[PATCH RFC 0/2] Bluetooth: Add support for RTL8821CS

[PATCH RFC 0/2] Bluetooth: Add support for RTL8821CS

[Chris Morgan]

From: Chris Morgan <macromorgan@hotmail.com>

This patch series is to add support for the RTL8821CS Bluetooth
controller found on the RTL8821CS WiFi/Bluetooth combo chip.

This has been tested with firmware version 0xaa9a4e68. I am submitting
as an RFC to hopefully get guidance from Realtek on submission of this
firmware (or a later version) to the linux-firmware repository.

Chris Morgan (2):
  dt-bindings: net: realtek-bluetooth: Add RTL8821CS
  Bluetooth: hci_h5: btrtl: Add support for RTL8821CS

 .../devicetree/bindings/net/realtek-bluetooth.yaml        | 1 +
 drivers/bluetooth/btrtl.c                                 | 8 ++++++++
 drivers/bluetooth/hci_h5.c                                | 2 ++
 3 files changed, 11 insertions(+)

-- 
2.34.1

[PATCH RFC 1/2] dt-bindings: net: realtek-bluetooth: Add RTL8821CS

[Chris Morgan]

From: Chris Morgan <macromorgan@hotmail.com>

Add compatible string for RTL8821CS for existing Realtek Bluetooth
driver.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
 Documentation/devicetree/bindings/net/realtek-bluetooth.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/net/realtek-bluetooth.yaml b/Documentation/devicetree/bindings/net/realtek-bluetooth.yaml
index 143b5667abad..5af4731338c0 100644
--- a/Documentation/devicetree/bindings/net/realtek-bluetooth.yaml
+++ b/Documentation/devicetree/bindings/net/realtek-bluetooth.yaml
@@ -21,6 +21,7 @@ properties:
       - realtek,rtl8723bs-bt
       - realtek,rtl8723cs-bt
       - realtek,rtl8723ds-bt
+      - realtek,rtl8821cs-bt
       - realtek,rtl8822cs-bt
 
   device-wake-gpios:
-- 
2.34.1

Re: [PATCH RFC 1/2] dt-bindings: net: realtek-bluetooth: Add RTL8821CS

[Krzysztof Kozlowski]

On 26/01/2023 17:55, Chris Morgan wrote:
> From: Chris Morgan <macromorgan@hotmail.com>
> 
> Add compatible string for RTL8821CS for existing Realtek Bluetooth
> driver.
> 
> Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
> ---
>  Documentation/devicetree/bindings/net/realtek-bluetooth.yaml | 1 +
>  1 file changed, 1 insertion(+)
> 

Based on your driver it is compatible with rtl8822cs, so you can
indicate it in the binding and use just one of_device_id entry.

Best regards,
Krzysztof

Re: [PATCH RFC 1/2] dt-bindings: net: realtek-bluetooth: Add RTL8821CS

[Chris Morgan]

On Fri, Jan 27, 2023 at 11:24:03AM +0100, Krzysztof Kozlowski wrote:
> On 26/01/2023 17:55, Chris Morgan wrote:
> > From: Chris Morgan <macromorgan@hotmail.com>
> > 
> > Add compatible string for RTL8821CS for existing Realtek Bluetooth
> > driver.
> > 
> > Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
> > ---
> >  Documentation/devicetree/bindings/net/realtek-bluetooth.yaml | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> 
> Based on your driver it is compatible with rtl8822cs, so you can
> indicate it in the binding and use just one of_device_id entry.

It's very similar, and uses some of the same constants, but has a
different firmware. I assumed the firmware difference is enough to
require it to be differentiated, but I wasn't sure. You are saying
it does not? I just want to be clear.

As always, thank you.

> 
> Best regards,
> Krzysztof
> 

Re: [PATCH RFC 1/2] dt-bindings: net: realtek-bluetooth: Add RTL8821CS

[Krzysztof Kozlowski]

On 27/01/2023 17:46, Chris Morgan wrote:
> On Fri, Jan 27, 2023 at 11:24:03AM +0100, Krzysztof Kozlowski wrote:
>> On 26/01/2023 17:55, Chris Morgan wrote:
>>> From: Chris Morgan <macromorgan@hotmail.com>
>>>
>>> Add compatible string for RTL8821CS for existing Realtek Bluetooth
>>> driver.
>>>
>>> Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
>>> ---
>>>  Documentation/devicetree/bindings/net/realtek-bluetooth.yaml | 1 +
>>>  1 file changed, 1 insertion(+)
>>>
>>
>> Based on your driver it is compatible with rtl8822cs, so you can
>> indicate it in the binding and use just one of_device_id entry.
> 
> It's very similar, and uses some of the same constants, but has a
> different firmware. I assumed the firmware difference is enough to
> require it to be differentiated, but I wasn't sure. You are saying
> it does not? I just want to be clear.

If by "differentiated" you mean "incompatible", then depends:
1. You have firmware-name property to indicate the firmware to load and
then you can use one compatible to bind and just load different firmware,
2. If device variant is autodectable, it's compatible.

realtek,rtl8723ds-bt also was added to the driver uselessly...

Best regards,
Krzysztof

Re: [PATCH RFC 1/2] dt-bindings: net: realtek-bluetooth: Add RTL8821CS

[Chris Morgan]

On Fri, Jan 27, 2023 at 05:53:49PM +0100, Krzysztof Kozlowski wrote:
> On 27/01/2023 17:46, Chris Morgan wrote:
> > On Fri, Jan 27, 2023 at 11:24:03AM +0100, Krzysztof Kozlowski wrote:
> >> On 26/01/2023 17:55, Chris Morgan wrote:
> >>> From: Chris Morgan <macromorgan@hotmail.com>
> >>>
> >>> Add compatible string for RTL8821CS for existing Realtek Bluetooth
> >>> driver.
> >>>
> >>> Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
> >>> ---
> >>>  Documentation/devicetree/bindings/net/realtek-bluetooth.yaml | 1 +
> >>>  1 file changed, 1 insertion(+)
> >>>
> >>
> >> Based on your driver it is compatible with rtl8822cs, so you can
> >> indicate it in the binding and use just one of_device_id entry.
> > 
> > It's very similar, and uses some of the same constants, but has a
> > different firmware. I assumed the firmware difference is enough to
> > require it to be differentiated, but I wasn't sure. You are saying
> > it does not? I just want to be clear.
> 
> If by "differentiated" you mean "incompatible", then depends:
> 1. You have firmware-name property to indicate the firmware to load and
> then you can use one compatible to bind and just load different firmware,
> 2. If device variant is autodectable, it's compatible.
> 
> realtek,rtl8723ds-bt also was added to the driver uselessly...

Gotcha.

They are incompatible, but the driver should be able to autodetect each
device as best I can tell. In fact all of the devices listed in the
bindings should be autodetectable by the driver (again, as best I can
tell). Honestly though that's assuming I'm using the correct firmware,
which is why I have this tagged as an RFC. I'm really hoping to get
Realtek's attention for them to chime in to confirm I'm using the
most recent firmware and under what license/terms the firmware can
be redistributed so that the firmware may be added to linux-firmware.

Assuming everything is good though, I can resubmit V2 and instead of
adding a new compatible just noting that the 8822CS and 8821CS use
the same bindings.

Thank you.

> 
> Best regards,
> Krzysztof
> 

Re: [PATCH RFC 1/2] dt-bindings: net: realtek-bluetooth: Add RTL8821CS

[Krzysztof Kozlowski]

On 27/01/2023 18:00, Chris Morgan wrote:
> On Fri, Jan 27, 2023 at 05:53:49PM +0100, Krzysztof Kozlowski wrote:
>> On 27/01/2023 17:46, Chris Morgan wrote:
>>> On Fri, Jan 27, 2023 at 11:24:03AM +0100, Krzysztof Kozlowski wrote:
>>>> On 26/01/2023 17:55, Chris Morgan wrote:
>>>>> From: Chris Morgan <macromorgan@hotmail.com>
>>>>>
>>>>> Add compatible string for RTL8821CS for existing Realtek Bluetooth
>>>>> driver.
>>>>>
>>>>> Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
>>>>> ---
>>>>>  Documentation/devicetree/bindings/net/realtek-bluetooth.yaml | 1 +
>>>>>  1 file changed, 1 insertion(+)
>>>>>
>>>>
>>>> Based on your driver it is compatible with rtl8822cs, so you can
>>>> indicate it in the binding and use just one of_device_id entry.
>>>
>>> It's very similar, and uses some of the same constants, but has a
>>> different firmware. I assumed the firmware difference is enough to
>>> require it to be differentiated, but I wasn't sure. You are saying
>>> it does not? I just want to be clear.
>>
>> If by "differentiated" you mean "incompatible", then depends:
>> 1. You have firmware-name property to indicate the firmware to load and
>> then you can use one compatible to bind and just load different firmware,
>> 2. If device variant is autodectable, it's compatible.
>>
>> realtek,rtl8723ds-bt also was added to the driver uselessly...
> 
> Gotcha.
> 
> They are incompatible, but the driver should be able to autodetect each
> device as best I can tell. In fact all of the devices listed in the
> bindings should be autodetectable by the driver (again, as best I can
> tell). Honestly though that's assuming I'm using the correct firmware,
> which is why I have this tagged as an RFC. I'm really hoping to get
> Realtek's attention for them to chime in to confirm I'm using the
> most recent firmware and under what license/terms the firmware can
> be redistributed so that the firmware may be added to linux-firmware.
> 
> Assuming everything is good though, I can resubmit V2 and instead of
> adding a new compatible just noting that the 8822CS and 8821CS use
> the same bindings.

They cannot use the same bindings. You always need specific compatible
and this was not discussed here. What's discussed is to drop the driver
change in of_device_id.

Best regards,
Krzysztof

[PATCH RFC 2/2] Bluetooth: hci_h5: btrtl: Add support for RTL8821CS

[Chris Morgan]

From: Chris Morgan <macromorgan@hotmail.com>

RTL8821CS is a WiFi + Bluetooth combo chip from Realtek that provides
WiFi A/B/G/N/AC over an SDIO interface and Bluetooth 4.2 over a UART
interface.

Note that the firmware this was tested with was firmware version
0xaa9a4e68 as reported by the driver. Attempts at using other
firmware were unsucessful.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
 drivers/bluetooth/btrtl.c  | 8 ++++++++
 drivers/bluetooth/hci_h5.c | 2 ++
 2 files changed, 10 insertions(+)

diff --git a/drivers/bluetooth/btrtl.c b/drivers/bluetooth/btrtl.c
index 69c3fe649ca7..c95e55d8d696 100644
--- a/drivers/bluetooth/btrtl.c
+++ b/drivers/bluetooth/btrtl.c
@@ -128,6 +128,14 @@ static const struct id_table ic_id_table[] = {
 	  .fw_name  = "rtl_bt/rtl8821c_fw.bin",
 	  .cfg_name = "rtl_bt/rtl8821c_config" },
 
+	/* 8821CS */
+	{ IC_INFO(RTL_ROM_LMP_8821A, 0xc, 0x8, HCI_UART),
+	  .config_needed = true,
+	  .has_rom_version = true,
+	  .has_msft_ext = true,
+	  .fw_name  = "rtl_bt/rtl8821cs_fw.bin",
+	  .cfg_name = "rtl_bt/rtl8821cs_config" },
+
 	/* 8761A */
 	{ IC_INFO(RTL_ROM_LMP_8761A, 0xa, 0x6, HCI_USB),
 	  .config_needed = false,
diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c
index 6455bc4fb5bb..9531f092a71a 100644
--- a/drivers/bluetooth/hci_h5.c
+++ b/drivers/bluetooth/hci_h5.c
@@ -1096,6 +1096,8 @@ static const struct dev_pm_ops h5_serdev_pm_ops = {
 
 static const struct of_device_id rtl_bluetooth_of_match[] = {
 #ifdef CONFIG_BT_HCIUART_RTL
+	{ .compatible = "realtek,rtl8821cs-bt",
+	  .data = (const void *)&h5_data_rtl8822cs },
 	{ .compatible = "realtek,rtl8822cs-bt",
 	  .data = (const void *)&h5_data_rtl8822cs },
 	{ .compatible = "realtek,rtl8723bs-bt",
-- 
2.34.1