[PATCH 0/5] Add support for ADIS16550 and ADIS16550W

[PATCH 0/5] Add support for ADIS16550 and ADIS16550W

[Robert Budai]

The ADIS16550 is a complete inertial system that includes a triaxis gyroscope
and a triaxis accelerometer. Each inertial sensor in the ADIS16550 combines
industry leading MEMS only technology with signal conditioning that optimizes
dynamic performance. The factory calibration characterizes each sensor for
sensitivity, bias, and alignment. As a result, each sensor has its own dynamic
compensation formulas that provide accurate sensor measurements.

Nuno Sá (3):
  iio: imu: adis: Add custom ops struct
  iio: imu: adis: Add DIAG_STAT register size
  iio: imu: adis16550: add adis16550 support

Ramona Gradinariu (2):
  dt-bindings: iio: Add adis16550 bindings
  docs: iio: add documentation for adis16550 driver

 .../bindings/iio/imu/adi,adis16550.yaml       |   95 ++
 Documentation/iio/adis16550.rst               |  389 ++++++
 Documentation/iio/index.rst                   |    1 +
 MAINTAINERS                                   |   10 +
 drivers/iio/imu/Kconfig                       |   13 +
 drivers/iio/imu/Makefile                      |    1 +
 drivers/iio/imu/adis.c                        |   33 +-
 drivers/iio/imu/adis16550.c                   | 1228 +++++++++++++++++
 include/linux/iio/imu/adis.h                  |   33 +-
 9 files changed, 1788 insertions(+), 15 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/iio/imu/adi,adis16550.yaml
 create mode 100644 Documentation/iio/adis16550.rst
 create mode 100644 drivers/iio/imu/adis16550.c

-- 
2.34.1

[PATCH 3/5] dt-bindings: iio: Add adis16550 bindings

[Robert Budai]

From: Ramona Gradinariu <ramona.gradinariu@analog.com>

Document the ADIS16550 device devicetree bindings.

Co-developed-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Signed-off-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
---
 .../bindings/iio/imu/adi,adis16550.yaml       | 95 +++++++++++++++++++
 MAINTAINERS                                   |  9 ++
 2 files changed, 104 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/imu/adi,adis16550.yaml

diff --git a/Documentation/devicetree/bindings/iio/imu/adi,adis16550.yaml b/Documentation/devicetree/bindings/iio/imu/adi,adis16550.yaml
new file mode 100644
index 000000000000..a4690b39f0bd
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/imu/adi,adis16550.yaml
@@ -0,0 +1,95 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/imu/adi,adis16550.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices ADIS16550 and similar IMUs
+
+maintainers:
+  - Nuno Sa <nuno.sa@analog.com>
+  - Ramona Gradinariu <ramona.gradinariu@analog.com>
+  - Antoniu Miclaus <antoniu.miclaus@analog.com>
+
+properties:
+  compatible:
+    enum:
+      - adi,adis16550
+      - adi,adis16550w
+
+  reg:
+    maxItems: 1
+
+  spi-cpha: true
+
+  spi-cpol: true
+
+  spi-max-frequency:
+    maximum: 15000000
+
+  vdd-supply: true
+
+  interrupts:
+    maxItems: 1
+
+  reset-gpios:
+    description:
+      Must be the device tree identifier of the RESET pin. If specified,
+      it will be asserted during driver probe. As the line is active low,
+      it should be marked GPIO_ACTIVE_LOW.
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+    description: If not provided, then the internal clock is used.
+
+  adi,sync-mode:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: |
+      Configures the device SYNC pin.
+    enum:
+      - direct_sync
+      - scaled_sync
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - spi-cpha
+  - spi-cpol
+  - spi-max-frequency
+  - vdd-supply
+
+allOf:
+  - if:
+      properties:
+        adi,sync-mode:
+          enum: [direct_sync, scaled_sync]
+
+    then:
+      dependencies:
+        adi,sync-mode: [ clocks ]
+
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        imu@0 {
+            compatible = "adi,adis16550";
+            reg = <0>;
+            spi-max-frequency = <15000000>;
+            spi-cpol;
+            spi-cpha;
+            vdd-supply = <&vdd>;
+            interrupts = <4 IRQ_TYPE_EDGE_FALLING>;
+            interrupt-parent = <&gpio>;
+        };
+    };
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index a27407950242..4f45478d271a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1411,6 +1411,15 @@ W:	https://ez.analog.com/linux-software-drivers
 F:	Documentation/devicetree/bindings/iio/imu/adi,adis16475.yaml
 F:	drivers/iio/imu/adis16475.c
 
+ANALOG DEVICES INC ADIS16550 DRIVER
+M:	Nuno Sa <nuno.sa@analog.com>
+M:	Ramona Gradinariu <ramona.gradinariu@analog.com>
+M:	Antoniu Miclaus <antoniu.miclaus@analog.com>
+L:	linux-iio@vger.kernel.org
+S:	Supported
+W:	https://ez.analog.com/linux-software-drivers
+F:	Documentation/devicetree/bindings/iio/imu/adi,adis16550.yaml
+
 ANALOG DEVICES INC ADM1177 DRIVER
 M:	Michael Hennerich <Michael.Hennerich@analog.com>
 L:	linux-hwmon@vger.kernel.org
-- 
2.34.1

Re: [PATCH 3/5] dt-bindings: iio: Add adis16550 bindings

[Jonathan Cameron]

On Mon, 28 Oct 2024 14:35:43 +0200
Robert Budai <robert.budai@analog.com> wrote:

> From: Ramona Gradinariu <ramona.gradinariu@analog.com>
> 
> Document the ADIS16550 device devicetree bindings.
What is the difference between the 16550 and 16550w.
Need to give an indication here of why the need separate compatibles.
 
> Co-developed-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> Signed-off-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
> ---
>  .../bindings/iio/imu/adi,adis16550.yaml       | 95 +++++++++++++++++++
>  MAINTAINERS                                   |  9 ++
>  2 files changed, 104 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/imu/adi,adis16550.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/imu/adi,adis16550.yaml b/Documentation/devicetree/bindings/iio/imu/adi,adis16550.yaml
> new file mode 100644
> index 000000000000..a4690b39f0bd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/imu/adi,adis16550.yaml
> @@ -0,0 +1,95 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/imu/adi,adis16550.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices ADIS16550 and similar IMUs
> +
> +maintainers:
> +  - Nuno Sa <nuno.sa@analog.com>
> +  - Ramona Gradinariu <ramona.gradinariu@analog.com>
> +  - Antoniu Miclaus <antoniu.miclaus@analog.com>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - adi,adis16550
> +      - adi,adis16550w
> +
> +  reg:
> +    maxItems: 1
> +
> +  spi-cpha: true
> +
> +  spi-cpol: true
> +
> +  spi-max-frequency:
> +    maximum: 15000000
> +
> +  vdd-supply: true
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  reset-gpios:
> +    description:
> +      Must be the device tree identifier of the RESET pin. If specified,
> +      it will be asserted during driver probe. As the line is active low,
> +      it should be marked GPIO_ACTIVE_LOW.
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +    description: If not provided, then the internal clock is used.
> +
> +  adi,sync-mode:
> +    $ref: /schemas/types.yaml#/definitions/string
> +    description: |
> +      Configures the device SYNC pin.
> +    enum:
> +      - direct_sync
> +      - scaled_sync
More detail needed on this. I'm not sure why it belongs in DT and
can't be controlled based on clock input and requested sampling
frequency.  

> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - spi-cpha
> +  - spi-cpol
> +  - spi-max-frequency
> +  - vdd-supply
> +
> +allOf:
> +  - if:
> +      properties:
> +        adi,sync-mode:
> +          enum: [direct_sync, scaled_sync]
> +
> +    then:
> +      dependencies:
> +        adi,sync-mode: [ clocks ]
> +
> +  - $ref: /schemas/spi/spi-peripheral-props.yaml#
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +    spi {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        imu@0 {
> +            compatible = "adi,adis16550";
> +            reg = <0>;
> +            spi-max-frequency = <15000000>;
> +            spi-cpol;
> +            spi-cpha;
> +            vdd-supply = <&vdd>;
> +            interrupts = <4 IRQ_TYPE_EDGE_FALLING>;
> +            interrupt-parent = <&gpio>;
> +        };
> +    };
> +...
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a27407950242..4f45478d271a 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1411,6 +1411,15 @@ W:	https://ez.analog.com/linux-software-drivers
>  F:	Documentation/devicetree/bindings/iio/imu/adi,adis16475.yaml
>  F:	drivers/iio/imu/adis16475.c
>  
> +ANALOG DEVICES INC ADIS16550 DRIVER
> +M:	Nuno Sa <nuno.sa@analog.com>
> +M:	Ramona Gradinariu <ramona.gradinariu@analog.com>
> +M:	Antoniu Miclaus <antoniu.miclaus@analog.com>
> +L:	linux-iio@vger.kernel.org
> +S:	Supported
> +W:	https://ez.analog.com/linux-software-drivers
> +F:	Documentation/devicetree/bindings/iio/imu/adi,adis16550.yaml
> +
>  ANALOG DEVICES INC ADM1177 DRIVER
>  M:	Michael Hennerich <Michael.Hennerich@analog.com>
>  L:	linux-hwmon@vger.kernel.org

Re: [PATCH 3/5] dt-bindings: iio: Add adis16550 bindings

[Krzysztof Kozlowski]

On Mon, Oct 28, 2024 at 05:11:46PM +0000, Jonathan Cameron wrote:
> On Mon, 28 Oct 2024 14:35:43 +0200
> Robert Budai <robert.budai@analog.com> wrote:
> 
> > From: Ramona Gradinariu <ramona.gradinariu@analog.com>
> > 
> > Document the ADIS16550 device devicetree bindings.
> What is the difference between the 16550 and 16550w.
> Need to give an indication here of why the need separate compatibles.

There were no answers and it's almost two weeks. I am marking the patch
in DT patchwork as changes requested (which means it will disappear from
our view).

Best regards,
Krzysztof

[PATCH 4/5] iio: imu: adis16550: add adis16550 support

[Robert Budai]

From: Nuno Sá <nuno.sa@analog.com>

The ADIS16550 is a complete inertial system that includes a triaxis
gyroscope and a triaxis accelerometer. Each inertial sensor in
the ADIS16550 combines industry leading MEMS only technology
with signal conditioning that optimizes dynamic performance. The
factory calibration characterizes each sensor for sensitivity, bias,
and alignment. As a result, each sensor has its own dynamic com-
pensation formulas that provide accurate sensor measurements

Co-developed-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
Signed-off-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
Co-developed-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Co-developed-by: Robert Budai <robert.budai@analog.com>
Signed-off-by: Robert Budai <robert.budai@analog.com>
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
 MAINTAINERS                 |    1 +
 drivers/iio/imu/Kconfig     |   13 +
 drivers/iio/imu/Makefile    |    1 +
 drivers/iio/imu/adis16550.c | 1228 +++++++++++++++++++++++++++++++++++
 4 files changed, 1243 insertions(+)
 create mode 100644 drivers/iio/imu/adis16550.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 4f45478d271a..26ca239d8ce6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1419,6 +1419,7 @@ L:	linux-iio@vger.kernel.org
 S:	Supported
 W:	https://ez.analog.com/linux-software-drivers
 F:	Documentation/devicetree/bindings/iio/imu/adi,adis16550.yaml
+F:	drivers/iio/imu/adis16550.c
 
 ANALOG DEVICES INC ADM1177 DRIVER
 M:	Michael Hennerich <Michael.Hennerich@analog.com>
diff --git a/drivers/iio/imu/Kconfig b/drivers/iio/imu/Kconfig
index 782fb80e44c2..1b80f7e488c4 100644
--- a/drivers/iio/imu/Kconfig
+++ b/drivers/iio/imu/Kconfig
@@ -52,6 +52,19 @@ config ADIS16480
 	  Say yes here to build support for Analog Devices ADIS16375, ADIS16480,
 	  ADIS16485, ADIS16488 inertial sensors.
 
+config ADIS16550
+	tristate "Analog Devices ADIS16550 and similar IMU driver"
+	depends on SPI
+	select IIO_ADIS_LIB
+	select IIO_ADIS_LIB_BUFFER if IIO_BUFFER
+	select CRC32
+	help
+	  Say yes here to build support for Analog Devices ADIS16550 inertial
+	  sensor.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called adis16550.
+
 source "drivers/iio/imu/bmi160/Kconfig"
 source "drivers/iio/imu/bmi323/Kconfig"
 source "drivers/iio/imu/bno055/Kconfig"
diff --git a/drivers/iio/imu/Makefile b/drivers/iio/imu/Makefile
index 7e2d7d5c3b7b..006fa5b71d12 100644
--- a/drivers/iio/imu/Makefile
+++ b/drivers/iio/imu/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_ADIS16400) += adis16400.o
 obj-$(CONFIG_ADIS16460) += adis16460.o
 obj-$(CONFIG_ADIS16475) += adis16475.o
 obj-$(CONFIG_ADIS16480) += adis16480.o
+obj-$(CONFIG_ADIS16550) += adis16550.o
 
 adis_lib-y += adis.o
 adis_lib-$(CONFIG_IIO_ADIS_LIB_BUFFER) += adis_trigger.o
diff --git a/drivers/iio/imu/adis16550.c b/drivers/iio/imu/adis16550.c
new file mode 100644
index 000000000000..204d72c9f442
--- /dev/null
+++ b/drivers/iio/imu/adis16550.c
@@ -0,0 +1,1228 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ADIS16550 IMU driver
+ *
+ * Copyright 2024 Analog Devices Inc.
+ */
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/crc32.h>
+#include <linux/debugfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/imu/adis.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/lcm.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+#include <linux/swab.h>
+
+#include <asm/unaligned.h>
+
+#define ADIS16550_REG_BURST_GYRO_ACCEL		0x0a
+#define ADIS16550_REG_BURST_DELTA_ANG_VEL	0x0b
+#define ADIS16550_BURST_DATA_GYRO_ACCEL_MASK	GENMASK(5, 0)
+#define ADIS16550_BURST_DATA_DELTA_ANG_VEL_MASK	GENMASK(12, 7)
+
+#define ADIS16550_REG_STATUS		0x0e
+#define ADIS16550_REG_TEMP		0x10
+#define ADIS16550_REG_X_GYRO		0x12
+#define ADIS16550_REG_Y_GYRO		0x14
+#define ADIS16550_REG_Z_GYRO		0x16
+#define ADIS16550_REG_X_ACCEL		0x18
+#define ADIS16550_REG_Y_ACCEL		0x1a
+#define ADIS16550_REG_Z_ACCEL		0x1c
+#define ADIS16550_REG_X_DELTANG_L	0x1E
+#define ADIS16550_REG_Y_DELTANG_L	0x20
+#define ADIS16550_REG_Z_DELTANG_L	0x22
+#define ADIS16550_REG_X_DELTVEL_L	0x24
+#define ADIS16550_REG_Y_DELTVEL_L	0x26
+#define ADIS16550_REG_Z_DELTVEL_L	0x28
+#define ADIS16550_REG_X_GYRO_SCALE	0x30
+#define ADIS16550_REG_Y_GYRO_SCALE	0x32
+#define ADIS16550_REG_Z_GYRO_SCALE	0x34
+#define ADIS16550_REG_X_ACCEL_SCALE	0x36
+#define ADIS16550_REG_Y_ACCEL_SCALE	0x38
+#define ADIS16550_REG_Z_ACCEL_SCALE	0x3a
+#define ADIS16550_REG_X_GYRO_BIAS	0x40
+#define ADIS16550_REG_Y_GYRO_BIAS	0x42
+#define ADIS16550_REG_Z_GYRO_BIAS	0x44
+#define ADIS16550_REG_X_ACCEL_BIAS	0x46
+#define ADIS16550_REG_Y_ACCEL_BIAS	0x48
+#define ADIS16550_REG_Z_ACCEL_BIAS	0x4a
+#define ADIS16550_REG_COMMAND		0x50
+#define ADIS16550_REG_CONFIG		0x52
+#define ADIS16550_GYRO_FIR_EN_MASK	BIT(3)
+#define ADIS16550_ACCL_FIR_EN_MASK	BIT(2)
+#define ADIS16550_SYNC_MASK	\
+			(ADIS16550_SYNC_EN_MASK | ADIS16550_SYNC_MODE_MASK)
+#define ADIS16550_SYNC_MODE_MASK	BIT(1)
+#define ADIS16550_SYNC_EN_MASK		BIT(0)
+/* max of 4000 SPS in scale sync */
+#define ADIS16550_SYNC_SCALE_MAX_RATE	(4000 * 1000)
+#define ADIS16550_REG_DEC_RATE		0x54
+#define ADIS16550_REG_SYNC_SCALE	0x56
+#define ADIS16550_REG_SERIAL_NUM	0x76
+#define ADIS16550_REG_FW_REV		0x7A
+#define ADIS16550_REG_FW_DATE		0x7C
+#define ADIS16550_REG_PROD_ID		0x7E
+#define ADIS16550_REG_FLASH_CNT		0x72
+/* spi protocol*/
+#define ADIS16550_SPI_DATA_MASK		GENMASK(31, 16)
+#define ADIS16550_SPI_REG_MASK		GENMASK(14, 8)
+#define ADIS16550_SPI_R_W_MASK		BIT(7)
+#define ADIS16550_SPI_CRC_MASK		GENMASK(3, 0)
+#define ADIS16550_SPI_SV_MASK		GENMASK(7, 6)
+/* burst read */
+#define ADIS16550_BURST_N_ELEM		12
+#define ADIS16550_BURST_DATA_LEN	(ADIS16550_BURST_N_ELEM * 4)
+#define ADIS16550_MAX_SCAN_DATA		12
+
+struct adis16550_sync {
+	u16 sync_mode;
+	u16 min_rate;
+	u16 max_rate;
+};
+
+struct adis16550_chip_info {
+	const struct iio_chan_spec *channels;
+	const struct adis16550_sync *sync_mode;
+	char *name;
+	u32 num_channels;
+	u32 gyro_max_val;
+	u32 gyro_max_scale;
+	u32 accel_max_val;
+	u32 accel_max_scale;
+	u32 temp_scale;
+	u32 deltang_max_val;
+	u32 deltvel_max_val;
+	u32 int_clk;
+	u16 max_dec;
+	u16 num_sync;
+};
+
+struct adis16550 {
+	const struct adis16550_chip_info *info;
+	struct adis adis;
+	unsigned long clk_freq;
+	u32 sync_mode;
+};
+
+enum {
+	ADIS16550_SV_INIT,
+	ADIS16550_SV_OK,
+	ADIS16550_SV_NOK,
+	ADIS16550_SV_SPI_ERROR,
+};
+
+/*
+ * This is a simplified implementation of lib/crc4.c. It could not be used
+ * directly since the polynomial used is different from the one used by the
+ * 16550 which is 0b10001
+ */
+static u8 spi_crc4(const u32 val)
+{
+	int i;
+	const int bits = 28;
+	u8 crc = 0xa;
+	/* ignore 4lsb */
+	const u32 __val = val >> 4;
+
+	/* Calculate crc4 over four-bit nibbles, starting at the MSbit */
+	for (i = bits - 4; i >= 0; i -= 4)
+		crc = crc ^ ((__val >> i) & 0xf);
+
+	return crc;
+}
+
+static int adis16550_spi_validate(const struct adis *adis, __be32 dout,
+				  u16 *data)
+{
+	u32 __dout;
+	u8 crc, crc_rcv, sv;
+
+	__dout = be32_to_cpu(dout);
+
+	/* validate received message */
+	crc_rcv = FIELD_GET(ADIS16550_SPI_CRC_MASK, __dout);
+	crc = spi_crc4(__dout);
+	if (crc_rcv != crc) {
+		dev_err(&adis->spi->dev,
+			"Invalid crc, rcv: 0x%02x, calc: 0x%02x!\n",
+			crc_rcv, crc);
+		return -EIO;
+	}
+	sv = FIELD_GET(ADIS16550_SPI_SV_MASK, __dout);
+	if (sv >= ADIS16550_SV_NOK) {
+		dev_err(&adis->spi->dev,
+			"State vector error detected: %02X", sv);
+		return -EIO;
+	}
+	*data = FIELD_GET(ADIS16550_SPI_DATA_MASK, __dout);
+
+	return 0;
+}
+
+static void adis16550_spi_msg_prepare(const u32 reg, const bool write,
+				      const u16 data, __be32 *din)
+{
+	u8 crc;
+	u32 __din;
+
+	__din = FIELD_PREP(ADIS16550_SPI_REG_MASK, reg);
+
+	if (write) {
+		__din |= FIELD_PREP(ADIS16550_SPI_R_W_MASK, true);
+		__din |= FIELD_PREP(ADIS16550_SPI_DATA_MASK, data);
+	}
+
+	crc = spi_crc4(__din);
+	__din |= FIELD_PREP(ADIS16550_SPI_CRC_MASK, crc);
+
+	*din = cpu_to_be32(__din);
+}
+
+static int adis16550_spi_xfer(const struct adis *adis, u32 reg, u32 len,
+			      u32 *readval, u32 writeval)
+{
+	struct spi_device *spi = adis->spi;
+	__be32 __din[2], __dout[2];
+	u16 data = 0;
+	int ret;
+	bool wr = readval ? false : true;
+	struct spi_message msg;
+	struct spi_transfer xfers[] = {
+		{
+			.tx_buf = &__din[0],
+			.len = 4,
+			.cs_change = 1,
+		}, {
+			.tx_buf = &__din[1],
+			.len = 4,
+			.cs_change = 1,
+			.rx_buf = __dout,
+		}, {
+			.tx_buf = &__din[1],
+			.rx_buf = &__dout[1],
+			.len = 4,
+		},
+	};
+
+	spi_message_init(&msg);
+
+	switch (len) {
+	case 4:
+		adis16550_spi_msg_prepare(reg + 1, wr, writeval >> 16,
+					  &__din[0]);
+		spi_message_add_tail(&xfers[0], &msg);
+		fallthrough;
+	case 2:
+		adis16550_spi_msg_prepare(reg, wr, writeval, &__din[1]);
+		spi_message_add_tail(&xfers[1], &msg);
+		spi_message_add_tail(&xfers[2], &msg);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = spi_sync(spi, &msg);
+	if (ret) {
+		dev_err(&spi->dev, "Spi failure %d\n", ret);
+		return ret;
+	}
+	/*
+	 * When writing a register, the device will reply with a readback on the
+	 * transfer so that we can validate if our data was actually written..
+	 */
+	switch (len) {
+	case 4:
+		ret = adis16550_spi_validate(adis, __dout[0], &data);
+		if (ret)
+			return ret;
+
+		if (readval) {
+			*readval = data << 16;
+		} else if ((writeval >> 16) != data && reg != ADIS16550_REG_COMMAND) {
+			dev_err(&spi->dev,
+				"Data not written: wr: 0x%04X, rcv: 0x%04X\n",
+				writeval >> 16, data);
+			return -EIO;
+		}
+
+		fallthrough;
+	case 2:
+		ret = adis16550_spi_validate(adis, __dout[1], &data);
+		if (ret)
+			return ret;
+
+		if (readval) {
+			*readval = (*readval & GENMASK(31, 16)) | data;
+		} else if ((writeval & GENMASK(15, 0)) != data && reg != ADIS16550_REG_COMMAND) {
+			dev_err(&spi->dev,
+				"Data not written: wr: 0x%04X, rcv: 0x%04X\n",
+				(u16)writeval, data);
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+static int adis16550_spi_read(struct adis *adis, const u32 reg,
+			      u32 *value, const u32 len)
+{
+	return adis16550_spi_xfer(adis, reg, len, value, 0);
+}
+
+static int adis16550_spi_write(struct adis *adis, const u32 reg,
+			       const u32 value, const u32 len)
+{
+	return adis16550_spi_xfer(adis, reg, len, NULL, value);
+}
+
+static ssize_t adis16550_show_firmware_revision(struct file *file,
+						char __user *userbuf,
+						size_t count, loff_t *ppos)
+{
+	struct adis16550 *st = file->private_data;
+	char buf[7];
+	size_t len;
+	u16 rev;
+	int ret;
+
+	ret = adis_read_reg_16(&st->adis, ADIS16550_REG_FW_REV, &rev);
+	if (ret)
+		return ret;
+
+	len = scnprintf(buf, sizeof(buf), "%x.%x\n", rev >> 8, rev & 0xff);
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
+}
+
+static const struct file_operations adis16550_firmware_revision_fops = {
+	.open = simple_open,
+	.read = adis16550_show_firmware_revision,
+	.llseek = default_llseek,
+	.owner = THIS_MODULE,
+};
+
+static ssize_t adis16550_show_firmware_date(struct file *file,
+					    char __user *userbuf,
+					    size_t count, loff_t *ppos)
+{
+	struct adis16550 *st = file->private_data;
+	u32 date;
+	char buf[12];
+	size_t len;
+	int ret;
+
+	ret = adis_read_reg_32(&st->adis, ADIS16550_REG_FW_DATE, &date);
+	if (ret)
+		return ret;
+
+	len = snprintf(buf, sizeof(buf), "%.2x-%.2x-%.4x\n", date & 0xff,
+		       (date >> 8) & 0xff, date >> 16);
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
+}
+
+static const struct file_operations adis16550_firmware_date_fops = {
+	.open = simple_open,
+	.read = adis16550_show_firmware_date,
+	.llseek = default_llseek,
+	.owner = THIS_MODULE,
+};
+
+static int adis16550_show_serial_number(void *arg, u64 *val)
+{
+	struct adis16550 *st = arg;
+	u32 serial;
+	int ret;
+
+	ret = adis_read_reg_32(&st->adis, ADIS16550_REG_SERIAL_NUM, &serial);
+	if (ret)
+		return ret;
+
+	*val = serial;
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(adis16550_serial_number_fops,
+			 adis16550_show_serial_number, NULL, "0x%.8llx\n");
+
+static int adis16550_show_product_id(void *arg, u64 *val)
+{
+	struct adis16550 *st = arg;
+	u16 prod_id;
+	int ret;
+
+	ret = adis_read_reg_16(&st->adis, ADIS16550_REG_PROD_ID, &prod_id);
+	if (ret)
+		return ret;
+
+	*val = prod_id;
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(adis16550_product_id_fops,
+			 adis16550_show_product_id, NULL, "%llu\n");
+
+static int adis16550_show_flash_count(void *arg, u64 *val)
+{
+	struct adis16550 *st = arg;
+	u16 flash_count;
+	int ret;
+
+	ret = adis_read_reg_16(&st->adis, ADIS16550_REG_FLASH_CNT, &flash_count);
+	if (ret)
+		return ret;
+
+	*val = flash_count;
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(adis16550_flash_count_fops,
+			 adis16550_show_flash_count, NULL, "%lld\n");
+
+static void adis16550_debugfs_init(struct iio_dev *indio_dev)
+{
+	struct adis16550 *st = iio_priv(indio_dev);
+	struct dentry *d = iio_get_debugfs_dentry(indio_dev);
+
+	if (!IS_ENABLED(CONFIG_DEBUG_FS))
+		return;
+
+	debugfs_create_file_unsafe("serial_number", 0400,
+				   d, st, &adis16550_serial_number_fops);
+	debugfs_create_file_unsafe("product_id", 0400,
+				   d, st, &adis16550_product_id_fops);
+	debugfs_create_file("firmware_revision", 0400,
+			    d, st, &adis16550_firmware_revision_fops);
+	debugfs_create_file("firmware_date", 0400, d,
+			    st, &adis16550_firmware_date_fops);
+	debugfs_create_file_unsafe("flash_count", 0400,
+				   d, st, &adis16550_flash_count_fops);
+}
+
+enum {
+	ADIS16550_SYNC_MODE_DIRECT,
+	ADIS16550_SYNC_MODE_SCALED,
+};
+
+static int adis16550_get_freq(struct adis16550 *st, u32 *freq)
+{
+	int ret;
+	u16 dec = 0;
+	u32 sample_rate = st->clk_freq;
+
+	adis_dev_lock(&st->adis);
+
+	if (st->sync_mode == ADIS16550_SYNC_MODE_SCALED) {
+		u16 sync_scale;
+
+		ret = __adis_read_reg_16(&st->adis, ADIS16550_REG_SYNC_SCALE, &sync_scale);
+		if (ret)
+			goto error;
+
+		sample_rate = st->clk_freq * sync_scale;
+	}
+
+	ret = __adis_read_reg_16(&st->adis, ADIS16550_REG_DEC_RATE, &dec);
+	if (ret)
+		return -EINVAL;
+
+	adis_dev_unlock(&st->adis);
+
+	*freq = DIV_ROUND_CLOSEST(sample_rate, dec + 1);
+
+	return 0;
+
+error:
+	adis_dev_unlock(&st->adis);
+
+	return ret;
+}
+
+static int adis16550_set_freq(struct adis16550 *st, u32 freq)
+{
+	u16 dec;
+	int ret;
+	u32 sample_rate = st->clk_freq;
+	/*
+	 * The optimal sample rate for the supported IMUs is between
+	 * int_clk - 1000 and int_clk + 500.
+	 */
+	u32 max_sample_rate =  st->info->int_clk * 1000 + 500000;
+	u32 min_sample_rate =  st->info->int_clk * 1000 - 1000000;
+
+	if (!freq)
+		return -EINVAL;
+
+	adis_dev_lock(&st->adis);
+
+	if (st->sync_mode == ADIS16550_SYNC_MODE_SCALED) {
+		unsigned long scaled_rate = lcm(st->clk_freq, freq);
+		int sync_scale;
+
+		if (scaled_rate > max_sample_rate)
+			scaled_rate = max_sample_rate / st->clk_freq * st->clk_freq;
+		else
+			scaled_rate = max_sample_rate / scaled_rate * scaled_rate;
+
+		if (scaled_rate < min_sample_rate)
+			scaled_rate = roundup(min_sample_rate, st->clk_freq);
+
+		sync_scale = scaled_rate / st->clk_freq;
+		ret = __adis_write_reg_16(&st->adis, ADIS16550_REG_SYNC_SCALE,
+					  sync_scale);
+		if (ret)
+			goto error;
+
+		sample_rate = scaled_rate;
+	}
+
+	dec = DIV_ROUND_CLOSEST(sample_rate, freq);
+
+	if (dec)
+		dec--;
+
+	if (dec > st->info->max_dec)
+		dec = st->info->max_dec;
+
+	ret = __adis_write_reg_16(&st->adis, ADIS16550_REG_DEC_RATE, dec);
+	if (ret)
+		goto error;
+
+	adis_dev_unlock(&st->adis);
+
+	return 0;
+
+error:
+	adis_dev_unlock(&st->adis);
+	return ret;
+}
+
+static int adis16550_get_accl_filter_freq(struct adis16550 *st, int *freq)
+{
+	int ret;
+	u16 config = 0;
+
+	ret = adis_read_reg_16(&st->adis, ADIS16550_REG_CONFIG, &config);
+	if (ret)
+		return -EINVAL;
+
+	if (FIELD_GET(ADIS16550_ACCL_FIR_EN_MASK, config))
+		*freq = 100;
+	else
+		*freq = 0;
+
+	return 0;
+}
+
+static int adis16550_set_accl_filter_freq(struct adis16550 *st, int freq)
+{
+	bool en = false;
+
+	if (freq)
+		en = true;
+
+	return __adis_update_bits(&st->adis, ADIS16550_REG_CONFIG,
+				  ADIS16550_ACCL_FIR_EN_MASK,
+				  (u32)FIELD_PREP(ADIS16550_ACCL_FIR_EN_MASK, en));
+}
+
+static int adis16550_get_gyro_filter_freq(struct adis16550 *st, int *freq)
+{
+	int ret;
+	u16 config = 0;
+
+	ret = adis_read_reg_16(&st->adis, ADIS16550_REG_CONFIG, &config);
+	if (ret)
+		return -EINVAL;
+
+	if (FIELD_GET(ADIS16550_GYRO_FIR_EN_MASK, config))
+		*freq = 100;
+	else
+		*freq = 0;
+
+	return 0;
+}
+
+static int adis16550_set_gyro_filter_freq(struct adis16550 *st, int freq)
+{
+	bool en = false;
+
+	if (freq)
+		en = true;
+
+	return __adis_update_bits(&st->adis, ADIS16550_REG_CONFIG,
+				  ADIS16550_GYRO_FIR_EN_MASK,
+				  (u32)FIELD_PREP(ADIS16550_GYRO_FIR_EN_MASK, en));
+}
+
+enum adis16550_variants {
+	ADIS16550,
+	ADIS16550W
+};
+
+enum {
+	ADIS16550_SCAN_GYRO_X,
+	ADIS16550_SCAN_GYRO_Y,
+	ADIS16550_SCAN_GYRO_Z,
+	ADIS16550_SCAN_ACCEL_X,
+	ADIS16550_SCAN_ACCEL_Y,
+	ADIS16550_SCAN_ACCEL_Z,
+	ADIS16550_SCAN_TEMP,
+	ADIS16550_SCAN_DELTANG_X,
+	ADIS16550_SCAN_DELTANG_Y,
+	ADIS16550_SCAN_DELTANG_Z,
+	ADIS16550_SCAN_DELTVEL_X,
+	ADIS16550_SCAN_DELTVEL_Y,
+	ADIS16550_SCAN_DELTVEL_Z,
+};
+
+static const u32 adis16550_calib_bias[] = {
+	[ADIS16550_SCAN_GYRO_X] = ADIS16550_REG_X_GYRO_BIAS,
+	[ADIS16550_SCAN_GYRO_Y] = ADIS16550_REG_Y_GYRO_BIAS,
+	[ADIS16550_SCAN_GYRO_Z] = ADIS16550_REG_Z_GYRO_BIAS,
+	[ADIS16550_SCAN_ACCEL_X] = ADIS16550_REG_X_ACCEL_BIAS,
+	[ADIS16550_SCAN_ACCEL_Y] = ADIS16550_REG_Y_ACCEL_BIAS,
+	[ADIS16550_SCAN_ACCEL_Z] = ADIS16550_REG_Z_ACCEL_BIAS,
+
+};
+
+static const u32 adis16550_calib_scale[] = {
+	[ADIS16550_SCAN_GYRO_X] = ADIS16550_REG_X_GYRO_SCALE,
+	[ADIS16550_SCAN_GYRO_Y] = ADIS16550_REG_Y_GYRO_SCALE,
+	[ADIS16550_SCAN_GYRO_Z] = ADIS16550_REG_Z_GYRO_SCALE,
+	[ADIS16550_SCAN_ACCEL_X] = ADIS16550_REG_X_ACCEL_SCALE,
+	[ADIS16550_SCAN_ACCEL_Y] = ADIS16550_REG_Y_ACCEL_SCALE,
+	[ADIS16550_SCAN_ACCEL_Z] = ADIS16550_REG_Z_ACCEL_SCALE,
+};
+
+static int adis16550_read_raw(struct iio_dev *indio_dev,
+			      const struct iio_chan_spec *chan,
+			      int *val, int *val2, long info)
+{
+	struct adis16550 *st = iio_priv(indio_dev);
+	int ret;
+	const int idx = chan->scan_index;
+	u32 tmp;
+	u16 scale;
+
+	switch (info) {
+	case IIO_CHAN_INFO_RAW:
+		return adis_single_conversion(indio_dev, chan, 0, val);
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_ANGL_VEL:
+			*val = st->info->gyro_max_val;
+			*val2 = st->info->gyro_max_scale;
+			return IIO_VAL_FRACTIONAL;
+		case IIO_ACCEL:
+			*val = st->info->accel_max_val;
+			*val2 = st->info->accel_max_scale;
+			return IIO_VAL_FRACTIONAL;
+		case IIO_TEMP:
+			*val = st->info->temp_scale;
+			return IIO_VAL_INT;
+		case IIO_DELTA_ANGL:
+			*val = st->info->deltang_max_val;
+			*val2 = 31;
+			return IIO_VAL_FRACTIONAL_LOG2;
+		case IIO_DELTA_VELOCITY:
+			*val = st->info->deltvel_max_val;
+			*val2 = 31;
+			return IIO_VAL_FRACTIONAL_LOG2;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_OFFSET:
+		/* temperature centered at 25°C */
+		*val = DIV_ROUND_CLOSEST(25000, st->info->temp_scale);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		ret = adis_read_reg_32(&st->adis,
+				       adis16550_calib_bias[idx], val);
+		if (ret)
+			return ret;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		ret = adis_read_reg_16(&st->adis,
+				       adis16550_calib_scale[idx], &scale);
+		if (ret)
+			return ret;
+
+		*val = scale;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret = adis16550_get_freq(st, &tmp);
+		if (ret)
+			return ret;
+
+		*val = tmp / 1000;
+		*val2 = (tmp % 1000) * 1000;
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+		switch (chan->type) {
+		case IIO_ANGL_VEL:
+			ret = adis16550_get_accl_filter_freq(st, val);
+			if (ret)
+				return ret;
+			return IIO_VAL_INT;
+		case IIO_ACCEL:
+			ret = adis16550_get_gyro_filter_freq(st, val);
+			if (ret)
+				return ret;
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+}
+
+static int adis16550_write_raw(struct iio_dev *indio_dev,
+			       const struct iio_chan_spec *chan,
+			       int val, int val2, long info)
+{
+	struct adis16550 *st = iio_priv(indio_dev);
+	u32 tmp;
+	const int idx = chan->scan_index;
+
+	switch (info) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		tmp = val * 1000 + val2 / 1000;
+		return adis16550_set_freq(st, tmp);
+	case IIO_CHAN_INFO_CALIBBIAS:
+		return adis_write_reg_32(&st->adis, adis16550_calib_bias[idx],
+					 val);
+	case IIO_CHAN_INFO_CALIBSCALE:
+		return adis_write_reg_16(&st->adis, adis16550_calib_scale[idx],
+					 val);
+	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+		switch (chan->type) {
+		case IIO_ANGL_VEL:
+			return adis16550_set_accl_filter_freq(st, val);
+		case IIO_ACCEL:
+			return adis16550_set_gyro_filter_freq(st, val);
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+}
+
+#define ADIS16550_MOD_CHAN(_type, _mod, _address, _si, _r_bits, _s_bits) \
+	{ \
+		.type = (_type), \
+		.modified = 1, \
+		.channel2 = (_mod), \
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+			BIT(IIO_CHAN_INFO_CALIBBIAS) | \
+			BIT(IIO_CHAN_INFO_CALIBSCALE), \
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
+					    BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY), \
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+		.address = (_address), \
+		.scan_index = (_si), \
+		.scan_type = { \
+			.sign = 's', \
+			.realbits = (_r_bits), \
+			.storagebits = (_s_bits), \
+			.endianness = IIO_BE, \
+		}, \
+	}
+
+#define ADIS16550_GYRO_CHANNEL(_mod) \
+	ADIS16550_MOD_CHAN(IIO_ANGL_VEL, IIO_MOD_ ## _mod, \
+	ADIS16550_REG_ ## _mod ## _GYRO, ADIS16550_SCAN_GYRO_ ## _mod, 32, \
+	32)
+
+#define ADIS16550_ACCEL_CHANNEL(_mod) \
+	ADIS16550_MOD_CHAN(IIO_ACCEL, IIO_MOD_ ## _mod, \
+	ADIS16550_REG_ ## _mod ## _ACCEL, ADIS16550_SCAN_ACCEL_ ## _mod, 32, \
+	32)
+
+#define ADIS16550_TEMP_CHANNEL() { \
+		.type = IIO_TEMP, \
+		.indexed = 1, \
+		.channel = 0, \
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+			BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET), \
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+		.address = ADIS16550_REG_TEMP, \
+		.scan_index = ADIS16550_SCAN_TEMP, \
+		.scan_type = { \
+			.sign = 's', \
+			.realbits = 16, \
+			.storagebits = 32, \
+			.endianness = IIO_BE, \
+		}, \
+	}
+
+#define ADIS16550_MOD_CHAN_DELTA(_type, _mod, _address, _si, _r_bits, _s_bits) { \
+		.type = (_type), \
+		.modified = 1, \
+		.channel2 = (_mod), \
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+		.address = (_address), \
+		.scan_index = _si, \
+		.scan_type = { \
+			.sign = 's', \
+			.realbits = (_r_bits), \
+			.storagebits = (_s_bits), \
+			.endianness = IIO_BE, \
+		}, \
+	}
+
+#define ADIS16550_DELTANG_CHAN(_mod) \
+	ADIS16550_MOD_CHAN_DELTA(IIO_DELTA_ANGL, IIO_MOD_ ## _mod, \
+			   ADIS16550_REG_ ## _mod ## _DELTANG_L, ADIS16550_SCAN_DELTANG_ ## _mod, 32, 32)
+
+#define ADIS16550_DELTVEL_CHAN(_mod) \
+	ADIS16550_MOD_CHAN_DELTA(IIO_DELTA_VELOCITY, IIO_MOD_ ## _mod, \
+			   ADIS16550_REG_ ## _mod ## _DELTVEL_L, ADIS16550_SCAN_DELTVEL_ ## _mod, 32, 32)
+
+#define ADIS16550_DELTANG_CHAN_NO_SCAN(_mod) \
+	ADIS16550_MOD_CHAN_DELTA(IIO_DELTA_ANGL, IIO_MOD_ ## _mod, \
+			   ADIS16550_REG_ ## _mod ## _DELTANG_L, -1, 32, 32)
+
+#define ADIS16550_DELTVEL_CHAN_NO_SCAN(_mod) \
+	ADIS16550_MOD_CHAN_DELTA(IIO_DELTA_VELOCITY, IIO_MOD_ ## _mod, \
+			   ADIS16550_REG_ ## _mod ## _DELTVEL_L, -1, 32, 32)
+
+static const struct iio_chan_spec adis16550_channels[] = {
+	ADIS16550_GYRO_CHANNEL(X),
+	ADIS16550_GYRO_CHANNEL(Y),
+	ADIS16550_GYRO_CHANNEL(Z),
+	ADIS16550_ACCEL_CHANNEL(X),
+	ADIS16550_ACCEL_CHANNEL(Y),
+	ADIS16550_ACCEL_CHANNEL(Z),
+	ADIS16550_TEMP_CHANNEL(),
+	ADIS16550_DELTANG_CHAN(X),
+	ADIS16550_DELTANG_CHAN(Y),
+	ADIS16550_DELTANG_CHAN(Z),
+	ADIS16550_DELTVEL_CHAN(X),
+	ADIS16550_DELTVEL_CHAN(Y),
+	ADIS16550_DELTVEL_CHAN(Z),
+	IIO_CHAN_SOFT_TIMESTAMP(13),
+};
+
+static const struct adis16550_sync adis16550_sync_modes[] = {
+	{ ADIS16550_SYNC_MODE_DIRECT, 3000, 4500 },
+	{ ADIS16550_SYNC_MODE_SCALED, 1, 128 },
+};
+
+#define ADIS16550_CHIP_INFO(_name) \
+	{ \
+		.num_channels = ARRAY_SIZE(adis16550_channels), \
+		.channels = adis16550_channels, \
+		.name = # _name, \
+		.gyro_max_val = 1, \
+		.gyro_max_scale = IIO_RAD_TO_DEGREE(80 << 16), \
+		.accel_max_val = 1, \
+		.accel_max_scale = IIO_M_S_2_TO_G(102400000), \
+		.temp_scale = 4, \
+		.deltang_max_val = IIO_DEGREE_TO_RAD(720), \
+		.deltvel_max_val = 125, \
+		.int_clk = 4000, \
+		.max_dec = 4095, \
+		.sync_mode = adis16550_sync_modes, \
+		.num_sync = ARRAY_SIZE(adis16550_sync_modes), \
+	}
+
+static const struct adis16550_chip_info adis16550_chip_info[] = {
+	[ADIS16550] =
+		ADIS16550_CHIP_INFO(adis16550),
+	[ADIS16550W] =
+		ADIS16550_CHIP_INFO(adis16550w),
+};
+
+static u32 adis16550_validate_crc(const u32 *buf, const u8 n_elem,
+				  const u32 crc)
+{
+	u32 crc_calc;
+	u32 crc_buf[ADIS16550_BURST_N_ELEM - 2];
+	int j;
+	/*
+	 * The crc calculation of the data is done in little endian. Hence, we
+	 * always swap the 32bit elements making sure that the data LSB is
+	 * always on address 0...
+	 */
+	for (j = 0; j < n_elem; j++)
+		crc_buf[j] = swab32(buf[j]);
+
+	crc_calc = crc32(~0, crc_buf, n_elem * 4);
+	crc_calc ^= ~0;
+
+	return (crc_calc == crc);
+}
+
+static irqreturn_t adis16550_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct adis *adis = iio_device_get_drvdata(indio_dev);
+	struct adis16550 *st = iio_priv(indio_dev);
+	__be32 *buffer = adis->buffer, data[ADIS16550_MAX_SCAN_DATA];
+	u32 crc;
+	u16 dummy;
+	int ret, bit, i = 0;
+	u8 data_offset = 4;
+	u8 buff_offset = 0;
+	bool valid;
+
+	ret = spi_sync(adis->spi, &adis->msg);
+	if (ret)
+		goto done;
+	/*
+	 * Validate the header. The header is a normal spi reply with state
+	 * vector and crc4.
+	 */
+	ret = adis16550_spi_validate(&st->adis, buffer[0], &dummy);
+	if (ret)
+		goto done;
+
+	crc = be32_to_cpu(buffer[ADIS16550_BURST_N_ELEM - 1]);
+	/* the header is not included in the crc */
+	valid = adis16550_validate_crc((u32 *)&buffer[1],
+				       ADIS16550_BURST_N_ELEM - 2, crc);
+	if (!valid) {
+		dev_err(&adis->spi->dev, "Burst Invalid crc!\n");
+		goto done;
+	}
+
+	for_each_set_bit(bit, indio_dev->active_scan_mask,
+			 indio_dev->masklength) {
+		switch (bit) {
+		case ADIS16550_SCAN_TEMP:
+			data[i++] = buffer[data_offset - 1];
+			break;
+		case ADIS16550_SCAN_DELTANG_X ... ADIS16550_SCAN_DELTVEL_Z:
+			buff_offset = ADIS16550_SCAN_DELTANG_X;
+			fallthrough;
+		case ADIS16550_SCAN_GYRO_X ... ADIS16550_SCAN_ACCEL_Z:
+			data[i++] = buffer[bit + data_offset - buff_offset];
+			break;
+		}
+	}
+
+	iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
+done:
+	iio_trigger_notify_done(indio_dev->trig);
+	return IRQ_HANDLED;
+}
+
+static const unsigned long adis16550_channel_masks[] = {
+	ADIS16550_BURST_DATA_GYRO_ACCEL_MASK | BIT(ADIS16550_SCAN_TEMP) | BIT(13),
+	ADIS16550_BURST_DATA_DELTA_ANG_VEL_MASK | BIT(ADIS16550_SCAN_TEMP) | BIT(13),
+	0,
+};
+
+static int adis16550_update_scan_mode(struct iio_dev *indio_dev,
+				      const unsigned long *scan_mask)
+{
+	struct adis *adis = iio_device_get_drvdata(indio_dev);
+	u8 *tx;
+	u16 burst_length = ADIS16550_BURST_DATA_LEN;
+	u8 burst_cmd;
+
+	if (*scan_mask & ADIS16550_BURST_DATA_GYRO_ACCEL_MASK)
+		burst_cmd = ADIS16550_REG_BURST_GYRO_ACCEL;
+	else
+		burst_cmd = ADIS16550_REG_BURST_DELTA_ANG_VEL;
+
+	kfree(adis->xfer);
+	kfree(adis->buffer);
+
+	adis->xfer = kcalloc(2, sizeof(*adis->xfer), GFP_KERNEL);
+	if (!adis->xfer)
+		return -ENOMEM;
+
+	adis->buffer = kzalloc(burst_length + sizeof(u32), GFP_KERNEL);
+	if (!adis->buffer) {
+		kfree(adis->xfer);
+		adis->xfer = NULL;
+		return -ENOMEM;
+	}
+
+	tx = adis->buffer + burst_length;
+	tx[0] = 0x00;
+	tx[1] = 0x00;
+	tx[2] = burst_cmd;
+	/* crc4 is 0 on burst command */
+	tx[3] = spi_crc4(get_unaligned_le32(tx));
+
+	adis->xfer[0].tx_buf = tx;
+	adis->xfer[0].len = 4;
+	adis->xfer[0].cs_change = 1;
+	adis->xfer[0].delay.value = 8;
+	adis->xfer[0].delay.unit = SPI_DELAY_UNIT_USECS;
+	adis->xfer[1].rx_buf = adis->buffer;
+	adis->xfer[1].len = burst_length;
+
+	spi_message_init_with_transfers(&adis->msg, adis->xfer, 2);
+
+	return 0;
+}
+
+static int adis16550_reset(struct adis *adis)
+{
+	return __adis_write_reg_16(adis, ADIS16550_REG_COMMAND, BIT(15));
+}
+
+static int adis16550_config_sync(struct adis16550 *st)
+{
+	int ret;
+	const struct adis16550_sync *sync;
+	struct device *dev = &st->adis.spi->dev;
+	u32 sync_mode;
+	struct clk *clk;
+	u16 mode;
+
+	if (!device_property_present(dev, "adi,sync-mode")) {
+		st->clk_freq = st->info->int_clk * 1000;
+		return 0;
+	}
+
+	if (!device_property_match_string(dev, "adi,sync-mode", "direct_sync"))
+		sync_mode = 0;
+	else if (!device_property_match_string(dev, "adi,sync-mode", "scaled_sync"))
+		sync_mode = 1;
+	else
+		return -EINVAL;
+
+	sync = &st->info->sync_mode[sync_mode];
+	st->sync_mode = sync->sync_mode;
+
+	clk = devm_clk_get_enabled(dev, NULL);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	st->clk_freq = clk_get_rate(clk);
+	if (st->clk_freq > sync->max_rate || st->clk_freq < sync->min_rate)
+		return dev_err_probe(dev, -EINVAL,
+				     "Clk rate: %lu not in a valid range:[%u %u]\n",
+				     st->clk_freq, sync->min_rate, sync->max_rate);
+
+	if (sync->sync_mode == ADIS16550_SYNC_MODE_SCALED) {
+		u16 sync_scale;
+		u32 scaled_freq = 0;
+		/*
+		 * In pps scaled sync we must scale the input clock to a range
+		 * of [3000 45000].
+		 */
+		ret = device_property_read_u32(dev, "adi,scaled-output-hz",
+					       &scaled_freq);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "adi,scaled-output-hz property not found");
+
+		if (scaled_freq < 3000 || scaled_freq > 4500)
+			return dev_err_probe(dev, -EINVAL,
+					     "Invalid value:%u for adi,scaled-output-hz",
+					     scaled_freq);
+
+		sync_scale = DIV_ROUND_CLOSEST(scaled_freq, st->clk_freq);
+
+		ret = adis_write_reg_16(&st->adis, ADIS16550_REG_SYNC_SCALE,
+					sync_scale);
+		if (ret)
+			return ret;
+
+		st->clk_freq = scaled_freq;
+	}
+
+	st->clk_freq *= 1000;
+
+	/* set sync mode */
+	mode = FIELD_PREP(ADIS16550_SYNC_MODE_MASK, sync->sync_mode);
+	mode |= FIELD_PREP(ADIS16550_SYNC_EN_MASK, true);
+
+	return __adis_update_bits(&st->adis, ADIS16550_REG_CONFIG,
+				  ADIS16550_SYNC_MASK, mode);
+}
+
+static const struct iio_info adis16550_info = {
+	.read_raw = &adis16550_read_raw,
+	.write_raw = &adis16550_write_raw,
+	.update_scan_mode = adis16550_update_scan_mode,
+	.debugfs_reg_access = adis_debugfs_reg_access,
+};
+
+enum {
+	ADIS16550_STATUS_CRC_CODE,
+	ADIS16550_STATUS_CRC_CONFIG,
+	ADIS16550_STATUS_FLASH_UPDATE,
+	ADIS16550_STATUS_INERIAL,
+	ADIS16550_STATUS_SENSOR,
+	ADIS16550_STATUS_TEMPERATURE,
+	ADIS16550_STATUS_SPI,
+	ADIS16550_STATUS_PROCESSING,
+	ADIS16550_STATUS_POWER,
+	ADIS16550_STATUS_BOOT,
+	ADIS16550_STATUS_WATCHDOG = 15,
+	ADIS16550_STATUS_REGULATOR = 28,
+	ADIS16550_STATUS_SENSOR_SUPPLY,
+	ADIS16550_STATUS_CPU_SUPPLY,
+	ADIS16550_STATUS_5V_SUPPLY
+};
+
+static const char * const adis16550_status_error_msgs[] = {
+	[ADIS16550_STATUS_CRC_CODE] = "Code CRC Error",
+	[ADIS16550_STATUS_CRC_CONFIG] = "Configuration/Calibration CRC Error",
+	[ADIS16550_STATUS_FLASH_UPDATE] = "Flash Update Error",
+	[ADIS16550_STATUS_INERIAL] = "Overrange for Inertial Signals",
+	[ADIS16550_STATUS_SENSOR] = "Sensor failure",
+	[ADIS16550_STATUS_TEMPERATURE] = "Temperature Error",
+	[ADIS16550_STATUS_SPI] = "SPI Communication Error",
+	[ADIS16550_STATUS_PROCESSING] = "Processing Overrun Error",
+	[ADIS16550_STATUS_POWER] = "Power Supply Failure",
+	[ADIS16550_STATUS_BOOT] = "Boot Memory Failure",
+	[ADIS16550_STATUS_WATCHDOG] = "Watchdog timer flag",
+	[ADIS16550_STATUS_REGULATOR] = "Internal Regulator Error",
+	[ADIS16550_STATUS_SENSOR_SUPPLY] = "Internal Sensor Supply Error.",
+	[ADIS16550_STATUS_CPU_SUPPLY] = "Internal Processor Supply Error.",
+	[ADIS16550_STATUS_5V_SUPPLY] = "External 5V Supply Error",
+};
+
+static const struct adis_timeout adis16550_timeouts = {
+	.reset_ms = 1000,
+	.sw_reset_ms = 1000,
+	.self_test_ms = 1000,
+};
+
+static const struct adis_data adis16550_data = {
+	.diag_stat_reg = ADIS16550_REG_STATUS,
+	.diag_stat_size = 4,
+	.prod_id_reg = ADIS16550_REG_PROD_ID,
+	.prod_id = 16550,
+	.self_test_mask = BIT(1),
+	.self_test_reg = ADIS16550_REG_COMMAND,
+	.cs_change_delay = 5,
+	.unmasked_drdy = true,
+	.status_error_msgs = adis16550_status_error_msgs,
+	.status_error_mask = BIT(ADIS16550_STATUS_CRC_CODE) |
+			BIT(ADIS16550_STATUS_CRC_CONFIG) |
+			BIT(ADIS16550_STATUS_FLASH_UPDATE) |
+			BIT(ADIS16550_STATUS_INERIAL) |
+			BIT(ADIS16550_STATUS_SENSOR) |
+			BIT(ADIS16550_STATUS_TEMPERATURE) |
+			BIT(ADIS16550_STATUS_SPI) |
+			BIT(ADIS16550_STATUS_PROCESSING) |
+			BIT(ADIS16550_STATUS_POWER) |
+			BIT(ADIS16550_STATUS_BOOT) |
+			BIT(ADIS16550_STATUS_WATCHDOG) |
+			BIT(ADIS16550_STATUS_REGULATOR) |
+			BIT(ADIS16550_STATUS_SENSOR_SUPPLY) |
+			BIT(ADIS16550_STATUS_CPU_SUPPLY) |
+			BIT(ADIS16550_STATUS_5V_SUPPLY) |
+			BIT(ADIS16550_STATUS_CRC_CODE),
+	.timeouts = &adis16550_timeouts,
+};
+
+static const struct adis_ops adis16550_ops = {
+	.write = adis16550_spi_write,
+	.read = adis16550_spi_read,
+	.reset = adis16550_reset,
+};
+
+static int adis16550_probe(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev;
+	struct adis16550 *st;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+
+	st->info =  device_get_match_data(&spi->dev);
+	if (!st->info)
+		return -EINVAL;
+
+	indio_dev->name = st->info->name;
+	indio_dev->channels = st->info->channels;
+	indio_dev->num_channels = st->info->num_channels;
+	indio_dev->available_scan_masks = adis16550_channel_masks;
+	indio_dev->info = &adis16550_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	st->adis.ops = &adis16550_ops;
+
+	ret = devm_regulator_get_enable(&spi->dev, "vdd");
+	if (ret)
+		return dev_err_probe(&spi->dev, ret,
+				     "Failed to get vdd regulator\n");
+
+	ret = adis_init(&st->adis, indio_dev, spi, &adis16550_data);
+	if (ret)
+		return ret;
+
+	ret = __adis_initial_startup(&st->adis);
+	if (ret)
+		return ret;
+
+	ret = adis16550_config_sync(st);
+	if (ret)
+		return ret;
+
+	ret = devm_adis_setup_buffer_and_trigger(&st->adis, indio_dev,
+						 adis16550_trigger_handler);
+	if (ret)
+		return ret;
+
+	ret = devm_iio_device_register(&spi->dev, indio_dev);
+	if (ret)
+		return ret;
+
+	adis16550_debugfs_init(indio_dev);
+
+	return 0;
+}
+
+static const struct spi_device_id adis16550_id[] = {
+	{ "adis16550", (kernel_ulong_t)&adis16550_chip_info[ADIS16550]  },
+	{ "adis16550w",  (kernel_ulong_t)&adis16550_chip_info[ADIS16550W] },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, adis16550_id);
+
+static const struct of_device_id adis16550_of_match[] = {
+	{ .compatible = "adi,adis16550", .data = &adis16550_chip_info[ADIS16550]},
+	{ .compatible = "adi,adis16550w", .data = &adis16550_chip_info[ADIS16550W] },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, adis16550_of_match);
+
+static struct spi_driver adis16550_driver = {
+	.driver = {
+		.name = "adis16550",
+		.of_match_table = adis16550_of_match,
+	},
+	.probe = adis16550_probe,
+	.id_table = adis16550_id,
+};
+module_spi_driver(adis16550_driver);
+
+MODULE_AUTHOR("Nuno Sa <nuno.sa@analog.com>");
+MODULE_AUTHOR("Ramona Gradinariu <ramona.gradinariu@analog.com>");
+MODULE_AUTHOR("Antoniu Miclaus <antoniu.miclaus@analog.com>");
+MODULE_DESCRIPTION("Analog Devices ADIS16550 IMU driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(IIO_ADISLIB);
-- 
2.34.1

Re: [PATCH 4/5] iio: imu: adis16550: add adis16550 support

[Christophe JAILLET]

Le 28/10/2024 à 13:35, Robert Budai a écrit :
> From: Nuno Sá <nuno.sa-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org>
> 
> The ADIS16550 is a complete inertial system that includes a triaxis
> gyroscope and a triaxis accelerometer. Each inertial sensor in
> the ADIS16550 combines industry leading MEMS only technology
> with signal conditioning that optimizes dynamic performance. The
> factory calibration characterizes each sensor for sensitivity, bias,
> and alignment. As a result, each sensor has its own dynamic com-
> pensation formulas that provide accurate sensor measurements

Hi,

...

> +static ssize_t adis16550_show_firmware_date(struct file *file,
> +					    char __user *userbuf,
> +					    size_t count, loff_t *ppos)
> +{
> +	struct adis16550 *st = file->private_data;
> +	u32 date;
> +	char buf[12];
> +	size_t len;
> +	int ret;
> +
> +	ret = adis_read_reg_32(&st->adis, ADIS16550_REG_FW_DATE, &date);
> +	if (ret)
> +		return ret;
> +
> +	len = snprintf(buf, sizeof(buf), "%.2x-%.2x-%.4x\n", date & 0xff,
> +		       (date >> 8) & 0xff, date >> 16);

scnprintf() ?

> +
> +	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
> +}

...

> +static void adis16550_debugfs_init(struct iio_dev *indio_dev)
> +{
> +	struct adis16550 *st = iio_priv(indio_dev);
> +	struct dentry *d = iio_get_debugfs_dentry(indio_dev);
> +
> +	if (!IS_ENABLED(CONFIG_DEBUG_FS))
> +		return;

I don't think that this is needed.
Functions below should ahndle it already.

> +
> +	debugfs_create_file_unsafe("serial_number", 0400,
> +				   d, st, &adis16550_serial_number_fops);
> +	debugfs_create_file_unsafe("product_id", 0400,
> +				   d, st, &adis16550_product_id_fops);
> +	debugfs_create_file("firmware_revision", 0400,
> +			    d, st, &adis16550_firmware_revision_fops);
> +	debugfs_create_file("firmware_date", 0400, d,
> +			    st, &adis16550_firmware_date_fops);
> +	debugfs_create_file_unsafe("flash_count", 0400,
> +				   d, st, &adis16550_flash_count_fops);
> +}

...

> +static int adis16550_set_freq(struct adis16550 *st, u32 freq)
> +{
> +	u16 dec;
> +	int ret;
> +	u32 sample_rate = st->clk_freq;
> +	/*
> +	 * The optimal sample rate for the supported IMUs is between
> +	 * int_clk - 1000 and int_clk + 500.
> +	 */
> +	u32 max_sample_rate =  st->info->int_clk * 1000 + 500000;
> +	u32 min_sample_rate =  st->info->int_clk * 1000 - 1000000;

Nitpick: 2 spaces after =

> +
> +	if (!freq)
> +		return -EINVAL;
> +
> +	adis_dev_lock(&st->adis);
> +
> +	if (st->sync_mode == ADIS16550_SYNC_MODE_SCALED) {
> +		unsigned long scaled_rate = lcm(st->clk_freq, freq);
> +		int sync_scale;
> +
> +		if (scaled_rate > max_sample_rate)
> +			scaled_rate = max_sample_rate / st->clk_freq * st->clk_freq;
> +		else
> +			scaled_rate = max_sample_rate / scaled_rate * scaled_rate;
> +
> +		if (scaled_rate < min_sample_rate)
> +			scaled_rate = roundup(min_sample_rate, st->clk_freq);
> +
> +		sync_scale = scaled_rate / st->clk_freq;
> +		ret = __adis_write_reg_16(&st->adis, ADIS16550_REG_SYNC_SCALE,
> +					  sync_scale);
> +		if (ret)
> +			goto error;
> +
> +		sample_rate = scaled_rate;
> +	}
> +
> +	dec = DIV_ROUND_CLOSEST(sample_rate, freq);
> +
> +	if (dec)
> +		dec--;
> +
> +	if (dec > st->info->max_dec)
> +		dec = st->info->max_dec;
> +
> +	ret = __adis_write_reg_16(&st->adis, ADIS16550_REG_DEC_RATE, dec);
> +	if (ret)
> +		goto error;
> +
> +	adis_dev_unlock(&st->adis);
> +
> +	return 0;
> +
> +error:
> +	adis_dev_unlock(&st->adis);
> +	return ret;
> +}

...

> +static const struct adis16550_chip_info adis16550_chip_info[] = {
> +	[ADIS16550] =
> +		ADIS16550_CHIP_INFO(adis16550),

This fits on the previous line.

> +	[ADIS16550W] =
> +		ADIS16550_CHIP_INFO(adis16550w),
> +};
> +
> +static u32 adis16550_validate_crc(const u32 *buf, const u8 n_elem,
> +				  const u32 crc)
> +{
> +	u32 crc_calc;
> +	u32 crc_buf[ADIS16550_BURST_N_ELEM - 2];
> +	int j;

Nitpick: i is more usual than j.
There also should be a newline here.

> +	/*
> +	 * The crc calculation of the data is done in little endian. Hence, we
> +	 * always swap the 32bit elements making sure that the data LSB is
> +	 * always on address 0...
> +	 */
> +	for (j = 0; j < n_elem; j++)
> +		crc_buf[j] = swab32(buf[j]);
> +
> +	crc_calc = crc32(~0, crc_buf, n_elem * 4);
> +	crc_calc ^= ~0;
> +
> +	return (crc_calc == crc);
> +}

...

> +static int adis16550_probe(struct spi_device *spi)
> +{
> +	struct iio_dev *indio_dev;
> +	struct adis16550 *st;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	st = iio_priv(indio_dev);
> +
> +	st->info =  device_get_match_data(&spi->dev);

Nitpick: 2 spaces after =

> +	if (!st->info)
> +		return -EINVAL;
> +
> +	indio_dev->name = st->info->name;
> +	indio_dev->channels = st->info->channels;
> +	indio_dev->num_channels = st->info->num_channels;
> +	indio_dev->available_scan_masks = adis16550_channel_masks;
> +	indio_dev->info = &adis16550_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	st->adis.ops = &adis16550_ops;
> +
> +	ret = devm_regulator_get_enable(&spi->dev, "vdd");
> +	if (ret)
> +		return dev_err_probe(&spi->dev, ret,
> +				     "Failed to get vdd regulator\n");
> +
> +	ret = adis_init(&st->adis, indio_dev, spi, &adis16550_data);
> +	if (ret)
> +		return ret;
> +
> +	ret = __adis_initial_startup(&st->adis);
> +	if (ret)
> +		return ret;
> +
> +	ret = adis16550_config_sync(st);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_adis_setup_buffer_and_trigger(&st->adis, indio_dev,
> +						 adis16550_trigger_handler);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_iio_device_register(&spi->dev, indio_dev);
> +	if (ret)
> +		return ret;
> +
> +	adis16550_debugfs_init(indio_dev);
> +
> +	return 0;
> +}
> +
> +static const struct spi_device_id adis16550_id[] = {
> +	{ "adis16550", (kernel_ulong_t)&adis16550_chip_info[ADIS16550]  },

Nitpick: extra space before ending }

> +	{ "adis16550w",  (kernel_ulong_t)&adis16550_chip_info[ADIS16550W] },

Nitpick: 2 spaces after first ,

> +	{ }
> +};
> +MODULE_DEVICE_TABLE(spi, adis16550_id);
> +
> +static const struct of_device_id adis16550_of_match[] = {
> +	{ .compatible = "adi,adis16550", .data = &adis16550_chip_info[ADIS16550]},

Nitpick: missing space before ending }

> +	{ .compatible = "adi,adis16550w", .data = &adis16550_chip_info[ADIS16550W] },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, adis16550_of_match);

...

CJ

Re: [PATCH 4/5] iio: imu: adis16550: add adis16550 support

[Jonathan Cameron]

On Mon, 28 Oct 2024 14:35:44 +0200
Robert Budai <robert.budai@analog.com> wrote:

> From: Nuno Sá <nuno.sa@analog.com>
> 
> The ADIS16550 is a complete inertial system that includes a triaxis
> gyroscope and a triaxis accelerometer. Each inertial sensor in
> the ADIS16550 combines industry leading MEMS only technology
> with signal conditioning that optimizes dynamic performance. The
> factory calibration characterizes each sensor for sensitivity, bias,
> and alignment. As a result, each sensor has its own dynamic com-
> pensation formulas that provide accurate sensor measurements
> 
> Co-developed-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
> Signed-off-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
> Co-developed-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> Co-developed-by: Robert Budai <robert.budai@analog.com>
> Signed-off-by: Robert Budai <robert.budai@analog.com>
> Signed-off-by: Nuno Sá <nuno.sa@analog.com>

Various minor things inline.

Robert, as sender your SoB should come last. (just move down your two
lines and it is fine).

> diff --git a/drivers/iio/imu/adis16550.c b/drivers/iio/imu/adis16550.c
> new file mode 100644
> index 000000000000..204d72c9f442
> --- /dev/null
> +++ b/drivers/iio/imu/adis16550.c
> @@ -0,0 +1,1228 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ADIS16550 IMU driver
> + *
> + * Copyright 2024 Analog Devices Inc.
> + */
> +#include <linux/bitfield.h>
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/crc32.h>
> +#include <linux/debugfs.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/imu/adis.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/lcm.h>
> +#include <linux/math.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/spi/spi.h>
> +#include <linux/swab.h>
> +
> +#include <asm/unaligned.h>
Moved. Now linux/unaligned.h (rc2 onwards)


> +
> +#define ADIS16550_REG_BURST_GYRO_ACCEL		0x0a
> +#define ADIS16550_REG_BURST_DELTA_ANG_VEL	0x0b
> +#define ADIS16550_BURST_DATA_GYRO_ACCEL_MASK	GENMASK(5, 0)
> +#define ADIS16550_BURST_DATA_DELTA_ANG_VEL_MASK	GENMASK(12, 7)
> +
> +#define ADIS16550_REG_STATUS		0x0e
> +#define ADIS16550_REG_TEMP		0x10
> +#define ADIS16550_REG_X_GYRO		0x12
> +#define ADIS16550_REG_Y_GYRO		0x14
> +#define ADIS16550_REG_Z_GYRO		0x16
> +#define ADIS16550_REG_X_ACCEL		0x18
> +#define ADIS16550_REG_Y_ACCEL		0x1a
> +#define ADIS16550_REG_Z_ACCEL		0x1c
> +#define ADIS16550_REG_X_DELTANG_L	0x1E
> +#define ADIS16550_REG_Y_DELTANG_L	0x20
> +#define ADIS16550_REG_Z_DELTANG_L	0x22
> +#define ADIS16550_REG_X_DELTVEL_L	0x24
> +#define ADIS16550_REG_Y_DELTVEL_L	0x26
> +#define ADIS16550_REG_Z_DELTVEL_L	0x28
> +#define ADIS16550_REG_X_GYRO_SCALE	0x30
> +#define ADIS16550_REG_Y_GYRO_SCALE	0x32
> +#define ADIS16550_REG_Z_GYRO_SCALE	0x34
> +#define ADIS16550_REG_X_ACCEL_SCALE	0x36
> +#define ADIS16550_REG_Y_ACCEL_SCALE	0x38
> +#define ADIS16550_REG_Z_ACCEL_SCALE	0x3a
> +#define ADIS16550_REG_X_GYRO_BIAS	0x40
> +#define ADIS16550_REG_Y_GYRO_BIAS	0x42
> +#define ADIS16550_REG_Z_GYRO_BIAS	0x44
> +#define ADIS16550_REG_X_ACCEL_BIAS	0x46
> +#define ADIS16550_REG_Y_ACCEL_BIAS	0x48
> +#define ADIS16550_REG_Z_ACCEL_BIAS	0x4a
> +#define ADIS16550_REG_COMMAND		0x50
> +#define ADIS16550_REG_CONFIG		0x52
> +#define ADIS16550_GYRO_FIR_EN_MASK	BIT(3)
> +#define ADIS16550_ACCL_FIR_EN_MASK	BIT(2)
> +#define ADIS16550_SYNC_MASK	\
> +			(ADIS16550_SYNC_EN_MASK | ADIS16550_SYNC_MODE_MASK)
> +#define ADIS16550_SYNC_MODE_MASK	BIT(1)
> +#define ADIS16550_SYNC_EN_MASK		BIT(0)
> +/* max of 4000 SPS in scale sync */
> +#define ADIS16550_SYNC_SCALE_MAX_RATE	(4000 * 1000)
> +#define ADIS16550_REG_DEC_RATE		0x54
> +#define ADIS16550_REG_SYNC_SCALE	0x56
> +#define ADIS16550_REG_SERIAL_NUM	0x76
> +#define ADIS16550_REG_FW_REV		0x7A
> +#define ADIS16550_REG_FW_DATE		0x7C
> +#define ADIS16550_REG_PROD_ID		0x7E
> +#define ADIS16550_REG_FLASH_CNT		0x72
> +/* spi protocol*/
> +#define ADIS16550_SPI_DATA_MASK		GENMASK(31, 16)
> +#define ADIS16550_SPI_REG_MASK		GENMASK(14, 8)
> +#define ADIS16550_SPI_R_W_MASK		BIT(7)
> +#define ADIS16550_SPI_CRC_MASK		GENMASK(3, 0)
> +#define ADIS16550_SPI_SV_MASK		GENMASK(7, 6)
> +/* burst read */
> +#define ADIS16550_BURST_N_ELEM		12
> +#define ADIS16550_BURST_DATA_LEN	(ADIS16550_BURST_N_ELEM * 4)
> +#define ADIS16550_MAX_SCAN_DATA		12

> +static int adis16550_set_freq(struct adis16550 *st, u32 freq)
name freq to indicate the units.

> +{
> +	u16 dec;
> +	int ret;
> +	u32 sample_rate = st->clk_freq;
> +	/*
> +	 * The optimal sample rate for the supported IMUs is between
> +	 * int_clk - 1000 and int_clk + 500.
> +	 */
> +	u32 max_sample_rate =  st->info->int_clk * 1000 + 500000;
> +	u32 min_sample_rate =  st->info->int_clk * 1000 - 1000000;
> +
> +	if (!freq)
> +		return -EINVAL;
> +
> +	adis_dev_lock(&st->adis);
adis_dev_auto_lock() here and in similar places
then you can directly return from error paths.


> +
> +	if (st->sync_mode == ADIS16550_SYNC_MODE_SCALED) {
> +		unsigned long scaled_rate = lcm(st->clk_freq, freq);
> +		int sync_scale;
> +
> +		if (scaled_rate > max_sample_rate)
> +			scaled_rate = max_sample_rate / st->clk_freq * st->clk_freq;
> +		else
> +			scaled_rate = max_sample_rate / scaled_rate * scaled_rate;
> +
> +		if (scaled_rate < min_sample_rate)
> +			scaled_rate = roundup(min_sample_rate, st->clk_freq);
> +
> +		sync_scale = scaled_rate / st->clk_freq;
> +		ret = __adis_write_reg_16(&st->adis, ADIS16550_REG_SYNC_SCALE,
> +					  sync_scale);
> +		if (ret)
> +			goto error;
> +
> +		sample_rate = scaled_rate;
> +	}
> +
> +	dec = DIV_ROUND_CLOSEST(sample_rate, freq);
> +
> +	if (dec)
> +		dec--;
> +
> +	if (dec > st->info->max_dec)
> +		dec = st->info->max_dec;

dec = min(dec, st->info->max_dec)

> +
> +	ret = __adis_write_reg_16(&st->adis, ADIS16550_REG_DEC_RATE, dec);
> +	if (ret)
> +		goto error;
> +
> +	adis_dev_unlock(&st->adis);
> +
> +	return 0;
> +
> +error:
> +	adis_dev_unlock(&st->adis);
> +	return ret;
> +}


> +static int adis16550_read_raw(struct iio_dev *indio_dev,
> +			      const struct iio_chan_spec *chan,
> +			      int *val, int *val2, long info)
> +{
> +	struct adis16550 *st = iio_priv(indio_dev);
> +	int ret;
> +	const int idx = chan->scan_index;
> +	u32 tmp;
> +	u16 scale;
reverse xmas tree.

> +
> +	switch (info) {
> +	case IIO_CHAN_INFO_RAW:
> +		return adis_single_conversion(indio_dev, chan, 0, val);
> +	case IIO_CHAN_INFO_SCALE:
> +		switch (chan->type) {
> +		case IIO_ANGL_VEL:
> +			*val = st->info->gyro_max_val;
> +			*val2 = st->info->gyro_max_scale;
This level of flexibility only makes sense if you are very soon
going to send additional support for devices where these change.
If you are, state that in the patch description.

> +			return IIO_VAL_FRACTIONAL;
> +		case IIO_ACCEL:
> +			*val = st->info->accel_max_val;
> +			*val2 = st->info->accel_max_scale;
> +			return IIO_VAL_FRACTIONAL;
> +		case IIO_TEMP:
> +			*val = st->info->temp_scale;
> +			return IIO_VAL_INT;
> +		case IIO_DELTA_ANGL:
> +			*val = st->info->deltang_max_val;
> +			*val2 = 31;
> +			return IIO_VAL_FRACTIONAL_LOG2;
> +		case IIO_DELTA_VELOCITY:
> +			*val = st->info->deltvel_max_val;
> +			*val2 = 31;
> +			return IIO_VAL_FRACTIONAL_LOG2;
> +		default:
> +			return -EINVAL;
> +		}
> +	case IIO_CHAN_INFO_OFFSET:
> +		/* temperature centered at 25°C */
> +		*val = DIV_ROUND_CLOSEST(25000, st->info->temp_scale);
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_CALIBBIAS:
> +		ret = adis_read_reg_32(&st->adis,
> +				       adis16550_calib_bias[idx], val);
> +		if (ret)
> +			return ret;
> +
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_CALIBSCALE:
> +		ret = adis_read_reg_16(&st->adis,
> +				       adis16550_calib_scale[idx], &scale);
> +		if (ret)
> +			return ret;
> +
> +		*val = scale;
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		ret = adis16550_get_freq(st, &tmp);
> +		if (ret)
> +			return ret;
> +
> +		*val = tmp / 1000;
> +		*val2 = (tmp % 1000) * 1000;
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
> +		switch (chan->type) {
> +		case IIO_ANGL_VEL:
> +			ret = adis16550_get_accl_filter_freq(st, val);
> +			if (ret)
> +				return ret;
> +			return IIO_VAL_INT;
> +		case IIO_ACCEL:
> +			ret = adis16550_get_gyro_filter_freq(st, val);
> +			if (ret)
> +				return ret;
> +			return IIO_VAL_INT;
> +		default:
> +			return -EINVAL;
> +		}
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int adis16550_write_raw(struct iio_dev *indio_dev,
> +			       const struct iio_chan_spec *chan,
> +			       int val, int val2, long info)
> +{
> +	struct adis16550 *st = iio_priv(indio_dev);
> +	u32 tmp;
> +	const int idx = chan->scan_index;
> +
> +	switch (info) {
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		tmp = val * 1000 + val2 / 1000;
> +		return adis16550_set_freq(st, tmp);
> +	case IIO_CHAN_INFO_CALIBBIAS:
> +		return adis_write_reg_32(&st->adis, adis16550_calib_bias[idx],
> +					 val);
> +	case IIO_CHAN_INFO_CALIBSCALE:
> +		return adis_write_reg_16(&st->adis, adis16550_calib_scale[idx],
> +					 val);
> +	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
> +		switch (chan->type) {
> +		case IIO_ANGL_VEL:
> +			return adis16550_set_accl_filter_freq(st, val);
> +		case IIO_ACCEL:
> +			return adis16550_set_gyro_filter_freq(st, val);
> +		default:
> +			return -EINVAL;
> +		}
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +#define ADIS16550_MOD_CHAN(_type, _mod, _address, _si, _r_bits, _s_bits) \
> +	{ \
> +		.type = (_type), \
> +		.modified = 1, \
> +		.channel2 = (_mod), \
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> +			BIT(IIO_CHAN_INFO_CALIBBIAS) | \
> +			BIT(IIO_CHAN_INFO_CALIBSCALE), \
> +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
> +					    BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY), \
> +		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
> +		.address = (_address), \
> +		.scan_index = (_si), \
> +		.scan_type = { \
> +			.sign = 's', \
> +			.realbits = (_r_bits), \
> +			.storagebits = (_s_bits), \
As below. These are always 32 , so just fix that for now.

> +			.endianness = IIO_BE, \
> +		}, \
> +	}
> +
> +#define ADIS16550_GYRO_CHANNEL(_mod) \
> +	ADIS16550_MOD_CHAN(IIO_ANGL_VEL, IIO_MOD_ ## _mod, \
> +	ADIS16550_REG_ ## _mod ## _GYRO, ADIS16550_SCAN_GYRO_ ## _mod, 32, \
> +	32)
> +
> +#define ADIS16550_ACCEL_CHANNEL(_mod) \
> +	ADIS16550_MOD_CHAN(IIO_ACCEL, IIO_MOD_ ## _mod, \
> +	ADIS16550_REG_ ## _mod ## _ACCEL, ADIS16550_SCAN_ACCEL_ ## _mod, 32, \
> +	32)
> +
> +#define ADIS16550_TEMP_CHANNEL() { \
> +		.type = IIO_TEMP, \
> +		.indexed = 1, \
> +		.channel = 0, \
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> +			BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET), \
> +		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
> +		.address = ADIS16550_REG_TEMP, \
> +		.scan_index = ADIS16550_SCAN_TEMP, \
> +		.scan_type = { \
> +			.sign = 's', \
> +			.realbits = 16, \
Add a comment here on why you aren't storing it in a be16
(I assume because it requires special casing and no one is ever going to
run this device as just a thermometer!

> +			.storagebits = 32, \
> +			.endianness = IIO_BE, \
> +		}, \
> +	}
> +
> +#define ADIS16550_MOD_CHAN_DELTA(_type, _mod, _address, _si, _r_bits, _s_bits) { \
> +		.type = (_type), \
> +		.modified = 1, \
> +		.channel2 = (_mod), \
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> +		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
> +		.address = (_address), \
> +		.scan_index = _si, \
> +		.scan_type = { \
> +			.sign = 's', \
> +			.realbits = (_r_bits), \
> +			.storagebits = (_s_bits), \
If they are always 32, encode them as that and we can revisit when you add
more parts that aren't. 

> +			.endianness = IIO_BE, \
> +		}, \
> +	}
> +
> +#define ADIS16550_DELTANG_CHAN(_mod) \
> +	ADIS16550_MOD_CHAN_DELTA(IIO_DELTA_ANGL, IIO_MOD_ ## _mod, \
> +			   ADIS16550_REG_ ## _mod ## _DELTANG_L, ADIS16550_SCAN_DELTANG_ ## _mod, 32, 32)
> +
> +#define ADIS16550_DELTVEL_CHAN(_mod) \
> +	ADIS16550_MOD_CHAN_DELTA(IIO_DELTA_VELOCITY, IIO_MOD_ ## _mod, \
> +			   ADIS16550_REG_ ## _mod ## _DELTVEL_L, ADIS16550_SCAN_DELTVEL_ ## _mod, 32, 32)
> +
> +#define ADIS16550_DELTANG_CHAN_NO_SCAN(_mod) \
> +	ADIS16550_MOD_CHAN_DELTA(IIO_DELTA_ANGL, IIO_MOD_ ## _mod, \
> +			   ADIS16550_REG_ ## _mod ## _DELTANG_L, -1, 32, 32)
> +
> +#define ADIS16550_DELTVEL_CHAN_NO_SCAN(_mod) \
> +	ADIS16550_MOD_CHAN_DELTA(IIO_DELTA_VELOCITY, IIO_MOD_ ## _mod, \
> +			   ADIS16550_REG_ ## _mod ## _DELTVEL_L, -1, 32, 32)

> +
> +#define ADIS16550_CHIP_INFO(_name) \
> +	{ \
> +		.num_channels = ARRAY_SIZE(adis16550_channels), \
> +		.channels = adis16550_channels, \
> +		.name = # _name, \

If only the name differs, then use a fallback compatible in DT.
Also do we care about the normal vs w variant?


> +		.gyro_max_val = 1, \
> +		.gyro_max_scale = IIO_RAD_TO_DEGREE(80 << 16), \
> +		.accel_max_val = 1, \
> +		.accel_max_scale = IIO_M_S_2_TO_G(102400000), \
> +		.temp_scale = 4, \
> +		.deltang_max_val = IIO_DEGREE_TO_RAD(720), \
> +		.deltvel_max_val = 125, \
> +		.int_clk = 4000, \
> +		.max_dec = 4095, \
> +		.sync_mode = adis16550_sync_modes, \
> +		.num_sync = ARRAY_SIZE(adis16550_sync_modes), \
> +	}
> +
> +static const struct adis16550_chip_info adis16550_chip_info[] = {
> +	[ADIS16550] =
> +		ADIS16550_CHIP_INFO(adis16550),
> +	[ADIS16550W] =
> +		ADIS16550_CHIP_INFO(adis16550w),
> +};

We've generally stopped using arrays of chip info structures because
it's easier to read
&adis16550_chip_info, &adis16550w_chip_info

So split this.  Note lots of older drivers do what you have here
so this is more of a 'new' best practice thing than anything
thing else.


> +
> +static u32 adis16550_validate_crc(const u32 *buf, const u8 n_elem,
> +				  const u32 crc)
> +{
> +	u32 crc_calc;
> +	u32 crc_buf[ADIS16550_BURST_N_ELEM - 2];
> +	int j;
> +	/*
> +	 * The crc calculation of the data is done in little endian. Hence, we
> +	 * always swap the 32bit elements making sure that the data LSB is
> +	 * always on address 0...
> +	 */
> +	for (j = 0; j < n_elem; j++)
> +		crc_buf[j] = swab32(buf[j]);
> +
> +	crc_calc = crc32(~0, crc_buf, n_elem * 4);
> +	crc_calc ^= ~0;
> +
> +	return (crc_calc == crc);
Drop the ()

> +}
> +
> +static irqreturn_t adis16550_trigger_handler(int irq, void *p)
> +{
> +	struct iio_poll_func *pf = p;
> +	struct iio_dev *indio_dev = pf->indio_dev;
> +	struct adis *adis = iio_device_get_drvdata(indio_dev);
> +	struct adis16550 *st = iio_priv(indio_dev);
> +	__be32 *buffer = adis->buffer, data[ADIS16550_MAX_SCAN_DATA];

Separate lines for those two. This is very hard to read.

> +	u32 crc;
> +	u16 dummy;
> +	int ret, bit, i = 0;
> +	u8 data_offset = 4;
> +	u8 buff_offset = 0;
> +	bool valid;
> +
> +	ret = spi_sync(adis->spi, &adis->msg);
> +	if (ret)
> +		goto done;
> +	/*
> +	 * Validate the header. The header is a normal spi reply with state
> +	 * vector and crc4.
> +	 */
> +	ret = adis16550_spi_validate(&st->adis, buffer[0], &dummy);
> +	if (ret)
> +		goto done;
> +
> +	crc = be32_to_cpu(buffer[ADIS16550_BURST_N_ELEM - 1]);
> +	/* the header is not included in the crc */
> +	valid = adis16550_validate_crc((u32 *)&buffer[1],
> +				       ADIS16550_BURST_N_ELEM - 2, crc);
> +	if (!valid) {
> +		dev_err(&adis->spi->dev, "Burst Invalid crc!\n");
> +		goto done;
> +	}
> +
> +	for_each_set_bit(bit, indio_dev->active_scan_mask,
> +			 indio_dev->masklength) {
> +		switch (bit) {
> +		case ADIS16550_SCAN_TEMP:
> +			data[i++] = buffer[data_offset - 1];
> +			break;
> +		case ADIS16550_SCAN_DELTANG_X ... ADIS16550_SCAN_DELTVEL_Z:
> +			buff_offset = ADIS16550_SCAN_DELTANG_X;

I assume these are contiguous and give available masks you will have
them all if any are set. Use memcpy()
This probably wants to be a bunch of if statements given you should just
check for an indicative element then copy in blocks.


> +			fallthrough;

Just repeat the assignment. The fallthrough makes this harder to read.

> +		case ADIS16550_SCAN_GYRO_X ... ADIS16550_SCAN_ACCEL_Z:
> +			data[i++] = buffer[bit + data_offset - buff_offset];
> +			break;
> +		}
> +	}
> +
> +	iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
> +done:
> +	iio_trigger_notify_done(indio_dev->trig);
> +	return IRQ_HANDLED;
> +}
> +
> +static const unsigned long adis16550_channel_masks[] = {
> +	ADIS16550_BURST_DATA_GYRO_ACCEL_MASK | BIT(ADIS16550_SCAN_TEMP) | BIT(13),
> +	ADIS16550_BURST_DATA_DELTA_ANG_VEL_MASK | BIT(ADIS16550_SCAN_TEMP) | BIT(13),

IIRC timestamp is handled separately so shouldn't need to be in here.
I think this is going to end up allocating larger storage than you need
because the timestamp will get counted twice when computing that buffer.

> +	0,
> +};
> +
> +static int adis16550_update_scan_mode(struct iio_dev *indio_dev,
> +				      const unsigned long *scan_mask)
> +{
> +	struct adis *adis = iio_device_get_drvdata(indio_dev);
> +	u8 *tx;

If no other reason for ordering, pick something like reverse xmas
tree and make the code consistent.

> +	u16 burst_length = ADIS16550_BURST_DATA_LEN;
> +	u8 burst_cmd;
> +
> +	if (*scan_mask & ADIS16550_BURST_DATA_GYRO_ACCEL_MASK)
> +		burst_cmd = ADIS16550_REG_BURST_GYRO_ACCEL;
> +	else
> +		burst_cmd = ADIS16550_REG_BURST_DELTA_ANG_VEL;
> +
> +	kfree(adis->xfer);
> +	kfree(adis->buffer);
> +
> +	adis->xfer = kcalloc(2, sizeof(*adis->xfer), GFP_KERNEL);
> +	if (!adis->xfer)
> +		return -ENOMEM;

Always the same size?  Why reallocate it in here - just do it once
at probe, or possibly embed it in the iio_priv() with appropriate
handling to make it dma safe.


> +
> +	adis->buffer = kzalloc(burst_length + sizeof(u32), GFP_KERNEL);
Use a local variable to set this up + __free() to clean it up and
finally no_free_ptr() to 'steal' the ownership after all opportunities
for error have passed.

> +	if (!adis->buffer) {
> +		kfree(adis->xfer);
> +		adis->xfer = NULL;
> +		return -ENOMEM;
> +	}
> +
> +	tx = adis->buffer + burst_length;
> +	tx[0] = 0x00;
> +	tx[1] = 0x00;
> +	tx[2] = burst_cmd;
> +	/* crc4 is 0 on burst command */
> +	tx[3] = spi_crc4(get_unaligned_le32(tx));
> +
> +	adis->xfer[0].tx_buf = tx;
> +	adis->xfer[0].len = 4;
> +	adis->xfer[0].cs_change = 1;
> +	adis->xfer[0].delay.value = 8;
> +	adis->xfer[0].delay.unit = SPI_DELAY_UNIT_USECS;
> +	adis->xfer[1].rx_buf = adis->buffer;
> +	adis->xfer[1].len = burst_length;
> +
> +	spi_message_init_with_transfers(&adis->msg, adis->xfer, 2);
> +
> +	return 0;
> +}

> +static int adis16550_config_sync(struct adis16550 *st)
> +{
> +	int ret;
> +	const struct adis16550_sync *sync;
> +	struct device *dev = &st->adis.spi->dev;
> +	u32 sync_mode;
> +	struct clk *clk;
> +	u16 mode;

I left a comment on the DT binding on this. I'm not sure why we need to explicitly
add a binding for it as opposed to picking right choice based on input clock
frequency and presence or not of the clock.

Maybe you can always pick based just on the clock frequency.
I've not checked the ranges.

> +
> +	if (!device_property_present(dev, "adi,sync-mode")) {
> +		st->clk_freq = st->info->int_clk * 1000;
> +		return 0;
> +	}
> +
> +	if (!device_property_match_string(dev, "adi,sync-mode", "direct_sync"))
> +		sync_mode = 0;
> +	else if (!device_property_match_string(dev, "adi,sync-mode", "scaled_sync"))
> +		sync_mode = 1;
> +	else
> +		return -EINVAL;
> +
> +	sync = &st->info->sync_mode[sync_mode];
> +	st->sync_mode = sync->sync_mode;
> +
> +	clk = devm_clk_get_enabled(dev, NULL);
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
> +
> +	st->clk_freq = clk_get_rate(clk);
> +	if (st->clk_freq > sync->max_rate || st->clk_freq < sync->min_rate)
> +		return dev_err_probe(dev, -EINVAL,
> +				     "Clk rate: %lu not in a valid range:[%u %u]\n",
> +				     st->clk_freq, sync->min_rate, sync->max_rate);
> +
> +	if (sync->sync_mode == ADIS16550_SYNC_MODE_SCALED) {
> +		u16 sync_scale;
> +		u32 scaled_freq = 0;
> +		/*
> +		 * In pps scaled sync we must scale the input clock to a range
> +		 * of [3000 45000].
> +		 */
> +		ret = device_property_read_u32(dev, "adi,scaled-output-hz",
> +					       &scaled_freq);
> +		if (ret)
> +			return dev_err_probe(dev, ret,
> +					     "adi,scaled-output-hz property not found");
> +

Not in the binding Docs that I can see..

> +		if (scaled_freq < 3000 || scaled_freq > 4500)
> +			return dev_err_probe(dev, -EINVAL,
> +					     "Invalid value:%u for adi,scaled-output-hz",
> +					     scaled_freq);
> +
> +		sync_scale = DIV_ROUND_CLOSEST(scaled_freq, st->clk_freq);
> +
> +		ret = adis_write_reg_16(&st->adis, ADIS16550_REG_SYNC_SCALE,
> +					sync_scale);
> +		if (ret)
> +			return ret;
> +
> +		st->clk_freq = scaled_freq;
> +	}
> +
> +	st->clk_freq *= 1000;
change clk_freq to include a unit.
clk_freq_hz or similar then it should be obvious why the multiplier is needed.


> +
> +	/* set sync mode */

Obvious from the field name. I'd drop the comment as it doesn't add
much.

> +	mode = FIELD_PREP(ADIS16550_SYNC_MODE_MASK, sync->sync_mode);
> +	mode |= FIELD_PREP(ADIS16550_SYNC_EN_MASK, true);
	mode = FIELD_PREP() |
	       FIELD_PREP();

cleaner if it's only two lines like this.

> +
> +	return __adis_update_bits(&st->adis, ADIS16550_REG_CONFIG,
> +				  ADIS16550_SYNC_MASK, mode);
> +}

> +static int adis16550_probe(struct spi_device *spi)
> +{
struct device *dev = &spi->dev;
will shorten just enough paths to be worth adding I think.
> +	struct iio_dev *indio_dev;
> +	struct adis16550 *st;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	st = iio_priv(indio_dev);
> +
> +	st->info =  device_get_match_data(&spi->dev);

Extra space before device

> +	if (!st->info)
> +		return -EINVAL;
> +
> +	indio_dev->name = st->info->name;
> +	indio_dev->channels = st->info->channels;
> +	indio_dev->num_channels = st->info->num_channels;
> +	indio_dev->available_scan_masks = adis16550_channel_masks;
> +	indio_dev->info = &adis16550_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	st->adis.ops = &adis16550_ops;
> +
> +	ret = devm_regulator_get_enable(&spi->dev, "vdd");
> +	if (ret)
> +		return dev_err_probe(&spi->dev, ret,
> +				     "Failed to get vdd regulator\n");
> +
> +	ret = adis_init(&st->adis, indio_dev, spi, &adis16550_data);
> +	if (ret)
> +		return ret;
> +
> +	ret = __adis_initial_startup(&st->adis);
> +	if (ret)
> +		return ret;
> +
> +	ret = adis16550_config_sync(st);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_adis_setup_buffer_and_trigger(&st->adis, indio_dev,
> +						 adis16550_trigger_handler);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_iio_device_register(&spi->dev, indio_dev);
> +	if (ret)
> +		return ret;
> +
> +	adis16550_debugfs_init(indio_dev);
> +
> +	return 0;
> +}

[PATCH 5/5] docs: iio: add documentation for adis16550 driver

[Robert Budai]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="y", Size: 21904 bytes --]

From: Ramona Gradinariu <ramona.gradinariu@analog.com>

Add documentation for adis16550 driver which describes the driver
device files and shows how the user may use the ABI for various
scenarios (configuration, measurement, etc.).

Co-developed-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Signed-off-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
---
 Documentation/iio/adis16550.rst | 389 ++++++++++++++++++++++++++++++++
 Documentation/iio/index.rst     |   1 +
 2 files changed, 390 insertions(+)
 create mode 100644 Documentation/iio/adis16550.rst

diff --git a/Documentation/iio/adis16550.rst b/Documentation/iio/adis16550.rst
new file mode 100644
index 000000000000..fde38060f8fe
--- /dev/null
+++ b/Documentation/iio/adis16550.rst
@@ -0,0 +1,389 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+================
+ADIS16550 driver
+================
+
+This driver supports Analog Device's IMUs on SPI bus.
+
+1. Supported devices
+====================
+
+* `ADIS16550 <https://www.analog.com/ADIS16550>`_
+
+The ADIS16550 is a complete inertial system that includes a triaxis gyroscope
+and a triaxis accelerometer. Each inertial sensor in the ADIS16550 combines
+industry leading MEMS only technology with signal conditioning that optimizes
+dynamic performance. The factory calibration characterizes each sensor for
+sensitivity, bias, and alignment. As a result, each sensor has its own dynamic
+compensation formulas that provide accurate sensor measurements.
+
+The ADIS16550 provides a simple, cost-effective method for integrating accurate,
+multiaxis inertial sensing into industrial systems, especially when compared
+with the complexity and investment associated with discrete designs. All
+necessary motion testing and calibration are part of the production process at
+the factory, greatly reducing system integration time. Tight orthogonal
+alignment simplifies inertial frame alignment in navigation systems. The serial
+peripheral interface (SPI) and register structure provide a simple interface for
+data collection and configuration control.
+
+2. Device attributes
+====================
+
+Accelerometer, gyroscope measurements are always provided. Furthermore, the
+driver offers the capability to retrieve the delta angle and the delta velocity
+measurements computed by the device.
+
+The delta angle measurements represent a calculation of angular displacement
+between each sample update, while the delta velocity measurements represent a
+calculation of linear velocity change between each sample update.
+
+Finally, temperature data are provided which show a coarse measurement of
+the temperature inside of the IMU device. This data is most useful for
+monitoring relative changes in the thermal environment.
+
+Each IIO device, has a device folder under ``/sys/bus/iio/devices/iio:deviceX``,
+where X is the IIO index of the device. Under these folders reside a set of
+device files, depending on the characteristics and features of the hardware
+device in questions. These files are consistently generalized and documented in
+the IIO ABI documentation.
+
+The following tables show the adis16550 related device files, found in the
+specific device folder path ``/sys/bus/iio/devices/iio:deviceX``.
+
++-------------------------------------------+----------------------------------------------------------+
+| 3-Axis Accelerometer related device files | Description                                              |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_scale                            | Scale for the accelerometer channels.                    |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_filter_low_pass_3db_frequency    | Bandwidth for the accelerometer channels.                |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_x_calibbias                      | Calibration offset for the X-axis accelerometer channel. |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_x_calibscale                     | Calibration scale for the X-axis accelerometer channel.  |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_x_raw                            | Raw X-axis accelerometer channel value.                  |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_y_calibbias                      | Calibration offset for the Y-axis accelerometer channel. |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_y_calibscale                     | Calibration scale for the Y-axis accelerometer channel.  |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_y_raw                            | Raw Y-axis accelerometer channel value.                  |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_z_calibbias                      | Calibration offset for the Z-axis accelerometer channel. |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_z_calibscale                     | Calibration scale for the Z-axis accelerometer channel.  |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_z_raw                            | Raw Z-axis accelerometer channel value.                  |
++-------------------------------------------+----------------------------------------------------------+
+| in_deltavelocity_scale                    | Scale for delta velocity channels.                       |
++-------------------------------------------+----------------------------------------------------------+
+| in_deltavelocity_x_raw                    | Raw X-axis delta velocity channel value.                 |
++-------------------------------------------+----------------------------------------------------------+
+| in_deltavelocity_y_raw                    | Raw Y-axis delta velocity channel value.                 |
++-------------------------------------------+----------------------------------------------------------+
+| in_deltavelocity_z_raw                    | Raw Z-axis delta velocity channel value.                 |
++-------------------------------------------+----------------------------------------------------------+
+
++--------------------------------------------+------------------------------------------------------+
+| 3-Axis Gyroscope related device files      | Description                                          |
++--------------------------------------------+------------------------------------------------------+
+| in_anglvel_scale                           | Scale for the gyroscope channels.                    |
++--------------------------------------------+------------------------------------------------------+
+| in_anglvel_filter_low_pass_3db_frequency   | Scale for the gyroscope channels.                    |
++--------------------------------------------+------------------------------------------------------+
+| in_anglvel_x_calibbias                     | Calibration offset for the X-axis gyroscope channel. |
++--------------------------------------------+------------------------------------------------------+
+| in_anglvel_x_calibscale                    | Calibration scale for the X-axis gyroscope channel.  |
++--------------------------------------------+------------------------------------------------------+
+| in_anglvel_x_raw                           | Raw X-axis gyroscope channel value.                  |
++--------------------------------------------+------------------------------------------------------+
+| in_anglvel_y_calibbias                     | Calibration offset for the Y-axis gyroscope channel. |
++--------------------------------------------+------------------------------------------------------+
+| in_anglvel_y_calibscale                    | Calibration scale for the Y-axis gyroscope channel.  |
++--------------------------------------------+------------------------------------------------------+
+| in_anglvel_y_raw                           | Raw Y-axis gyroscope channel value.                  |
++--------------------------------------------+------------------------------------------------------+
+| in_anglvel_z_calibbias                     | Calibration offset for the Z-axis gyroscope channel. |
++--------------------------------------------+------------------------------------------------------+
+| in_anglvel_z_calibscale                    | Calibration scale for the Z-axis gyroscope channel.  |
++--------------------------------------------+------------------------------------------------------+
+| in_anglvel_z_raw                           | Raw Z-axis gyroscope channel value.                  |
++--------------------------------------------+------------------------------------------------------+
+| in_deltaangl_scale                         | Scale for delta angle channels.                      |
++--------------------------------------------+------------------------------------------------------+
+| in_deltaangl_x_raw                         | Raw X-axis delta angle channel value.                |
++--------------------------------------------+------------------------------------------------------+
+| in_deltaangl_y_raw                         | Raw Y-axis delta angle channel value.                |
++--------------------------------------------+------------------------------------------------------+
+| in_deltaangl_z_raw                         | Raw Z-axis delta angle channel value.                |
++--------------------------------------------+------------------------------------------------------+
+
++----------------------------------+-------------------------------------------+
+| Temperature sensor related files | Description                               |
++----------------------------------+-------------------------------------------+
+| in_temp0_raw                     | Raw temperature channel value.            |
++----------------------------------+-------------------------------------------+
+| in_temp0_offset                  | Offset for the temperature sensor channel.|
++----------------------------------+-------------------------------------------+
+| in_temp0_scale                   | Scale for the temperature sensor channel. |
++----------------------------------+-------------------------------------------+
+
++----------------------------+--------------------------------------------------------------------------------+
+| Miscellaneous device files | Description                                                                    |
++----------------------------+--------------------------------------------------------------------------------+
+| name                       | Name of the IIO device.                                                        |
++----------------------------+--------------------------------------------------------------------------------+
+| sampling_frequency         | Currently selected sample rate.                                                |
++----------------------------+--------------------------------------------------------------------------------+
+| write_lock_enable          | Lock the device from further configuration. Only a reset will remove the lock. |
++----------------------------+--------------------------------------------------------------------------------+
+
+The following table shows the adis16550 related device debug files, found in the
+specific device debug folder path ``/sys/kernel/debug/iio/iio:deviceX``.
+
++----------------------+-------------------------------------------------------------------------+
+| Debugfs device files | Description                                                             |
++----------------------+-------------------------------------------------------------------------+
+| serial_number        | The serial number of the chip in hexadecimal format.                    |
++----------------------+-------------------------------------------------------------------------+
+| product_id           | Chip specific product id (16550).                                       |
++----------------------+-------------------------------------------------------------------------+
+| flash_count          | The number of flash writes performed on the device.                     |
++----------------------+-------------------------------------------------------------------------+
+| firmware_revision    | String containing the firmware revision in the following format ##.##.  |
++----------------------+-------------------------------------------------------------------------+
+| firmware_date        | String containing the firmware date in the following format mm-dd-yyyy. |
++----------------------+-------------------------------------------------------------------------+
+
+Channels processed values
+-------------------------
+
+A channel value can be read from its _raw attribute. The value returned is the
+raw value as reported by the devices. To get the processed value of the channel,
+apply the following formula:
+
+.. code-block:: bash
+
+        processed value = (_raw + _offset) * _scale
+
+Where _offset and _scale are device attributes. If no _offset attribute is
+present, simply assume its value is 0.
+
+The adis16550 driver offers data for 5 types of channels, the table below shows
+the measurement units for the processed value, which are defined by the IIO
+framework:
+
++--------------------------------------+---------------------------+
+| Channel type                         | Measurement unit          |
++--------------------------------------+---------------------------+
+| Acceleration on X, Y, and Z axis     | Meters per Second squared |
++--------------------------------------+---------------------------+
+| Angular velocity on X, Y and Z axis  | Radians per second        |
++--------------------------------------+---------------------------+
+| Delta velocity on X. Y, and Z axis   | Meters per Second         |
++--------------------------------------+---------------------------+
+| Delta angle on X, Y, and Z axis      | Radians                   |
++--------------------------------------+---------------------------+
+| Temperature                          | Millidegrees Celsius      |
++--------------------------------------+---------------------------+
+
+Usage examples
+--------------
+
+Show device name:
+
+.. code-block:: bash
+
+	root:/sys/bus/iio/devices/iio:device0> cat name
+        adis16550
+
+Show accelerometer channels value:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_raw
+        6903851
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_y_raw
+        5650550
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_z_raw
+        104873530
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_scale
+        0.000000095
+
+- X-axis acceleration = in_accel_x_raw * in_accel_scale = 0.655865845 m/s^2
+- Y-axis acceleration = in_accel_y_raw * in_accel_scale = 0.53680225 m/s^2
+- Z-axis acceleration = in_accel_z_raw * in_accel_scale = 9.96298535 m/s^2
+
+Show gyroscope channels value:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_x_raw
+        193309
+        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_raw
+        -763676
+        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_z_raw
+        -358108
+        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_scale
+        0.000000003
+
+- X-axis angular velocity = in_anglvel_x_raw * in_anglvel_scale = 0.000579927 rad/s
+- Y-axis angular velocity = in_anglvel_y_raw * in_anglvel_scale = −0.002291028 rad/s
+- Z-axis angular velocity = in_anglvel_z_raw * in_anglvel_scale = −0.001074324 rad/s
+
+Set calibration offset for accelerometer channels:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias
+        0
+
+        root:/sys/bus/iio/devices/iio:device0> echo 5000 > in_accel_x_calibbias
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias
+        5000
+
+Set calibration offset for gyroscope channels:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias
+        0
+
+        root:/sys/bus/iio/devices/iio:device0> echo -5000 > in_anglvel_y_calibbias
+        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias
+        -5000
+
+Set sampling frequency:
+
+.. code-block:: bash
+
+	root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency
+        4000.000000
+
+        root:/sys/bus/iio/devices/iio:device0> echo 1000 > sampling_frequency
+        1000.000000
+
+Set bandwidth for accelerometer channels:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency
+        0
+
+        root:/sys/bus/iio/devices/iio:device0> echo 100 > in_accel_filter_low_pass_3db_frequency
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency
+        100
+
+Show serial number:
+
+.. code-block:: bash
+
+        root:/sys/kernel/debug/iio/iio:device0> cat serial_number
+        0x000000b6
+
+Show product id:
+
+.. code-block:: bash
+
+        root:/sys/kernel/debug/iio/iio:device0> cat product_id
+        16550
+
+Show flash count:
+
+.. code-block:: bash
+
+        root:/sys/kernel/debug/iio/iio:device0> cat flash_count
+        13
+
+Show firmware revision:
+
+.. code-block:: bash
+
+        root:/sys/kernel/debug/iio/iio:device0> cat firmware_revision
+        1.5
+
+Show firmware date:
+
+.. code-block:: bash
+
+        root:/sys/kernel/debug/iio/iio:device0> cat firmware_date
+        28-04-2021
+
+3. Device buffers
+=================
+
+This driver supports IIO buffers.
+
+The device supports retrieving the raw acceleration, gyroscope, delta velocity,
+delta angle and temperature measurements using buffers.
+
+However, when retrieving acceleration or gyroscope data using buffers, delta
+readings will not be available and vice versa. This is because the device only
+allows to read either acceleration and gyroscope data or delta velocity and
+delta angle data at a time and switching between these two burst data selection
+modes is time consuming.
+
+Usage examples
+--------------
+
+Set device trigger in current_trigger, if not already set:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger
+
+        root:/sys/bus/iio/devices/iio:device0> echo adis16550-dev0 > trigger/current_trigger
+        root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger
+        adis16550-dev0
+
+Select channels for buffer read:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_x_en
+        root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_y_en
+        root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_z_en
+        root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_temp0_en
+
+Set the number of samples to be stored in the buffer:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> echo 10 > buffer/length
+
+Enable buffer readings:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> echo 1 > buffer/enable
+
+Obtain buffered data:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> hexdump -C /dev/iio\:device0
+        ...
+        0000cdf0  00 00 0d 2f 00 00 08 43  00 00 09 09 00 00 a4 5f  |.../...C......._|
+        0000ce00  00 00 0d 2f 00 00 07 de  00 00 08 db 00 00 a4 4b  |.../...........K|
+        0000ce10  00 00 0d 2f 00 00 07 58  00 00 08 a3 00 00 a4 55  |.../...X.......U|
+        0000ce20  00 00 0d 2f 00 00 06 d6  00 00 08 5c 00 00 a4 62  |.../.......\...b|
+        0000ce30  00 00 0d 2f 00 00 06 45  00 00 08 37 00 00 a4 47  |.../...E...7...G|
+        0000ce40  00 00 0d 2f 00 00 05 d4  00 00 08 30 00 00 a3 fa  |.../.......0....|
+        0000ce50  00 00 0d 2f 00 00 05 d0  00 00 08 12 00 00 a3 d3  |.../............|
+        0000ce60  00 00 0d 2f 00 00 05 dd  00 00 08 2e 00 00 a3 e9  |.../............|
+        0000ce70  00 00 0d 2f 00 00 05 cc  00 00 08 51 00 00 a3 d5  |.../.......Q....|
+        0000ce80  00 00 0d 2f 00 00 05 ba  00 00 08 22 00 00 a3 9a  |.../......."....|
+        0000ce90  00 00 0d 2f 00 00 05 9c  00 00 07 d9 00 00 a3 40  |.../...........@|
+        0000cea0  00 00 0d 2f 00 00 05 68  00 00 07 94 00 00 a2 e4  |.../...h........|
+        0000ceb0  00 00 0d 2f 00 00 05 25  00 00 07 8d 00 00 a2 ce  |.../...%........|
+        ...
+
+See ``Documentation/iio/iio_devbuf.rst`` for more information about how buffered
+data is structured.
+
+4. IIO Interfacing Tools
+========================
+
+See ``Documentation/iio/iio_tools.rst`` for the description of the available IIO
+interfacing tools.
diff --git a/Documentation/iio/index.rst b/Documentation/iio/index.rst
index dfcf9618568a..03829b2de2c0 100644
--- a/Documentation/iio/index.rst
+++ b/Documentation/iio/index.rst
@@ -24,6 +24,7 @@ Industrial I/O Kernel Drivers
    ad7944
    adis16475
    adis16480
+   adis16550
    adxl380
    bno055
    ep93xx_adc
-- 
2.34.1

Re: [PATCH 0/5] Add support for ADIS16550 and ADIS16550W

[Jonathan Cameron]

On Mon, 28 Oct 2024 14:35:42 +0200
Robert Budai <robert.budai@analog.com> wrote:

> The ADIS16550 is a complete inertial system that includes a triaxis gyroscope
> and a triaxis accelerometer. Each inertial sensor in the ADIS16550 combines
> industry leading MEMS only technology with signal conditioning that optimizes
> dynamic performance. The factory calibration characterizes each sensor for
> sensitivity, bias, and alignment. As a result, each sensor has its own dynamic
> compensation formulas that provide accurate sensor measurements.


Dropping the more marketing parts of this preferred.  Second
sentence doesn't add much that we care about.
The rest is fine.

> 
> Nuno Sá (3):
>   iio: imu: adis: Add custom ops struct
>   iio: imu: adis: Add DIAG_STAT register size
>   iio: imu: adis16550: add adis16550 support
> 
> Ramona Gradinariu (2):
>   dt-bindings: iio: Add adis16550 bindings
>   docs: iio: add documentation for adis16550 driver
> 
>  .../bindings/iio/imu/adi,adis16550.yaml       |   95 ++
>  Documentation/iio/adis16550.rst               |  389 ++++++
>  Documentation/iio/index.rst                   |    1 +
>  MAINTAINERS                                   |   10 +
>  drivers/iio/imu/Kconfig                       |   13 +
>  drivers/iio/imu/Makefile                      |    1 +
>  drivers/iio/imu/adis.c                        |   33 +-
>  drivers/iio/imu/adis16550.c                   | 1228 +++++++++++++++++
>  include/linux/iio/imu/adis.h                  |   33 +-
>  9 files changed, 1788 insertions(+), 15 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/iio/imu/adi,adis16550.yaml
>  create mode 100644 Documentation/iio/adis16550.rst
>  create mode 100644 drivers/iio/imu/adis16550.c
>