Bluetooth: hci_uart: Add basic support for Intel Lightning Peak devices

The Intel Lightning Peak devices do not come with Bluetooth firmware
loaded and thus require a full download of the operational Bluetooth
firmware when the device is attached via the Bluetooth line discipline.

Lightning Peak devices start with a bootloader mode that only accepts
a very limited set of HCI commands. The supported commands are enough
to identify the hardware and select the right firmware to load.
Signed-off-by: Loic Poulain <loic.poulain@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/Kconfig

@@ -132,6 +132,7 @@ config BT_HCIUART_3WIRE
 config BT_HCIUART_INTEL
 	bool "Intel protocol support"
 	depends on BT_HCIUART
+	select BT_HCIUART_H4
 	select BT_INTEL
 	help
 	  The Intel protocol support enables Bluetooth HCI over serial

drivers/bluetooth/hci_ldisc.c

@@ -804,6 +804,9 @@ static int __init hci_uart_init(void)
 #ifdef CONFIG_BT_HCIUART_3WIRE
 	h5_init();
 #endif
+#ifdef CONFIG_BT_HCIUART_INTEL
+	intel_init();
+#endif
 #ifdef CONFIG_BT_HCIUART_BCM
 	bcm_init();
 #endif
@@ -830,6 +833,9 @@ static void __exit hci_uart_exit(void)
 #ifdef CONFIG_BT_HCIUART_3WIRE
 	h5_deinit();
 #endif
+#ifdef CONFIG_BT_HCIUART_INTEL
+	intel_deinit();
+#endif
 #ifdef CONFIG_BT_HCIUART_BCM
 	bcm_deinit();
 #endif

drivers/bluetooth/hci_uart.h

@@ -167,6 +167,11 @@ int h5_init(void);
 int h5_deinit(void);
 #endif
 
+#ifdef CONFIG_BT_HCIUART_INTEL
+int intel_init(void);
+int intel_deinit(void);
+#endif
+
 #ifdef CONFIG_BT_HCIUART_BCM
 int bcm_init(void);
 int bcm_deinit(void);