iio: accel: Add driver for Murata SCA3300 accelerometer
authorTomas Melin <tomas.melin@vaisala.com>
Mon, 26 Apr 2021 08:10:41 +0000 (11:10 +0300)
committerJonathan Cameron <Jonathan.Cameron@huawei.com>
Mon, 17 May 2021 12:49:09 +0000 (13:49 +0100)
Add initial support for Murata SCA3300 3-axis industrial
accelerometer with digital SPI interface. This device also
provides a temperature measurement.

Datasheet: https://www.murata.com/en-global/products/sensor/accel/sca3300
Signed-off-by: Tomas Melin <tomas.melin@vaisala.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210426081041.59807-3-tomas.melin@vaisala.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
drivers/iio/accel/Kconfig
drivers/iio/accel/Makefile
drivers/iio/accel/sca3300.c [new file with mode: 0644]

index 8b17236..ba4ffc2 100644 (file)
@@ -449,6 +449,19 @@ 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
index 32cd134..4b56527 100644 (file)
@@ -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 (file)
index 0000000..f7ef8ec
--- /dev/null
@@ -0,0 +1,472 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Murata SCA3300 3-axis industrial accelerometer
+ *
+ * Copyright (c) 2021 Vaisala Oyj. All rights reserved.
+ */
+
+#include <linux/bitops.h>
+#include <linux/crc8.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+
+#include <asm/unaligned.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 SCA3300_ALIAS "sca3300"
+
+#define SCA3300_CRC8_POLYNOMIAL 0x1d
+
+/* Device mode register */
+#define SCA3300_REG_MODE       0xd
+#define SCA3300_MODE_SW_RESET  0x20
+
+/* Last register in map */
+#define SCA3300_REG_SELBANK    0x1f
+
+/* Device status and mask */
+#define SCA3300_REG_STATUS     0x6
+#define SCA3300_STATUS_MASK    GENMASK(8, 0)
+
+/* Device ID */
+#define SCA3300_REG_WHOAMI     0x10
+#define SCA3300_WHOAMI_ID      0x51
+
+/* Device return status and mask */
+#define SCA3300_VALUE_RS_ERROR 0x3
+#define SCA3300_MASK_RS_STATUS GENMASK(1, 0)
+
+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,                                      \
+               .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,
+                       .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
+ * @scan: Triggered buffer. Four channel 16-bit data + 64-bit timestamp
+ * @txbuf: Transmit buffer
+ * @rxbuf: Receive buffer
+ */
+struct sca3300_data {
+       struct spi_device *spi;
+       struct mutex lock;
+       struct {
+               s16 channels[4];
+               s64 ts __aligned(sizeof(s64));
+       } scan;
+       u8 txbuf[4] ____cacheline_aligned;
+       u8 rxbuf[4];
+};
+
+DECLARE_CRC8_TABLE(sca3300_crc_table);
+
+static int sca3300_transfer(struct sca3300_data *sca_data, int *val)
+{
+       /* Consecutive requests min. 10 us delay (Datasheet section 5.1.2) */
+       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,
+                       .len = ARRAY_SIZE(sca_data->txbuf),
+                       .delay = delay,
+                       .cs_change = 1,
+               },
+               {
+                       .rx_buf = sca_data->rxbuf,
+                       .len = ARRAY_SIZE(sca_data->rxbuf),
+                       .delay = delay,
+               }
+       };
+
+       /* 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) {
+               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] & SCA3300_MASK_RS_STATUS;
+       if (rs == SCA3300_VALUE_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] = SCA3300_REG_STATUS << 2;
+       ret = sca3300_transfer(sca_data, &val);
+       mutex_unlock(&sca_data->lock);
+       /*
+        * Return status error is cleared after reading status register once,
+        * expect EINVAL here.
+        */
+       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%lx\n",
+               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] = reg << 2;
+       ret = sca3300_transfer(sca_data, val);
+       mutex_unlock(&sca_data->lock);
+       if (ret != -EINVAL)
+               return ret;
+
+       return sca3300_error_handler(sca_data);
+}
+
+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);
+       /* BIT(7) for write operation */
+       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)
+               return ret;
+
+       return sca3300_error_handler(sca_data);
+}
+
+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;
+
+       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])
+                               return sca3300_write_reg(data, SCA3300_REG_MODE, i);
+               }
+               return -EINVAL;
+
+       case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+               ret = sca3300_read_reg(data, SCA3300_REG_MODE, &reg_val);
+               if (ret)
+                       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);
+               if (reg_val == 3 && val == sca3300_lp_freq[2])
+                       return sca3300_write_reg(data, SCA3300_REG_MODE, 2);
+               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)
+                       return ret;
+               return IIO_VAL_INT;
+       case IIO_CHAN_INFO_SCALE:
+               ret = sca3300_read_reg(data, SCA3300_REG_MODE, &reg_val);
+               if (ret)
+                       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)
+                       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) {
+                       dev_err_ratelimited(&data->spi->dev,
+                               "failed to read register, error: %d\n", ret);
+                       /* handled, but bailing out due to errors */
+                       goto out;
+               }
+               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 value = 0;
+       int ret;
+
+       ret = sca3300_write_reg(sca_data, SCA3300_REG_MODE,
+                               SCA3300_MODE_SW_RESET);
+       if (ret)
+               return ret;
+
+       /*
+        * Wait 1ms after SW-reset command.
+        * Wait 15ms for settling of signal paths.
+        */
+       usleep_range(16e3, 50e3);
+
+       ret = sca3300_read_reg(sca_data, SCA3300_REG_WHOAMI, &value);
+       if (ret)
+               return ret;
+
+       if (value != SCA3300_WHOAMI_ID) {
+               dev_err(&sca_data->spi->dev,
+                       "device id not expected value, %d != %u\n",
+                       value, SCA3300_WHOAMI_ID);
+               return -ENODEV;
+       }
+       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_REG_SELBANK)
+               return -EINVAL;
+
+       if (!readval)
+               return sca3300_write_reg(data, reg, writeval);
+
+       ret = sca3300_read_reg(data, reg, &value);
+       if (ret)
+               return ret;
+
+       *readval = 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)
+               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->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) {
+               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) {
+               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) {
+               dev_err(&spi->dev, "iio device register failed, error: %d\n",
+                       ret);
+       }
+
+       return ret;
+}
+
+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,
+               .of_match_table = sca3300_dt_ids,
+       },
+       .probe  = sca3300_probe,
+};
+module_spi_driver(sca3300_driver);
+
+MODULE_AUTHOR("Tomas Melin <tomas.melin@vaisala.com>");
+MODULE_DESCRIPTION("Murata SCA3300 SPI Accelerometer");
+MODULE_LICENSE("GPL v2");