[PATCH v2 1/2] dt-bindings: net: bluetooth: nxp: Add support for 4M baudrate

[PATCH v2 1/2] dt-bindings: net: bluetooth: nxp: Add support for 4M baudrate

[Neeraj Sanjay Kale]

Add support for 4000000 as secondary baudrate.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
---
v2: Use the available 'max-speed' device tree property. (Krzysztof)
---
 .../devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml  | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml b/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml
index 3ab60c70286f..4a1b6ea48a2f 100644
--- a/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml
+++ b/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml
@@ -34,6 +34,12 @@ properties:
       This property depends on the module vendor's
       configuration.
 
+  max-speed:
+    enum:
+      - 3000000
+      - 4000000
+    default: 3000000
+
   firmware-name:
     maxItems: 1
 
@@ -78,6 +84,7 @@ examples:
         bluetooth {
             compatible = "nxp,88w8987-bt";
             fw-init-baudrate = <3000000>;
+            max-speed = <4000000>;
             firmware-name = "uartuart8987_bt_v0.bin";
             device-wakeup-gpios = <&gpio 11 GPIO_ACTIVE_HIGH>;
             nxp,wakein-pin = /bits/ 8 <18>;
-- 
2.34.1

[PATCH v2 2/2] Bluetooth: btnxpuart: Add support for 4M baudrate

[Neeraj Sanjay Kale]

This adds support for 4000000 as secondary baudrate.
This value is selected from device tree property "max-speed"
which is then used to download FW chunks, and as operational baudrate after
HCI initialization is done.

This feature is applicable for all new V3 bootloader chips and w8987 V1
bootloader chip.

This property does not apply for w8997 compatible device, since it
downloads a helper.bin FW file that sets secondary baudrate as 3000000
only.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
---
v2: Change DT property to 'max-speed'. (Krzysztof)
    Add support for 4M baudrate to w8987. Update commit message.
(Sherry)
---
 drivers/bluetooth/btnxpuart.c | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c
index 6b13feed06df..c9b3e158f438 100644
--- a/drivers/bluetooth/btnxpuart.c
+++ b/drivers/bluetooth/btnxpuart.c
@@ -73,7 +73,8 @@
 #define FW_AUTH_ENC		0xc0
 
 #define HCI_NXP_PRI_BAUDRATE	115200
-#define HCI_NXP_SEC_BAUDRATE	3000000
+#define HCI_NXP_SEC_BAUDRATE_3M	3000000
+#define HCI_NXP_SEC_BAUDRATE_4M	4000000
 
 #define MAX_FW_FILE_NAME_LEN    50
 
@@ -201,6 +202,7 @@ struct btnxpuart_dev {
 	u32 new_baudrate;
 	u32 current_baudrate;
 	u32 fw_init_baudrate;
+	u32 secondary_baudrate;
 	enum bootloader_param_change timeout_changed;
 	enum bootloader_param_change baudrate_changed;
 	bool helper_downloaded;
@@ -802,7 +804,10 @@ static bool nxp_fw_change_baudrate(struct hci_dev *hdev, u16 req_len)
 		nxpdev->fw_v3_offset_correction += req_len;
 	} else if (req_len == sizeof(uart_config)) {
 		uart_config.clkdiv.address = __cpu_to_le32(clkdivaddr);
-		uart_config.clkdiv.value = __cpu_to_le32(0x00c00000);
+		if (nxpdev->new_baudrate == HCI_NXP_SEC_BAUDRATE_4M)
+			uart_config.clkdiv.value = __cpu_to_le32(0x01000000);
+		else
+			uart_config.clkdiv.value = __cpu_to_le32(0x00c00000);
 		uart_config.uartdiv.address = __cpu_to_le32(uartdivaddr);
 		uart_config.uartdiv.value = __cpu_to_le32(1);
 		uart_config.mcr.address = __cpu_to_le32(uartmcraddr);
@@ -966,12 +971,13 @@ static int nxp_recv_fw_req_v1(struct hci_dev *hdev, struct sk_buff *skb)
 			goto free_skb;
 		}
 		if (nxpdev->baudrate_changed != changed) {
+			nxpdev->new_baudrate = nxpdev->secondary_baudrate;
 			if (nxp_fw_change_baudrate(hdev, len)) {
 				nxpdev->baudrate_changed = changed;
 				serdev_device_set_baudrate(nxpdev->serdev,
-							   HCI_NXP_SEC_BAUDRATE);
+							   nxpdev->secondary_baudrate);
 				serdev_device_set_flow_control(nxpdev->serdev, true);
-				nxpdev->current_baudrate = HCI_NXP_SEC_BAUDRATE;
+				nxpdev->current_baudrate = nxpdev->secondary_baudrate;
 			}
 			goto free_skb;
 		}
@@ -992,7 +998,7 @@ static int nxp_recv_fw_req_v1(struct hci_dev *hdev, struct sk_buff *skb)
 			nxpdev->helper_downloaded = true;
 			serdev_device_wait_until_sent(nxpdev->serdev, 0);
 			serdev_device_set_baudrate(nxpdev->serdev,
-						   HCI_NXP_SEC_BAUDRATE);
+						   HCI_NXP_SEC_BAUDRATE_3M);
 			serdev_device_set_flow_control(nxpdev->serdev, true);
 		} else {
 			clear_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
@@ -1216,12 +1222,13 @@ static int nxp_recv_fw_req_v3(struct hci_dev *hdev, struct sk_buff *skb)
 	}
 
 	if (nxpdev->baudrate_changed != changed) {
+		nxpdev->new_baudrate = nxpdev->secondary_baudrate;
 		if (nxp_fw_change_baudrate(hdev, len)) {
 			nxpdev->baudrate_changed = cmd_sent;
 			serdev_device_set_baudrate(nxpdev->serdev,
-						   HCI_NXP_SEC_BAUDRATE);
+						   nxpdev->secondary_baudrate);
 			serdev_device_set_flow_control(nxpdev->serdev, true);
-			nxpdev->current_baudrate = HCI_NXP_SEC_BAUDRATE;
+			nxpdev->current_baudrate = nxpdev->secondary_baudrate;
 		}
 		goto free_skb;
 	}
@@ -1447,8 +1454,8 @@ static int nxp_post_init(struct hci_dev *hdev)
 	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
 	struct ps_data *psdata = &nxpdev->psdata;
 
-	if (nxpdev->current_baudrate != HCI_NXP_SEC_BAUDRATE) {
-		nxpdev->new_baudrate = HCI_NXP_SEC_BAUDRATE;
+	if (nxpdev->current_baudrate != nxpdev->secondary_baudrate) {
+		nxpdev->new_baudrate = nxpdev->secondary_baudrate;
 		nxp_set_baudrate_cmd(hdev, NULL);
 	}
 	if (psdata->cur_h2c_wakeupmode != psdata->h2c_wakeupmode)
@@ -1773,6 +1780,11 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
 	if (!nxpdev->fw_init_baudrate)
 		nxpdev->fw_init_baudrate = FW_INIT_BAUDRATE;
 
+	device_property_read_u32(&nxpdev->serdev->dev, "max-speed",
+				 &nxpdev->secondary_baudrate);
+	if (!nxpdev->secondary_baudrate)
+		nxpdev->secondary_baudrate = HCI_NXP_SEC_BAUDRATE_3M;
+
 	set_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
 
 	crc8_populate_msb(crc8_table, POLYNOMIAL8);
-- 
2.34.1

Re: [PATCH v2 1/2] dt-bindings: net: bluetooth: nxp: Add support for 4M baudrate

[Paul Menzel]

Dear Neeraj,


Thank you for the patch.

Am 18.06.25 um 16:20 schrieb Neeraj Sanjay Kale:
> Add support for 4000000 as secondary baudrate.

Could you specify how you tested this, that means, how did you set the 
speed, and then do the test, that it actually works at that speed.

> Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
> ---
> v2: Use the available 'max-speed' device tree property. (Krzysztof)
> ---
>   .../devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml  | 7 +++++++
>   1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml b/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml
> index 3ab60c70286f..4a1b6ea48a2f 100644
> --- a/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml
> +++ b/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml
> @@ -34,6 +34,12 @@ properties:
>         This property depends on the module vendor's
>         configuration.
>   
> +  max-speed:
> +    enum:
> +      - 3000000
> +      - 4000000
> +    default: 3000000
> +
>     firmware-name:
>       maxItems: 1
>   
> @@ -78,6 +84,7 @@ examples:
>           bluetooth {
>               compatible = "nxp,88w8987-bt";
>               fw-init-baudrate = <3000000>;
> +            max-speed = <4000000>;
>               firmware-name = "uartuart8987_bt_v0.bin";
>               device-wakeup-gpios = <&gpio 11 GPIO_ACTIVE_HIGH>;
>               nxp,wakein-pin = /bits/ 8 <18>;


Kind regards,

Paul

RE: [PATCH v2 2/2] Bluetooth: btnxpuart: Add support for 4M baudrate

[Sherry Sun]

> -----Original Message-----
> From: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
> Sent: Wednesday, June 18, 2025 10:20 PM
> To: marcel@holtmann.org; luiz.dentz@gmail.com; robh@kernel.org;
> krzk+dt@kernel.org; conor+dt@kernel.org
> Cc: linux-bluetooth@vger.kernel.org; linux-kernel@vger.kernel.org;
> devicetree@vger.kernel.org; Amitkumar Karwar
> <amitkumar.karwar@nxp.com>; Neeraj Sanjay Kale
> <neeraj.sanjaykale@nxp.com>; Sherry Sun <sherry.sun@nxp.com>; Manjeet
> Gupta <manjeet.gupta@nxp.com>
> Subject: [PATCH v2 2/2] Bluetooth: btnxpuart: Add support for 4M baudrate
> 
> This adds support for 4000000 as secondary baudrate.
> This value is selected from device tree property "max-speed"
> which is then used to download FW chunks, and as operational baudrate
> after HCI initialization is done.
> 
> This feature is applicable for all new V3 bootloader chips and w8987 V1
> bootloader chip.
> 
> This property does not apply for w8997 compatible device, since it downloads
> a helper.bin FW file that sets secondary baudrate as 3000000 only.
> 
> Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
> ---
> v2: Change DT property to 'max-speed'. (Krzysztof)
>     Add support for 4M baudrate to w8987. Update commit message.
> (Sherry)
> ---
>  drivers/bluetooth/btnxpuart.c | 30 +++++++++++++++++++++---------
>  1 file changed, 21 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c
> index 6b13feed06df..c9b3e158f438 100644
> --- a/drivers/bluetooth/btnxpuart.c
> +++ b/drivers/bluetooth/btnxpuart.c
> @@ -73,7 +73,8 @@
>  #define FW_AUTH_ENC		0xc0
> 
>  #define HCI_NXP_PRI_BAUDRATE	115200
> -#define HCI_NXP_SEC_BAUDRATE	3000000
> +#define HCI_NXP_SEC_BAUDRATE_3M	3000000
> +#define HCI_NXP_SEC_BAUDRATE_4M	4000000
> 
>  #define MAX_FW_FILE_NAME_LEN    50
> 
> @@ -201,6 +202,7 @@ struct btnxpuart_dev {
>  	u32 new_baudrate;
>  	u32 current_baudrate;
>  	u32 fw_init_baudrate;
> +	u32 secondary_baudrate;
>  	enum bootloader_param_change timeout_changed;
>  	enum bootloader_param_change baudrate_changed;
>  	bool helper_downloaded;
> @@ -802,7 +804,10 @@ static bool nxp_fw_change_baudrate(struct hci_dev
> *hdev, u16 req_len)
>  		nxpdev->fw_v3_offset_correction += req_len;
>  	} else if (req_len == sizeof(uart_config)) {
>  		uart_config.clkdiv.address = __cpu_to_le32(clkdivaddr);
> -		uart_config.clkdiv.value = __cpu_to_le32(0x00c00000);
> +		if (nxpdev->new_baudrate == HCI_NXP_SEC_BAUDRATE_4M)
> +			uart_config.clkdiv.value =
> __cpu_to_le32(0x01000000);
> +		else
> +			uart_config.clkdiv.value =
> __cpu_to_le32(0x00c00000);
>  		uart_config.uartdiv.address = __cpu_to_le32(uartdivaddr);
>  		uart_config.uartdiv.value = __cpu_to_le32(1);
>  		uart_config.mcr.address = __cpu_to_le32(uartmcraddr); @@
> -966,12 +971,13 @@ static int nxp_recv_fw_req_v1(struct hci_dev *hdev,
> struct sk_buff *skb)
>  			goto free_skb;
>  		}
>  		if (nxpdev->baudrate_changed != changed) {
> +			nxpdev->new_baudrate = nxpdev-
> >secondary_baudrate;
>  			if (nxp_fw_change_baudrate(hdev, len)) {
>  				nxpdev->baudrate_changed = changed;
>  				serdev_device_set_baudrate(nxpdev->serdev,
> -
> HCI_NXP_SEC_BAUDRATE);
> +							   nxpdev-
> >secondary_baudrate);
>  				serdev_device_set_flow_control(nxpdev-
> >serdev, true);
> -				nxpdev->current_baudrate =
> HCI_NXP_SEC_BAUDRATE;
> +				nxpdev->current_baudrate = nxpdev-
> >secondary_baudrate;
>  			}
>  			goto free_skb;
>  		}
> @@ -992,7 +998,7 @@ static int nxp_recv_fw_req_v1(struct hci_dev *hdev,
> struct sk_buff *skb)
>  			nxpdev->helper_downloaded = true;
>  			serdev_device_wait_until_sent(nxpdev->serdev, 0);
>  			serdev_device_set_baudrate(nxpdev->serdev,
> -						   HCI_NXP_SEC_BAUDRATE);
> +
> HCI_NXP_SEC_BAUDRATE_3M);
>  			serdev_device_set_flow_control(nxpdev->serdev,
> true);
>  		} else {
>  			clear_bit(BTNXPUART_FW_DOWNLOADING,
> &nxpdev->tx_state); @@ -1216,12 +1222,13 @@ static int
> nxp_recv_fw_req_v3(struct hci_dev *hdev, struct sk_buff *skb)
>  	}
> 
>  	if (nxpdev->baudrate_changed != changed) {
> +		nxpdev->new_baudrate = nxpdev->secondary_baudrate;
>  		if (nxp_fw_change_baudrate(hdev, len)) {
>  			nxpdev->baudrate_changed = cmd_sent;
>  			serdev_device_set_baudrate(nxpdev->serdev,
> -						   HCI_NXP_SEC_BAUDRATE);
> +						   nxpdev-
> >secondary_baudrate);
>  			serdev_device_set_flow_control(nxpdev->serdev,
> true);
> -			nxpdev->current_baudrate =
> HCI_NXP_SEC_BAUDRATE;
> +			nxpdev->current_baudrate = nxpdev-
> >secondary_baudrate;
>  		}
>  		goto free_skb;
>  	}
> @@ -1447,8 +1454,8 @@ static int nxp_post_init(struct hci_dev *hdev)
>  	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
>  	struct ps_data *psdata = &nxpdev->psdata;
> 
> -	if (nxpdev->current_baudrate != HCI_NXP_SEC_BAUDRATE) {
> -		nxpdev->new_baudrate = HCI_NXP_SEC_BAUDRATE;
> +	if (nxpdev->current_baudrate != nxpdev->secondary_baudrate) {
> +		nxpdev->new_baudrate = nxpdev->secondary_baudrate;
>  		nxp_set_baudrate_cmd(hdev, NULL);
>  	}
>  	if (psdata->cur_h2c_wakeupmode != psdata->h2c_wakeupmode) @@
> -1773,6 +1780,11 @@ static int nxp_serdev_probe(struct serdev_device
> *serdev)
>  	if (!nxpdev->fw_init_baudrate)
>  		nxpdev->fw_init_baudrate = FW_INIT_BAUDRATE;
> 
> +	device_property_read_u32(&nxpdev->serdev->dev, "max-speed",
> +				 &nxpdev->secondary_baudrate);
> +	if (!nxpdev->secondary_baudrate)
> +		nxpdev->secondary_baudrate =
> HCI_NXP_SEC_BAUDRATE_3M;

Hi Neeraj,

Seems you missed my comment here in V1 patch, attach again.
What if the user sets the wrong secondary_baudrate/max-speed in dts (not 3M or 4M)?
Need to add the corresponding error handling here. Make sure the value is 3M or 4M, otherwise report an error.

Best Regards
Sherry
> +
>  	set_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
> 
>  	crc8_populate_msb(crc8_table, POLYNOMIAL8);
> --
> 2.34.1

Re: [PATCH v2 1/2] dt-bindings: net: bluetooth: nxp: Add support for 4M baudrate

[Neeraj Sanjay Kale]

Hi Paul,

Thank you for reviewing this patch.
> 
> Am 18.06.25 um 16:20 schrieb Neeraj Sanjay Kale:
> > Add support for 4000000 as secondary baudrate.
> 
> Could you specify how you tested this, that means, how did you set the
> speed, and then do the test, that it actually works at that speed.

The driver starts at fw-init-baudrate, and if this 'max-speed' baudrate is different, it sends a vendor command to the FW to switch to max-speed.
After this point, both driver and chip communicate over 4000000 baudrate.

I have verified this using Saleae Logic Analyzer, where we have to set the baudrate to decode the UART packets properly. 

I can add these details in V3 driver patch.

> 
> > Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
> > ---
> > v2: Use the available 'max-speed' device tree property. (Krzysztof)
> > ---
> >   .../devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml  | 7 +++++++
> >   1 file changed, 7 insertions(+)
> >
> > diff --git
> > a/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml
> > b/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml
> > index 3ab60c70286f..4a1b6ea48a2f 100644
> > ---
> > a/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml
> > +++ b/Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.y
> > +++ aml
> > @@ -34,6 +34,12 @@ properties:
> >         This property depends on the module vendor's
> >         configuration.
> >
> > +  max-speed:
> > +    enum:
> > +      - 3000000
> > +      - 4000000
> > +    default: 3000000
> > +
> >     firmware-name:
> >       maxItems: 1
> >
> > @@ -78,6 +84,7 @@ examples:
> >           bluetooth {
> >               compatible = "nxp,88w8987-bt";
> >               fw-init-baudrate = <3000000>;
> > +            max-speed = <4000000>;
> >               firmware-name = "uartuart8987_bt_v0.bin";
> >               device-wakeup-gpios = <&gpio 11 GPIO_ACTIVE_HIGH>;
> >               nxp,wakein-pin = /bits/ 8 <18>;

Thanks,
Neeraj