[PATCH v5 0/2] Bluetooth: mediatek: add gpio pin to reset bt

[PATCH v5 0/2] Bluetooth: mediatek: add gpio pin to reset bt

[Zhangchao Zhang]

The enhanced BT reset feature builds upon the previous software-based
BT reset by adding support for hardware pin resets.
To maintain compatibility with existing projects that
still use the software BT reset, both methods are supported.

When performing a BT reset, the system first checks whether the
Device Tree Source (DTS) is configured with the appropriate settings.
If the specified compatible and BT reset GPIO are defined in the DTS,
the system will pull the designated GPIO pin low for at least 200ms,
then pull it high to trigger the BT reset. If these settings are not
configured, the system will fall back to the original software
BT reset methods.

Compared with the previously submitted version, the following
information are some specific revision histories

V4-->V5 modifications:
-Modify the comments mentioned in v1.
-Modify dt_binding files and 
   make dt binding a separate patch.

V3-->V4 modifications:
Modify dt binding format information and
   the explanation text in the patch

V2-->V3 modifications:
-Changed the capitalization of co-developer names,
   using the correct capitalization of abbreviations and full
   name, and corrected obvious spelling errors.
-Add a revision history.
-Remove the "BT Driver" in the prefix.
-Add the bt-binding document, include inforamtion related to reset
   pin and compatibility matching.
-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.
-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.

V2 modifications:
Modify gpio to GPIO, SW to software,
and fix other obvious spelling errors.

-- 
2.46.0

[PATCH v5 1/2] Bluetooth: mediatek: add gpio pin to reset bt

[Zhangchao Zhang]

Makes the platform Bluetooth to be reset by hardware pin,
it provides two methods to do it for mediatek controller,
and it has been tested locally many times and can reset normally.

When an exception occurs, resetting Bluetooth by hardware pin
is more stable than resetting Bluetooth by software.
If the corresponding pin is not found in dts,
bluetooth can also be reset successfully.

Co-developed: 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>
---
 drivers/bluetooth/btmtk.c | 69 +++++++++++++++++++++++++++++++++++++++
 drivers/bluetooth/btmtk.h |  5 +++
 2 files changed, 74 insertions(+)

diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
index 4390fd571dbd..4f677f86af1e 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 provides 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

[PATCH v5 2/2] dt-bindings: net: mediatek,mt7925-bluetooth.yaml

[Zhangchao Zhang]

Add hardware pins and compatible strings.

As a binding file for the MTK Bluetooth driver code,
it provides a set of compatible fields and hardware
pins for the driver to use.

Signed-off-by: Zhangchao Zhang <ot_zhangchao.zhang@mediatek.com>
---
 .../bluetooth/mediatek,mt7925-bluetooth.yaml  | 57 +++++++++++++++++++
 MAINTAINERS                                   |  1 +
 2 files changed, 58 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..230c24ada3b4
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml
@@ -0,0 +1,57 @@
+# 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: Bluetooth mediatek add gpio pin to reset bt
+
+maintainers:
+  - Sean Wang <sean.wang@mediatek.com>
+
+description:
+  7925 uses the USB bus to communicate with the host.
+  Two methods are used to reset Bluetooth.
+  Provide hardware pin, when an exception occurs,
+  resetting Bluetooth by hardware pin is more stable
+  than resetting Bluetooth by software.
+  If the corresponding pin is not found in dts,
+  bluetooth can also be reset successfully.
+
+allOf:
+  - $ref: bluetooth-controller.yaml#
+
+properties:
+  compatible:
+    enum:
+      - mediatek,usb-bluetooth
+
+  gpio-controller:
+    description:
+      Marks the device node as s GPIO controller.
+
+  "#gpio-cells":
+    const: 2
+
+  reset-gpios:
+    maxItems: 1
+
+    description:
+      An active-high reset pin for the Bluetooth core; on typical M.2
+      key E modules this is the W_DISABLE2# pin.
+
+required:
+  - compatible
+  - "#gpio-cells"
+  - reset-gpios
+
+unevaluatedProperties: false
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+      bluetooth {
+        compatible = "mediatek,usb-bluetooth";
+        #gpio-cells = <2>;
+        reset-gpios = <&pio 248 GPIO_ACTIVE_HIGH>;
+      };
diff --git a/MAINTAINERS b/MAINTAINERS
index 5959513a7359..d104a5821f20 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14676,6 +14676,7 @@ L:	linux-mediatek@lists.infradead.org (moderated for non-subscribers)
 S:	Maintained
 F:	Documentation/devicetree/bindings/net/bluetooth/mediatek,bluetooth.txt
 F:	Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7921s-bluetooth.yaml
+F:	Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml
 F:	drivers/bluetooth/btmtkuart.c
 
 MEDIATEK BOARD LEVEL SHUTDOWN DRIVERS
-- 
2.46.0

Re: [PATCH v5 0/2] Bluetooth: mediatek: add gpio pin to reset bt

[Krzysztof Kozlowski]

On Fri, Jun 27, 2025 at 01:59:22PM +0800, Zhangchao Zhang wrote:
> The enhanced BT reset feature builds upon the previous software-based
> BT reset by adding support for hardware pin resets.
> To maintain compatibility with existing projects that
> still use the software BT reset, both methods are supported.
> 
> When performing a BT reset, the system first checks whether the
> Device Tree Source (DTS) is configured with the appropriate settings.
> If the specified compatible and BT reset GPIO are defined in the DTS,
> the system will pull the designated GPIO pin low for at least 200ms,
> then pull it high to trigger the BT reset. If these settings are not
> configured, the system will fall back to the original software
> BT reset methods.
> 
> Compared with the previously submitted version, the following
> information are some specific revision histories
> 
> V4-->V5 modifications:
> -Modify the comments mentioned in v1.

What? This is so vague, means nothing.

> -Modify dt_binding files and 
>    make dt binding a separate patch.

This means nothing. Everything is "modify". Your changelog is terribly
uninforming. This must be detailed.

Best regards,
Krzysztof

Re: [PATCH v5 2/2] dt-bindings: net: mediatek,mt7925-bluetooth.yaml

[Krzysztof Kozlowski]

How did you manage to make mistake in my email is beyond my understand.
Tools should generate address list, not humans.

Where is the changelog?

On Fri, Jun 27, 2025 at 01:59:24PM +0800, Zhangchao Zhang wrote:
> Add hardware pins and compatible strings.

I don't see any pins here.

 
> As a binding file for the MTK Bluetooth driver code,
> it provides a set of compatible fields and hardware
> pins for the driver to use.

All this is not relevant. Describe the hardware here.

> 
> Signed-off-by: Zhangchao Zhang <ot_zhangchao.zhang@mediatek.com>
> ---


>  .../bluetooth/mediatek,mt7925-bluetooth.yaml  | 57 +++++++++++++++++++
>  MAINTAINERS                                   |  1 +
>  2 files changed, 58 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..230c24ada3b4
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml
> @@ -0,0 +1,57 @@
> +# 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: Bluetooth mediatek add gpio pin to reset bt

Not relevant. This is the title describing this specific hardware.

> +
> +maintainers:
> +  - Sean Wang <sean.wang@mediatek.com>
> +
> +description:
> +  7925 uses the USB bus to communicate with the host.

Waht is 7925?

> +  Two methods are used to reset Bluetooth.
> +  Provide hardware pin, when an exception occurs,
> +  resetting Bluetooth by hardware pin is more stable
> +  than resetting Bluetooth by software.
> +  If the corresponding pin is not found in dts,
> +  bluetooth can also be reset successfully.

Wrap this properly. The same commit msg.

> +
> +allOf:
> +  - $ref: bluetooth-controller.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - mediatek,usb-bluetooth

NAK, you cannot have such compatible. I already said at v1 or v2 that it
will be rejected!

Why are you pushing this all the time, without reading the feedback?

You need SoC and device specific compatibles. There is no such hardware
as "usb-bluetooth". If there is, point me to datasheet for it.


> +
> +  gpio-controller:
> +    description:
> +      Marks the device node as s GPIO controller.

Irrelevant. Drop. See other schemas.

> +
> +  "#gpio-cells":
> +    const: 2
> +
> +  reset-gpios:
> +    maxItems: 1
> +

Drop blank line. Look how other files are doing this.


> +    description:
> +      An active-high reset pin for the Bluetooth core; on typical M.2

active-high? Really? I have doubts.

> +      key E modules this is the W_DISABLE2# pin.
> +
> +required:
> +  - compatible
> +  - "#gpio-cells"
> +  - reset-gpios
> +
> +unevaluatedProperties: false

This is random style. Why doing something completely different than
every other file? Missing blank line.

> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +      bluetooth {

Messed indentation.

To summarize:
Except writing something entirely different than every other binding
(why?), this does not represent hardware. Your commit msg explains ZERO
about the hardware. Binding description says nothing and is actually not
correct.

So again, if you send the same it will be rejected.

I expect answers UNDER EACH OF MY COMMENTS, because you keep ignoring
entire feedback given to you.

Best regards,
Krzysztof