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This version (16 Nov 2012 12:45) was approved by larsc.The Previously approved version (05 Sep 2012 14:02) is available.Diff

ADIS16060 IIO Yaw Rate Gyroscope Linux Driver

Supported Devices

Evaluation Boards

Description

This is a Linux industrial I/O (IIO) subsystem driver, targeting serial interface Gyroscopes. The industrial I/O subsystem provides a unified framework for drivers for many different types of converters and sensors using a number of different physical interfaces (i2c, spi, etc). See IIO for more information.

Source Code

Status

Source Mainlined?
git Yes

Files

Declaring SPI slave devices

Unlike PCI or USB devices, SPI devices are not enumerated at the hardware level. Instead, the software must know which devices are connected on each SPI bus segment, and what slave selects these devices are using. For this reason, the kernel code must instantiate SPI devices explicitly. The most common method is to declare the SPI devices by bus number.

This method is appropriate when the SPI bus is a system bus, as in many embedded systems, wherein each SPI bus has a number which is known in advance. It is thus possible to pre-declare the SPI devices that inhabit this bus. This is done with an array of struct spi_board_info, which is registered by calling spi_register_board_info().

For more information see: Documentation/spi/spi-summary

21 Oct 2010 16:10 · Michael Hennerich

Depending on the converter IC used, you may need to set the modalias accordingly, matching your part name. It may also required to adjust max_speed_hz. Please consult the datasheet, for maximum spi clock supported by the device in question.

static struct spi_board_info board_spi_board_info[] __initdata = {
#if defined(CONFIG_ADIS16060) \
	|| defined(CONFIG_ADIS16060_MODULE)
	{
		.modalias = "adis16060_r",
		.max_speed_hz = 2900000,     /* max spi clock (SCK) speed in HZ */
		.bus_num = 0,
		.chip_select = 1, /* CS for read, change it for your board */
		.platform_data = NULL, /* No spi_driver specific config */
		.mode = SPI_MODE_0,
	},
	{
		.modalias = "adis16060_w",
		.max_speed_hz = 2900000,     /* max spi clock (SCK) speed in HZ */
		.bus_num = 0,
		.chip_select = 2, /* CS for write, change it for your board */
		.platform_data = NULL, /* No spi_driver specific config */
		.mode = SPI_MODE_1,
	},
#endif
};
static int __init board_init(void)
{
	[--snip--]
 
	spi_register_board_info(board_spi_board_info, ARRAY_SIZE(board_spi_board_info));
 
	[--snip--]
 
	return 0;
}
arch_initcall(board_init);

Adding Linux driver support

Configure kernel with “make menuconfig” (alternatively use “make xconfig” or “make qconfig”)

The ADIS16060 Driver depends on CONFIG_SPI

Linux Kernel Configuration
	Device Drivers  --->
		[*] Staging drivers  --->
			<*>     Industrial I/O support --->
			    --- Industrial I/O support
			    -*-   Enable ring buffer support within IIO
			    -*-     Industrial I/O lock free software ring
			    -*-   Enable triggered sampling support

			          *** Digital gyroscope sensors ***
			    [--snip--]

			    <*>   Analog Devices ADIS16060 Yaw Rate Gyroscope with SPI driver

			    [--snip--]

Hardware configuration

Driver testing

Each and every IIO device, typically a hardware chip, has a device folder under /sys/bus/iio/devices/iio:deviceX. Where X is the IIO index of the device. Under every of these directory folders reside a set of files, depending on the characteristics and features of the hardware device in question. These files are consistently generalized and documented in the IIO ABI documentation. In order to determine which IIO deviceX corresponds to which hardware device, the user can read the name file /sys/bus/iio/devices/iio:deviceX/name. In case the sequence in which the iio device drivers are loaded/registered is constant, the numbering is constant and may be known in advance.

02 Mar 2011 15:16 · Michael Hennerich

This specifies any shell prompt running on the target

root:/> cd /sys/bus/iio/devices/
root:/sys/bus/iio/devices> ls
iio:device0  trigger0


root:/sys/bus/iio/devices> cd iio:device0
root:/sys/devices/platform/bfin-spi.0/spi0.1/iio:device0> ls -l
-r--r--r--    1 root     root          4096 Jan  3 19:32 dev
-r--r--r--    1 root     root          4096 Jan  3 19:32 in_gyro_z_raw
-rw-r--r--    1 root     root          4096 Jan  3 19:32 in_temp0_offset
-r--r--r--    1 root     root          4096 Jan  3 19:32 in_temp0_raw
-rw-r--r--    1 root     root          4096 Jan  3 19:32 in_temp0_scale
-r--r--r--    1 root     root          4096 Jan  3 19:32 in_voltage0_raw
-r--r--r--    1 root     root          4096 Jan  3 19:32 in_voltage1_raw
-r--r--r--    1 root     root          4096 Jan  3 19:32 name
drwxr-xr-x    2 root     root             0 Jan  3 19:32 power
lrwxrwxrwx    1 root     root             0 Jan  3 19:32 subsystem -> ../../../../../bus/iio
-rw-r--r--    1 root     root          4096 Jan  3 19:32 uevent
root:/sys/devices/platform/bfin-spi.0/spi0.1/iio:device0>

Show device name

This specifies any shell prompt running on the target

root:/sys/devices/platform/bfin-spi.0/spi0.1/iio:device0> cat name
adis16060_r

ADIS16060 device attributes

For a detailed description please see: drivers/staging/iio/Documentation/sysfs-bus-iio

Device files
in_gyro_z_raw
in_temp0_offset
in_temp0_raw
in_temp0_scale
in_voltage0_raw
in_voltage1_raw
name

More Information