver"
+ depends on SPI
+ select CRC8
+ select IIO_BUFFER
+ select IIO_TRIGGERED_BUFFER
+ help
+ Say yes here to build support for Murata SCA3300 3-Axis
+ accelerometer.
+
+ To compile this driver as a module, choose M here: the module will be
+ called sca3300.
+
config STK8312
tristate "Sensortek STK8312 3-Axis Accelerometer Driver"
depends on I2C
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index 32cd1342a31a..4b56527a2b97 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -50,6 +50,7 @@ obj-$(CONFIG_MXC4005) += mxc4005.o
obj-$(CONFIG_MXC6255) += mxc6255.o

obj-$(CONFIG_SCA3000) += sca3000.o
+obj-$(CONFIG_SCA3300) += sca3300.o

obj-$(CONFIG_STK8312) += stk8312.o
obj-$(CONFIG_STK8BA50) += stk8ba50.o
diff --git a/drivers/iio/accel/sca3300.c b/drivers/iio/accel/sca3300.c
new file mode 100644
index 000000000000..79c3c60f9fab
--- /dev/null
+++ b/drivers/iio/accel/sca3300.c
@@ -0,0 +1,468 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2021 Vaisala Oyj. All rights reserved.
+ */
+#include <asm/unaligned.h>
+#include <linux/bitops.h>
+#include <linux/crc8.h>
+#include <linux/delay.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>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+
+#define SCA3300_ALIAS "sca3300"
+
+#define SCA3300_REG_STATUS 0x6
+#define SCA3300_REG_MODE 0xd
+#define SCA3300_REG_WHOAMI 0x10
+#define SCA3300_VALUE_SW_RESET 0x20
+#define SCA3300_CRC8_POLYNOMIAL 0x1d
+#define SCA3300_DEVICE_ID 0x51
+#define SCA3300_RS_ERROR 0x3
+#define SCA3300_SELBANK 0x1f
+#define SCA3300_STATUS_MASK 0x1ff
+
+enum sca3300_scan_indexes {
+ SCA3300_ACC_X = 0,
+ SCA3300_ACC_Y,
+ SCA3300_ACC_Z,
+ SCA3300_TEMP,
+ SCA3300_TIMESTAMP,
+};
+
+#define SCA3300_ACCEL_CHANNEL(index, reg, axis) { \
+ .type = IIO_ACCEL, \
+ .address = reg, \
+ .modified = 1, \
+ .channel2 = IIO_MOD_##axis, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = \
+ BIT(IIO_CHAN_INFO_SCALE) | \
+ BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY), \
+ .info_mask_shared_by_type_available = \
+ BIT(IIO_CHAN_INFO_SCALE) | \
+ BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY), \
+ .scan_index = index, \
+ .scan_type = { \
+ .sign = 's', \
+ .realbits = 16, \
+ .storagebits = 16, \
+ .shift = 0, \
+ .endianness = IIO_CPU, \
+ }, \
+ }
+
+static const struct iio_chan_spec sca3300_channels[] = {
+ SCA3300_ACCEL_CHANNEL(SCA3300_ACC_X, 0x1, X),
+ SCA3300_ACCEL_CHANNEL(SCA3300_ACC_Y, 0x2, Y),
+ SCA3300_ACCEL_CHANNEL(SCA3300_ACC_Z, 0x3, Z),
+ {
+ .type = IIO_TEMP,
+ .address = 0x5,
+ .scan_index = SCA3300_TEMP,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .scan_type = {
+ .sign = 's',
+ .realbits = 16,
+ .storagebits = 16,
+ .shift = 0,
+ .endianness = IIO_CPU,
+ },
+ },
+ IIO_CHAN_SOFT_TIMESTAMP(4),
+};
+
+static const int sca3300_lp_freq[] = {70, 70, 70, 10};
+static const int sca3300_accel_scale[][2] = {{0, 370}, {0, 741}, {0, 185},
+ {0, 185}};
+
+static const unsigned long sca3300_scan_masks[] = {
+ BIT(SCA3300_ACC_X) | BIT(SCA3300_ACC_Y) | BIT(SCA3300_ACC_Z) |
+ BIT(SCA3300_TEMP),
+ 0};
+
+/**
+ * struct sca3300_data - device data
+ * @spi: SPI device structure
+ * @lock: Data buffer lock
+ * @txbuf: Transmit buffer
+ * @rxbuf: Receive buffer
+ * @scan: Triggered buffer. Four channel 16-bit data + 64-bit timestamp
+ */
+struct sca3300_data {
+ struct spi_device *spi;
+ struct mutex lock;
+ u8 txbuf[4];
+ u8 rxbuf[4];
+ struct {
+ s16 channels[4];
+ s64 ts __aligned(sizeof(s64));
+ } scan;
+};
+
+DECLARE_CRC8_TABLE(sca3300_crc_table);
+
+static int sca3300_transfer(struct sca3300_data *sca_data, int *val)
+{
+ struct spi_delay delay = {.value = 10, .unit = SPI_DELAY_UNIT_USECS};
+ int32_t ret;
+ int rs;
+ u8 crc;
+ struct spi_transfer xfers[2] = {
+ {
+ .tx_buf = sca_data->txbuf,
+ .rx_buf = NULL,
+ .len = ARRAY_SIZE(sca_data->txbuf),
+ .delay = delay,
+ .cs_change = 1,
+ },
+ {
+ .tx_buf = NULL,
+ .rx_buf = sca_data->rxbuf,
+ .len = ARRAY_SIZE(sca_data->rxbuf),
+ .delay = delay,
+ .cs_change = 0,
+ }
+ };
+
+ /* inverted crc value as described in device data sheet */
+ crc = ~crc8(sca3300_crc_table, &sca_data->txbuf[0], 3, CRC8_INIT_VALUE);
+ sca_data->txbuf[3] = crc;
+
+ ret = spi_sync_transfer(sca_data->spi, xfers, ARRAY_SIZE(xfers));
+ if (ret < 0) {
+ dev_err(&sca_data->spi->dev,
+ "transfer error, error: %d\n", ret);
+ return -EIO;
+ }
+
+ crc = ~crc8(sca3300_crc_table, &sca_data->rxbuf[0], 3, CRC8_INIT_VALUE);
+ if (sca_data->rxbuf[3] != crc) {
+ dev_err(&sca_data->spi->dev, "CRC checksum mismatch");
+ return -EIO;
+ }
+
+ /* get return status */
+ rs = sca_data->rxbuf[0] & 0x03;
+ if (rs == SCA3300_RS_ERROR)
+ ret = -EINVAL;
+
+ *val = sign_extend32(get_unaligned_be16(&sca_data->rxbuf[1]), 15);
+
+ return ret;
+}
+
+static int sca3300_error_handler(struct sca3300_data *sca_data)
+{
+ int ret;
+ int val;
+
+ mutex_lock(&sca_data->lock);
+ sca_data->txbuf[0] = 0x0 | (SCA3300_REG_STATUS << 2);
+ ret = sca3300_transfer(sca_data, &val);
+ mutex_unlock(&sca_data->lock);
+ /* return status is cleared after reading status register */
+ if (ret != -EINVAL) {
+ dev_err(&sca_data->spi->dev,
+ "error reading device status: %d\n", ret);
+ return ret;
+ }
+
+ dev_err(&sca_data->spi->dev, "device status: 0x%x\n",
+ (u16)(val & SCA3300_STATUS_MASK));
+ return 0;
+}
+
+static int sca3300_read_reg(struct sca3300_data *sca_data, u8 reg, int *val)
+{
+ int ret;
+
+ mutex_lock(&sca_data->lock);
+ sca_data->txbuf[0] = 0x0 | (reg << 2);
+ ret = sca3300_transfer(sca_data, val);
+ mutex_unlock(&sca_data->lock);
+ if (ret == -EINVAL)
+ ret = sca3300_error_handler(sca_data);
+
+ return ret;
+}
+
+static int sca3300_write_reg(struct sca3300_data *sca_data, u8 reg, int val)
+{
+ int reg_val = 0;
+ int ret;
+
+ mutex_lock(&sca_data->lock);
+ sca_data->txbuf[0] = BIT(7) | (reg << 2);
+ put_unaligned_be16(val, &sca_data->txbuf[1]);
+ ret = sca3300_transfer(sca_data, &reg_val);
+ mutex_unlock(&sca_data->lock);
+ if (ret == -EINVAL)
+ ret = sca3300_error_handler(sca_data);
+
+ return ret;
+}
+
+static int sca3300_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct sca3300_data *data = iio_priv(indio_dev);
+ int reg_val;
+ int ret;
+ int i;
+ int idx = -1;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_SCALE:
+ if (val)
+ return -EINVAL;
+
+ for (i = 0; i < ARRAY_SIZE(sca3300_accel_scale); i++) {
+ if (val2 == sca3300_accel_scale[i][1]) {
+ idx = i;
+ break;
+ }
+ }
+ if (idx == -1)
+ return -EINVAL;
+
+ return sca3300_write_reg(data, SCA3300_REG_MODE, idx);
+ case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+ ret = sca3300_read_reg(data, SCA3300_REG_MODE, &reg_val);
+ if (ret < 0)
+ return ret;
+ /* freq. change is possible only for mode 3 and 4 */
+ if (reg_val == 2 && val == sca3300_lp_freq[3])
+ return sca3300_write_reg(data, SCA3300_REG_MODE, 3);
+ else if (reg_val == 3 && val == sca3300_lp_freq[2])
+ return sca3300_write_reg(data, SCA3300_REG_MODE, 2);
+ else
+ return -EINVAL;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int sca3300_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct sca3300_data *data = iio_priv(indio_dev);
+ int ret;
+ int reg_val;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = sca3300_read_reg(data, chan->address, val);
+ if (ret < 0)
+ return ret;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ ret = sca3300_read_reg(data, SCA3300_REG_MODE, &reg_val);
+ if (ret < 0)
+ return ret;
+ *val = 0;
+ *val2 = sca3300_accel_scale[reg_val][1];
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+ ret = sca3300_read_reg(data, SCA3300_REG_MODE, &reg_val);
+ if (ret < 0)
+ return ret;
+ *val = sca3300_lp_freq[reg_val];
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+static irqreturn_t sca3300_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct sca3300_data *data = iio_priv(indio_dev);
+ int bit, ret, val, i = 0;
+
+ for_each_set_bit(bit, indio_dev->active_scan_mask,
+ indio_dev->masklength) {
+ ret = sca3300_read_reg(data, sca3300_channels[bit].address,
+ &val);
+ if (ret < 0) {
+ dev_err(&data->spi->dev,
+ "failed to read register, error: %d\n", ret);
+ goto out;
+ }
+ ((s16 *)data->scan.channels)[i++] = val;
+ }
+
+ iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
+ iio_get_time_ns(indio_dev));
+out:
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * sca3300_init - Device init sequence. See datasheet rev 2 section
+ * 4.2 Start-Up Sequence for details.
+ */
+static int sca3300_init(struct sca3300_data *sca_data,
+ struct iio_dev *indio_dev)
+{
+ int ret;
+ int value = 0;
+
+ ret = sca3300_write_reg(sca_data, SCA3300_REG_MODE,
+ SCA3300_VALUE_SW_RESET);
+ if (ret != 0)
+ return ret;
+ /* wait at least 1ms after SW-reset command */
+ usleep_range(1e3, 10e3);
+
+ /* wait 15ms for settling of signal paths */
+ usleep_range(15e3, 50e3);
+ ret = sca3300_read_reg(sca_data, SCA3300_REG_WHOAMI, &value);
+ if (ret != 0)
+ return ret;
+
+ if (value != SCA3300_DEVICE_ID) {
+ dev_err(&sca_data->spi->dev,
+ "device id not expected value, %d != %u\n",
+ value, SCA3300_DEVICE_ID);
+ return -EIO;
+ }
+ return 0;
+}
+
+static int sca3300_debugfs_reg_access(struct iio_dev *indio_dev,
+ unsigned int reg, unsigned int writeval,
+ unsigned int *readval)
+{
+ struct sca3300_data *data = iio_priv(indio_dev);
+ int value;
+ int ret;
+
+ if (reg > SCA3300_SELBANK)
+ return -EINVAL;
+
+ if (!readval)
+ return sca3300_write_reg(data, reg, writeval);
+
+ ret = sca3300_read_reg(data, reg, &value);
+ if (ret < 0)
+ return ret;
+
+ *readval = (unsigned int)value;
+
+ return 0;
+}
+
+static int sca3300_read_avail(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ const int **vals,
+ int *type,
+ int *length,
+ long mask)
+{
+ switch (mask) {
+ case IIO_CHAN_INFO_SCALE:
+ *vals = (const int *)sca3300_accel_scale;
+ *length = ARRAY_SIZE(sca3300_accel_scale) * 2 - 2;
+ *type = IIO_VAL_INT_PLUS_MICRO;
+ return IIO_AVAIL_LIST;
+ case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+ *vals = &sca3300_lp_freq[2];
+ *length = 2;
+ *type = IIO_VAL_INT;
+ return IIO_AVAIL_LIST;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info sca3300_info = {
+ .read_raw = sca3300_read_raw,
+ .write_raw = sca3300_write_raw,
+ .debugfs_reg_access = &sca3300_debugfs_reg_access,
+ .read_avail = sca3300_read_avail,
+};
+
+static int sca3300_probe(struct spi_device *spi)
+{
+ struct sca3300_data *sca_data;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*sca_data));
+ if (!indio_dev) {
+ dev_err(&spi->dev,
+ "failed to allocate memory for iio device\n");
+ return -ENOMEM;
+ }
+
+ sca_data = iio_priv(indio_dev);
+ mutex_init(&sca_data->lock);
+ sca_data->spi = spi;
+
+ crc8_populate_msb(sca3300_crc_table, SCA3300_CRC8_POLYNOMIAL);
+
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->info = &sca3300_info;
+ indio_dev->name = SCA3300_ALIAS;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = sca3300_channels;
+ indio_dev->num_channels = ARRAY_SIZE(sca3300_channels);
+ indio_dev->available_scan_masks = sca3300_scan_masks;
+
+ ret = sca3300_init(sca_data, indio_dev);
+ if (ret < 0) {
+ dev_err(&spi->dev, "failed to init device, error: %d\n", ret);
+ return ret;
+ }
+
+ ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
+ iio_pollfunc_store_time,
+ sca3300_trigger_handler, NULL);
+ if (ret < 0) {
+ dev_err(&spi->dev,
+ "iio triggered buffer setup failed, error: %d\n", ret);
+ return ret;
+ }
+
+ ret = devm_iio_device_register(&spi->dev, indio_dev);
+ if (ret < 0) {
+ dev_err(&spi->dev, "iio device register failed, error: %d\n",
+ ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id sca3300_dt_ids[] = {
+ { .compatible = "murata,sca3300"},
+ {},
+};
+MODULE_DEVICE_TABLE(of, sca3300_dt_ids);
+
+static struct spi_driver sca3300_driver = {
+ .driver = {
+ .name = SCA3300_ALIAS,
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(sca3300_dt_ids),
+ },
+
+ .probe = sca3300_probe,
+};
+
+module_spi_driver(sca3300_driver);
+
+MODULE_AUTHOR("Tomas Melin <tomas.melin@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Murata SCA3300 SPI Accelerometer");
+MODULE_LICENSE("GPL v2");
--
2.21.3