Bluetooth: Add support for RTL8821CS

From: Chris Morgan <[email protected]>

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

From: Chris Morgan <[email protected]>

Add compatible string for RTL8821CS for existing Realtek Bluetooth driver.

---
 Documentation/devicetree/bindings/net/realtek-bluetooth.yaml | 1 +
 1 file changed, 1 insertion(+)

index 143b5667abad..5af4731338c0 100644
@@ -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

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list. This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=715934

---Test result---

Test Summary:

CheckPatch                    PASS      2.17 seconds
GitLint                       PASS      0.75 seconds
SubjectPrefix                 FAIL      0.58 seconds
BuildKernel                   PASS      38.49 seconds
CheckAllWarning               PASS      41.50 seconds
CheckSparse                   WARNING   47.05 seconds
CheckSmatch                   WARNING   127.35 seconds
BuildKernel32                 PASS      36.70 seconds
TestRunnerSetup               PASS      526.86 seconds
TestRunner_l2cap-tester       PASS      19.05 seconds
TestRunner_iso-tester         PASS      20.75 seconds
TestRunner_bnep-tester        PASS      6.80 seconds
TestRunner_mgmt-tester        PASS      129.94 seconds
TestRunner_rfcomm-tester      PASS      10.75 seconds
TestRunner_sco-tester         PASS      9.87 seconds
TestRunner_ioctl-tester       PASS      11.82 seconds
TestRunner_mesh-tester        PASS      8.72 seconds
TestRunner_smp-tester         PASS      9.75 seconds
TestRunner_userchan-tester    PASS      7.21 seconds
IncrementalBuild              PASS      40.32 seconds

Details
##############################
Test: SubjectPrefix - FAIL
Desc: Check subject contains "Bluetooth" prefix
Output:
"Bluetooth: " prefix is not specified in the subject
##############################
Test: CheckSparse - WARNING
Desc: Run sparse tool with linux kernel
Output:
drivers/bluetooth/btrtl.c: note: in included file:drivers/bluetooth/btrtl.h:47:45: warning: array of flexible structures
##############################
Test: CheckSmatch - WARNING
Desc: Run smatch tool with source
Output:
drivers/bluetooth/btrtl.c: note: in included file:drivers/bluetooth/btrtl.h:47:45: warning: array of flexible structures

---
Regards,
Linux Bluetooth

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

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.

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

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.

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

From: Chris Morgan <[email protected]>

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.

---
 drivers/bluetooth/btrtl.c  | 8 ++++++++
 drivers/bluetooth/hci_h5.c | 2 ++
 2 files changed, 10 insertions(+)

index 69c3fe649ca7..c95e55d8d696 100644
@@ -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,

index 6455bc4fb5bb..9531f092a71a 100644
@@ -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