From Texas Instruments Wiki
The goal of Porting Guide is to provide valuable information and instructions to people who want to run Android OS on their (new) HW. Information covered here will mainly be useful to port TI Android JB DevKit on Sitara-based devices.
Note: Detailed porting information in the different technical areas is dependent on the respective h/w architecture. The information provided here generally refers to the AM335x devices. Information specific to AM37x shall be provided if necessary.
The Android Board-specific configuration files are present in device/ti/&boardname&. e.g for am335xevm, the files are at &android sources root&/device/ti/am335xevm.
The Jelly Bean release uses board-specific init file instead of the unified init.rc used in previous releases. The board name is determined by the android property ro.hardware which is the machine name set in the board file in the kernel. So the init file for am335xevm becomes init.am335xevm.rc.
This section of the porting guide describes the display system with respect to TI Android JB DevKit. AM335x EVM, AM335x Starter Kit, BeagleBone with LCD cape, AM37x EVM and Flashboard use LCD interface for display while BeagleBoard uses DVI output.
Depending on the display size, android uses either the phone layout (e.g. AM37xevm, AM335xevm) or tablet layout (Beagleboard).
Supports LCD display interface on AM335x EVM, AM335x Starter Kit, AM37xevm, Flashboard and BeagleBone with LCD cape
Supports DVI output on Beagleboard, AM37xevm, Flashboard and BeagleBone with DVI-D cape
for AM335x
This section explains how the LCD backlight control is implemented in the DevKit. For variable backlight intensity, PWM-controlled backlight is generally used.
For integration with the Android Backlight settings configuration, the liblights HAL needs to be implemented for the board. The output HAL library should have the name lights.&TARGET_PRODUCT&.so. E.g. for AM335x EVM, the liblights HAL is called lights.am335xevm.so.
The liblights backlight HAL for AM335x EVM is implemented at .
The touchscreen is the primary input device for TI Android DevKit on AM335xevm, EVM-SK, BeagleBone LCD7/LCD3 cape, AM37xevm and Flashboard.
The features supported by Touchscreen in Android are:
Single touch input
Single click
Single long click
Uni-direction motion touch
AM335x evm: Refer
for details
AM37x : TBD
Once ADC Touchscreen driver is up through board file (e.g. board-am335xevm.c) configuration.
Test with AndroidFS as events are coming while touching the LCD display. Run on command prompt:
# getevent
add device 1: /dev/input/event1
&ti-tsc-adcc&
/dev/input/event1: 000659
/dev/input/event1: 000a31
/dev/input/event1: 000001
/dev/input/event1: 000000
/dev/input/event1: 000654
/dev/input/event1: 000000
It confirms that touch inputs and irq based event generation is working fine.
The platform data for TSC driver for AM335x contains the following fields to provide calibration data:
static struct tsc_data am335xevm_touchscreen_data = {
.min = 0xCB,
.max = 0xF9B,
.inverted = 1,
.min = 0xC8,
.max = 0xE93,
.inverted = 1,
X-axis is from left to right and Y-axis from top to bottom.
min and max values are the actual touch data obtained at the extreme corners of the LCD screen. You can obtain the raw value returned by the touchscreen at the corners using the getevent utility in Android. Use the values for ABS_X and ABS_Y
root@android:/ # getevent -tl /dev/input/event3
ABS_PRESSURE
SYN_REPORT
Run android on the board.
select "Menu" -& "Dev Tools" -& "Pointer Location" utility
Touch and draw on the screen and observe that the expected points are getting marked on the LCD screen.
if drawing on LCD is not proper then driver needs to be fine tune the above mentioned macros.
See also :
In the TI Android DevKit, touchscreen is set as the default input device.
The matrix gpio keypad and Volume gpio keys are in AM335x EVM. Here porting explanation for matrix gpio keypad controller.
3x2 matrix key layout supported
single click input
Add keypad driver support
start the Linux Kernel Configuration tool:
$ make ARCH=arm menuconfig
Select Device Drivers from the main menu.
Power management options ---&
[*] Networking support ---&
'''Device Drivers ---&'''
File systems ---&
Kernel hacking ---&
Select Input device support form the next menu:
[ ] ISDN support
& & Telephony support
'''Input device support
Character devices
-*- I2C support
from the next menu:
*** Input Device Drivers ***
Joysticks/Gamepads
GPIO driven matrix keypad support and GPIO Buttons from the next menu:
DECstation/VAXstation LK201/LK401 keyboard
GPIO Buttons
Polled GPIO buttons
TCA6416/TCA6408A Keypad Support
GPIO driven matrix keypad support
Maxim MAX7359 Key Switch Controller
Board-specific Configuration
The board-specific configuration includes, specifying the GPIOs, no. of rows and columns, debounce, scan settings etc. The following code snippet shows the configuration for AM335x EVM (arch/arm/mach-omap2/board-am335xevm.c).
static const uint32_t am335x_evm_matrix_keys[] = {
KEY(0, 0, KEY_MENU),
KEY(1, 0, KEY_BACK),
KEY(2, 0, KEY_LEFT),
KEY(0, 1, KEY_RIGHT),
KEY(1, 1, KEY_ENTER),
KEY(2, 1, KEY_DOWN),
const struct matrix_keymap_data am335x_evm_keymap_data = {
= am335x_evm_matrix_keys,
.keymap_size = ARRAY_SIZE(am335x_evm_matrix_keys),
static const unsigned int am335x_evm_keypad_row_gpios[] = {
GPIO_TO_PIN(1, 25), GPIO_TO_PIN(1, 26), GPIO_TO_PIN(1, 27)
static const unsigned int am335x_evm_keypad_col_gpios[] = {
GPIO_TO_PIN(1, 21), GPIO_TO_PIN(1, 22)
static struct matrix_keypad_platform_data am335x_evm_keypad_platform_data = {
.keymap_data
= &am335x_evm_keymap_data,
.row_gpios
= am335x_evm_keypad_row_gpios,
.num_row_gpios
= ARRAY_SIZE(am335x_evm_keypad_row_gpios),
.col_gpios
= am335x_evm_keypad_col_gpios,
.num_col_gpios
= ARRAY_SIZE(am335x_evm_keypad_col_gpios),
.active_low
.debounce_ms
.col_scan_delay_us = 2,
static struct gpio_keys_button am335x_evm_volume_gpio_buttons[] = {
= KEY_VOLUMEUP,
= GPIO_TO_PIN(0, 2),
.active_low
= &volume-up&,
= KEY_VOLUMEDOWN,
= GPIO_TO_PIN(0, 3),
.active_low
= &volume-down&,
static struct gpio_keys_platform_data am335x_evm_volume_gpio_key_info = {
= am335x_evm_volume_gpio_buttons,
= ARRAY_SIZE(am335x_evm_volume_gpio_buttons),
Test keypad driver using getevent
Once matrix gpio keypad and volume gpio keys driver is up through board file (e.g. board-am335xevm.c) configuration.
Test with AndroidFS as events are coming while pressing the keys. Run on command prompt:
# getevent
add device 1: /dev/input/event2
name: &gpio-keys&
add device 2: /dev/input/event0
name: &matrix-keypad&
/dev/input/event0: 000002
/dev/input/event0: 000001
/dev/input/event0: 000000
/dev/input/event0: 000002
/dev/input/event0: 000000
/dev/input/event0: 000000
It confirms that keypad inputs and irq based event generation is working fine.
Android requires Key layout files (.kl files) for mapping Linux key codes and axis codes to Android key codes and axis codes and specifying associated policy flags.
The &matrix keypad driver name&.kl (e.g. QWERTY_Keypad.kl) or &gpio keypad driver name&.kl (e.g. gpio-keys.kl) should be present in root directory of AndroidFS.
Syntax of a Key layout File (Refer to the link: ):
Key declarations each consist of the keyword "key" followed by a Linux key code number(In Decimal), an Android key code name, and optional set of whitespace delimited policy flags.
For example:
The gpio-keys.kl for Beaglebone looks like:
# Beaglebone LCD Cape
GPIO KEYPAD keylayout
For finding a suitable Android key code name for your requirement, follow the link:
The Policy Flags specify extra information such as: whether this key should wake the device, also while waking the device should this key press be considered etc. Complete information is available under the "Key Declarations" in the link:
The MMC/SD card is used as the primary boot device and storage device on TI Android DevKit. This section gives details on configuring the MMC interface and supporting MMC/SD storage card.
The MMC/SD/SDIO driver supports following features
The driver is built in-kernel (part of vmlinux).
MMC cards including High Speed cards.
SD cards including SD High Speed and SDHC cards
Uses block bounce buffer to aggregate scattered blocks
for AM335x
Android system uses vold as the mount daemon, which detects, mounts and monitors the status of sdcard. The mount daemon needs a configuration file to tell it what the sdcard device is. Since Android 2.2 (froyo), it ships with a new implementation of vold (aka vold2). The configuration is changed to /etc/vold.fstab and its format is also changed. See
in the Android source tree for the detailed explanations of the format.
However, a fixed vold.fstab can only support block device with fixed name.
# cat /etc/vold.fstab
dev_mount sdcard /mnt/sdcard 3 /devices/platform/omap/omap_hsmmc.0/mmc_host/mmc0
dev_mount usb /mnt/usb2 auto /devices/platform/omap/ti81xx-usbss/musb-hdrc.1/usb1
Depending on the interface used these values can change. Best way is to probe sysfs directories to find the fixed name. For MMC the entry will be of the form:
/sys/devices/platform/omap/omap_hsmmc.X/mmc_host/mmcY
Update the android storage list overlay at overlay/frameworks/base/core/res/res/xml/storage_list.xml
&StorageList xmlns:android=&/apk/res/android&&
&storage android:mountPoint=&/storage/sdcard0&
android:storageDescription=&@string/storage_internal&
android:primary=&true&
android:emulated=&true&
android:mtpReserve=&100& /&
&/StorageList&
This release supports audio playback and capture at 44.1kHz. For application-specific usage, the audio HAL supports the software resampler. The audio HAL is implemented at . The audio HAL uses the file mixer_paths.xml to configure the audio driver. This file contains the ALSA mixer settings for the various audio paths supported by the driver. The mixer_paths.xml is present at device/ti/&boardname& and is copied to the filesystem by the entry in device.mk. The following is the contents of
&!-- These are the initial mixer settings --&
&ctl name=&DAC IF1 SWITCH& value=&Normal& /&
&path name=&speaker&&
&ctl name=&PCM Playback Volume& value=&120& /&
&path name=&headphone&&
&ctl name=&PCM Playback Volume& value=&120& /&
&path name=&headset-mic&&
&ctl name=&Mic Jack Switch& value=&1& /&
&ctl name=&Analog Left AUXL Capture Switch& value=&1& /&
&ctl name=&Analog Right AUXR Capture Switch& value=&1& /&
&ctl name=&Analog Capture Volume& value=&3&/&
The mixers setting commands at the beginning of the file are executed when the audio HAL is initialized. The mixer settings within the various &paths& are executed when that mode of operation is selected.
You can use tinyalsa utilities to test audio input/output from shell.
To play simple audio
# tinyplay testfile.wav -n 16
To record simple audio
# tinycap testfile.wav -n 16
NOTE: The above commands are specific to AM335x-based devices. For AM37x devices -n 16 option is not required.
NOTE: Android handles volume control in software. We recommend to keep the default volume levels close to maximum in the audio HAL.
This section of guide provides a step by step explanation of what's involved in adding a new WiFi driver and making WiFi work in a custom Android build like Rowboat.
WLAN (802.11 b/g/n)
Core IP pre-tested against WiFi specifications.
Station mode is fully supported.
Initial support for SoftAP/WiFi hotspot and WiFi Direct is available
Diagram explains WLAN event flow from application to h/w with respect to rowboat android source tree.
Settings/Connection Manager:&android-src&/packages/apps/Settings/src/com/android/settings/WirelessSettings.java
WiFi manager:&android-src&/frameworks/base/wifi/java/android/net/wifi
JNI Implementation:&android-src&/frameworks/base/core/jni/android_net_wifi_Wifi.cpp
libhardware_legacy:&android-src&/hardware/libhardware_legacy/wifi/wifi.c
wpa_supplicant (Daemon):&android-src&/external/hostap/wpa_supplicant
Higher level network management is done in &android-src&/frameworks/base/core/java/android/net.
In this Devkit release we are using WL12XX Compat wireless SDK. The drivers and firmwares of WL12XX Compat release are at hardware/ti/wlan
To enable WLAN support in kernel the following settings need to be enabled:
First enable Wireless LAN device driver as shown below:
Device Drivers
[*] Network device support
Wireless LAN ---&
Enable WLAN Networking support as shown below:
[*] Networking support
Wireless extensions sysfs files
This enables the following CONFIG options in kernel and allows WL12xx compat wlan drivers to be built:
CONFIG_WLAN=y
CONFIG_WIRELESS_EXT=y
CONFIG_WEXT_CORE=y
CONFIG_WEXT_PROC=y
CONFIG_WEXT_PRIV=y
The following additional options need to be enabled in kernel for WLAN to operate
CONFIG_KEYS=y
CONFIG_SECURITY=y
CONFIG_CRYPTO=y
CONFIG_CRYPTO_ARC4=y
CONFIG_CRYPTO_ECB=y
CONFIG_CRYPTO_AES=y
CONFIG_CRYPTO_MICHAEL_MIC=y
CONFIG_CRC7=y
The relevant initialization and pin-muxing for MMC bus is done in the relevant board file e.g for AM335xevm . Do take care of this initialization and pin-muxing if using any other MMC bus e.g. MMC3.
The following code snippet shows the board-specific WLAN configuration done on AM335xevm. The code below is provided for information only and is not complete. Please refer to the source for more details.
File: arch/arm/mach-omap2/board-am335xevm.c arch/arm/mach-omap2/board-am335xevm.c
struct wl12xx_platform_data am335xevm_wlan_data = {
.irq = OMAP_GPIO_IRQ(AM335XEVM_WLAN_IRQ_GPIO),
.board_ref_clock = WL12XX_REFCLOCK_38_XTAL, /* 38.4Mhz */
.bt_enable_gpio = GPIO_TO_PIN(3, 21),
.wlan_enable_gpio = GPIO_TO_PIN(1, 16),
/* Module pin mux for wlan and bluetooth */
static struct pinmux_config mmc2_wl12xx_pin_mux[] = {
{&gpmc_a1.mmc2_dat0&, OMAP_MUX_MODE3 | AM33XX_PIN_INPUT_PULLUP},
{&gpmc_a2.mmc2_dat1&, OMAP_MUX_MODE3 | AM33XX_PIN_INPUT_PULLUP},
{&gpmc_a3.mmc2_dat2&, OMAP_MUX_MODE3 | AM33XX_PIN_INPUT_PULLUP},
{&gpmc_ben1.mmc2_dat3&, OMAP_MUX_MODE3 | AM33XX_PIN_INPUT_PULLUP},
{&gpmc_csn3.mmc2_cmd&, OMAP_MUX_MODE3 | AM33XX_PIN_INPUT_PULLUP},
{&gpmc_clk.mmc2_clk&, OMAP_MUX_MODE3 | AM33XX_PIN_INPUT_PULLUP},
{NULL, 0},
static int wl12xx_set_power(struct device *dev, int slot, int on, int vdd)
gpio_direction_output(am335xevm_wlan_data.wlan_enable_gpio, 1);
mdelay(70);
gpio_direction_output(am335xevm_wlan_data.wlan_enable_gpio, 0);
static void wl12xx_init(int evm_id, int profile)
if (wl12xx_set_platform_data(&am335xevm_wlan_data))
pr_err(&error setting wl12xx data\n&);
dev = am335x_mmc[1].
if (!dev) {
pr_err(&wl12xx mmc device initialization failed\n&);
ret = gpio_request_one(am335xevm_wlan_data.wlan_enable_gpio,
GPIOF_OUT_INIT_LOW, &wlan_en&);
setup_pin_mux(wl12xx_pin_mux);
pdata-&slots[0].set_power = wl12xx_set_
Enable building of TI version of wpa_supplicant 0.8.x in your BoardConfig.mk (e.g. device/ti/am335xevm/BoardConfig.mk for AM335xevm and device/ti/omap3evm/BoardConfig.mk for AM37xevm)
This is by simply adding following options in BoardConfig.mk:
BOARD_WPA_SUPPLICANT_DRIVER
 := NL80211
WPA_SUPPLICANT_VERSION
 := VER_0_8_X_TI
BOARD_WLAN_DEVICE
 := wl12xx_mac80211
BOARD_SOFTAP_DEVICE
 := wl12xx_mac80211
WIFI_DRIVER_MODULE_PATH
 := "/system/lib/modules/wl12xx_sdio.ko"
WIFI_DRIVER_MODULE_NAME
 := "wl12xx_sdio"
This will set
WPA_BUILD_SUPPLICANT to true in external/wpa_supplicant_8_ti/Android.mk enabling building of wpa_supplicant 0.8.x with NL80211. At run time wl12xx_sdio will get loaded from WIFI_DRIVER_MODULE_PATH.
BOARD_SOFTAP_DEVICE := wl12xx_mac80211 needs to be set only if SoftAP/hotspot feature is required.
Next we need to provide a proper wpa_supplicant.conf for our device. That we will keep in /data/misc/wifi.
Set the correct permissions and paths created and load the core wi-fi drivers from init.am335xevm.rc
mkdir /data/misc/wifi/sockets 0770 wifi wifi
mkdir /data/misc/dhcp 0770 dhcp dhcp
insmod /system/lib/modules/compat.ko
insmod /system/lib/modules/cfg80211.ko
insmod /system/lib/modules/mac80211.ko
insmod /system/lib/modules/wlcore.ko
insmod /system/lib/modules/wl12xx.ko
insmod /system/lib/modules/wl18xx.ko
Set the wifi interface name in device.mk
PRODUCT_PROPERTY_OVERRIDES := \
wifi.interface=wlan0
Start wpa_supplicant and dhcpcd from init.am335xevm.rc.
service wpa_supplicant /system/bin/wpa_supplicant \
-iwlan0 -Dnl80211 -c/data/misc/wifi/wpa_supplicant.conf \
-e/data/misc/wifi/entropy.bin
class main
socket wpa_wlan0 dgram 660 wifi wifi
service dhcpcd_wlan0 /system/bin/dhcpcd -ABKL
class main
service iprenew_wlan0 /system/bin/dhcpcd -n
class main
The following entries are required to configure SoftAP/hotspot and WiFi Direct functions:
Register hostap service for SoftAP/hotspot:
service hostapd_bin /system/bin/hostapd -d /data/misc/wifi/hostapd.conf
socket wpa_wlan0 dgram 660 wifi wifi
Register the supplicant and dhcp hooks for WiFi Direct:
service p2p_supplicant /system/bin/wpa_supplicant \
-iwlan0 -Dnl80211 -c/data/misc/wifi/wpa_supplicant.conf -N \
-ip2p0 -Dnl80211 -c/data/misc/wifi/p2p_supplicant.conf \
-puse_p2p_group_interface=1
class main
socket wpa_wlan0 dgram 660 wifi wifi
service dhcpcd_p2p /system/bin/dhcpcd -aABKL
service iprenew_p2p /system/bin/dhcpcd -n
The following entries enable Wi-Fi for use by android network manager.
Add the following entries in device/ti/&boardname&/overlay/frameworks/base/core/res/res/values/config.xml
&string-array translatable=&false& name=&networkAttributes&&
&item&&wifi,1,1,1,-1,true&&/item&
&item&&wifi_p2p,13,1,0,-1,true&&/item&
&/string-array&
&string-array translatable=&false& name=&radioAttributes&&
&item&&1,1&&/item&
&/string-array&
Add the required permissions file into the android filesystem by updating device.mk. This also enables the Wi-Fi and Wi-Fi Direct options in the Settings App.
PRODUCT_COPY_FILES := \
frameworks/native/data/etc/android.hardware.wifi.xml:system/etc/permissions/android.hardware.wifi.xml \
frameworks/native/data/etc/android.hardware.wifi.direct.xml:system/etc/permissions/android.hardware.wifi.direct.xml
The following steps perform basic checks to see if WiFi driver is operational:
- Live 0xbf08d000 (O)
mac 1 wl12xx, Live 0xbf03c000 (O)
cfg 2 wl12xx,mac80211, Live 0xbf004000 (O)
compat 1706 0 - Live 0xbf000000 (O)
# insmod /system/lib/modules/wl12xx_sdio.ko
154.549804] wl1271: loaded
If you do not see the message wl1271: loaded after inserting wl12xx_sdio.ko kernel module, the wifi driver initialization may not be correct. Please ensure that all the relevant pinmuxing and gpio configuration is correct and not over-written.
Next, check that the driver is not unloaded after initialization:
127.0.0.1/8
0x:00:00:00:00:00
0x:00:00:00:00:00
172.24.190.76/22
0x:5f:c2:76:4c:99
0x:12:34:56:78:90
If wlan0 is not available in netcfg output, the driver might have been unloaded due to some error.
Now, we try to up the wlan0 interface:
# netcfg wlan0 up
[ ] wl1271: firmware booted (Rev 6.3.6.0.79_2)
[ ] wl1271: Driver version: R4_SP2_03_00
[ ] ADDRCONF(NETDEV_UP): wlan0: link is not ready
The above messages show that the interface is up and the firmware is downloaded to wlan module and booted.
Ensure that wlan drivers are unloaded before trying the Android UI for wireless settings
# netcfg wlan0 down
# rmmod wl12xx_sdio
If wlan0 is not available in netcfg output, the driver might have been unloaded due to some error.
Copy the ini files used for calibration to the sdcard
sudo cp -rv rowboat/hardware/ti/wlan/mac80211/ti-utils/ini_files /media/rootfs/system/etc/wifi
Boot the board. Make sure WLAN is disabled. wl12xx_sdio.ko should NOT be loaded
root@android:/ # lsmod
omaplfb 10662 0 - Live 0xbf0ed000 (O)
omaplfb, Live 0xbf0bc000 (O)
- Live 0xbf08e000 (O)
mac 1 wl12xx, Live 0xbf03c000 (O)
cfg 2 wl12xx,mac80211, Live 0xbf004000 (O)
compat 1706 0 - Live 0xbf000000 (O)
Remove existing calibration file
rm /system/etc/firmware/ti-connectivity/wl1271-nvs.bin
Run the calibrator tool
calibrator plt autocalibrate wlan0 /system/lib/modules/wl12xx_sdio.ko /system/etc/wifi/ini_files/127x/TQS_S_2.6.ini /system/etc/firmware/ti-connectivity/wl1271-nvs.bin
NOTE: Running the calibration results in a random MAC address being set. To set the desired MAC address, run the following step:
calibrator set nvs_mac /system/etc/firmware/ti-connectivity/wl1271-nvs.bin &MAC Address&
You can verify the MAC address using the following command:
calibrator get nvs_mac /system/etc/firmware/ti-connectivity/wl1271-nvs.bin
This section describes how to enable Bluetooth support on Android for wl1271 chipset.
Bluetooth 2.1
OPP, A2DP, AVRCP, HID profiles are supported.
HSP, HFP profiles are NOT supported
Enable Bluetooth with the following setting in BoardConfig.mk (e.g. device/ti/am335xevm/BoardConfig.mk)
# Bluetooth
BOARD_HAVE_BLUETOOTH := true
This enables bluez external/bluez HAL layer, which is used to connect with Android Frameworks (frameworks/base/core/jni/android_bluetooth_*.cpp, frameworks/base/core/java/android/bluetooth/*.java and SystemServer via DBUS .
TI Android DevKit uses the TI Wilink7 Bluetooth driver along with the TI Shared-Transport driver (TI-ST) for managing the BT-UART.
WL12xx BT is interfaced to UART1 on AM37xevm and AM335xevm. UART1 initialization and BT module registration with TI-ST is implemented at arch/arm/mach-omap2/board-am335xevm.c for AM37xevm and arch/arm/mach-omap2/board-am335xevm.c for AM335xevm.
Bluetooth support is enabled in the kernel as shown below:
[*] Networking support
Bluetooth subsystem support
L2CAP protocol support
RFCOMM protocol support
RFCOMM protocol support
BNEP protocol support
Multicast filter support
Protocol filter support
HIDP protocol support
Bluetooth device drivers
&*& HCI UART driver
UART (H4) protocol support
HCILL protocol support
RF switch subsystem support
This enables the following CONFIG options:
CONFIG_BT=y
CONFIG_BT_L2CAP=y
CONFIG_BT_RFCOMM=y
CONFIG_BT_RFCOMM_TTY=y
CONFIG_BT_BNEP=y
CONFIG_BT_BNEP_MC_FILTER=y
CONFIG_BT_BNEP_PROTO_FILTER=y
CONFIG_BT_HIDP=y
CONFIG_BT_HCIUART=y
CONFIG_BT_HCIUART_H4=y
CONFIG_BT_HCIUART_LL=y
CONFIG_RFKILL=y
The following CONFIG options enable TI-ST and WiLink Bluetooth driver support:
CONFIG_BT_WILINK=y
CONFIG_TI_ST=y
The following kernel configs are required for Bluetooth AVRCP support:
CONFIG_INPUT_MISC=y
CONFIG_INPUT_UINPUT=y
You can check this as follows:
Device Drivers
Input device support
Miscellaneous devices
User level driver support
The following code-snippet shows board-level configuration for TI-ST on AM335xevm:
File: arch/arm/mach-omap2/board-am335xevm.c
struct ti_st_plat_data wilink_pdata = {
.nshutdown_gpio = GPIO_TO_PIN(3, 21),
.dev_name = &/dev/ttyO1&,
.flow_cntrl = 1,
.baud_rate = 3000000,
.suspend = plat_kim_suspend,
.resume = plat_kim_resume,
.chip_enable = plat_kim_chip_enable,
.chip_disable = plat_kim_chip_disable,
static struct platform_device wl12xx_device = {
.dev.platform_data = &wilink_pdata,
static struct platform_device btwilink_device = {
.name = &btwilink&,
static inline void __init am335xevm_init_btwilink(void)
pr_info(&am335xevm: bt init\n&);
platform_device_register(&wl12xx_device);
platform_device_register(&btwilink_device);
Set the correct permissions and paths created from init.rc
#Owners, Modes for Bluetooth
chmod 0660 /dev/ttyO1
chown bluetooth bluetooth /dev/ttyO1
chmod 0660 /sys/class/rfkill/rfkill0/state
chown bluetooth bluetooth /sys/class/rfkill/rfkill0/state
The following services are registered in init.rc for Bluetooth operation:
dbus-daemon: (deal connections between hcid and system server)
service dbus /system/bin/dbus-daemon --system --nofork
class main
socket dbus stream 660 bluetooth bluetooth
user bluetooth
group bluetooth net_bt_admin
bluetoothd: create hcid (Bluetooth Host Controller Interface Daemon) service, but disabled at first
service bluetoothd /system/bin/bluetoothd -n
class main
socket bluetooth stream 660 bluetooth bluetooth
socket dbus_bluetooth stream 660 bluetooth bluetooth
# init.rc does not yet support applying capabilities, so run as root and
# let bluetoothd drop uid to bluetooth with the right linux capabilities
group bluetooth net_bt_admin misc
uim-sysfs: userspace module for TI-ST kernel driver. This service attaches the BT UART HCI interface to the bluetooth stack at 3000000 baud rate. It is also responsible for loading the BT firmware on WL1271. The sources for uim-sysfs is found in hadware/ti/wpan
#shared transport user space mgr service for Bluetooth, FM and GPS
service uim /system/bin/uim-sysfs
class core
user bluetooth
group bluetooth net_bt_admin
Add bluetooth entry in the overlay to indicate bluetooth availability to network manager
&string-array translatable=&false& name=&networkAttributes&&
&item&&bluetooth,7,7,0,-1,true&&/item&
&/string-array&
&string-array translatable=&false& name=&radioAttributes&&
&item&&7,1&&/item&
Copy the Bluetooth permissions file and the relevant bluez conf file. The permissions file also enables Bluetooth menu in Settings
PRODUCT_COPY_FILES += \
frameworks/native/data/etc/android.hardware.bluetooth.xml:system/etc/permissions/android.hardware.bluetooth.xml \
system/bluetooth/data/main.nonsmartphone.conf:system/etc/bluetooth/main.conf
Android JB supports both USB host and USB device ports. USB host can be used to connect Keyboard/Mouse, Mass storage device, modem dongles etc, while the USB device port is mainly used for adb and USB accessory gadgets.
for AM335xevm
The USB Android Gadget driver on AM335x is enabled as shown below:
-& Device Drivers
-& USB support
-& USB Gadget Support
-& USB Gadget Drivers
(X) Android Gadget
The Android gadget driver is configured via the sysfs entries. These are done from init.&ro.hardware&.usb.rc. For am335xevm, this is init.am335xevm.usb.rc
write /sys/class/android_usb/android0/iManufacturer ${ro.product.manufacturer}
write /sys/class/android_usb/android0/iProduct ${ro.product.model}
write /sys/class/android_usb/android0/iSerial ${ro.serialno}
on property:sys.usb.config=none
write /sys/class/android_usb/android0/enable 0
write /sys/class/android_usb/android0/bDeviceClass 0
setprop sys.usb.state ${sys.usb.config}
on property:sys.usb.config=adb
write /sys/class/android_usb/android0/enable 0
write /sys/class/android_usb/android0/idVendor 18d1
write /sys/class/android_usb/android0/idProduct D002
write /sys/class/android_usb/android0/functions ${sys.usb.config}
write /sys/class/android_usb/android0/enable 1
setprop sys.usb.state ${sys.usb.config}
on property:sys.usb.config=mtp
write /sys/class/android_usb/android0/enable 0
write /sys/class/android_usb/android0/idVendor 18d1
write /sys/class/android_usb/android0/idProduct D108
write /sys/class/android_usb/android0/functions ${sys.usb.config}
write /sys/class/android_usb/android0/enable 1
setprop sys.usb.state ${sys.usb.config}
on property:sys.usb.config=mtp,adb
write /sys/class/android_usb/android0/enable 0
write /sys/class/android_usb/android0/idVendor 18d1
write /sys/class/android_usb/android0/idProduct D109
write /sys/class/android_usb/android0/functions ${sys.usb.config}
write /sys/class/android_usb/android0/enable 1
start adbd
setprop sys.usb.state ${sys.usb.config}
The sysfs settings need to be done depending on the features required to be enabled. By default only the adb and mtp mode is configured.
To indicate that the platform supports USB Host port add the following to device.mk:
PRODUCT_COPY_FILES += \
frameworks/native/data/etc/android.hardware.usb.accessory.xml:system/etc/permissions/android.hardware.usb.accessory.xml
PRODUCT_PACKAGES += \
com.android.future.usb.accessory
NOTE: The USB accessory does not work over USB Hub.
To indicate that the platform supports USB Host port add the following to device.mk:
PRODUCT_COPY_FILES += \
frameworks/native/data/etc/android.hardware.usb.host.xml:system/etc/permissions/android.hardware.usb.host.xml
The STMicro LIS33 Accelerometer is supported on Am37x Flashboard and AM335x evm.
Kernel driver for accelerometer on AM335x :
Android HAL on AM335xevm:
To indicate accelerometer support to android add the following line in device.mk
PRODUCT_COPY_FILES += \
frameworks/native/data/etc/android.hardware.sensor.accelerometer.xml:system/etc/permissions/android.hardware.sensor.accelerometer.xml
AM335x evm supports light sensor TSL2550.
Light sensor kernel driver :
Please note that the standard linux driver is modified to report light sensor values to the input sub-system. See .
Android HAL on AM335xevm:
To indicate light sensor support to android add the following line in device.mk
PRODUCT_COPY_FILES += \
frameworks/native/data/etc/android.hardware.sensor.light.xml:system/etc/permissions/android.hardware.sensor.light.xml
You can use the light sensor input to modify the LCD backlight intensity. You need to add the following entry in the overlay:
&bool name="config_automatic_brightness_available"&true&/bool&
Also you need to implement a lookup table to map the light intensity to the LCD backlight values. Please refer to the
file for more details.
AM335xevm supports temperature sensor LM75.
Kernel driver path :
The driver is modified to be compatible with the android sensor input subsystem. See commits
Android HAL for AM335xevm is at :
This section discusses interfacing USB camera with android
Enable the following CONFIGs to add support for USB camera in kernel:
CONFIG_USB_VIDEO_CLASS=y
CONFIG_USB_VIDEO_CLASS_INPUT_EVDEV=y
Enable USB Camera support in BoardConfig.mk. Also disable stub camera
BOARD_USB_CAMERA := true
#USE_CAMERA_STUB := true
Add the following entries in device.mk
PRODUCT_PACKAGES += \
camera.omap3 \
NOTE: The Camera icon will automatically appear in apps due to presence of camera.omap3.so in the filesystem.
Add permission for camera in init.am335xevm.rc. This is used for temporary storage before capture.
mkdir /data/misc/camera 0770 media media
Add camera permissions in ueventd.am335xevm.rc
/dev/video0
The Camera HAL is at .
NOTE: By default it is assumed that the USB camera is registered as /dev/video0 (
). You may need to change this for your device.
The USB 3G Modem section describes how to connect USB Modem to the android.
PPP is the protocol used for establishing internet links over dial-up modems, DSL connections, and many other types of point-to-point links. The pppd daemon works together with the kernel PPP driver to establish and maintain a PPP link with another system (called the peer) and to negotiate Internet Protocol (IP) addresses for each end of the link.
Device Drivers
[*] Network device support
PPP (point-to-point protocol) support
PPP BSD-Compress compression
PPP Deflate compression
PPP support for async serial ports
PPP support for sync tty ports
[*] USB support
USB Modem (CDC ACM) support
USB Serial Converter support
USB Generic Serial Driver
USB driver for GSM and CDMA modems
To get the Modem Working, we need usb_modeswitch, usb_modeswicth.conf(configuration file) for the specific modem or Hardware vendor and the airtel.chat(dialer script) for the specific network.
Copy the usb_modeswitch (ARM Compiled binary) and usb_modeswitch.conf to the /system/xbin folder. The ARM compiled binary and the sources can be obtained from
Copy the airtel.chat(dialer script) to the /system/etc/ppp folder
Below is the description of an example usb_modeswitch.conf file for the Huawei E1731 Modem (Airtel in India)
Huawei E1731
EnableLogging=1
DefaultVendor= 0x12d1
DefaultProduct=0x1446
TargetVendor=
TargetProductList="0b,140c,36,14ac,1506"
CheckSuccess=20
MessageEndpoint= 0x01
MessageContent="00"
The DefaultVendor and DefaultProduct is the ID displayed for CDROM or mass storage, the TargetVendor and TargetProduct is for Modem. Plug the device into linux system and do "dmesg" or "lsusb" to know the IDs.
Example: HUAWEI E1731 Modem Below is the log when plugged to PC
[033] usb 1-4: new high speed USB device number 10 using ehci_hcd
[394] usb 1-4: New USB device found, idVendor=12d1, idProduct=1446
[400] usb 1-4: New USB device strings: Mfr=3, Product=2, SerialNumber=0
[404] usb 1-4: Product: HUAWEI Mobile
[407] usb 1-4: Manufacturer: HUAWEI Technology
[040] scsi16 : usb-storage 1-4:1.0
[652] scsi17 : usb-storage 1-4:1.1
[546] usb 1-4: USB disconnect, device number 10
[047] usb 1-4: new high speed USB device number 11 using ehci_hcd
[645] usb 1-4: New USB device found, idVendor=12d1, idProduct=1436
[651] usb 1-4: New USB device strings: Mfr=4, Product=3, SerialNumber=0
[654] usb 1-4: Product: HUAWEI Mobile
[657] usb 1-4: Manufacturer: HUAWEI Technology
[476] option 1-4:1.0: GSM modem (1-port) converter detected
[663] usb 1-4: GSM modem (1-port) converter now attached to ttyUSB0
[425] cdc_ether 1-4:1.1: wwan0: register 'cdc_ether' at usb-d.7-4, Mobile Broadband Network Device, 02:50:f3:00:00:00
[066] option 1-4:1.3: GSM modem (1-port) converter detected
[268] usb 1-4: GSM modem (1-port) converter now attached to ttyUSB1
[509] option 1-4:1.4: GSM modem (1-port) converter detected
[646] usb 1-4: GSM modem (1-port) converter now attached to ttyUSB2
[203] scsi22 : usb-storage 1-4:1.5
[812] scsi23 : usb-storage 1-4:1.6
[809] scsi 22:0:0:0: CD-ROM
Mass Storage
2.31 PQ: 0 ANSI: 2
[303] scsi 23:0:0:0: Direct-Access
SD Storage
2.31 PQ: 0 ANSI: 2
[169] sr1: scsi-1 drive
[426] sr 22:0:0:0: Attached scsi CD-ROM sr1
[593] sr 22:0:0:0: Attached scsi generic sg5 type 5
[394] sd 23:0:0:0: Attached scsi generic sg6 type 0
[181] sd 23:0:0:0: [sde] Attached SCSI removable disk
Below is the description of an example airtel.chat(dialer script) file for AirTel (INDIA)
TIMEOUT 10
ABORT 'BUSY'
ABORT 'NO ANSWER'
ABORT 'ERROR'
SAY 'Starting GPRS connect script\n'
SAY 'Setting APN\n'
OK 'AT+CGDCONT=1,"IP",""'
ABORT 'NO CARRIER'
SAY 'Dialing...\n'
OK 'ATD*99***1#'
NOTE: the single quotes in the above chat file must be together. ie no space allowed.
This file is network service provider dependent, so modify the < according to your service provider.
Below are the steps to perform once android boots up with the above necessary modifications
Disable wireless and ethernet settings
Plug the USB Modem
Run the following commands
mount -t usbfs usbfs /proc/bus/usb
/system/xbin/usb_modeswitch -I -W -c /system/xbin/usb_modeswitch.conf
Mount the usbfs file system to /proc/bus/usb. This is necessary to
avoid the “Couldn’t opendir()” error you get otherwise on running
usb_modeswitch. Once Mode Switch Succeeds, modem will be enumerated as /dev/ttyUSB* (* can be 0,1,2). If you place the usb_modeswitch and usb_modeswitch.conf at other place, change the above command accordingly.
Once Modem succeeds in enumeration, run the follwoing command
/system/bin/pppd /dev/ttyUSB0 115200 persist defaultroute usepeerdns updetach crtscts noauth debug connect "/system/xbin/chat -v -s -f /system/etc/ppp/airtel.chat"
From the logcat check what primary and secondary dns server IPs you got, you can kill the logcat after getting the IPs. Set those primary and secondary DNS server IPs for your device with the following commands replacing IP1 and IP2
with whatever IPs you got.
setprop net.dns1 &IP1&
setprop net.dns2 &IP2&
You are ready to browse that net after this if everything went well in the previous steps. Enjoy the 3G fast speed surfing on your device.
All components explained in this porting guide are validated against TI Android DevKit release 4.0.0 and 4.0.1 only.
This guide can be taken as reference to port mentioned components on similar architecture.
For further information or to report any problems, contact
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