[PATCH v5 0/2] iio: accel: sca3300: Accelerometer support and binding doc

[PATCH v5 0/2] iio: accel: sca3300: Accelerometer support and binding doc

[Tomas Melin]

Patch series adds driver and dt-binding for Murata SCA3300 accelerometer.

Device is a 3-axis Accelerometer with digital SPI interface.

Patches are tested and based on linux-next.

Changes V5:
Addressed comments from Andy Shevchenko
- Reversed xtree declaration fix
- Add clarifying comment and spacing

Changes V4:
Addressed comments from Andy Shevchenko
- Regrouped and renamed #define statements
- Added cacheline alignment for tx/rx buffers
- Changed irq handler print to be ratelimited
- Commented use of goto in irq handler
- Removed redundant 0x0 value
- Spacing errors fixed
- Removed redundant return statement

Changes V3:
Addressed comments from Jonathan Cameron and Andy Shevchenko
- Grouped include statements
- Revised SCA* define naming and grouped statements
- Changed to GENMASK() for masks
- Indentation fix for ACCEL_CHANNEL define
- Remove field declarations using default values
- Change to if(ret) style for checking return values
- Add defined mask value SCA3300_MASK_STATUS for return status
- Remove redundant casts
- Clarify comment wording
- Refactor to remove variable idx and redundant else branches
- Unify sleep in device init, separate sleeps not needed since operation mode change dropped
- Drop redundant memory allocation error message in probe
- dev.parent is set by iio core, removed from driver probe
- Drop of_match_ptr()


Changes V2:
Addressed comments from Jonathan Cameron
- Add manufacturer name to dt-binding file
- Update spdx license statement for dt-bindings
- Remove murata,opmode devicetree property in favor of driver scale + frequency properties
- Add copyright year for driver
- Remove X_READ and X_WRITE defines
- Add _available sysfs attributes
- Fix errors in documentation formatting
- Use ARRAY_SIZE where applicable
- Use get/put_unaligned_be16() helpers where applicable
- Factor out error handling to separate function
- Return only negative values from transfer function
- Fix INFO_SCALE to return multiplier instead of inverted value
- Change INFO_SCALE values to be actual scale instead of mode value
- Do not provide INFO_PROCESSED values for user space
- Add error message for failed data read in irq handler
- Move trigger handler timestamping as part of pushing data to buffers
- Document startup sequence, providing reference to data sheet section
- Convert iio_triggered_buffer_setup to devm_iio_triggered_buffer_setup,
making remove() obsolete

Tomas Melin (2):
  dt-bindings: iio: accel: Add SCA3300 documentation
  iio: accel: Add driver for Murata SCA3300 accelerometer

 .../bindings/iio/accel/murata,sca3300.yaml    |  44 ++
 drivers/iio/accel/Kconfig                     |  13 +
 drivers/iio/accel/Makefile                    |   1 +
 drivers/iio/accel/sca3300.c                   | 472 ++++++++++++++++++
 4 files changed, 530 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/accel/murata,sca3300.yaml
 create mode 100644 drivers/iio/accel/sca3300.c

-- 
2.21.3

[PATCH v5 1/2] dt-bindings: iio: accel: Add SCA3300 documentation

[Tomas Melin]

initial DT bindings for Murata SCA3300 Accelerometer.

Signed-off-by: Tomas Melin <tomas.melin@vaisala.com>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 .../bindings/iio/accel/murata,sca3300.yaml    | 44 +++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/accel/murata,sca3300.yaml

diff --git a/Documentation/devicetree/bindings/iio/accel/murata,sca3300.yaml b/Documentation/devicetree/bindings/iio/accel/murata,sca3300.yaml
new file mode 100644
index 000000000000..55fd3548e3b6
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/accel/murata,sca3300.yaml
@@ -0,0 +1,44 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/accel/murata,sca3300.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Murata SCA3300 Accelerometer
+
+description: |
+  3-axis industrial accelerometer with digital SPI interface
+  https://www.murata.com/en-global/products/sensor/accel/sca3300
+
+maintainers:
+  - Tomas Melin <tomas.melin@vaisala.com>
+
+properties:
+  compatible:
+    enum:
+      - murata,sca3300
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency:
+    maximum: 8000000
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        accelerometer@0 {
+            compatible = "murata,sca3300";
+            reg = <0x0>;
+            spi-max-frequency = <4000000>;
+        };
+    };
+...
-- 
2.21.3

[PATCH v5 2/2] iio: accel: Add driver for Murata SCA3300 accelerometer

[Tomas Melin]

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>
---
 drivers/iio/accel/Kconfig   |  13 +
 drivers/iio/accel/Makefile  |   1 +
 drivers/iio/accel/sca3300.c | 472 ++++++++++++++++++++++++++++++++++++
 3 files changed, 486 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..f7ef8ecfd34a
--- /dev/null
+++ b/drivers/iio/accel/sca3300.c
@@ -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");
-- 
2.21.3

Re: [PATCH v5 2/2] iio: accel: Add driver for Murata SCA3300 accelerometer

[Andy Shevchenko]

On Mon, Apr 26, 2021 at 11:11 AM Tomas Melin <tomas.melin@vaisala.com> wrote:
>
> Add initial support for Murata SCA3300 3-axis industrial
> accelerometer with digital SPI interface. This device also
> provides a temperature measurement.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

> Datasheet: https://www.murata.com/en-global/products/sensor/accel/sca3300
> Signed-off-by: Tomas Melin <tomas.melin@vaisala.com>
> ---
>  drivers/iio/accel/Kconfig   |  13 +
>  drivers/iio/accel/Makefile  |   1 +
>  drivers/iio/accel/sca3300.c | 472 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 486 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..f7ef8ecfd34a
> --- /dev/null
> +++ b/drivers/iio/accel/sca3300.c
> @@ -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");
> --
> 2.21.3
>


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 0/2] iio: accel: sca3300: Accelerometer support and binding doc

[Jonathan Cameron]

On Mon, 26 Apr 2021 11:10:39 +0300
Tomas Melin <tomas.melin@vaisala.com> wrote:

> Patch series adds driver and dt-binding for Murata SCA3300 accelerometer.
> 
> Device is a 3-axis Accelerometer with digital SPI interface.
> 
> Patches are tested and based on linux-next.
> 
Very nice.

Series applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to poke at it.  As we are mid merge window I won't push
this out anywhere that will turn up in linux-next until rc1 is out.

Thanks,

Jonathan

> Changes V5:
> Addressed comments from Andy Shevchenko
> - Reversed xtree declaration fix
> - Add clarifying comment and spacing
> 
> Changes V4:
> Addressed comments from Andy Shevchenko
> - Regrouped and renamed #define statements
> - Added cacheline alignment for tx/rx buffers
> - Changed irq handler print to be ratelimited
> - Commented use of goto in irq handler
> - Removed redundant 0x0 value
> - Spacing errors fixed
> - Removed redundant return statement
> 
> Changes V3:
> Addressed comments from Jonathan Cameron and Andy Shevchenko
> - Grouped include statements
> - Revised SCA* define naming and grouped statements
> - Changed to GENMASK() for masks
> - Indentation fix for ACCEL_CHANNEL define
> - Remove field declarations using default values
> - Change to if(ret) style for checking return values
> - Add defined mask value SCA3300_MASK_STATUS for return status
> - Remove redundant casts
> - Clarify comment wording
> - Refactor to remove variable idx and redundant else branches
> - Unify sleep in device init, separate sleeps not needed since operation mode change dropped
> - Drop redundant memory allocation error message in probe
> - dev.parent is set by iio core, removed from driver probe
> - Drop of_match_ptr()
> 
> 
> Changes V2:
> Addressed comments from Jonathan Cameron
> - Add manufacturer name to dt-binding file
> - Update spdx license statement for dt-bindings
> - Remove murata,opmode devicetree property in favor of driver scale + frequency properties
> - Add copyright year for driver
> - Remove X_READ and X_WRITE defines
> - Add _available sysfs attributes
> - Fix errors in documentation formatting
> - Use ARRAY_SIZE where applicable
> - Use get/put_unaligned_be16() helpers where applicable
> - Factor out error handling to separate function
> - Return only negative values from transfer function
> - Fix INFO_SCALE to return multiplier instead of inverted value
> - Change INFO_SCALE values to be actual scale instead of mode value
> - Do not provide INFO_PROCESSED values for user space
> - Add error message for failed data read in irq handler
> - Move trigger handler timestamping as part of pushing data to buffers
> - Document startup sequence, providing reference to data sheet section
> - Convert iio_triggered_buffer_setup to devm_iio_triggered_buffer_setup,
> making remove() obsolete
> 
> Tomas Melin (2):
>   dt-bindings: iio: accel: Add SCA3300 documentation
>   iio: accel: Add driver for Murata SCA3300 accelerometer
> 
>  .../bindings/iio/accel/murata,sca3300.yaml    |  44 ++
>  drivers/iio/accel/Kconfig                     |  13 +
>  drivers/iio/accel/Makefile                    |   1 +
>  drivers/iio/accel/sca3300.c                   | 472 ++++++++++++++++++
>  4 files changed, 530 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/accel/murata,sca3300.yaml
>  create mode 100644 drivers/iio/accel/sca3300.c
>