[PATCH v8 1/2] dt-bindings: iio: accel: Add bmi088 accelerometer bindings

[PATCH v8 1/2] dt-bindings: iio: accel: Add bmi088 accelerometer bindings

[Mike Looijmans]

This adds the device-tree bindings for the Bosch Sensortec BMI088 IMU,
the accelerometer part.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>

---

Changes in v8:
Add spi-max-frequency: true

Changes in v7:
Add additionalProperties
Change bmi088_accel to bmi088-accel
Add interrupt-names and adjust description

Changes in v6:
I't been almost a year since the last commit, sorry...
Fixed the yaml errors
Add interrupt, vdd and vddio properties

Changes in v5:
submit together with driver code as patch series

Changes in v2:
convert to yaml format

 .../bindings/iio/accel/bosch,bmi088.yaml      | 68 +++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/accel/bosch,bmi088.yaml

diff --git a/Documentation/devicetree/bindings/iio/accel/bosch,bmi088.yaml b/Documentation/devicetree/bindings/iio/accel/bosch,bmi088.yaml
new file mode 100644
index 000000000000..911a1ae9c83f
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/accel/bosch,bmi088.yaml
@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/accel/bosch,bmi088.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Bosch BMI088 IMU accelerometer part
+
+maintainers:
+  - Mike Looijmans <mike.looijmans@topic.nl>
+
+description: |
+  Acceleration part of the IMU sensor with an SPI interface
+  Specifications about the sensor can be found at:
+    https://www.bosch-sensortec.com/media/boschsensortec/downloads/datasheets/bst-bmi088-ds001.pdf
+
+properties:
+  compatible:
+    enum:
+      - bosch,bmi088-accel
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency: true
+
+  vdd-supply: true
+
+  vddio-supply: true
+
+  interrupts:
+    minItems: 1
+    maxItems: 2
+    description: |
+      Type should be either IRQ_TYPE_LEVEL_HIGH or IRQ_TYPE_LEVEL_LOW.
+      Two configurable interrupt lines exist.
+
+  interrupt-names:
+    description: Specify which interrupt line is in use.
+    items:
+      enum:
+        - INT1
+        - INT2
+    minItems: 1
+    maxItems: 2
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    spi {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      bmi088-accel@1 {
+        compatible = "bosch,bmi088-accel";
+        reg = <1>;
+        spi-max-frequency = <10000000>;
+        interrupt-parent = <&gpio6>;
+        interrupts = <19 IRQ_TYPE_LEVEL_LOW>;
+        interrupt-names = "INT2";
+      };
+    };
+...
-- 
2.17.1

[PATCH v8 2/2] iio: accel: Add support for the Bosch-Sensortec BMI088

[Mike Looijmans]

The BMI088 is a combined module with both accelerometer and gyroscope.
This adds the accelerometer driver support for the SPI interface.
The gyroscope part is already supported by the BMG160 driver.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>

---

Changes in v8:
include order asm/ after linux/
Suspend/resume redesigned, use runtime PM for both cases. Removed the
pm wrappers and let runtime PM handle power up/down. This also removed
the need for an internal mutex, thus reducing code further.

Changes in v7:
Change bmi088_accel to bmi088-accel
Order includes alphabetically
Suspend and disable on remove
Make bmi088_regmap_spi_{read|write} static

Changes in v6:
Hope you have good memory - v5 was almost a year ago now
Remove superfluous *val=0
Make sample_frequency selection into read_avail list

Changes in v5:
Add includes and forward defines in header
BIT(7) instead of 0x80
Reset already sets defaults, do not set them again
Remove now unused bmi088_accel_set_bw
Remove unused AXIS_MAX
Use MASK define for ODR setting
Explain buffer use and alignment
Split bmi088_accel_set_power_state into "on" and "off" parts
Cosmetic changes to improve readability

Changes in v4:
Remove unused #include directives
Remove unused #defines for event and irq
Replace (ret < 0) with (ret) for all regmap calls
Consistent checking of IO errors in probe and init
Removed #ifdef CONFIG_PM guard
Use bitops for set_frequency instead of loop with shift
s/__s16/s16/g
Remove excess blank lines
Don't return -EAGAIN in pm_runtime

Changes in v3:
Processed comments from Jonathan Cameron and Lars-Peter Clausen
implement runtime PM (tested by code tracing) and sleep
fix scale and offset factors for accel and temperature and
return raw values instead of pre-scaled ones
Use iio_device_{claim,release}_direct_mode
Remove unused code and structs
Use a cache-aligned buffer for bulk read
Configure and enable caching register values

Changes in v2:
Remove unused typedefs and variables
Fix error return when iio_device_register fails

 drivers/iio/accel/Kconfig             |  18 +
 drivers/iio/accel/Makefile            |   2 +
 drivers/iio/accel/bmi088-accel-core.c | 570 ++++++++++++++++++++++++++
 drivers/iio/accel/bmi088-accel-spi.c  |  83 ++++
 drivers/iio/accel/bmi088-accel.h      |  18 +
 5 files changed, 691 insertions(+)
 create mode 100644 drivers/iio/accel/bmi088-accel-core.c
 create mode 100644 drivers/iio/accel/bmi088-accel-spi.c
 create mode 100644 drivers/iio/accel/bmi088-accel.h

diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index 2e0c62c39155..cceda3cecbcf 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -157,6 +157,24 @@ config BMC150_ACCEL_SPI
 	tristate
 	select REGMAP_SPI
 
+config BMI088_ACCEL
+	tristate "Bosch BMI088 Accelerometer Driver"
+	depends on SPI
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	select REGMAP
+	select BMI088_ACCEL_SPI
+	help
+	  Say yes here to build support for the Bosch BMI088 accelerometer.
+
+	  This is a combo module with both accelerometer and gyroscope. This
+	  driver only implements the accelerometer part, which has its own
+	  address and register map. BMG160 provides the gyroscope driver.
+
+config BMI088_ACCEL_SPI
+	tristate
+	select REGMAP_SPI
+
 config DA280
 	tristate "MiraMEMS DA280 3-axis 14-bit digital accelerometer driver"
 	depends on I2C
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index 4f6c1ebe13b0..32cd1342a31a 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -20,6 +20,8 @@ obj-$(CONFIG_BMA400_SPI) += bma400_spi.o
 obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o
 obj-$(CONFIG_BMC150_ACCEL_I2C) += bmc150-accel-i2c.o
 obj-$(CONFIG_BMC150_ACCEL_SPI) += bmc150-accel-spi.o
+obj-$(CONFIG_BMI088_ACCEL) += bmi088-accel-core.o
+obj-$(CONFIG_BMI088_ACCEL_SPI) += bmi088-accel-spi.o
 obj-$(CONFIG_DA280)	+= da280.o
 obj-$(CONFIG_DA311)	+= da311.o
 obj-$(CONFIG_DMARD06)	+= dmard06.o
diff --git a/drivers/iio/accel/bmi088-accel-core.c b/drivers/iio/accel/bmi088-accel-core.c
new file mode 100644
index 000000000000..f86010a3cda3
--- /dev/null
+++ b/drivers/iio/accel/bmi088-accel-core.c
@@ -0,0 +1,570 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 3-axis accelerometer driver supporting following Bosch-Sensortec chips:
+ *  - BMI088
+ *
+ * Copyright (c) 2018-2021, Topic Embedded Products
+ */
+
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <asm/unaligned.h>
+
+#include "bmi088-accel.h"
+
+#define BMI088_ACCEL_REG_CHIP_ID			0x00
+#define BMI088_ACCEL_REG_ERROR				0x02
+
+#define BMI088_ACCEL_REG_INT_STATUS			0x1D
+#define BMI088_ACCEL_INT_STATUS_BIT_DRDY		BIT(7)
+
+#define BMI088_ACCEL_REG_RESET				0x7E
+#define BMI088_ACCEL_RESET_VAL				0xB6
+
+#define BMI088_ACCEL_REG_PWR_CTRL			0x7D
+#define BMI088_ACCEL_REG_PWR_CONF			0x7C
+
+#define BMI088_ACCEL_REG_INT_MAP_DATA			0x58
+#define BMI088_ACCEL_INT_MAP_DATA_BIT_INT1_DRDY		BIT(2)
+#define BMI088_ACCEL_INT_MAP_DATA_BIT_INT2_FWM		BIT(5)
+
+#define BMI088_ACCEL_REG_INT1_IO_CONF			0x53
+#define BMI088_ACCEL_INT1_IO_CONF_BIT_ENABLE_OUT	BIT(3)
+#define BMI088_ACCEL_INT1_IO_CONF_BIT_LVL		BIT(1)
+
+#define BMI088_ACCEL_REG_INT2_IO_CONF			0x54
+#define BMI088_ACCEL_INT2_IO_CONF_BIT_ENABLE_OUT	BIT(3)
+#define BMI088_ACCEL_INT2_IO_CONF_BIT_LVL		BIT(1)
+
+#define BMI088_ACCEL_REG_ACC_CONF			0x40
+#define BMI088_ACCEL_MODE_ODR_MASK			0x0f
+
+#define BMI088_ACCEL_REG_ACC_RANGE			0x41
+#define BMI088_ACCEL_RANGE_3G				0x00
+#define BMI088_ACCEL_RANGE_6G				0x01
+#define BMI088_ACCEL_RANGE_12G				0x02
+#define BMI088_ACCEL_RANGE_24G				0x03
+
+#define BMI088_ACCEL_REG_TEMP				0x22
+#define BMI088_ACCEL_REG_TEMP_SHIFT			5
+#define BMI088_ACCEL_TEMP_UNIT				125
+#define BMI088_ACCEL_TEMP_OFFSET			23000
+
+#define BMI088_ACCEL_REG_XOUT_L				0x12
+#define BMI088_ACCEL_AXIS_TO_REG(axis) \
+	(BMI088_ACCEL_REG_XOUT_L + (axis * 2))
+
+#define BMI088_ACCEL_MAX_STARTUP_TIME_US		1000
+#define BMI088_AUTO_SUSPEND_DELAY_MS			2000
+
+#define BMI088_ACCEL_REG_FIFO_STATUS			0x0E
+#define BMI088_ACCEL_REG_FIFO_CONFIG0			0x48
+#define BMI088_ACCEL_REG_FIFO_CONFIG1			0x49
+#define BMI088_ACCEL_REG_FIFO_DATA			0x3F
+#define BMI088_ACCEL_FIFO_LENGTH			100
+
+#define BMI088_ACCEL_FIFO_MODE_FIFO			0x40
+#define BMI088_ACCEL_FIFO_MODE_STREAM			0x80
+
+enum bmi088_accel_axis {
+	AXIS_X,
+	AXIS_Y,
+	AXIS_Z,
+};
+
+static const int bmi088_sample_freqs[] = {
+	12, 500000,
+	25, 0,
+	50, 0,
+	100, 0,
+	200, 0,
+	400, 0,
+	800, 0,
+	1600, 0,
+};
+
+/* Available OSR (over sampling rate) sets the 3dB cut-off frequency */
+enum bmi088_osr_modes {
+	BMI088_ACCEL_MODE_OSR_NORMAL = 0xA,
+	BMI088_ACCEL_MODE_OSR_2 = 0x9,
+	BMI088_ACCEL_MODE_OSR_4 = 0x8,
+};
+
+/* Available ODR (output data rates) in Hz */
+enum bmi088_odr_modes {
+	BMI088_ACCEL_MODE_ODR_12_5 = 0x5,
+	BMI088_ACCEL_MODE_ODR_25 = 0x6,
+	BMI088_ACCEL_MODE_ODR_50 = 0x7,
+	BMI088_ACCEL_MODE_ODR_100 = 0x8,
+	BMI088_ACCEL_MODE_ODR_200 = 0x9,
+	BMI088_ACCEL_MODE_ODR_400 = 0xa,
+	BMI088_ACCEL_MODE_ODR_800 = 0xb,
+	BMI088_ACCEL_MODE_ODR_1600 = 0xc,
+};
+
+struct bmi088_scale_info {
+	int scale;
+	u8 reg_range;
+};
+
+struct bmi088_accel_chip_info {
+	const char *name;
+	u8 chip_id;
+	const struct iio_chan_spec *channels;
+	int num_channels;
+};
+
+struct bmi088_accel_data {
+	struct regmap *regmap;
+	const struct bmi088_accel_chip_info *chip_info;
+	u8 buffer[2] ____cacheline_aligned; /* shared DMA safe buffer */
+};
+
+static const struct regmap_range bmi088_volatile_ranges[] = {
+	/* All registers below 0x40 are volatile, except the CHIP ID. */
+	regmap_reg_range(BMI088_ACCEL_REG_ERROR, 0x3f),
+	/* Mark the RESET as volatile too, it is self-clearing */
+	regmap_reg_range(BMI088_ACCEL_REG_RESET, BMI088_ACCEL_REG_RESET),
+};
+
+static const struct regmap_access_table bmi088_volatile_table = {
+	.yes_ranges	= bmi088_volatile_ranges,
+	.n_yes_ranges	= ARRAY_SIZE(bmi088_volatile_ranges),
+};
+
+const struct regmap_config bmi088_regmap_conf = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0x7E,
+	.volatile_table = &bmi088_volatile_table,
+	.cache_type = REGCACHE_RBTREE,
+};
+EXPORT_SYMBOL_GPL(bmi088_regmap_conf);
+
+static int bmi088_accel_power_up(struct bmi088_accel_data *data)
+{
+	struct device *dev = regmap_get_device(data->regmap);
+	int ret;
+
+	/* Enable accelerometer and temperature sensor */
+	ret = regmap_write(data->regmap, BMI088_ACCEL_REG_PWR_CTRL, 0x4);
+	if (ret)
+		return ret;
+
+	/* Datasheet recommends to wait at least 5ms before communication */
+	usleep_range(5000, 6000);
+
+	/* Disable suspend mode */
+	ret = regmap_write(data->regmap, BMI088_ACCEL_REG_PWR_CONF, 0x0);
+	if (ret)
+		return ret;
+
+	/* Recommended at least 1ms before further communication */
+	usleep_range(1000, 1200);
+
+	return 0;
+}
+
+static int bmi088_accel_power_down(struct bmi088_accel_data *data)
+{
+	struct device *dev = regmap_get_device(data->regmap);
+	int ret;
+
+	/* Enable suspend mode */
+	ret = regmap_write(data->regmap, BMI088_ACCEL_REG_PWR_CONF, 0x3);
+	if (ret)
+		return ret;
+
+	/* Recommended at least 1ms before further communication */
+	usleep_range(1000, 1200);
+
+	/* Disable accelerometer and temperature sensor */
+	ret = regmap_write(data->regmap, BMI088_ACCEL_REG_PWR_CTRL, 0x0);
+	if (ret)
+		return ret;
+
+	/* Datasheet recommends to wait at least 5ms before communication */
+	usleep_range(5000, 6000);
+
+	return 0;
+}
+
+static int bmi088_accel_get_sample_freq(struct bmi088_accel_data *data,
+					int *val, int *val2)
+{
+	unsigned int value;
+	int ret;
+
+	ret = regmap_read(data->regmap, BMI088_ACCEL_REG_ACC_CONF,
+			  &value);
+	if (ret)
+		return ret;
+
+	value &= BMI088_ACCEL_MODE_ODR_MASK;
+	value -= BMI088_ACCEL_MODE_ODR_12_5;
+	value <<= 1;
+
+	if (value >= ARRAY_SIZE(bmi088_sample_freqs) - 1)
+		return -EINVAL;
+
+	*val = bmi088_sample_freqs[value];
+	*val2 = bmi088_sample_freqs[value + 1];
+
+	return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int bmi088_accel_set_sample_freq(struct bmi088_accel_data *data, int val)
+{
+	unsigned int regval;
+	int index = 0;
+
+	while (index < ARRAY_SIZE(bmi088_sample_freqs) &&
+	       bmi088_sample_freqs[index] != val)
+		index += 2;
+
+	if (index >= ARRAY_SIZE(bmi088_sample_freqs))
+		return -EINVAL;
+
+	regval = (index >> 1) + BMI088_ACCEL_MODE_ODR_12_5;
+
+	return regmap_update_bits(data->regmap, BMI088_ACCEL_REG_ACC_CONF,
+				  BMI088_ACCEL_MODE_ODR_MASK, regval);
+}
+
+static int bmi088_accel_get_temp(struct bmi088_accel_data *data, int *val)
+{
+	int ret;
+	s16 temp;
+
+	ret = regmap_bulk_read(data->regmap, BMI088_ACCEL_REG_TEMP,
+			       &data->buffer, sizeof(__be16));
+	if (ret)
+		return ret;
+
+	/* data->buffer is cacheline aligned */
+	temp = be16_to_cpu(*(__be16 *)data->buffer);
+
+	*val = temp >> BMI088_ACCEL_REG_TEMP_SHIFT;
+
+	return IIO_VAL_INT;
+}
+
+static int bmi088_accel_get_axis(struct bmi088_accel_data *data,
+				 struct iio_chan_spec const *chan,
+				 int *val)
+{
+	int ret;
+	s16 raw_val;
+
+	ret = regmap_bulk_read(data->regmap,
+			       BMI088_ACCEL_AXIS_TO_REG(chan->scan_index),
+			       data->buffer, sizeof(__le16));
+	if (ret)
+		return ret;
+
+	raw_val = le16_to_cpu(*(__le16 *)data->buffer);
+	*val = raw_val;
+
+	return IIO_VAL_INT;
+}
+
+static int bmi088_accel_read_raw(struct iio_dev *indio_dev,
+				 struct iio_chan_spec const *chan,
+				 int *val, int *val2, long mask)
+{
+	struct bmi088_accel_data *data = iio_priv(indio_dev);
+	struct device *dev = regmap_get_device(data->regmap);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (chan->type) {
+		case IIO_TEMP:
+			pm_runtime_get_sync(dev);
+			ret = bmi088_accel_get_temp(data, val);
+			goto out_read_raw_pm_put;
+		case IIO_ACCEL:
+			pm_runtime_get_sync(dev);
+			ret = iio_device_claim_direct_mode(indio_dev);
+			if (ret)
+				goto out_read_raw_pm_put;
+
+			ret = bmi088_accel_get_axis(data, chan, val);
+			iio_device_release_direct_mode(indio_dev);
+			if (!ret)
+				ret = IIO_VAL_INT;
+
+			goto out_read_raw_pm_put;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_OFFSET:
+		switch (chan->type) {
+		case IIO_TEMP:
+			/* Offset applies before scale */
+			*val = BMI088_ACCEL_TEMP_OFFSET/BMI088_ACCEL_TEMP_UNIT;
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_TEMP:
+			/* 0.125 degrees per LSB */
+			*val = BMI088_ACCEL_TEMP_UNIT;
+			return IIO_VAL_INT;
+		case IIO_ACCEL:
+			pm_runtime_get_sync(dev);
+			ret = regmap_read(data->regmap,
+					  BMI088_ACCEL_REG_ACC_RANGE, val);
+			if (ret)
+				goto out_read_raw_pm_put;
+
+			*val2 = 15 - (*val & 0x3);
+			*val = 3 * 980;
+			ret = IIO_VAL_FRACTIONAL_LOG2;
+
+			goto out_read_raw_pm_put;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		pm_runtime_get_sync(dev);
+		ret = bmi088_accel_get_sample_freq(data, val, val2);
+		goto out_read_raw_pm_put;
+	default:
+		break;
+	}
+
+	return -EINVAL;
+
+out_read_raw_pm_put:
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
+
+	return ret;
+}
+
+static int bmi088_accel_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_SAMP_FREQ:
+		*type = IIO_VAL_INT_PLUS_MICRO;
+		*vals = bmi088_sample_freqs;
+		*length = ARRAY_SIZE(bmi088_sample_freqs);
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int bmi088_accel_write_raw(struct iio_dev *indio_dev,
+				  struct iio_chan_spec const *chan,
+				  int val, int val2, long mask)
+{
+	struct bmi088_accel_data *data = iio_priv(indio_dev);
+	struct device *dev = regmap_get_device(data->regmap);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		pm_runtime_get_sync(dev);
+		ret = bmi088_accel_set_sample_freq(data, val);
+		pm_runtime_mark_last_busy(dev);
+		pm_runtime_put_autosuspend(dev);
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+#define BMI088_ACCEL_CHANNEL(_axis) { \
+	.type = IIO_ACCEL, \
+	.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), \
+	.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+	.scan_index = AXIS_##_axis, \
+}
+
+static const struct iio_chan_spec bmi088_accel_channels[] = {
+	{
+		.type = IIO_TEMP,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE) |
+				      BIT(IIO_CHAN_INFO_OFFSET),
+		.scan_index = -1,
+	},
+	BMI088_ACCEL_CHANNEL(X),
+	BMI088_ACCEL_CHANNEL(Y),
+	BMI088_ACCEL_CHANNEL(Z),
+	IIO_CHAN_SOFT_TIMESTAMP(3),
+};
+
+static const struct bmi088_accel_chip_info bmi088_accel_chip_info_tbl[] = {
+	[0] = {
+		.name = "bmi088a",
+		.chip_id = 0x1E,
+		.channels = bmi088_accel_channels,
+		.num_channels = ARRAY_SIZE(bmi088_accel_channels),
+	},
+};
+
+static const struct iio_info bmi088_accel_info = {
+	.read_raw	= bmi088_accel_read_raw,
+	.write_raw	= bmi088_accel_write_raw,
+	.read_avail	= bmi088_accel_read_avail,
+};
+
+static const unsigned long bmi088_accel_scan_masks[] = {
+	BIT(AXIS_X) | BIT(AXIS_Y) | BIT(AXIS_Z),
+	0
+};
+
+static int bmi088_accel_chip_init(struct bmi088_accel_data *data)
+{
+	struct device *dev = regmap_get_device(data->regmap);
+	int ret, i;
+	unsigned int val;
+
+	/* Do a dummy read to enable SPI interface, won't harm I2C */
+	regmap_read(data->regmap, BMI088_ACCEL_REG_INT_STATUS, &val);
+
+	/*
+	 * Reset chip to get it in a known good state. A delay of 1ms after
+	 * reset is required according to the data sheet
+	 */
+	ret = regmap_write(data->regmap, BMI088_ACCEL_REG_RESET,
+			   BMI088_ACCEL_RESET_VAL);
+	if (ret)
+		return ret;
+
+	usleep_range(1000, 2000);
+
+	/* Do a dummy read again after a reset to enable the SPI interface */
+	regmap_read(data->regmap, BMI088_ACCEL_REG_INT_STATUS, &val);
+
+	/* Read chip ID */
+	ret = regmap_read(data->regmap, BMI088_ACCEL_REG_CHIP_ID, &val);
+	if (ret) {
+		dev_err(dev, "Error: Reading chip id\n");
+		return ret;
+	}
+
+	/* Validate chip ID */
+	for (i = 0; i < ARRAY_SIZE(bmi088_accel_chip_info_tbl); i++) {
+		if (bmi088_accel_chip_info_tbl[i].chip_id == val) {
+			data->chip_info = &bmi088_accel_chip_info_tbl[i];
+			break;
+		}
+	}
+	if (i == ARRAY_SIZE(bmi088_accel_chip_info_tbl)) {
+		dev_err(dev, "Invalid chip %x\n", val);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+int bmi088_accel_core_probe(struct device *dev, struct regmap *regmap,
+	int irq, const char *name, bool block_supported)
+{
+	struct bmi088_accel_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	dev_set_drvdata(dev, indio_dev);
+
+	data->regmap = regmap;
+
+	ret = bmi088_accel_chip_init(data);
+	if (ret)
+		return ret;
+
+	indio_dev->dev.parent = dev;
+	indio_dev->channels = data->chip_info->channels;
+	indio_dev->num_channels = data->chip_info->num_channels;
+	indio_dev->name = name ? name : data->chip_info->name;
+	indio_dev->available_scan_masks = bmi088_accel_scan_masks;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &bmi088_accel_info;
+
+	/* Enable runtime PM */
+	pm_runtime_get_noresume(dev);
+	pm_runtime_set_suspended(dev);
+	pm_runtime_enable(dev);
+	/* We need ~6ms to startup, so set the delay to 6 seconds */
+	pm_runtime_set_autosuspend_delay(dev, 6000);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_put(dev);
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		dev_err(dev, "Unable to register iio device\n");
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(bmi088_accel_core_probe);
+
+
+int bmi088_accel_core_remove(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct bmi088_accel_data *data = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	pm_runtime_put_noidle(dev);
+	bmi088_accel_power_down(data);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(bmi088_accel_core_remove);
+
+static int __maybe_unused bmi088_accel_runtime_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct bmi088_accel_data *data = iio_priv(indio_dev);
+
+	return bmi088_accel_power_down(data);
+}
+
+static int __maybe_unused bmi088_accel_runtime_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct bmi088_accel_data *data = iio_priv(indio_dev);
+
+	return bmi088_accel_power_up(data);
+}
+
+const struct dev_pm_ops bmi088_accel_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+	SET_RUNTIME_PM_OPS(bmi088_accel_runtime_suspend,
+			   bmi088_accel_runtime_resume, NULL)
+};
+EXPORT_SYMBOL_GPL(bmi088_accel_pm_ops);
+
+MODULE_AUTHOR("Niek van Agt <niek.van.agt@topicproducts.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("BMI088 accelerometer driver (core)");
diff --git a/drivers/iio/accel/bmi088-accel-spi.c b/drivers/iio/accel/bmi088-accel-spi.c
new file mode 100644
index 000000000000..dd1e3f6cf211
--- /dev/null
+++ b/drivers/iio/accel/bmi088-accel-spi.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 3-axis accelerometer driver supporting following Bosch-Sensortec chips:
+ *  - BMI088
+ *
+ * Copyright (c) 2018-2020, Topic Embedded Products
+ */
+
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+
+#include "bmi088-accel.h"
+
+static int bmi088_regmap_spi_write(void *context, const void *data, size_t count)
+{
+	struct spi_device *spi = context;
+
+	/* Write register is same as generic SPI */
+	return spi_write(spi, data, count);
+}
+
+static int bmi088_regmap_spi_read(void *context, const void *reg,
+				size_t reg_size, void *val, size_t val_size)
+{
+	struct spi_device *spi = context;
+	u8 addr[2];
+
+	addr[0] = *(u8 *)reg;
+	addr[0] |= BIT(7); /* Set RW = '1' */
+	addr[1] = 0; /* Read requires a dummy byte transfer */
+
+	return spi_write_then_read(spi, addr, sizeof(addr), val, val_size);
+}
+
+static struct regmap_bus bmi088_regmap_bus = {
+	.write = bmi088_regmap_spi_write,
+	.read = bmi088_regmap_spi_read,
+};
+
+static int bmi088_accel_probe(struct spi_device *spi)
+{
+	struct regmap *regmap;
+	const struct spi_device_id *id = spi_get_device_id(spi);
+
+	regmap = devm_regmap_init(&spi->dev, &bmi088_regmap_bus,
+			spi, &bmi088_regmap_conf);
+
+	if (IS_ERR(regmap)) {
+		dev_err(&spi->dev, "Failed to initialize spi regmap\n");
+		return PTR_ERR(regmap);
+	}
+
+	return bmi088_accel_core_probe(&spi->dev, regmap, spi->irq, id->name,
+				       true);
+}
+
+static int bmi088_accel_remove(struct spi_device *spi)
+{
+	return bmi088_accel_core_remove(&spi->dev);
+}
+
+static const struct spi_device_id bmi088_accel_id[] = {
+	{"bmi088-accel", },
+	{}
+};
+MODULE_DEVICE_TABLE(spi, bmi088_accel_id);
+
+static struct spi_driver bmi088_accel_driver = {
+	.driver = {
+		.name	= "bmi088_accel_spi",
+		.pm	= &bmi088_accel_pm_ops,
+	},
+	.probe		= bmi088_accel_probe,
+	.remove		= bmi088_accel_remove,
+	.id_table	= bmi088_accel_id,
+};
+module_spi_driver(bmi088_accel_driver);
+
+MODULE_AUTHOR("Niek van Agt <niek.van.agt@topicproducts.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("BMI088 accelerometer driver (SPI)");
diff --git a/drivers/iio/accel/bmi088-accel.h b/drivers/iio/accel/bmi088-accel.h
new file mode 100644
index 000000000000..5c25f16b672c
--- /dev/null
+++ b/drivers/iio/accel/bmi088-accel.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef BMI088_ACCEL_H
+#define BMI088_ACCEL_H
+
+#include <linux/pm.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+struct device;
+
+extern const struct regmap_config bmi088_regmap_conf;
+extern const struct dev_pm_ops bmi088_accel_pm_ops;
+
+int bmi088_accel_core_probe(struct device *dev, struct regmap *regmap, int irq,
+			    const char *name, bool block_supported);
+int bmi088_accel_core_remove(struct device *dev);
+
+#endif /* BMI088_ACCEL_H */
-- 
2.17.1

Re: [PATCH v8 2/2] iio: accel: Add support for the Bosch-Sensortec BMI088

[Linus Walleij]

On Mon, Jan 25, 2021 at 4:07 PM Mike Looijmans <mike.looijmans@topic.nl> wrote:

> The BMI088 is a combined module with both accelerometer and gyroscope.
> This adds the accelerometer driver support for the SPI interface.
> The gyroscope part is already supported by the BMG160 driver.
>
> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>

Excellent!
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

Re: [PATCH v8 1/2] dt-bindings: iio: accel: Add bmi088 accelerometer bindings

[Rob Herring]

On Mon, 25 Jan 2021 16:07:31 +0100, Mike Looijmans wrote:
> This adds the device-tree bindings for the Bosch Sensortec BMI088 IMU,
> the accelerometer part.
> 
> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
> 
> ---
> 
> Changes in v8:
> Add spi-max-frequency: true
> 
> Changes in v7:
> Add additionalProperties
> Change bmi088_accel to bmi088-accel
> Add interrupt-names and adjust description
> 
> Changes in v6:
> I't been almost a year since the last commit, sorry...
> Fixed the yaml errors
> Add interrupt, vdd and vddio properties
> 
> Changes in v5:
> submit together with driver code as patch series
> 
> Changes in v2:
> convert to yaml format
> 
>  .../bindings/iio/accel/bosch,bmi088.yaml      | 68 +++++++++++++++++++
>  1 file changed, 68 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/accel/bosch,bmi088.yaml
> 

Reviewed-by: Rob Herring <robh@kernel.org>

Re: [PATCH v8 2/2] iio: accel: Add support for the Bosch-Sensortec BMI088

[Jonathan Cameron]

On Sun, 31 Jan 2021 12:16:45 +0000
Jonathan Cameron <jic23@kernel.org> wrote:

> On Mon, 25 Jan 2021 16:07:32 +0100
> Mike Looijmans <mike.looijmans@topic.nl> wrote:
> 
> > The BMI088 is a combined module with both accelerometer and gyroscope.
> > This adds the accelerometer driver support for the SPI interface.
> > The gyroscope part is already supported by the BMG160 driver.
> > 
> > Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>  
> Hi Mike,
> 
> I'll drop the include <linux/acpi.h> as no acpi stuff in
> here that I can see.
> 
> Otherwise, looks good to me.  Will give a bit of time for Rob or
> anyone else to take another look at this and the binding patch.
> 
I couple of warnings popped up during my local build tests with W=1 C=1

drivers/iio/accel/bmi088-accel-core.c: In function ‘bmi088_accel_power_up’:
drivers/iio/accel/bmi088-accel-core.c:153:17: warning: unused variable ‘dev’ [-Wunused-variable]
  153 |  struct device *dev = regmap_get_device(data->regmap);
      |                 ^~~
drivers/iio/accel/bmi088-accel-core.c: In function ‘bmi088_accel_power_down’:
drivers/iio/accel/bmi088-accel-core.c:177:17: warning: unused variable ‘dev’ [-Wunused-variable]
  177 |  struct device *dev = regmap_get_device(data->regmap);

As they are both obvious, I fixed them by dropping both those lines.

Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to poke at it.

Thanks for persisting with this Mike!

Jonathan

> Thanks,
> 
> Jonathan
> 
> > 
> > ---
> > 
> > Changes in v8:
> > include order asm/ after linux/
> > Suspend/resume redesigned, use runtime PM for both cases. Removed the
> > pm wrappers and let runtime PM handle power up/down. This also removed
> > the need for an internal mutex, thus reducing code further.
> > 
> > Changes in v7:
> > Change bmi088_accel to bmi088-accel
> > Order includes alphabetically
> > Suspend and disable on remove
> > Make bmi088_regmap_spi_{read|write} static
> > 
> > Changes in v6:
> > Hope you have good memory - v5 was almost a year ago now
> > Remove superfluous *val=0
> > Make sample_frequency selection into read_avail list
> > 
> > Changes in v5:
> > Add includes and forward defines in header
> > BIT(7) instead of 0x80
> > Reset already sets defaults, do not set them again
> > Remove now unused bmi088_accel_set_bw
> > Remove unused AXIS_MAX
> > Use MASK define for ODR setting
> > Explain buffer use and alignment
> > Split bmi088_accel_set_power_state into "on" and "off" parts
> > Cosmetic changes to improve readability
> > 
> > Changes in v4:
> > Remove unused #include directives
> > Remove unused #defines for event and irq
> > Replace (ret < 0) with (ret) for all regmap calls
> > Consistent checking of IO errors in probe and init
> > Removed #ifdef CONFIG_PM guard
> > Use bitops for set_frequency instead of loop with shift
> > s/__s16/s16/g
> > Remove excess blank lines
> > Don't return -EAGAIN in pm_runtime
> > 
> > Changes in v3:
> > Processed comments from Jonathan Cameron and Lars-Peter Clausen
> > implement runtime PM (tested by code tracing) and sleep
> > fix scale and offset factors for accel and temperature and
> > return raw values instead of pre-scaled ones
> > Use iio_device_{claim,release}_direct_mode
> > Remove unused code and structs
> > Use a cache-aligned buffer for bulk read
> > Configure and enable caching register values
> > 
> > Changes in v2:
> > Remove unused typedefs and variables
> > Fix error return when iio_device_register fails
> > 
> >  drivers/iio/accel/Kconfig             |  18 +
> >  drivers/iio/accel/Makefile            |   2 +
> >  drivers/iio/accel/bmi088-accel-core.c | 570 ++++++++++++++++++++++++++
> >  drivers/iio/accel/bmi088-accel-spi.c  |  83 ++++
> >  drivers/iio/accel/bmi088-accel.h      |  18 +
> >  5 files changed, 691 insertions(+)
> >  create mode 100644 drivers/iio/accel/bmi088-accel-core.c
> >  create mode 100644 drivers/iio/accel/bmi088-accel-spi.c
> >  create mode 100644 drivers/iio/accel/bmi088-accel.h
> > 
> > diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
> > index 2e0c62c39155..cceda3cecbcf 100644
> > --- a/drivers/iio/accel/Kconfig
> > +++ b/drivers/iio/accel/Kconfig
> > @@ -157,6 +157,24 @@ config BMC150_ACCEL_SPI
> >  	tristate
> >  	select REGMAP_SPI
> >  
> > +config BMI088_ACCEL
> > +	tristate "Bosch BMI088 Accelerometer Driver"
> > +	depends on SPI
> > +	select IIO_BUFFER
> > +	select IIO_TRIGGERED_BUFFER
> > +	select REGMAP
> > +	select BMI088_ACCEL_SPI
> > +	help
> > +	  Say yes here to build support for the Bosch BMI088 accelerometer.
> > +
> > +	  This is a combo module with both accelerometer and gyroscope. This
> > +	  driver only implements the accelerometer part, which has its own
> > +	  address and register map. BMG160 provides the gyroscope driver.
> > +
> > +config BMI088_ACCEL_SPI
> > +	tristate
> > +	select REGMAP_SPI
> > +
> >  config DA280
> >  	tristate "MiraMEMS DA280 3-axis 14-bit digital accelerometer driver"
> >  	depends on I2C
> > diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
> > index 4f6c1ebe13b0..32cd1342a31a 100644
> > --- a/drivers/iio/accel/Makefile
> > +++ b/drivers/iio/accel/Makefile
> > @@ -20,6 +20,8 @@ obj-$(CONFIG_BMA400_SPI) += bma400_spi.o
> >  obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o
> >  obj-$(CONFIG_BMC150_ACCEL_I2C) += bmc150-accel-i2c.o
> >  obj-$(CONFIG_BMC150_ACCEL_SPI) += bmc150-accel-spi.o
> > +obj-$(CONFIG_BMI088_ACCEL) += bmi088-accel-core.o
> > +obj-$(CONFIG_BMI088_ACCEL_SPI) += bmi088-accel-spi.o
> >  obj-$(CONFIG_DA280)	+= da280.o
> >  obj-$(CONFIG_DA311)	+= da311.o
> >  obj-$(CONFIG_DMARD06)	+= dmard06.o
> > diff --git a/drivers/iio/accel/bmi088-accel-core.c b/drivers/iio/accel/bmi088-accel-core.c
> > new file mode 100644
> > index 000000000000..f86010a3cda3
> > --- /dev/null
> > +++ b/drivers/iio/accel/bmi088-accel-core.c
> > @@ -0,0 +1,570 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * 3-axis accelerometer driver supporting following Bosch-Sensortec chips:
> > + *  - BMI088
> > + *
> > + * Copyright (c) 2018-2021, Topic Embedded Products
> > + */
> > +
> > +#include <linux/acpi.h>  
> 
> Why?  I'll tidy this up whilst applying if there isn't a v9.
> 
> > +#include <linux/delay.h>
> > +#include <linux/iio/iio.h>
> > +#include <linux/iio/sysfs.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/module.h>
> > +#include <linux/pm.h>
> > +#include <linux/pm_runtime.h>
> > +#include <linux/regmap.h>
> > +#include <linux/slab.h>
> > +#include <asm/unaligned.h>
> > +
> > +#include "bmi088-accel.h"
> > +
> > +#define BMI088_ACCEL_REG_CHIP_ID			0x00
> > +#define BMI088_ACCEL_REG_ERROR				0x02
> > +
> > +#define BMI088_ACCEL_REG_INT_STATUS			0x1D
> > +#define BMI088_ACCEL_INT_STATUS_BIT_DRDY		BIT(7)
> > +
> > +#define BMI088_ACCEL_REG_RESET				0x7E
> > +#define BMI088_ACCEL_RESET_VAL				0xB6
> > +
> > +#define BMI088_ACCEL_REG_PWR_CTRL			0x7D
> > +#define BMI088_ACCEL_REG_PWR_CONF			0x7C
> > +
> > +#define BMI088_ACCEL_REG_INT_MAP_DATA			0x58
> > +#define BMI088_ACCEL_INT_MAP_DATA_BIT_INT1_DRDY		BIT(2)
> > +#define BMI088_ACCEL_INT_MAP_DATA_BIT_INT2_FWM		BIT(5)
> > +
> > +#define BMI088_ACCEL_REG_INT1_IO_CONF			0x53
> > +#define BMI088_ACCEL_INT1_IO_CONF_BIT_ENABLE_OUT	BIT(3)
> > +#define BMI088_ACCEL_INT1_IO_CONF_BIT_LVL		BIT(1)
> > +
> > +#define BMI088_ACCEL_REG_INT2_IO_CONF			0x54
> > +#define BMI088_ACCEL_INT2_IO_CONF_BIT_ENABLE_OUT	BIT(3)
> > +#define BMI088_ACCEL_INT2_IO_CONF_BIT_LVL		BIT(1)
> > +
> > +#define BMI088_ACCEL_REG_ACC_CONF			0x40
> > +#define BMI088_ACCEL_MODE_ODR_MASK			0x0f
> > +
> > +#define BMI088_ACCEL_REG_ACC_RANGE			0x41
> > +#define BMI088_ACCEL_RANGE_3G				0x00
> > +#define BMI088_ACCEL_RANGE_6G				0x01
> > +#define BMI088_ACCEL_RANGE_12G				0x02
> > +#define BMI088_ACCEL_RANGE_24G				0x03
> > +
> > +#define BMI088_ACCEL_REG_TEMP				0x22
> > +#define BMI088_ACCEL_REG_TEMP_SHIFT			5
> > +#define BMI088_ACCEL_TEMP_UNIT				125
> > +#define BMI088_ACCEL_TEMP_OFFSET			23000
> > +
> > +#define BMI088_ACCEL_REG_XOUT_L				0x12
> > +#define BMI088_ACCEL_AXIS_TO_REG(axis) \
> > +	(BMI088_ACCEL_REG_XOUT_L + (axis * 2))
> > +
> > +#define BMI088_ACCEL_MAX_STARTUP_TIME_US		1000
> > +#define BMI088_AUTO_SUSPEND_DELAY_MS			2000
> > +
> > +#define BMI088_ACCEL_REG_FIFO_STATUS			0x0E
> > +#define BMI088_ACCEL_REG_FIFO_CONFIG0			0x48
> > +#define BMI088_ACCEL_REG_FIFO_CONFIG1			0x49
> > +#define BMI088_ACCEL_REG_FIFO_DATA			0x3F
> > +#define BMI088_ACCEL_FIFO_LENGTH			100
> > +
> > +#define BMI088_ACCEL_FIFO_MODE_FIFO			0x40
> > +#define BMI088_ACCEL_FIFO_MODE_STREAM			0x80
> > +
> > +enum bmi088_accel_axis {
> > +	AXIS_X,
> > +	AXIS_Y,
> > +	AXIS_Z,
> > +};
> > +
> > +static const int bmi088_sample_freqs[] = {
> > +	12, 500000,
> > +	25, 0,
> > +	50, 0,
> > +	100, 0,
> > +	200, 0,
> > +	400, 0,
> > +	800, 0,
> > +	1600, 0,
> > +};
> > +
> > +/* Available OSR (over sampling rate) sets the 3dB cut-off frequency */
> > +enum bmi088_osr_modes {
> > +	BMI088_ACCEL_MODE_OSR_NORMAL = 0xA,
> > +	BMI088_ACCEL_MODE_OSR_2 = 0x9,
> > +	BMI088_ACCEL_MODE_OSR_4 = 0x8,
> > +};
> > +
> > +/* Available ODR (output data rates) in Hz */
> > +enum bmi088_odr_modes {
> > +	BMI088_ACCEL_MODE_ODR_12_5 = 0x5,
> > +	BMI088_ACCEL_MODE_ODR_25 = 0x6,
> > +	BMI088_ACCEL_MODE_ODR_50 = 0x7,
> > +	BMI088_ACCEL_MODE_ODR_100 = 0x8,
> > +	BMI088_ACCEL_MODE_ODR_200 = 0x9,
> > +	BMI088_ACCEL_MODE_ODR_400 = 0xa,
> > +	BMI088_ACCEL_MODE_ODR_800 = 0xb,
> > +	BMI088_ACCEL_MODE_ODR_1600 = 0xc,
> > +};
> > +
> > +struct bmi088_scale_info {
> > +	int scale;
> > +	u8 reg_range;
> > +};
> > +
> > +struct bmi088_accel_chip_info {
> > +	const char *name;
> > +	u8 chip_id;
> > +	const struct iio_chan_spec *channels;
> > +	int num_channels;
> > +};
> > +
> > +struct bmi088_accel_data {
> > +	struct regmap *regmap;
> > +	const struct bmi088_accel_chip_info *chip_info;
> > +	u8 buffer[2] ____cacheline_aligned; /* shared DMA safe buffer */
> > +};
> > +
> > +static const struct regmap_range bmi088_volatile_ranges[] = {
> > +	/* All registers below 0x40 are volatile, except the CHIP ID. */
> > +	regmap_reg_range(BMI088_ACCEL_REG_ERROR, 0x3f),
> > +	/* Mark the RESET as volatile too, it is self-clearing */
> > +	regmap_reg_range(BMI088_ACCEL_REG_RESET, BMI088_ACCEL_REG_RESET),
> > +};
> > +
> > +static const struct regmap_access_table bmi088_volatile_table = {
> > +	.yes_ranges	= bmi088_volatile_ranges,
> > +	.n_yes_ranges	= ARRAY_SIZE(bmi088_volatile_ranges),
> > +};
> > +
> > +const struct regmap_config bmi088_regmap_conf = {
> > +	.reg_bits = 8,
> > +	.val_bits = 8,
> > +	.max_register = 0x7E,
> > +	.volatile_table = &bmi088_volatile_table,
> > +	.cache_type = REGCACHE_RBTREE,
> > +};
> > +EXPORT_SYMBOL_GPL(bmi088_regmap_conf);
> > +
> > +static int bmi088_accel_power_up(struct bmi088_accel_data *data)
> > +{
> > +	struct device *dev = regmap_get_device(data->regmap);
> > +	int ret;
> > +
> > +	/* Enable accelerometer and temperature sensor */
> > +	ret = regmap_write(data->regmap, BMI088_ACCEL_REG_PWR_CTRL, 0x4);
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* Datasheet recommends to wait at least 5ms before communication */
> > +	usleep_range(5000, 6000);
> > +
> > +	/* Disable suspend mode */
> > +	ret = regmap_write(data->regmap, BMI088_ACCEL_REG_PWR_CONF, 0x0);
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* Recommended at least 1ms before further communication */
> > +	usleep_range(1000, 1200);
> > +
> > +	return 0;
> > +}
> > +
> > +static int bmi088_accel_power_down(struct bmi088_accel_data *data)
> > +{
> > +	struct device *dev = regmap_get_device(data->regmap);
> > +	int ret;
> > +
> > +	/* Enable suspend mode */
> > +	ret = regmap_write(data->regmap, BMI088_ACCEL_REG_PWR_CONF, 0x3);
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* Recommended at least 1ms before further communication */
> > +	usleep_range(1000, 1200);
> > +
> > +	/* Disable accelerometer and temperature sensor */
> > +	ret = regmap_write(data->regmap, BMI088_ACCEL_REG_PWR_CTRL, 0x0);
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* Datasheet recommends to wait at least 5ms before communication */
> > +	usleep_range(5000, 6000);
> > +
> > +	return 0;
> > +}
> > +
> > +static int bmi088_accel_get_sample_freq(struct bmi088_accel_data *data,
> > +					int *val, int *val2)
> > +{
> > +	unsigned int value;
> > +	int ret;
> > +
> > +	ret = regmap_read(data->regmap, BMI088_ACCEL_REG_ACC_CONF,
> > +			  &value);
> > +	if (ret)
> > +		return ret;
> > +
> > +	value &= BMI088_ACCEL_MODE_ODR_MASK;
> > +	value -= BMI088_ACCEL_MODE_ODR_12_5;
> > +	value <<= 1;
> > +
> > +	if (value >= ARRAY_SIZE(bmi088_sample_freqs) - 1)
> > +		return -EINVAL;
> > +
> > +	*val = bmi088_sample_freqs[value];
> > +	*val2 = bmi088_sample_freqs[value + 1];
> > +
> > +	return IIO_VAL_INT_PLUS_MICRO;
> > +}
> > +
> > +static int bmi088_accel_set_sample_freq(struct bmi088_accel_data *data, int val)
> > +{
> > +	unsigned int regval;
> > +	int index = 0;
> > +
> > +	while (index < ARRAY_SIZE(bmi088_sample_freqs) &&
> > +	       bmi088_sample_freqs[index] != val)
> > +		index += 2;
> > +
> > +	if (index >= ARRAY_SIZE(bmi088_sample_freqs))
> > +		return -EINVAL;
> > +
> > +	regval = (index >> 1) + BMI088_ACCEL_MODE_ODR_12_5;
> > +
> > +	return regmap_update_bits(data->regmap, BMI088_ACCEL_REG_ACC_CONF,
> > +				  BMI088_ACCEL_MODE_ODR_MASK, regval);
> > +}
> > +
> > +static int bmi088_accel_get_temp(struct bmi088_accel_data *data, int *val)
> > +{
> > +	int ret;
> > +	s16 temp;
> > +
> > +	ret = regmap_bulk_read(data->regmap, BMI088_ACCEL_REG_TEMP,
> > +			       &data->buffer, sizeof(__be16));
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* data->buffer is cacheline aligned */
> > +	temp = be16_to_cpu(*(__be16 *)data->buffer);
> > +
> > +	*val = temp >> BMI088_ACCEL_REG_TEMP_SHIFT;
> > +
> > +	return IIO_VAL_INT;
> > +}
> > +
> > +static int bmi088_accel_get_axis(struct bmi088_accel_data *data,
> > +				 struct iio_chan_spec const *chan,
> > +				 int *val)
> > +{
> > +	int ret;
> > +	s16 raw_val;
> > +
> > +	ret = regmap_bulk_read(data->regmap,
> > +			       BMI088_ACCEL_AXIS_TO_REG(chan->scan_index),
> > +			       data->buffer, sizeof(__le16));
> > +	if (ret)
> > +		return ret;
> > +
> > +	raw_val = le16_to_cpu(*(__le16 *)data->buffer);
> > +	*val = raw_val;
> > +
> > +	return IIO_VAL_INT;
> > +}
> > +
> > +static int bmi088_accel_read_raw(struct iio_dev *indio_dev,
> > +				 struct iio_chan_spec const *chan,
> > +				 int *val, int *val2, long mask)
> > +{
> > +	struct bmi088_accel_data *data = iio_priv(indio_dev);
> > +	struct device *dev = regmap_get_device(data->regmap);
> > +	int ret;
> > +
> > +	switch (mask) {
> > +	case IIO_CHAN_INFO_RAW:
> > +		switch (chan->type) {
> > +		case IIO_TEMP:
> > +			pm_runtime_get_sync(dev);
> > +			ret = bmi088_accel_get_temp(data, val);
> > +			goto out_read_raw_pm_put;
> > +		case IIO_ACCEL:
> > +			pm_runtime_get_sync(dev);
> > +			ret = iio_device_claim_direct_mode(indio_dev);
> > +			if (ret)
> > +				goto out_read_raw_pm_put;
> > +
> > +			ret = bmi088_accel_get_axis(data, chan, val);
> > +			iio_device_release_direct_mode(indio_dev);
> > +			if (!ret)
> > +				ret = IIO_VAL_INT;
> > +
> > +			goto out_read_raw_pm_put;
> > +		default:
> > +			return -EINVAL;
> > +		}
> > +	case IIO_CHAN_INFO_OFFSET:
> > +		switch (chan->type) {
> > +		case IIO_TEMP:
> > +			/* Offset applies before scale */
> > +			*val = BMI088_ACCEL_TEMP_OFFSET/BMI088_ACCEL_TEMP_UNIT;
> > +			return IIO_VAL_INT;
> > +		default:
> > +			return -EINVAL;
> > +		}
> > +	case IIO_CHAN_INFO_SCALE:
> > +		switch (chan->type) {
> > +		case IIO_TEMP:
> > +			/* 0.125 degrees per LSB */
> > +			*val = BMI088_ACCEL_TEMP_UNIT;
> > +			return IIO_VAL_INT;
> > +		case IIO_ACCEL:
> > +			pm_runtime_get_sync(dev);
> > +			ret = regmap_read(data->regmap,
> > +					  BMI088_ACCEL_REG_ACC_RANGE, val);
> > +			if (ret)
> > +				goto out_read_raw_pm_put;
> > +
> > +			*val2 = 15 - (*val & 0x3);
> > +			*val = 3 * 980;
> > +			ret = IIO_VAL_FRACTIONAL_LOG2;
> > +
> > +			goto out_read_raw_pm_put;
> > +		default:
> > +			return -EINVAL;
> > +		}
> > +	case IIO_CHAN_INFO_SAMP_FREQ:
> > +		pm_runtime_get_sync(dev);
> > +		ret = bmi088_accel_get_sample_freq(data, val, val2);
> > +		goto out_read_raw_pm_put;
> > +	default:
> > +		break;
> > +	}
> > +
> > +	return -EINVAL;
> > +
> > +out_read_raw_pm_put:
> > +	pm_runtime_mark_last_busy(dev);
> > +	pm_runtime_put_autosuspend(dev);
> > +
> > +	return ret;
> > +}
> > +
> > +static int bmi088_accel_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_SAMP_FREQ:
> > +		*type = IIO_VAL_INT_PLUS_MICRO;
> > +		*vals = bmi088_sample_freqs;
> > +		*length = ARRAY_SIZE(bmi088_sample_freqs);
> > +		return IIO_AVAIL_LIST;
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +}
> > +
> > +static int bmi088_accel_write_raw(struct iio_dev *indio_dev,
> > +				  struct iio_chan_spec const *chan,
> > +				  int val, int val2, long mask)
> > +{
> > +	struct bmi088_accel_data *data = iio_priv(indio_dev);
> > +	struct device *dev = regmap_get_device(data->regmap);
> > +	int ret;
> > +
> > +	switch (mask) {
> > +	case IIO_CHAN_INFO_SAMP_FREQ:
> > +		pm_runtime_get_sync(dev);
> > +		ret = bmi088_accel_set_sample_freq(data, val);
> > +		pm_runtime_mark_last_busy(dev);
> > +		pm_runtime_put_autosuspend(dev);
> > +		return ret;
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +}
> > +
> > +#define BMI088_ACCEL_CHANNEL(_axis) { \
> > +	.type = IIO_ACCEL, \
> > +	.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), \
> > +	.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
> > +	.scan_index = AXIS_##_axis, \
> > +}
> > +
> > +static const struct iio_chan_spec bmi088_accel_channels[] = {
> > +	{
> > +		.type = IIO_TEMP,
> > +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> > +				      BIT(IIO_CHAN_INFO_SCALE) |
> > +				      BIT(IIO_CHAN_INFO_OFFSET),
> > +		.scan_index = -1,
> > +	},
> > +	BMI088_ACCEL_CHANNEL(X),
> > +	BMI088_ACCEL_CHANNEL(Y),
> > +	BMI088_ACCEL_CHANNEL(Z),
> > +	IIO_CHAN_SOFT_TIMESTAMP(3),
> > +};
> > +
> > +static const struct bmi088_accel_chip_info bmi088_accel_chip_info_tbl[] = {
> > +	[0] = {
> > +		.name = "bmi088a",
> > +		.chip_id = 0x1E,
> > +		.channels = bmi088_accel_channels,
> > +		.num_channels = ARRAY_SIZE(bmi088_accel_channels),
> > +	},
> > +};
> > +
> > +static const struct iio_info bmi088_accel_info = {
> > +	.read_raw	= bmi088_accel_read_raw,
> > +	.write_raw	= bmi088_accel_write_raw,
> > +	.read_avail	= bmi088_accel_read_avail,
> > +};
> > +
> > +static const unsigned long bmi088_accel_scan_masks[] = {
> > +	BIT(AXIS_X) | BIT(AXIS_Y) | BIT(AXIS_Z),
> > +	0
> > +};
> > +
> > +static int bmi088_accel_chip_init(struct bmi088_accel_data *data)
> > +{
> > +	struct device *dev = regmap_get_device(data->regmap);
> > +	int ret, i;
> > +	unsigned int val;
> > +
> > +	/* Do a dummy read to enable SPI interface, won't harm I2C */
> > +	regmap_read(data->regmap, BMI088_ACCEL_REG_INT_STATUS, &val);
> > +
> > +	/*
> > +	 * Reset chip to get it in a known good state. A delay of 1ms after
> > +	 * reset is required according to the data sheet
> > +	 */
> > +	ret = regmap_write(data->regmap, BMI088_ACCEL_REG_RESET,
> > +			   BMI088_ACCEL_RESET_VAL);
> > +	if (ret)
> > +		return ret;
> > +
> > +	usleep_range(1000, 2000);
> > +
> > +	/* Do a dummy read again after a reset to enable the SPI interface */
> > +	regmap_read(data->regmap, BMI088_ACCEL_REG_INT_STATUS, &val);
> > +
> > +	/* Read chip ID */
> > +	ret = regmap_read(data->regmap, BMI088_ACCEL_REG_CHIP_ID, &val);
> > +	if (ret) {
> > +		dev_err(dev, "Error: Reading chip id\n");
> > +		return ret;
> > +	}
> > +
> > +	/* Validate chip ID */
> > +	for (i = 0; i < ARRAY_SIZE(bmi088_accel_chip_info_tbl); i++) {
> > +		if (bmi088_accel_chip_info_tbl[i].chip_id == val) {
> > +			data->chip_info = &bmi088_accel_chip_info_tbl[i];
> > +			break;
> > +		}
> > +	}
> > +	if (i == ARRAY_SIZE(bmi088_accel_chip_info_tbl)) {
> > +		dev_err(dev, "Invalid chip %x\n", val);
> > +		return -ENODEV;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +int bmi088_accel_core_probe(struct device *dev, struct regmap *regmap,
> > +	int irq, const char *name, bool block_supported)
> > +{
> > +	struct bmi088_accel_data *data;
> > +	struct iio_dev *indio_dev;
> > +	int ret;
> > +
> > +	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
> > +	if (!indio_dev)
> > +		return -ENOMEM;
> > +
> > +	data = iio_priv(indio_dev);
> > +	dev_set_drvdata(dev, indio_dev);
> > +
> > +	data->regmap = regmap;
> > +
> > +	ret = bmi088_accel_chip_init(data);
> > +	if (ret)
> > +		return ret;
> > +
> > +	indio_dev->dev.parent = dev;
> > +	indio_dev->channels = data->chip_info->channels;
> > +	indio_dev->num_channels = data->chip_info->num_channels;
> > +	indio_dev->name = name ? name : data->chip_info->name;
> > +	indio_dev->available_scan_masks = bmi088_accel_scan_masks;
> > +	indio_dev->modes = INDIO_DIRECT_MODE;
> > +	indio_dev->info = &bmi088_accel_info;
> > +
> > +	/* Enable runtime PM */
> > +	pm_runtime_get_noresume(dev);
> > +	pm_runtime_set_suspended(dev);
> > +	pm_runtime_enable(dev);
> > +	/* We need ~6ms to startup, so set the delay to 6 seconds */
> > +	pm_runtime_set_autosuspend_delay(dev, 6000);
> > +	pm_runtime_use_autosuspend(dev);
> > +	pm_runtime_put(dev);
> > +
> > +	ret = iio_device_register(indio_dev);
> > +	if (ret)
> > +		dev_err(dev, "Unable to register iio device\n");
> > +
> > +	return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(bmi088_accel_core_probe);
> > +
> > +
> > +int bmi088_accel_core_remove(struct device *dev)
> > +{
> > +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> > +	struct bmi088_accel_data *data = iio_priv(indio_dev);
> > +
> > +	iio_device_unregister(indio_dev);
> > +
> > +	pm_runtime_disable(dev);
> > +	pm_runtime_set_suspended(dev);
> > +	pm_runtime_put_noidle(dev);
> > +	bmi088_accel_power_down(data);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(bmi088_accel_core_remove);
> > +
> > +static int __maybe_unused bmi088_accel_runtime_suspend(struct device *dev)
> > +{
> > +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> > +	struct bmi088_accel_data *data = iio_priv(indio_dev);
> > +
> > +	return bmi088_accel_power_down(data);
> > +}
> > +
> > +static int __maybe_unused bmi088_accel_runtime_resume(struct device *dev)
> > +{
> > +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> > +	struct bmi088_accel_data *data = iio_priv(indio_dev);
> > +
> > +	return bmi088_accel_power_up(data);
> > +}
> > +
> > +const struct dev_pm_ops bmi088_accel_pm_ops = {
> > +	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> > +				pm_runtime_force_resume)
> > +	SET_RUNTIME_PM_OPS(bmi088_accel_runtime_suspend,
> > +			   bmi088_accel_runtime_resume, NULL)
> > +};
> > +EXPORT_SYMBOL_GPL(bmi088_accel_pm_ops);
> > +
> > +MODULE_AUTHOR("Niek van Agt <niek.van.agt@topicproducts.com>");
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_DESCRIPTION("BMI088 accelerometer driver (core)");
> > diff --git a/drivers/iio/accel/bmi088-accel-spi.c b/drivers/iio/accel/bmi088-accel-spi.c
> > new file mode 100644
> > index 000000000000..dd1e3f6cf211
> > --- /dev/null
> > +++ b/drivers/iio/accel/bmi088-accel-spi.c
> > @@ -0,0 +1,83 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * 3-axis accelerometer driver supporting following Bosch-Sensortec chips:
> > + *  - BMI088
> > + *
> > + * Copyright (c) 2018-2020, Topic Embedded Products
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/regmap.h>
> > +#include <linux/slab.h>
> > +#include <linux/spi/spi.h>
> > +
> > +#include "bmi088-accel.h"
> > +
> > +static int bmi088_regmap_spi_write(void *context, const void *data, size_t count)
> > +{
> > +	struct spi_device *spi = context;
> > +
> > +	/* Write register is same as generic SPI */
> > +	return spi_write(spi, data, count);
> > +}
> > +
> > +static int bmi088_regmap_spi_read(void *context, const void *reg,
> > +				size_t reg_size, void *val, size_t val_size)
> > +{
> > +	struct spi_device *spi = context;
> > +	u8 addr[2];
> > +
> > +	addr[0] = *(u8 *)reg;
> > +	addr[0] |= BIT(7); /* Set RW = '1' */
> > +	addr[1] = 0; /* Read requires a dummy byte transfer */
> > +
> > +	return spi_write_then_read(spi, addr, sizeof(addr), val, val_size);
> > +}
> > +
> > +static struct regmap_bus bmi088_regmap_bus = {
> > +	.write = bmi088_regmap_spi_write,
> > +	.read = bmi088_regmap_spi_read,
> > +};
> > +
> > +static int bmi088_accel_probe(struct spi_device *spi)
> > +{
> > +	struct regmap *regmap;
> > +	const struct spi_device_id *id = spi_get_device_id(spi);
> > +
> > +	regmap = devm_regmap_init(&spi->dev, &bmi088_regmap_bus,
> > +			spi, &bmi088_regmap_conf);
> > +
> > +	if (IS_ERR(regmap)) {
> > +		dev_err(&spi->dev, "Failed to initialize spi regmap\n");
> > +		return PTR_ERR(regmap);
> > +	}
> > +
> > +	return bmi088_accel_core_probe(&spi->dev, regmap, spi->irq, id->name,
> > +				       true);
> > +}
> > +
> > +static int bmi088_accel_remove(struct spi_device *spi)
> > +{
> > +	return bmi088_accel_core_remove(&spi->dev);
> > +}
> > +
> > +static const struct spi_device_id bmi088_accel_id[] = {
> > +	{"bmi088-accel", },
> > +	{}
> > +};
> > +MODULE_DEVICE_TABLE(spi, bmi088_accel_id);
> > +
> > +static struct spi_driver bmi088_accel_driver = {
> > +	.driver = {
> > +		.name	= "bmi088_accel_spi",
> > +		.pm	= &bmi088_accel_pm_ops,
> > +	},
> > +	.probe		= bmi088_accel_probe,
> > +	.remove		= bmi088_accel_remove,
> > +	.id_table	= bmi088_accel_id,
> > +};
> > +module_spi_driver(bmi088_accel_driver);
> > +
> > +MODULE_AUTHOR("Niek van Agt <niek.van.agt@topicproducts.com>");
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_DESCRIPTION("BMI088 accelerometer driver (SPI)");
> > diff --git a/drivers/iio/accel/bmi088-accel.h b/drivers/iio/accel/bmi088-accel.h
> > new file mode 100644
> > index 000000000000..5c25f16b672c
> > --- /dev/null
> > +++ b/drivers/iio/accel/bmi088-accel.h
> > @@ -0,0 +1,18 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef BMI088_ACCEL_H
> > +#define BMI088_ACCEL_H
> > +
> > +#include <linux/pm.h>
> > +#include <linux/regmap.h>
> > +#include <linux/types.h>
> > +
> > +struct device;
> > +
> > +extern const struct regmap_config bmi088_regmap_conf;
> > +extern const struct dev_pm_ops bmi088_accel_pm_ops;
> > +
> > +int bmi088_accel_core_probe(struct device *dev, struct regmap *regmap, int irq,
> > +			    const char *name, bool block_supported);
> > +int bmi088_accel_core_remove(struct device *dev);
> > +
> > +#endif /* BMI088_ACCEL_H */  
>