Device Driver Interface of WiLink Solution

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Generally used OMAP and Connectivity combinations are OMAP3 and WL127x (as in Zoom2, Zoom3 devices) or OMAP4 and WL128x (as in Blaze devices). However, few customers and internal TI teams need combinations OMAP3 + WL128x and OMAP4 + WL127x. The following hints should help in case you have combination of devices and not making use of the devices on-board.

For on-board devices, i.e Zoom2/3(with WL127x), Blaze(with WL128x) and Panda (with WL127x) - The relevant releases for the board should get Bluetooth, FM work out of the box.

There are multiple WiLink devices that can be supported on multiple OMAP platforms. Below list provides combination of platforms available:

Porting shared transport solution

Shared Transport driver is a line discipline driver, which acts a generic transport for Bluetooth, FM and GPS (in case of WL128x). Each such protocol drivers have a register, unregister mechanism with the shared transport driver and upon registration can do a write concurrently, and shared transport would queue up the data and would send it over UART. Upon receiving protocol specific data, shared transport would interpret the data and forward it to protocol driver via callbacks.

Shared transport driver is also a platform device driver and hence any platform which has a WL127x/WL128x device and wants to make use of this driver, need to have an entry of adding the platform device in their architecture specific board file.


/* wl128x BT, FM, GPS connectivity chip */
struct ti_st_plat_data wilink_pdata = {
        .nshutdown_gpio = 55,
        .dev_name = "/dev/ttyO1",
        .flow_cntrl = 1,
        .baud_rate = 3000000,
static struct platform_device wl128x_device = {
        .name           = "kim",
        .id             = -1,
        .dev.platform_data = &wilink_pdata,

and in one of the architecture init functions, perform :- platform_device_register(&wl128x_device);

Hardware Interface and MUX mode configuration

The WiLink Connectivity chip's BT/FM/GPS IPs are interfaced with the application processor(OMAP) by UARTs. A GPIO line called "nShutDown" acts as the chip enable line for the connectivity chip. Apart from this the connectivity chip is interfaced to BT core via PCM lines (mcbsp if OMAP) and the FM core via i2S(or PCM). The BT-PCM lines carry the voice data during call scenario, and the FM i2S lines can be used for FM Rx audio (digital) or FM Tx audio.

The mux-mode configurations of these hardware interfaces can be done via the OMAP MUX framework supported by the BSP

Example: On Zoom3 where the N-Shut-Down line is connected to GPIO 109.
        omap_mux_init_gpio(109, OMAP_PIN_OUTPUT);

The configurations can also be done in the u-boot

Example: On OMAP3SDP/Blaze, the McBSP1 is connected to the BT-PCM lines,
        MV(CP(ABE_MCBSP1_DX),   (OFF_EN | OFF_OUT_PTD | M0)) /* abe_mcbsp1_dx */ \
        MV(CP(ABE_MCBSP1_FSX),  (IEN | OFF_EN | OFF_PD | OFF_IN | M0)) /* abe_mcbsp1_fsx */ \
        MV(CP(ABE_MCBSP1_DX),   (OFF_EN | OFF_OUT_PTD | M0)) /* abe_mcbsp1_dx */ \
        MV(CP(ABE_MCBSP1_FSX),  (IEN | OFF_EN | OFF_PD | OFF_IN | M0)) /* abe_mcbsp1_fsx */ \

Example: On OMAP4SDP/Blaze, the OMAP UART2 is connected to the BT-HCI-UART
        MV(CP(UART2_CTS),       (PTU | IEN | M0)) /* uart2_cts */ \
        MV(CP(UART2_RTS),       (M0)) /* uart2_rts */ \
        MV(CP(UART2_RX),        (IEN | M0)) /* uart2_rx */ \
        MV(CP(UART2_TX),        (M0)) /* uart2_tx */ \

Note: Since there lacks a standard way to configure the hardware interfaces, please look into relevant BSP or contact the email ID mentioned below.

btwilink driver

BTWILINK driver at drivers/bluetooth/btwilink.c provides the bluetooth driver which makes use of the shared transport driver which talks to the bluetooth core on the WiLink chipsets. Enable this driver either as a module or as a built-in component along with necessary bluetooth functionality in the kernel.

Similar to the TI ST driver, this is also a platform device driver and requires a relevant platform device registration,

static struct platform_device btwilink_device = {
       .name = "btwilink",
       .id = -1,

The above platform device along with addition in one of the architecture init functions, would enable the Bluetooth driver for WiLink chipsets.

User Space components

A utility known as UIM is very much required for the shared transport [TI_ST] driver to be working. Most line disciplines if not all require a user-space daemon to be opening the UART and installing the line discipline thereby giving out the control to the line discipline driver.

UIM can be found @;a=summary The latest can be found at gingerbread branch by name uim-sysfs,;a=tree;f=ti_st/uim-sysfs;h=12ce6bafd461474ad90d41a0b9523a94534e4c0a;hb=refs/heads/gingerbread

UIM needs to be run at boot, Since linux flavors might require Bluetooth or GPS to be turned on at boot. For this have the UIM entry in your either one of your rc.S files or you can have special udev rule based on the platform driver addition of device "kim". For Android, the following entry in init.rc should suffice,

service uim /system/bin/uim-sysfs
    user root
    group media bluetooth


Bluetooth, FM and GPS all require their own firmware files, with the Bluetooth firmware being required to be downloaded before any of the other cores are made use of in WiLink. - Should point to the latest firmware files that are released.

Shared Transport driver uses the firmware class sub-system to download firmware and hence the firmware ".bts" files need to exist in /system/etc/firmware/ for Android and /lib/firmware/ for ubuntu.

On boot check

Since there are many versions of the drivers floating around and a lot needs to be done to get them all working fine. A few things below can be checked if the port went well.

Enabling profiles on Android

Important Notes

The platform data and its structure tend to keep changing, and hence before adding the platform device, please make sure the platform data matches in type and structure of the platform data defined in include/linux/ti_wilink_st.h

Support Contacts

Write your queries to WCG Leads

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