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Reply-To: yunhanw@nestlabs.com
From: Yunhan Wang <yunhanw@nestlabs.com>
Date: Sun, 6 Aug 2017 23:18:22 -0700
Message-ID: <CALvjcs88qDooFW-L1ANXoNrp9KKwXHh+_NaLLzKhbOQvMDLcTQ@mail.gmail.com>
Subject: Re: bluetoothctl: how to send notification/indcation from peripheral
 to central
To: linux-bluetooth@vger.kernel.org
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Hi Luiz,

Do you have any idea about this issue?

Best wishes
Yunhan

On Sun, Aug 6, 2017 at 1:25 AM, Yunhan Wang <yunhanw@nestlabs.com> wrote:
> Hi
>
> Has any one been able to send notification from LE peripheral to LE
> central using bluetoothctl?
>
> Now I am trying to update "Value" with 0x02 for the below
> characteristic with read and indicate flag, i am expecting a
> notification can be sent from peripheral to central automatically. It
> seems there is no such support in bluetoothctl. Then I do simple code
> change on below, and try to update value via "update-chrc 0x02", well,
> the value has been successfully updated, but there is no
> message/notification sent from peripheral to central automatically. I
> have confirmed that chrc read from central is showing updated value,
> 02, correctly. The question is that how can we send characteristic
> notification/indication using bluez dbus API?
>
> btw, I see the video(BlueZ Meets Zephyr made by Luiz)
> https://www.youtube.com/watch?v=SdmZX5q-XDg
> In 30:05, I see Zephyr is sending notification to bluetoothctl
> automatically. How can we just use bluez dbus API to achieve this?
>
> for example,
> In LE peripheral:
> I setup the below characteristic with read and indicate flag
> register-service 00001820-0000-1000-8000-00805f9b34fb
> register-characteristic 00002a06-0000-1000-8000-00805f9b34fb read,indicate
> register-application
> advertise peripheral
>
> In LE central:
> connect 00:AA:01:00:00:23
> select-attribute /org/bluez/hci1/dev_00_AA_01_00_00_23/service000a/char000b
> notify on
>
> The code change snippet
> --- a/client/gatt.c
> +++ b/client/gatt.c
> -void gatt_register_chrc(DBusConnection *conn, GDBusProxy *proxy, wordexp_t *w)
> +void chrc_set_value1(const char *input, void *user_data, DBusConnection *conn)
> +{
> +    struct chrc *chrc = user_data;
> +
> +    g_free(chrc->value);
> +
> +    chrc->value = str2bytearray((char *) input, &chrc->value_len);
> +    g_dbus_emit_property_changed(conn, chrc->path,
> "org.bluez.GattCharacteristic1", "Value");
> +
> +}
> +struct chrc * gatt_register_chrc(DBusConnection *conn, GDBusProxy
> *proxy, wordexp_t *w)
>  {
>         struct service *service;
>         struct chrc *chrc;
> @@ -1489,6 +1500,8 @@ void gatt_register_chrc(DBusConnection *conn,
> GDBusProxy *proxy, wordexp_t *w)
>         print_chrc(chrc, COLORED_NEW);
>
>         rl_prompt_input(chrc->path, "Enter value:", chrc_set_value, chrc);
> +
> +    return chrc;
>  }
>
> --- a/client/main.c
> +++ b/client/main.c
> +static void cmd_update_chrc(const char *arg)
> +{
> +    chrc_set_value1(arg, default_chrc, dbus_conn);
> +
> +}
> +
>  static void cmd_unregister_characteristic(const char *arg)
>  {
>         wordexp_t w;
> @@ -2541,6 +2547,9 @@ static const struct {
>         { "register-characteristic", "<UUID> <Flags=read,write,notify...>",
>                                         cmd_register_characteristic,
>                                         "Register application characteristic" },
> +    { "update-chrc", "<value.>",
> +            cmd_update_chrc,
> +            "update chrc value" },
>
> Thanks
> Best wishes
> Yunhan