This V2 patch provides two methods btmtk_reset_by_gpio,
btmtk_reset_by_gpio_work for mediatek controller,
it has been tested locally many times and can reset normally.

The pin is configured in dts files, bluetooth is reset by pulling
the pin, when exception or coredump occurs, the above methods will
be used to reset the bluetooth, if the pin is not found, it also can
reset bluetooth successfully by software reset.

Compared with the previously submitted version, the following
information has been revised in version V2
1)-Changed the capitalization of co-developer names,
   using the correct capitalization of abbreviations and full
   name, and corrected obvious spelling errors.
2)-Add a revision history.
3)-Remove the "BT Driver" in the prefix.
4)-Add the bt-binding document, include inforamtion related to reset
   pin and compatibility matching.
5)-Add a comment before the schedule_delayed_work function call,
   although schedule_delayed_work is asynchronous, there is no risk.
   Even if it is not completed within 200ms, it will only postpone
   the subsequent probe and will not have any impact.
6-)Add a comment before the btmtk_reset_by_gpio function call,
   if the compatibility filed or pin cannot be found in the dts
   files, it can still reset bluetooth using software reset.

Co-developed-by Hao Qin <hao.qin@mediatek.com>
Co-developed-Chris Lu <chris.lu@mediatek.com>
Co-developed-Jiande Lu <jiande.lu@mediatek.com>
Signed-off-by: Zhangchao Zhang <ot_zhangchao.zhang@mediatek.com>
---
 .../bluetooth/mediatek,mt7925-bluetooth.yaml  | 54 +++++++++++++++
 drivers/bluetooth/btmtk.c                     | 69 +++++++++++++++++++
 drivers/bluetooth/btmtk.h                     |  5 ++
 3 files changed, 128 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml

diff --git a/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml b/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml
new file mode 100644
index 000000000000..bcdb46effdba
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml
@@ -0,0 +1,54 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/bluetooth/mediatek,mt7925-bluetooth.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek MT7925 Bluetooth
+
+maintainers:
+  - Zhangchao Zhang <zhangchao.zhang@mediatek.com>
+
+description:
+  7925 uses the USB bus to communicate with the host.
+  Two methods are used to reset Bluetooth.
+  When Bluetooth crashes or core dumps,
+  the pin will be pulled low, then held for 200ms,
+  and then pulled high again before next probe.
+
+allOf:
+  - $ref: bluetooth-controller.yaml#
+
+properties:
+  compatible:
+    enum:
+      - mediatek,mt7925-bluetooth
+
+  reg:
+    const: 2
+
+  reset-gpios:
+    maxItems: 1
+    description:
+      An active-high reset pin for the Bluetooth core;
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    &xhci0 {
+      vbus-supply = <&pp5000_usb>;
+      usb2-lpm-disable;
+
+      status = "okay";
+
+      bt_reset: bt-reset{
+        compatible = "mediatek,usb-bluetooth";
+        reset-gpios = <&pio 248 GPIO_ACTIVE_HIGH>;
+      };
+    };
\ No newline at end of file
diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
index 4390fd571dbd..3e5f3ca6f0d5 100644
--- a/drivers/bluetooth/btmtk.c
+++ b/drivers/bluetooth/btmtk.c
@@ -6,6 +6,8 @@
 #include <linux/firmware.h>
 #include <linux/usb.h>
 #include <linux/iopoll.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
 #include <linux/unaligned.h>
 
 #include <net/bluetooth/bluetooth.h>
@@ -109,6 +111,65 @@ static void btmtk_coredump_notify(struct hci_dev *hdev, int state)
 	}
 }
 
+static void btmtk_reset_by_gpio_work(struct work_struct *work)
+{
+	struct btmtk_reset_gpio *reset_gpio_data =
+			container_of(work, struct btmtk_reset_gpio, reset_work.work);
+
+	gpio_direction_output(reset_gpio_data->gpio_number, 1);
+	kfree(reset_gpio_data);
+}
+
+static int btmtk_reset_by_gpio(struct hci_dev *hdev)
+{
+	struct btmtk_data *data = hci_get_priv(hdev);
+	struct btmtk_reset_gpio *reset_gpio_data;
+	struct device_node *node;
+	int reset_gpio_number;
+
+	node = of_find_compatible_node(NULL, NULL, "mediatek,usb-bluetooth");
+	if (node) {
+		reset_gpio_number = of_get_named_gpio(node, "reset-gpios", 0);
+		if (!gpio_is_valid(reset_gpio_number)) {
+			bt_dev_warn(hdev, "invalid reset GPIO, use software reset");
+			return -EINVAL;
+		}
+	} else {
+		bt_dev_warn(hdev, "no reset GPIO, use software reset");
+		return -ENODEV;
+	}
+
+	/* Toggle the hard reset line. The Mediatek device is going to
+	 * yank itself off the USB and then replug. The cleanup is handled
+	 * correctly on the way out (standard USB disconnect), and the new
+	 * device is detected cleanly and bound to the driver again like
+	 * it should be.
+	 */
+
+	if (test_and_set_bit(BTMTK_HW_RESET_ACTIVE, &data->flags)) {
+		bt_dev_err(hdev, "last reset failed? Not resetting again");
+		return 0;
+	}
+
+	reset_gpio_data = kzalloc(sizeof(*reset_gpio_data), GFP_KERNEL);
+	if (!reset_gpio_data)
+		return -ENOMEM;
+
+	INIT_DELAYED_WORK(&reset_gpio_data->reset_work, btmtk_reset_by_gpio_work);
+	reset_gpio_data->gpio_number = reset_gpio_number;
+
+	gpio_direction_output(reset_gpio_number, 0);
+
+	/* It requires 200ms for mtk bt chip to do reset,
+	 * although Schedule_delayed_work is asynchronous,
+	 * it is risk-free. If it is not completed in 200ms,
+	 * it will only postpone the next probe, which will
+	 * only make the probe run later. There is no other risk.
+	 */
+	schedule_delayed_work(&reset_gpio_data->reset_work, msecs_to_jiffies(200));
+	return 0;
+}
+
 void btmtk_fw_get_filename(char *buf, size_t size, u32 dev_id, u32 fw_ver,
 			   u32 fw_flavor)
 {
@@ -364,6 +425,14 @@ void btmtk_reset_sync(struct hci_dev *hdev)
 	struct btmtk_data *reset_work = hci_get_priv(hdev);
 	int err;
 
+	/* Toggle reset gpio if the platform provieds one,
+	 * if the compatibility field or pin cannot be found
+	 * in the dts files, it can still reset bluetooth using
+	 * software reset.
+	 */
+	err = btmtk_reset_by_gpio(hdev);
+	if (!err)
+		return;
 	hci_dev_lock(hdev);
 
 	err = hci_cmd_sync_queue(hdev, reset_work->reset_sync, NULL, NULL);
diff --git a/drivers/bluetooth/btmtk.h b/drivers/bluetooth/btmtk.h
index 5df7c3296624..8a265ce367d1 100644
--- a/drivers/bluetooth/btmtk.h
+++ b/drivers/bluetooth/btmtk.h
@@ -179,6 +179,11 @@ struct btmtk_data {
 	spinlock_t isorxlock;
 };
 
+struct btmtk_reset_gpio {
+	struct delayed_work reset_work;
+	int gpio_number;
+};
+
 typedef int (*wmt_cmd_sync_func_t)(struct hci_dev *,
 				   struct btmtk_hci_wmt_params *);
 
-- 
2.46.0

On 12/06/2025 09:22, Zhangchao Zhang wrote:
> This V2 patch provides two methods btmtk_reset_by_gpio,
> btmtk_reset_by_gpio_work for mediatek controller,
> it has been tested locally many times and can reset normally.
> 
> The pin is configured in dts files, bluetooth is reset by pulling
> the pin, when exception or coredump occurs, the above methods will
> be used to reset the bluetooth, if the pin is not found, it also can
> reset bluetooth successfully by software reset.
> 
> Compared with the previously submitted version, the following
> information has been revised in version V2
> 1)-Changed the capitalization of co-developer names,
>    using the correct capitalization of abbreviations and full
>    name, and corrected obvious spelling errors.
> 2)-Add a revision history.
> 3)-Remove the "BT Driver" in the prefix.
> 4)-Add the bt-binding document, include inforamtion related to reset
>    pin and compatibility matching.
> 5)-Add a comment before the schedule_delayed_work function call,
>    although schedule_delayed_work is asynchronous, there is no risk.
>    Even if it is not completed within 200ms, it will only postpone
>    the subsequent probe and will not have any impact.
> 6-)Add a comment before the btmtk_reset_by_gpio function call,
>    if the compatibility filed or pin cannot be found in the dts
>    files, it can still reset bluetooth using software reset.
> 
> Co-developed-by Hao Qin <hao.qin@mediatek.com>
> Co-developed-Chris Lu <chris.lu@mediatek.com>
> Co-developed-Jiande Lu <jiande.lu@mediatek.com>
> Signed-off-by: Zhangchao Zhang <ot_zhangchao.zhang@mediatek.com>

<form letter>
Please use scripts/get_maintainers.pl to get a list of necessary people
and lists to CC. It might happen, that command when run on an older
kernel, gives you outdated entries. Therefore please be sure you base
your patches on recent Linux kernel.

Tools like b4 or scripts/get_maintainer.pl provide you proper list of
people, so fix your workflow. Tools might also fail if you work on some
ancient tree (don't, instead use mainline) or work on fork of kernel
(don't, instead use mainline). Just use b4 and everything should be
fine, although remember about `b4 prep --auto-to-cc` if you added new
patches to the patchset.

You missed at least devicetree list (maybe more), so this won't be
tested by automated tooling. Performing review on untested code might be
a waste of time.

Please kindly resend and include all necessary To/Cc entries.
</form letter>


Best regards,
Krzysztof

On 12/06/2025 09:22, Zhangchao Zhang wrote:
> This V2 patch provides two methods btmtk_reset_by_gpio,

Please do not use "This commit/patch/change", but imperative mood. See
longer explanation here:
https://elixir.bootlin.com/linux/v5.17.1/source/Documentation/process/submitting-patches.rst#L95


And v2 makes no sense here. Describe the commit, why you are doing this,
what you are doing here, not your process.

> btmtk_reset_by_gpio_work for mediatek controller,
> it has been tested locally many times and can reset normally.
> 
> The pin is configured in dts files, bluetooth is reset by pulling

That's redundant. Do not explain us how DTS works. We all know it.
Explain WHY you are doing this, what sort of problem or hardware you are
dealing here with.

> the pin, when exception or coredump occurs, the above methods will
> be used to reset the bluetooth, if the pin is not found, it also can
> reset bluetooth successfully by software reset.
> 
> Compared with the previously submitted version, the following
> information has been revised in version V2

This goes to changelog or cover letter. See submitting patches.

And that's a v3, because you already sent v2.


> 1)-Changed the capitalization of co-developer names,
>    using the correct capitalization of abbreviations and full
>    name, and corrected obvious spelling errors.
> 2)-Add a revision history.
> 3)-Remove the "BT Driver" in the prefix.
> 4)-Add the bt-binding document, include inforamtion related to reset
>    pin and compatibility matching.
> 5)-Add a comment before the schedule_delayed_work function call,
>    although schedule_delayed_work is asynchronous, there is no risk.
>    Even if it is not completed within 200ms, it will only postpone
>    the subsequent probe and will not have any impact.
> 6-)Add a comment before the btmtk_reset_by_gpio function call,
>    if the compatibility filed or pin cannot be found in the dts
>    files, it can still reset bluetooth using software reset.
> 
> Co-developed-by Hao Qin <hao.qin@mediatek.com>
> Co-developed-Chris Lu <chris.lu@mediatek.com>
> Co-developed-Jiande Lu <jiande.lu@mediatek.com>
> Signed-off-by: Zhangchao Zhang <ot_zhangchao.zhang@mediatek.com>
> ---
>  .../bluetooth/mediatek,mt7925-bluetooth.yaml  | 54 +++++++++++++++

Please run scripts/checkpatch.pl on the patches and fix reported
warnings. After that, run also 'scripts/checkpatch.pl --strict' on the
patches and (probably) fix more warnings. Some warnings can be ignored,
especially from --strict run, but the code here looks like it needs a
fix. Feel free to get in touch if the warning is not clear.

Please use subject prefixes matching the subsystem. You can get them for
example with `git log --oneline -- DIRECTORY_OR_FILE` on the directory
your patch is touching. For bindings, the preferred subjects are
explained here:
https://www.kernel.org/doc/html/latest/devicetree/bindings/submitting-patches.html#i-for-patch-submitters

>  drivers/bluetooth/btmtk.c                     | 69 +++++++++++++++++++
>  drivers/bluetooth/btmtk.h                     |  5 ++
>  3 files changed, 128 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml
> 
> diff --git a/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml b/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml
> new file mode 100644
> index 000000000000..bcdb46effdba
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml
> @@ -0,0 +1,54 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/net/bluetooth/mediatek,mt7925-bluetooth.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: MediaTek MT7925 Bluetooth
> +
> +maintainers:
> +  - Zhangchao Zhang <zhangchao.zhang@mediatek.com>
> +
> +description:
> +  7925 uses the USB bus to communicate with the host.
> +  Two methods are used to reset Bluetooth.
> +  When Bluetooth crashes or core dumps,
> +  the pin will be pulled low, then held for 200ms,
> +  and then pulled high again before next probe.
> +
> +allOf:
> +  - $ref: bluetooth-controller.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - mediatek,mt7925-bluetooth
> +
> +  reg:
> +    const: 2
> +
> +  reset-gpios:
> +    maxItems: 1
> +    description:
> +      An active-high reset pin for the Bluetooth core;

Blank line and drop final ;

> +required:
> +  - compatible
> +  - reg
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    &xhci0 {
> +      vbus-supply = <&pp5000_usb>;
> +      usb2-lpm-disable;

Drop node above

> +
> +      status = "okay";

Drop

> +
> +      bt_reset: bt-reset{

Messy style, missing space. See DTS coding style.

> +        compatible = "mediatek,usb-bluetooth";

Look at your binding which you *just* wrote.

> +        reset-gpios = <&pio 248 GPIO_ACTIVE_HIGH>;

That's so incomplete... and will fail tests. You need to write COMPLETE
binding and then COMPLETE example.

> +      };
> +    };
> \ No newline at end of file

You have patch warnings.


> diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
> index 4390fd571dbd..3e5f3ca6f0d5 100644
> --- a/drivers/bluetooth/btmtk.c
> +++ b/drivers/bluetooth/btmtk.c
> @@ -6,6 +6,8 @@
>  #include <linux/firmware.h>
>  #include <linux/usb.h>
>  #include <linux/iopoll.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
>  #include <linux/unaligned.h>
>  
>  #include <net/bluetooth/bluetooth.h>
> @@ -109,6 +111,65 @@ static void btmtk_coredump_notify(struct hci_dev *hdev, int state)
>  	}
>  }
>  
> +static void btmtk_reset_by_gpio_work(struct work_struct *work)
> +{
> +	struct btmtk_reset_gpio *reset_gpio_data =
> +			container_of(work, struct btmtk_reset_gpio, reset_work.work);
> +
> +	gpio_direction_output(reset_gpio_data->gpio_number, 1);
> +	kfree(reset_gpio_data);
> +}
> +
> +static int btmtk_reset_by_gpio(struct hci_dev *hdev)
> +{
> +	struct btmtk_data *data = hci_get_priv(hdev);
> +	struct btmtk_reset_gpio *reset_gpio_data;
> +	struct device_node *node;
> +	int reset_gpio_number;
> +
> +	node = of_find_compatible_node(NULL, NULL, "mediatek,usb-bluetooth");

Same comment as before. Nothing improved.

Best regards,
Krzysztof