Ilya: /* Host Controller Interface (HCI) Initialization */

2017-06-15T11:55:20Z

‎Host Controller Interface (HCI) Initialization

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== Overview ==
The example run-time Linux filesystem image for the CompuLab UCM-iMX7 System-on-Module / Computer-on-Module is based on Debian GNU/Linux Sid.
The CompuLab Linux package for UCM-iMX7 includes ready to run image, Linux kernel configuration and source code patches, and an archive of the root filesystem, used to create the image.

The default Debian Wheezy Linux image includes more than 400 software packages. Among them:

* Core system
* Debian package management system
* X11 Windowing System
* Fluxbox desktop manager
* SSH server and client
* PulseAudio configuration and usage utilities
* Bluez5 Bluetooth tools and daemons

The [[UCM-iMX7: Linux: Automatic Installation|Automatic Linux installation on UCM-iMX7]] page provides a brief introduction on how to install the run-time Linux image.
This article describes package structure and peripheral device options specific to the UCM-iMX7.

{{Note|The article uses {{cmd|cl-rootfs}} hostname. A real hostname may be different.}}

== Using Debian Linux on UCM-iMX7 ==

=== Connection and Logging In ===
{{:Transclusion: Debian: Logging In}}

=== Networking ===
{{:Transclusion: Debian: Networking}}

=== Consoles ===
{{:Transclusion: Debian: Consoles}}

=== X Windows system ===
{{:Transclusion: Debian: X Windows: Fluxbox}}

=== Software Management ===
{{:Transclusion: Debian: Software Management}}

=== Analog Audio ===
UCM-iMX7 provides an analog audio interface, which is registered as a standard ALSA sound card.
Use {{cmd|aplay -l}} to list all soundcards and digital audio devices registered on the system:
<pre>
root@cl-rootfs:~# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: ucmimx7 [ucm-imx7], device 0: 308a0000.sai-wm8731-hifi wm8731-hifi-0 []
Subdevices: 1/1
Subdevice #0: subdevice #0
</pre>
{{:Transclusion: Debian: CL-SOM-iMX7: Analog Audio}}

=== USB On-The-Go (OTG) ===
{{:Transclusion: Debian: iMX7: USB OTG}}

=== WiFi ===
UCM-iMX7 features 802.11b/g/n wireless connectivity solution, implemented with a Broadcom BCM4343W chipset.

==== WiFi Initialization ====
* WiFi requires no user interaction for being configured. The driver gets loaded automatically by the means of ''/etc/modules-load.d/wifi.conf'' configuration file. The driver options are specified with the options file ''/etc/modprobe.d/bcmdhd.conf''. Make sure that the WiFi driver is loaded:
<pre>
root@cl-rootfs:~# lsmod | grep bcmdhd
bcmdhd 597255 0
</pre>
* The WiFi driver can be loaded manually.
<blockquote>
* Create the driver options file:
<pre>
cat << eof > /etc/modprobe.d/bcmdhd.conf
options bcmdhd firmware_path=/lib/firmware/brcm/1DX/fw_bcmdhd.bin
options bcmdhd nvram_path=/lib/firmware/brcm/1DX/bcmdhd.1DX.SDIO.cal
options bcmdhd dhd_msg_level=0x1
eof
</pre>
* Load the WiFi driver module:
<pre>
root@cl-debian:~# modprobe bcmdhd
dhd_module_init in
...
Register interface [wlan0] MAC: b0:72:bf:09:b5:fc
</pre>
</blockquote>
* {{cmd|iwconfig}} command from {{filename|wireless-tools}} package can be used to retrieve detailed information about the WiFi interfaces:
<pre>
root@cl-rootfs:~# iwconfig wlan0
wlan0 IEEE 802.11bg ESSID:off/any
Mode:Managed Access Point: Not-Associated
Retry short limit:7 RTS thr:off Fragment thr:off
Encryption key:off
Power Management:on
</pre>
* Activate the interface:
<pre>
root@cl-rootfs:~# ifconfig wlan0 up
</pre>
* Sample WiFi scanning:
<pre>
root@cl-rootfs:~# iwlist wlan0 scan
</pre>
The output will show the list of Access Points and Ad-Hoc cells in range.
For more information about connecting to wireless networks and tuning WiFi interfaces refer to “wpa_supplicant” and “wireless-tools” man pages.

==== wpa_supplicant ====
* Configuration sample
{{cmd|wpa_supplicant}} requires a configuration file to be created in order to get connected to a scanned wireless network.<br>
Make use of the example bellow and put the network name and the password into the "ssid/psk" fields.

<pre>
root@cl-rootfs:~# cat << eof > /etc/wpa_supplicant.conf
ctrl_interface=/var/run/wpa_supplicant

network={
ssid="wireless_network_name"
key_mgmt=WPA-PSK
psk="wireless_network_password"
}
eof
</pre>
* Sample run
<pre>
root@cl-rootfs:~# ifconfig wlan0 up
root@cl-rootfs:~# wpa_supplicant -B -Dwext -c /etc/wpa_supplicant.conf -i wlan0
root@cl-rootfs:~# dhclient wlan0
</pre>

=== Bluetooth ===
UCM-iMX7 features Bluetooth 4.1 + High Speed (HS) interface. Following sections describe the initialization and simple use cases of the Bluetooth interface.

==== Host Controller Interface (HCI) Initialization ====
* Start Bluetooth:
<pre>
root@cl-debian:~# bt-start
bcm43xx_init
Set Controller UART speed to 3000000 bit/s
Flash firmware /etc/firmware/BCM43430A1.1DX.hcd
Set Controller UART speed to 3000000 bit/s
Bluetooth: HCI UART driver ver 2.3
Bluetooth: HCI UART protocol H4 registered
Bluetooth: HCI UART protocol BCM registered
Device setup complete
</pre>
* Make sure that the Bluetooth drivers are loaded:
<pre>
root@cl-debian:~# lsmod
Module Size Used by
hci_uart 7594 1
btbcm 5344 1 hci_uart
...
</pre>

* HCI device configuration utility can be run to retrieve detailed information about the Bluetooth interfaces:
<pre>
root@cl-debian:~# hciconfig -a
hci0: Type: BR/EDR Bus: UART
BD Address: 43:43:A1:12:1F:AC ACL MTU: 1021:8 SCO MTU: 64:1
UP RUNNING
RX bytes:675 acl:0 sco:0 events:39 errors:0
TX bytes:1271 acl:0 sco:0 commands:39 errors:0
Features: 0xbf 0xfe 0xcf 0xfe 0xdb 0xff 0x7b 0x87
Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3
Link policy: RSWITCH SNIFF
Link mode: SLAVE ACCEPT
Name: 'BlueZ 5.36'
Class: 0x000000
Service Classes: Unspecified
Device Class: Miscellaneous,
HCI Version: 4.0 (0x6) Revision: 0x16
LMP Version: 4.0 (0x6) Subversion: 0x2209
Manufacturer: Broadcom Corporation (15)
</pre>

* If the HCI device is not running, use the below command to enable the HCI device:
<pre>
root@cl-debian:~# hciconfig hci0 up
</pre>

{{:Transclusion: Debian: iMX7: Bluez5 PulseAudio}}

=== Controller–area network (CAN) ===
UCM-iMX7 features two Flexible Controller Area Network (FLEXCAN) modules. Each FLEXCAN implements full CAN protocol version 2.0B and supports both the standard and the extended frame format as well as a programmable data bit rate up to 1Mbit/s.
{{Note|Please prepare the hardware as described in the [[UCM-iMX7: Evaluation Kit: Hardware Guide#CAN | UCM-iMX7 Evaluation Kit Hardware Guide]] and [[SB-UCM: HOWTO: CAN Connection | CAN node connection guide]].}}
{{:Transclusion: Debian: iMX7: CAN Bus}}

=== Touchscreen ===
The touchscreen driver is modularized if you use default UCM-iMX7 configuration and is not loaded by {{filename|udev}} automatically on Linux boot. Use the following command to load the touchscreen driver module:

* For TI TSC2046 touch panel:
<pre>
root@cl-rootfs:~# modprobe ads7846
</pre>

The X Windows system of UCM-iMX7 uses tslib X server input driver to get the input from the touchscreen.

==== Touchscreen calibration ====
All supported touchscreen devices can be calibrated using {{cmd|xinput_calibrator}} utility.

To calibrate the touchscreen:
* Run X Server by issuing {{cmd|startx &}} command
* Make sure the touchscreen driver is loaded as described in [[#Touchscreen|Touchscreen]] section
* Set the {{parameter|DISPLAY}} environment variable:
<pre> export DISPLAY=:0</pre>
* Run {{cmd|xinput_calibrator}} utility. For proper calibration you are required to touch the touchscreen corners and center in the following order: top-left, top-right, bottom-right, bottom-left, center.
* Create a file {{filename|/usr/share/X11/xorg.conf.d/99-calibration.conf}} and paste there a snippet with the calibration results:
<pre>
root@cl-rootfs:~# xinput_calibrator
Setting calibration data: 0, 4095, 0, 4095
Calibrating EVDEV driver for "ADS7846 Touchscreen" id=6
current calibration values (from XInput): min_x=0, max_x=4095 and min_y=0, max_y=4095

Doing dynamic recalibration:
Setting calibration data: 165, 3864, 3789, 268
--> Making the calibration permanent <--
copy the snippet below into '/etc/X11/xorg.conf.d/99-calibration.conf' (/usr/share/X11/xorg.conf.d/ in some distro's)
Section "InputClass"
Identifier "calibration"
MatchProduct "ADS7846 Touchscreen"
Option "Calibration" "165 3864 3789 268"
Option "SwapAxes" "0"
EndSection
</pre>

=== MMC/SD ===
{{:Transclusion: Debian: CL-SOM-iMX7: MMC}}

=== GPIO access ===
{{:Transclusion: Debian: GPIO}}

== See also ==

* [[UCM-iMX7: Evaluation Kit: Getting Started]]
* [[UCM-iMX7: Evaluation Kit: Hardware Guide]]
* [[UCM-iMX7: Linux: Automatic Installation]]
* [[UCM-iMX7: Linux: Manual Installation]]
* [[UCM-iMX7: Linux: Kernel]]
* [[Linux: Development for ARM modules]]
* [[Linux: Debian: Minimal ARM filesystem]]
* [http://www.debian.org/doc/manuals/reference/index.en.html Debian Reference].

[[Category:Linux]]
[[Category:UCM-iMX7]]

UCM-iMX7: Linux: Debian - Revision history

Ilya: /* Host Controller Interface (HCI) Initialization */