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Subject[PATCH v3 1/4] iio: gyro: add support for fxas21002c
Date
FXAS21002C is a 3 axis gyroscope with integrated temperature sensor

Signed-off-by: Afonso Bordado <afonsobordado@az8.co>
---
Changes in v3
- Use unsigned int on regmap functions
- Remove the export of the regmap config
- Fix undefined behaviour on dev_err call
- Minor cleanups

Changes in v2
- Use ANSI C Comments
- Minor cleanups
- More dscriptive devicetree bindings

drivers/iio/gyro/Kconfig | 11 +
drivers/iio/gyro/Makefile | 1 +
drivers/iio/gyro/fxas21002c.c | 372 ++++++++++++++++++++++++++++++++++
3 files changed, 384 insertions(+)
create mode 100644 drivers/iio/gyro/fxas21002c.c

diff --git a/drivers/iio/gyro/Kconfig b/drivers/iio/gyro/Kconfig
index 3126cf05e6b9..d71e33ea9fa4 100644
--- a/drivers/iio/gyro/Kconfig
+++ b/drivers/iio/gyro/Kconfig
@@ -73,6 +73,17 @@ config BMG160_SPI
tristate
select REGMAP_SPI

+config FXAS21002C
+ tristate "Freescale FXAS21002C Gyroscope"
+ depends on I2C
+ select REGMAP_I2C
+ help
+ Say yes here to build support for the Freescale FXAS21002C Gyroscope
+ driver connected via I2C.
+
+ This driver can also be built as a module. If so, the module
+ will be called fxas21002c.
+
config HID_SENSOR_GYRO_3D
depends on HID_SENSOR_HUB
select IIO_BUFFER
diff --git a/drivers/iio/gyro/Makefile b/drivers/iio/gyro/Makefile
index 295ec780c4eb..ec3e2aeae92a 100644
--- a/drivers/iio/gyro/Makefile
+++ b/drivers/iio/gyro/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_ADXRS450) += adxrs450.o
obj-$(CONFIG_BMG160) += bmg160_core.o
obj-$(CONFIG_BMG160_I2C) += bmg160_i2c.o
obj-$(CONFIG_BMG160_SPI) += bmg160_spi.o
+obj-$(CONFIG_FXAS21002C) += fxas21002c.o

obj-$(CONFIG_HID_SENSOR_GYRO_3D) += hid-sensor-gyro-3d.o

diff --git a/drivers/iio/gyro/fxas21002c.c b/drivers/iio/gyro/fxas21002c.c
new file mode 100644
index 000000000000..1668e6f3fe11
--- /dev/null
+++ b/drivers/iio/gyro/fxas21002c.c
@@ -0,0 +1,372 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * FXAS21002C - Digital Angular Rate Gyroscope driver
+ *
+ * Copyright (c) 2018, Afonso Bordado <afonsobordado@az8.co>
+ *
+ * IIO driver for FXAS21002C (7-bit I2C slave address 0x20 or 0x21).
+ * Datasheet: https://www.nxp.com/docs/en/data-sheet/FXAS21002.pdf
+ * TODO:
+ * ODR / Scale Support
+ * Devicetree
+ * Power management
+ * GPIO Reset
+ * Power supplies
+ * Mount Matrix
+ * LowPass/HighPass Filters
+ * Buffers
+ * Interrupts
+ * Alarms
+ * SPI Support
+ */
+
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#define FXAS21002C_DRV_NAME "fxas21002c"
+
+#define FXAS21002C_MAX_TRANSITION_TIME_MS 61
+
+#define FXAS21002C_CHIP_ID 0xD7
+
+#define FXAS21002C_REG_STATUS 0x00
+#define FXAS21002C_REG_OUT_X_MSB 0x01
+#define FXAS21002C_REG_OUT_X_LSB 0x02
+#define FXAS21002C_REG_OUT_Y_MSB 0x03
+#define FXAS21002C_REG_OUT_Y_LSB 0x04
+#define FXAS21002C_REG_OUT_Z_MSB 0x05
+#define FXAS21002C_REG_OUT_Z_LSB 0x06
+#define FXAS21002C_REG_DR_STATUS 0x07
+#define FXAS21002C_REG_F_STATUS 0x08
+#define FXAS21002C_REG_F_SETUP 0x09
+#define FXAS21002C_REG_F_EVENT 0x0A
+#define FXAS21002C_REG_INT_SRC_FLAG 0x0B
+#define FXAS21002C_REG_WHO_AM_I 0x0C
+#define FXAS21002C_REG_CTRL_REG0 0x0D
+#define FXAS21002C_REG_RT_CFG 0x0E
+#define FXAS21002C_REG_RT_SRC 0x0F
+#define FXAS21002C_REG_RT_THS 0x10
+#define FXAS21002C_REG_RT_COUNT 0x11
+#define FXAS21002C_REG_TEMP 0x12
+
+#define FXAS21002C_REG_CTRL_REG1 0x13
+#define FXAS21002C_RST_BIT BIT(6)
+#define FXAS21002C_ACTIVE_BIT BIT(1)
+#define FXAS21002C_READY_BIT BIT(0)
+
+#define FXAS21002C_REG_CTRL_REG2 0x14
+#define FXAS21002C_REG_CTRL_REG3 0x15
+
+#define FXAS21002C_DEFAULT_ODR_HZ 800
+
+/* 0.0625 deg/s */
+#define FXAS21002C_DEFAULT_SENSITIVITY IIO_DEGREE_TO_RAD(62500)
+
+#define FXAS21002C_TEMP_SCALE 1000
+
+enum {
+ ID_FXAS21002C,
+};
+
+enum fxas21002c_operating_mode {
+ FXAS21002C_OM_BOOT,
+ FXAS21002C_OM_STANDBY,
+ FXAS21002C_OM_READY,
+ FXAS21002C_OM_ACTIVE,
+};
+
+struct fxas21002c_data {
+ struct i2c_client *client;
+ struct regmap *regmap;
+};
+
+static const struct regmap_range fxas21002c_writable_ranges[] = {
+ regmap_reg_range(FXAS21002C_REG_F_SETUP, FXAS21002C_REG_F_SETUP),
+ regmap_reg_range(FXAS21002C_REG_CTRL_REG0, FXAS21002C_REG_RT_CFG),
+ regmap_reg_range(FXAS21002C_REG_RT_THS, FXAS21002C_REG_RT_COUNT),
+ regmap_reg_range(FXAS21002C_REG_CTRL_REG1, FXAS21002C_REG_CTRL_REG3),
+};
+
+static const struct regmap_access_table fxas21002c_writable_table = {
+ .yes_ranges = fxas21002c_writable_ranges,
+ .n_yes_ranges = ARRAY_SIZE(fxas21002c_writable_ranges),
+};
+
+static const struct regmap_range fxas21002c_volatile_ranges[] = {
+ regmap_reg_range(FXAS21002C_REG_STATUS, FXAS21002C_REG_F_STATUS),
+ regmap_reg_range(FXAS21002C_REG_F_EVENT, FXAS21002C_REG_INT_SRC_FLAG),
+ regmap_reg_range(FXAS21002C_REG_RT_COUNT, FXAS21002C_REG_CTRL_REG1),
+};
+
+static const struct regmap_access_table fxas21002c_volatile_table = {
+ .yes_ranges = fxas21002c_volatile_ranges,
+ .n_yes_ranges = ARRAY_SIZE(fxas21002c_volatile_ranges),
+};
+
+const struct regmap_config fxas21002c_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+
+ .max_register = FXAS21002C_REG_CTRL_REG3,
+ /* We don't specify a .rd_table because everything is readable */
+ .wr_table = &fxas21002c_writable_table,
+ .volatile_table = &fxas21002c_volatile_table,
+};
+
+#define FXAS21002C_GYRO_CHAN(_axis) { \
+ .type = IIO_ANGL_VEL, \
+ .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_SAMP_FREQ), \
+ .address = FXAS21002C_REG_OUT_ ## _axis ## _MSB, \
+}
+
+static const struct iio_chan_spec fxas21002c_channels[] = {
+ {
+ .type = IIO_TEMP,
+ .address = FXAS21002C_REG_TEMP,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ },
+ FXAS21002C_GYRO_CHAN(X),
+ FXAS21002C_GYRO_CHAN(Y),
+ FXAS21002C_GYRO_CHAN(Z),
+ IIO_CHAN_SOFT_TIMESTAMP(3),
+};
+
+static int fxas21002c_set_operating_mode(struct fxas21002c_data *data,
+ enum fxas21002c_operating_mode om)
+{
+ int ret;
+ int mask;
+
+ switch (om) {
+ case FXAS21002C_OM_STANDBY:
+ mask = 0;
+ break;
+ case FXAS21002C_OM_READY:
+ mask = FXAS21002C_READY_BIT;
+ break;
+ case FXAS21002C_OM_ACTIVE:
+ mask = FXAS21002C_ACTIVE_BIT;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ ret = regmap_write(data->regmap, FXAS21002C_REG_CTRL_REG1, mask);
+ if (ret) {
+ dev_err(&data->client->dev,
+ "could not switch operating mode\n");
+ return ret;
+ }
+
+ msleep(FXAS21002C_MAX_TRANSITION_TIME_MS);
+
+ return 0;
+}
+
+static void fxas21002c_standby(void *_data)
+{
+ struct fxas21002c_data *data = _data;
+
+ fxas21002c_set_operating_mode(data, FXAS21002C_OM_STANDBY);
+}
+
+static int fxas21002c_reset(struct fxas21002c_data *data)
+{
+ int ret;
+
+ /*
+ * On issuing a Software Reset command over an I2C interface,
+ * the device immediately resets and does not send any
+ * acknowledgment (ACK) of the written byte to the Master.
+ *
+ * This is documented in table 46 on the datasheet. Due to this
+ * the write will fail with EREMOTEIO.
+ */
+ ret = regmap_write(data->regmap,
+ FXAS21002C_REG_CTRL_REG1, FXAS21002C_RST_BIT);
+
+ if (ret != -EREMOTEIO) {
+ dev_err(&data->client->dev, "could not reset device\n");
+ return ret;
+ }
+
+ regcache_mark_dirty(data->regmap);
+
+ /* Wait for device to boot up */
+ msleep(FXAS21002C_MAX_TRANSITION_TIME_MS);
+
+ return 0;
+}
+
+static int fxas21002c_verify_chip(struct fxas21002c_data *data)
+{
+ int ret;
+ unsigned int chip_id;
+
+ ret = regmap_read(data->regmap, FXAS21002C_REG_WHO_AM_I, &chip_id);
+ if (ret) {
+ dev_err(&data->client->dev, "could not read device id\n");
+ return ret;
+ }
+
+ if (chip_id != FXAS21002C_CHIP_ID) {
+ dev_err(&data->client->dev,
+ "unsupported chip id %02x\n", chip_id);
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+static int fxas21002c_read_oneshot(struct fxas21002c_data *data,
+ struct iio_chan_spec const *chan, int *val)
+{
+ int ret;
+ __be16 bulk_raw;
+ unsigned int uval;
+
+ switch (chan->type) {
+ case IIO_ANGL_VEL:
+ ret = regmap_bulk_read(data->regmap, chan->address,
+ &bulk_raw, sizeof(bulk_raw));
+ if (ret)
+ return ret;
+
+ *val = sign_extend32(be16_to_cpu(bulk_raw), 15);
+ return IIO_VAL_INT;
+ case IIO_TEMP:
+ ret = regmap_read(data->regmap, chan->address, &uval);
+ if (ret)
+ return ret;
+
+ *val = sign_extend32(uval, 7);
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int fxas21002c_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ struct fxas21002c_data *data = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ return fxas21002c_read_oneshot(data, chan, val);
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_ANGL_VEL:
+ *val = 0;
+ *val2 = FXAS21002C_DEFAULT_SENSITIVITY;
+
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_TEMP:
+ *val = FXAS21002C_TEMP_SCALE;
+
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ if (chan->type != IIO_ANGL_VEL)
+ return -EINVAL;
+
+ *val = FXAS21002C_DEFAULT_ODR_HZ;
+
+ return IIO_VAL_INT;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_info fxas21002c_info = {
+ .read_raw = fxas21002c_read_raw,
+};
+
+static int fxas21002c_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int ret;
+ struct iio_dev *indio_dev;
+ struct fxas21002c_data *data;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, indio_dev);
+ data = iio_priv(indio_dev);
+ data->client = client;
+
+ data->regmap = devm_regmap_init_i2c(client, &fxas21002c_regmap_config);
+ if (IS_ERR(data->regmap)) {
+ ret = PTR_ERR(data->regmap);
+ dev_err(&client->dev,
+ "Failed to allocate regmap, err: %d\n", ret);
+ return ret;
+ }
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->channels = fxas21002c_channels;
+ indio_dev->num_channels = ARRAY_SIZE(fxas21002c_channels);
+ indio_dev->name = id->name;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &fxas21002c_info;
+
+ ret = fxas21002c_verify_chip(data);
+ if (ret < 0)
+ return ret;
+
+ ret = fxas21002c_reset(data);
+ if (ret < 0)
+ return ret;
+
+ ret = fxas21002c_set_operating_mode(data, FXAS21002C_OM_ACTIVE);
+ if (ret < 0)
+ return ret;
+
+ ret = devm_add_action(&client->dev, fxas21002c_standby, data);
+ if (ret < 0) {
+ fxas21002c_standby(data);
+ dev_err(&client->dev, "failed to add standby action\n");
+ return ret;
+ }
+
+ ret = iio_device_register(indio_dev);
+ if (ret < 0)
+ dev_err(&client->dev, "failed to register iio device\n");
+
+ return ret;
+}
+
+static const struct i2c_device_id fxas21002c_id[] = {
+ {"fxas21002c", ID_FXAS21002C},
+ {}
+};
+
+MODULE_DEVICE_TABLE(i2c, fxas21002c_id);
+
+static struct i2c_driver fxas21002c_driver = {
+ .driver = {
+ .name = FXAS21002C_DRV_NAME,
+ },
+ .probe = fxas21002c_probe,
+ .id_table = fxas21002c_id,
+};
+
+module_i2c_driver(fxas21002c_driver);
+
+MODULE_AUTHOR("Afonso Bordado <afonsobordado@az8.co>");
+MODULE_DESCRIPTION("FXAS21002C Digital Angular Rate Gyroscope driver");
+MODULE_LICENSE("GPL v2");
--
2.18.0

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