COM AM335x Linux: Difference between revisions

Revision as of 13:27, 22 March 2016

Linux virtual machine for development

Please have a look at: Virtual Machine for Application Development

Linux Kernel

Sources for the DHCOM AM335x Linux Kernel v4.1.x

The latest Linux Kernel source code is available on GitHub: https://github.com/dh-electronics/linux-am33x

How to build a Kernel

Get sources from Github

1. Start a terminal on Linux 2. `# git clone https://github.com/dh-electronics/linux-am33x.git` 3. `# cd linux-am33x` 4. `# git checkout release/20160219 # checkout latest/required release branch`

Configure and build the kernel using 5 threads in a separate build directory

5. `# mkdir ../build` 6. `# ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- make O=../build/ am335x_dhcom_defconfig` 7. `# ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- make O=../build/ menuconfig` (optional: Add/Remove Kernel Features) 8. `# ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- make -j5 O=../build/ zImage` 9. `# ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- make -j5 O=../build/ dtbs`

Your new zImage file is available in ../build/arch/arm/boot
The Devicetree file am335x-dheva01.dtb is available in ../build/arch/arm/boot/dts

Update the Kernel and Devicetree with U-Boot

Please refere to the DHCOM Update Mechanism for am335x.

Update Kernel and Devicetree on a running Linux

Kernel

1. Copy the kernel zImage file to the path `/boot` 2. Check whether the correct zImage file name is set in `/boot/uLinuxEnv.txt` (e.g. `zImage_file=zImage`)

Devicetree

3. Copy the devicetree file am335x-dheva01.dtb to the path `/boot/dtbs` 4. Check fdtfile variable in `/boot/uLinuxEnv.txt` (e.g. `fdtfile=/dtbs/am335x-dheva01.dtb`)

Reboot System

5. Restart the system (e.g. `reboot`)

Debian Rootfilesystem

Available Rootfilesystems

Please have a look at the DHCOM AM335x Downloads section.

External Documentation

The Debian Administrator's Handbook: A reference book presenting the Debian distribution, from initial installation to configuration of services. The administration and configuration chapters apply to our Debian based root filesystems.
Debian Documentation

Login

`Debian GNU/Linux 8 dhcom ttyO0` `dhcom login: root Password: foo`

Shutdown

`# shutdown -h now`

Calibrating the touchscreen (tslib has to be installed)

`# source setup_tslib.sh` # setup environment for use of tslib `# ts_calibrate`

Check the enviroment variable "TSLIB_TSDEVICE=/dev/input/event0" with printenv if an error occurs.

How to create a microSD-card with a rootfilesystem on it

1. Format a microSD card like following (in linux e.g. gparted, palimpsest) with Master Boot Record partition scheme

`P1 ext3, name="boot" (Primary partition: 100MiB)` `P2 ext3, name="rootfs" (Primary part.: Residual space)`

2. Untar the root file system to the "rootfs" partition of the microSD card (Don't copy the tar archive directly to the microSD card)

Start the Console on Linux `# su` `# chmod 755 /path/of/the/microSD_card` `# cd /path/of/the/microSD_card` `# tar xfjv path/to/RootFS/Name_of_RootFS_file.tar.bz2`

Remark: If you got a *.tar.gz file so type tar xfzv ... to extract the rootfilesystem.

Kernel Userspace Interfaces to Access Hardware

Serial (UART) Interfaces

DHCOM (FF) UART 1	`/dev/ttyO0`
DHCOM (BT) UART 2	`/dev/ttyO1`
DHCOM (STD) UART 3	not available

I2C Interfaces

DHCOM I2C 1	`/dev/i2c-2`
DHCOM I2C 2	not available
On Module Devices	`/dev/i2c-0`

SPI Interfaces

DHCOM SPI 1	`/dev/spidev1.1`
DHCOM SPI 2	not available

Remark: DHCOM SPI1 interface doesn‘t work with DHCOM Premium Developer Kit (HD00013).

Reason: At DHCOM Premium Developer Kit SPI 1 isn‘t connected, because otherwise AM335x doesn‘t boot with the current schematic.

MMC/SD/eMMC Interfaces

DHCOM SD-Interface	`/dev/mmcblk0pX` (optional)
on module µSD Card	`/dev/mmcblk0pX` (optional)
on module eMMC	`/dev/mmcblk1pX`

'X' has to be replaced with the partition number

DHCOM SD-Interface or on module µSD slot is available

Control the display brightness

echo [0..8] > /sys/class/backlight/backlight/brightness

Control GPIOs

DHCOM Name:	alt. DHCOM Name:	SO-DIMM Pin#	Linux <GPIO#>
GPIO A		154	20
GPIO B		156	115
GPIO C		162	116
GPIO D		163	65
GPIO E		164	114
GPIO F		165	112
GPIO G		167	111
GPIO H		173	7
GPIO I		175	113
CIF HSYNC	GPIO J	74	117
CIF PCLK	GPIO K	72	57
CIF MCLK	GPIO L	70	56
CIF VSYNC	GPIO M	68	55
CIF D9	GPIO N	66	54
CIF D8	GPIO O	64	51
CIF D7	GPIO P	62	50
CIF D6	GPIO Q	60	49

Remark: The parallel camera interface is not available on DHCOM AM335x.

Export

`echo <GPIO#> >/sys/class/gpio/export`

Remark: Have a look into /sys/class/gpio/ for already configured gpios.

Set direction

`echo in >/sys/class/gpio/gpio<GPIO#>/direction`
`echo out >/sys/class/gpio/gpio<GPIO#>/direction`

Set state

`echo 0 >/sys/class/gpio/gpio<GPIO#>/value`
`echo 1 >/sys/class/gpio/gpio<GPIO#>/value`

Initialize and Test CAN Interface

Initialize:

`ip link set can0 up type can bitrate 500000`

Send test message via cansend (part of can-utils):

`cansend can0 100#11.2233.44556677.88`

Receive can messages (part of can-utils):

`candump can0`

Get can-utils:

Debian package containing can-utils (ARM)

Configure your own display

To configure your own display you have to do the following steps:

1. Type in the display values into the device tree file /arch/arm/boot/dts/imx6qdl-dheva01.dtsi

Where in the file?

Parallel display:	`display@di0`
LVDS display:	`&ldb`
Remarks: If you don't want to use both interfaces comment the unwanted out! The frame buffer resolution depends on the higher display resolution of both displays

How?

Here is an example:


 display-timings {
   DataImage_7inch_FG0700G3DSSW {
   clock-frequency = <33260000>;
   hactive = <800>;
   vactive = <480>;
   hback-porch = <86>;
   hfront-porch = <42>;
   vback-porch = <33>;
   vfront-porch = <10>;
   hsync-len = <128>;
   vsync-len = <2>;
   hsync-active = <0>;
   vsync-active = <0>;
   de-active = <1>;
   pixelclk-active = <1>;
   };
 };

2. Build the device tree dtb files ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- make dtbs

3. Copy the dtb files onto your boot partition /dtbs (SD, µSD or eMMC)

The built imx6xx-dheva01.dtb device tree files will you find in arch/arm/boot/dts

@@ Line 112: / Line 112: @@
 === Serial (UART) Interfaces ===
 :{| class="wikitable" style="width: 400px"
-  ||DHCOM (FF) UART 1||<code>/dev/ttymxc0</code>
+  ||DHCOM (FF) UART 1||<code>/dev/ttyO0</code>
   |-
-  ||DHCOM (BT) UART 2 ||<code>/dev/ttymxc4</code>
+  ||DHCOM (BT) UART 2 ||<code>/dev/ttyO1</code>
   |-
-  ||DHCOM (STD) UART 3 ||<code>/dev/ttymxc3</code>
+  ||DHCOM (STD) UART 3 || not available
   |}
 === I2C Interfaces ===
-:dhcom3B = Hardware revision 300
 :{| class="wikitable" style="width: 400px"
-  ||DHCOM I2C 1||<code>/dev/i2c-1</code>
+  ||DHCOM I2C 1||<code>/dev/i2c-2</code>
   |-
-  ||DHCOM I2C 2 ||<code>/dev/i2c-0</code>
+  ||DHCOM I2C 2 || not available
   |-
-  ||On Module Devices ||<code>/dev/i2c-2</code>
+  ||On Module Devices ||<code>/dev/i2c-0</code>
   |}
-:old: dhcom2B = Hardware revision 200
-:{| class="wikitable" style="width: 400px"
- ||DHCOM I2C 1||<code>/dev/i2c-0</code>
- |-
- ||DHCOM I2C 2 ||<code>/dev/i2c-1</code>
- |-
- ||On Module Devices ||<code>/dev/i2c-2</code>
- |}
 === SPI Interfaces ===
 :{| class="wikitable" style="width: 400px"
-  ||DHCOM SPI 1||<code>/dev/spidev0.2</code>
+  ||DHCOM SPI 1||<code>/dev/spidev1.1</code>
   |-
-  ||DHCOM SPI 2 ||<code>/dev/spidev1.0</code>
+  ||DHCOM SPI 2 || not available
   |}
 :: '''Remark:''' DHCOM SPI1 interface doesn‘t work with DHCOM Premium Developer Kit (HD00013).
-::Reason: At DHCOM Premium Developer Kit SPI 1 isn‘t connected, because otherwise i.MX6 doesn‘t boot with the current schematic.
+::Reason: At DHCOM Premium Developer Kit SPI 1 isn‘t connected, because otherwise AM335x doesn‘t boot with the current schematic.
 === MMC/SD/eMMC Interfaces ===
 :{| class="wikitable" style="width: 400px"
-  ||DHCOM SD-Interface ||<code>/dev/mmcblk0pX</code>
+  ||DHCOM SD-Interface ||<code>/dev/mmcblk0pX</code> (optional)
   |-
-  ||on module µSD Card ||<code>/dev/mmcblk1pX</code>
+  ||on module µSD Card ||<code>/dev/mmcblk0pX</code> (optional)
   |-
-  ||on module eMMC ||<code>/dev/mmcblk2pX</code>
+  ||on module eMMC ||<code>/dev/mmcblk1pX</code>
   |}
 : 'X' has to be replaced with the partition number
+: DHCOM SD-Interface '''or''' on module µSD slot is available
 === Control the display brightness ===
-: Coming soon
+:{|class="wikitable" style="text-align: center; width: 600px"
+|-
+|echo [0..8] > /sys/class/backlight/backlight/brightness
+|}
 === Control GPIOs ===
@@ Line 167: / Line 162: @@
 ! DHCOM Name: !! alt. DHCOM Name: !! SO-DIMM Pin# !! Linux <GPIO#>
 |-
-| GPIO A || || 154 || 2
+| GPIO A || || 154 || 20
-|-
-| GPIO B || || 156 || 4
-|-
-| GPIO C || || 162 || 5
-|-
-| GPIO D || || 163 || 163
-|-
-| GPIO E || || 164 || 101
-|-
-| GPIO F || || 165 || 116
-|-
-| GPIO G || || 167 || 91
 |-
-| GPIO H || || 173 || 103
+| GPIO B || || 156 || 115
 |-
-| GPIO I || || 175 || 104
+| GPIO C || || 162 || 116
 |-
-| CIF HSYNC || GPIO J || 74 || 174
+| GPIO D || || 163 || 65
 |-
-| CIF PCLK || GPIO K || 72 || 175
+| GPIO E || || 164 || 114
 |-
-| CIF MCLK || GPIO L || 70 || 105
+| GPIO F || || 165 || 112
 |-
-| CIF VSYNC || GPIO M || 68 || 192
+| GPIO G || || 167 || 111
 |-
-| CIF D9 || GPIO N || 66 || 193
+| GPIO H || || 173 || 7
 |-
-| CIF D8 || GPIO O || 64 || 149
+| GPIO I || || 175 || 113
 |-
-| CIF D7 || GPIO P || 62 || 205
+| CIF HSYNC || GPIO J || 74 || 117
 |-
-| CIF D6 || GPIO Q || 60 || 18
+| CIF PCLK || GPIO K || 72 || 57
 |-
-| CIF D5 || GPIO R || 58 || 16
+| CIF MCLK || GPIO L || 70 || 56
 |-
-| CIF D4 || GPIO S || 56 || 17
+| CIF VSYNC || GPIO M || 68 || 55
 |-
-| CIF D3 || GPIO T || 54 || 19
+| CIF D9 || GPIO N || 66 || 54
 |-
-| CIF D2 || GPIO U || 52 || 20
+| CIF D8 || GPIO O || 64 || 51
 |-
-| CIF D1 || GPIO V || 50 || 146
+| CIF D7 || GPIO P || 62 || 50
 |-
-| CIF D0 || GPIO W || 48 || 147
+| CIF D6 || GPIO Q || 60 || 49
 |}
-:: '''Remark:''' Depending on your board configuration some of the additional gpios shared with the camera interface are not available on your system.
+:: '''Remark:''' The parallel camera interface is not available on DHCOM AM335x.
 :Export