[PATCH] Bluetooth: BT Driver: mediatek: add gpio pin to reset bt

[PATCH] Bluetooth: BT Driver: mediatek: add gpio pin to reset bt

[Zhangchao Zhang]

This patch provides some methods btmtk_reset_by_gpio,
btmtk_reset_by_gpio_work_for mediatek controller.

The pin is configured in dts files, bluetooth is reset by pulling
the pin, when an exception or coredump occurs, the above method will
be used to reset the bluetooth.

Co-developed-by Hao qin <hao.qin@mediatek.com>
Co-developed-by Chirs lu <chris.lu@mediatek.com>
Co-developed-by Jiande lu <jiande.lu@mediatek.com>
Signed-off-by: Zhangchao Zhang <ot_zhangchao.zhang@mediatek.com>
---
 drivers/bluetooth/btmtk.c | 59 +++++++++++++++++++++++++++++++++++++++
 drivers/bluetooth/btmtk.h |  5 ++++
 2 files changed, 64 insertions(+)

diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
index 4390fd571dbd..16542c724b40 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 +111,59 @@ 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 SW reset");
+			return -EINVAL;
+		}
+	} else {
+		bt_dev_warn(hdev, "no reset gpio, use SW reet");
+		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);
+	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 +419,10 @@ 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*/
+	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

Re: [PATCH] Bluetooth: BT Driver: mediatek: add gpio pin to reset bt

[Paul Menzel]

Dear Zhangchao,


Thank you for your patch. For the summary, I’d just use:

Bluetooth: btmtk: Add gpio pin to reset bt


Am 28.05.25 um 09:03 schrieb Zhangchao Zhang:
> This patch provides some methods btmtk_reset_by_gpio,

some → the two

> btmtk_reset_by_gpio_work_for mediatek controller.
> 
> The pin is configured in dts files, bluetooth is reset by pulling
> the pin, when an exception or coredump occurs, the above method will
> be used to reset the bluetooth.

How did you test this? Could you please add that to the commit message.

> Co-developed-by Hao qin <hao.qin@mediatek.com>

qin → Qin

> Co-developed-by Chirs lu <chris.lu@mediatek.com>

Chirs → Chris
lu → Lu

> Co-developed-by Jiande lu <jiande.lu@mediatek.com>

lu → Lu

> Signed-off-by: Zhangchao Zhang <ot_zhangchao.zhang@mediatek.com>
> ---
>   drivers/bluetooth/btmtk.c | 59 +++++++++++++++++++++++++++++++++++++++
>   drivers/bluetooth/btmtk.h |  5 ++++
>   2 files changed, 64 insertions(+)
> 
> diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
> index 4390fd571dbd..16542c724b40 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 +111,59 @@ 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 SW reset");

gpio → GPIO
SW → software
reet → reset?

Please also log the GPIO number. Also, a hint, what the user should do 
in this situation would be great.

> +			return -EINVAL;
> +		}
> +	} else {
> +		bt_dev_warn(hdev, "no reset gpio, use SW reet");

gpio → GPIO
SW → software
reet → 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");

It’d be great, if this error message could be rephrased, so users know 
what is wrong, and what to do.

> +		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);
> +	schedule_delayed_work(&reset_gpio_data->reset_work, msecs_to_jiffies(200));

A 200 ms delay is quite long. Maybe add the datasheet section as a 
reference in a comment?

> +
> +	return 0;
> +}
> +
>   void btmtk_fw_get_filename(char *buf, size_t size, u32 dev_id, u32 fw_ver,
>   			   u32 fw_flavor)
>   {
> @@ -364,6 +419,10 @@ 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*/

1.  Please add a space in the beginning and end.
2.  provides (A spell checker should have found this.)

> +	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 *);
>   


Kind regards,

Paul

Re: [PATCH] Bluetooth: BT Driver: mediatek: add gpio pin to reset bt

[Krzysztof Kozlowski]

On 28/05/2025 09:03, Zhangchao Zhang wrote:
> +
> +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");

There is no such compatible. Just git grep for it.

> +	if (node) {
> +		reset_gpio_number = of_get_named_gpio(node, "reset-gpios", 0);

Where is the ABI documented? Anyway, you should not pick GPIOs from
random devices.


Best regards,
Krzysztof

Re: [PATCH] Bluetooth: BT Driver: mediatek: add gpio pin to reset bt

[Chris Lu (陸稚泓)]

Hi Krzysztof,

Sorry for late reply. Some problem with Zhangchao's envrionment that he
can't reply the mail. So I'll reply on his behalf.

Before submitting the next version, we'd like to discuss and confirm
the questions you mentioned in v1 according to the suggestion from
Bluetooth Maintainer Luiz.

On Wed, 2025-05-28 at 14:07 +0200, Krzysztof Kozlowski wrote:
> 
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> On 28/05/2025 09:03, Zhangchao Zhang wrote:
> > +
> > +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");
> 
> There is no such compatible. Just git grep for it.
> 
> > +     if (node) {
> > +             reset_gpio_number = of_get_named_gpio(node, "reset-
> > gpios", 0);
> 
> Where is the ABI documented? Anyway, you should not pick GPIOs from
> random devices.
> 
In v1, we haven't prepared yaml file about dts setting yet. Does your
question above referring to the same thing?

Zhangchao will add it in the next submission and run it through
"dt_binding_check" according to the Kernel's document.

> 
> Best regards,
> Krzysztof

Thanks a lot,
Chris Lu

Re: [PATCH] Bluetooth: BT Driver: mediatek: add gpio pin to reset bt

[Krzysztof Kozlowski]

On 25/06/2025 05:42, Chris Lu (陸稚泓) wrote:
> Hi Krzysztof,
> 
> Sorry for late reply. Some problem with Zhangchao's envrionment that he
> can't reply the mail. So I'll reply on his behalf.
> 
> Before submitting the next version, we'd like to discuss and confirm
> the questions you mentioned in v1 according to the suggestion from
> Bluetooth Maintainer Luiz.
> 
> On Wed, 2025-05-28 at 14:07 +0200, Krzysztof Kozlowski wrote:
>>
>> External email : Please do not click links or open attachments until
>> you have verified the sender or the content.
>>
>>
>> On 28/05/2025 09:03, Zhangchao Zhang wrote:
>>> +
>>> +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");
>>
>> There is no such compatible. Just git grep for it.
>>
>>> +     if (node) {
>>> +             reset_gpio_number = of_get_named_gpio(node, "reset-
>>> gpios", 0);
>>
>> Where is the ABI documented? Anyway, you should not pick GPIOs from
>> random devices.
>>
> In v1, we haven't prepared yaml file about dts setting yet. Does your
> question above referring to the same thing?
> 
> Zhangchao will add it in the next submission and run it through
> "dt_binding_check" according to the Kernel's document.
> 
No, because this does not explain what you send in v2 and why now you
sent again v1!

Nothing here makes sense, not only mediatek,usb-bluetooth which does not
exist and has 1% chances of acceptance anyway.

Best regards,
Krzysztof