WL1837MOD Bluetooth

Hi Kenneth,

Rebooting allows you to use the hciconfig command and download the firmware?

Can you try using:

hciattach “your serial port” texas

Thanks,

Jacob

Serial driver for UART is not available in user space when Bluetooth is configured in device tree. So there isn't a /dev/ttySx to be passed to hciattach.

git.ti.com/.../ti-bluetooth.txt

Excerpt from DTS:

uart10: serial@0 {
    compatible = "ti,dra742-uart", "ti,omap4-uart";
    reg = <0x0 0x100>;
    interrupts = <0 221 4>;
    clock-frequency = <48000000>;
    status = "disabled";
   };

&uart10 {
 status = "okay";
 pinctrl-names = "default";
 pinctrl-0 = <&uart10_pins_default &bt_pins>;
 uart-has-rtscts;

 interrupts-extended = <&crossbar_mpu 0 221 4
    &dra7_pmx_core 0x394>;

 bluetooth {
  compatible = "ti,wl1837-st";
  enable-gpios = <&gpio2 20 0>;
 };

Hi Kenneth,

I think that you have to define the UART instance to communicate with the WL1837 in Linux. 

For example, I use this file https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/538/am335x_2D00_bone_2D00_e14_2D00_wl1837.dtsi to define the Bluetooth UART serial instance and reference it with this file https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/538/am335x_2D00_boneblack.dts.

Have you defined the UART pins to be used for Bluetooth? It looks like UART10 is disabled.

Thanks,
Jacob

I think there may be some confusion about the issue I am describing. After boot, I can issue 'hciconfig hci0 up' and Bluetooth works correctly. If after the adapter is up, I issue 'hciconfig hci0 down' and then 'hciconfig hci0 up', then I get a timeout error from the driver.

In am335x-bone-e14-wl1837.dtsi you supplied, the driver is 'compatible = "tibt"'. What is the source for this driver? I am using hci_ll.c from ti-linux-kernel 5.10 (links below).

Pin definitions:

uart10_pins_default: uart10_pins_default {
pinctrl-single,pins = <
0x394 (PIN_INPUT_PULLUP | MUX_MODE2) /* mmc3_dat4.uart10_rxd */
0x398 (PIN_OUTPUT | MUX_MODE2 | SLEWCONTROL) /* mmc3_dat5.uart10_txd */
0x39c (PIN_INPUT_PULLDOWN | MUX_MODE2) /* mmc3_dat6.uart10_ctsn */
0x3a0 (PIN_OUTPUT_PULLUP | MUX_MODE2 | SLEWCONTROL) /* mmc3_dat7.uart10_rtsn */
>;
};

bt_pins: pinmux_bt_pins {
pinctrl-single,pins = <
DRA7XX_CORE_IOPAD(0x34B8, PIN_OUTPUT | MUX_MODE14) /* gpio2_10 BT_EN */
>;
};

uart10 is enabled (see line 'status = "okay"')

&uart10 {
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&uart10_pins_default &bt_pins>;
uart-has-rtscts;

interrupts-extended = <&crossbar_mpu GIC_SPI 221 IRQ_TYPE_LEVEL_HIGH
&dra7_pmx_core 0x394>;

bluetooth {
compatible = "ti,wl1837-st";
enable-gpios = <&gpio2 20 GPIO_ACTIVE_HIGH>;
};

};

git.ti.com/.../ti-bluetooth.txt
git.ti.com/.../hci_ll.c

Hey Kenneth,

Sorry for the delay - what MPU host are you using?

Thanks,
Jacob

TI AM5728

Thanks Kenneth,

I'll add more input tomorrow.

Best,
Jacob

Hey Kenneth,

TI doesn't officially support BlueZ, but I will try to give you some assistance. We previously used the 4.19 kernel and introduced "tibt" in the kernel. "hciattach" was used to connect the Bluetooth controller to the Linux host tty serial instance in user space and send the firmware to the controller (.bts). 

Do you know how BlueZ in kernel 5.10 sends the firmware to the WL1837MOD? Is it just by toggling the interface?

Thanks,
Jacob 

Hi Jacob,

TI supplied HCI Link Layer driver can be found here.

https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/drivers/bluetooth/hci_ll.c?h=linux-5.10.y

I believe you will find the answer to your question in functions ll_setup() and download_firmware().

I am open to considering alternatives to BlueZ. What Bluetooth stack does TI support on ti-linux-kernel 5.10?

Be well,

Ken

Hi Jacob,

We have been able to reproduce the issue on BeagleBoard Green. With this image:

https://dr-download.ti.com/software-development/software-development-kit-sdk/MD-1BUptXj3op/08.02.00.24/tisdk-default-image-am335x-evm.wic.xz

Note that CONFIG_BT_HCIUART_LL needs to be enabled in kernel configuration.

Be well,

Ken

Hey Kenneth,

Kenneth Dunahee said:

What Bluetooth stack does TI support on ti-linux-kernel 5.10?

TI officially supports the BluetopiaPM stack which is contained in user space (and leverages the built-in Linux kernel features). The latest version (v5.1) is available here with documentation for getting started here. 

Kenneth Dunahee said:

Note that CONFIG_BT_HCIUART_LL needs to be enabled in kernel configuration.

Yes, you are right. I forgot to mention this before, but the HCILL protocol flag needs to be compiled in the kernel.  

Thanks,
Jacob