Re: [PATCH v2 3/3] Bluetooth: hci_bcm: Add serdev support

Add basic support for Broadcom serial slave devices.
Probe the serial device, retrieve its maximum speed and
register a new hci uart device.

Tested/compatible with bcm43438 (RPi3).

Signed-off-by: Loic Poulain <redacted>
---
v2: dt-bindings as separate patch
   rebase on upcoming pi3 dts changes

drivers/bluetooth/hci_bcm.c | 82 ++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 78 insertions(+), 4 deletions(-)

diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
index 6b42372..f824738 100644
--- a/drivers/bluetooth/hci_bcm.c
+++ b/drivers/bluetooth/hci_bcm.c

@@ -27,6 +27,7 @@

#include <linux/firmware.h>
#include <linux/module.h>
#include <linux/acpi.h>
+#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/gpio/consumer.h>

@@ -34,6 +35,7 @@

#include <linux/interrupt.h>
#include <linux/dmi.h>
#include <linux/pm_runtime.h>
+#include <linux/serdev.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>

@@ -46,6 +48,7 @@

#define BCM_AUTOSUSPEND_DELAY	5000 /* default autosleep delay */

+/* platform device driver resources */
struct bcm_device {
	struct list_head	list;

@@ -68,6 +71,12 @@ struct bcm_device {

#endif
};

+/* serdev driver resources */
+struct bcm_bt_device {
+	struct hci_uart hu;
+};

+
+/* generic bcm uart resources */
struct bcm_data {
	struct sk_buff		*rx_skb;
	struct sk_buff_head	txq;

@@ -289,6 +298,11 @@ static int bcm_open(struct hci_uart *hu)

	hu->priv = bcm;

+	if (hu->serdev) {
+		serdev_device_open(hu->serdev);
+		goto out;
+	}
+

	if (!hu->tty->dev)
		goto out;

@@ -323,6 +337,9 @@ static int bcm_close(struct hci_uart *hu)

	bt_dev_dbg(hu->hdev, "hu %p", hu);

+	if (hu->serdev)
+		serdev_device_close(hu->serdev);
+

	/* Protect bcm->dev against removal of the device or driver */
	mutex_lock(&bcm_device_lock);
	if (bcm_device_exists(bdev)) {

@@ -397,8 +414,12 @@ static int bcm_setup(struct hci_uart *hu)

	else
		speed = 0;

-	if (speed)
-		hci_uart_set_baudrate(hu, speed);
+	if (speed) {
+		if (hu->serdev)
+			serdev_device_set_baudrate(hu->serdev, speed);
+		else
+			hci_uart_set_baudrate(hu, speed);
+	}

	/* Operational speed if any */
	if (hu->oper_speed)

@@ -410,8 +431,12 @@ static int bcm_setup(struct hci_uart *hu)

	if (speed) {
		err = bcm_set_baudrate(hu, speed);
-		if (!err)
-			hci_uart_set_baudrate(hu, speed);
+		if (!err) {
+			if (hu->serdev)
+				serdev_device_set_baudrate(hu->serdev, speed);
+			else
+				hci_uart_set_baudrate(hu, speed);
+		}

	}

finalize:

@@ -903,9 +928,57 @@ static int bcm_remove(struct platform_device *pdev)

	},
};

+static int bcm_serdev_probe(struct serdev_device *serdev)
+{
+	struct bcm_bt_device *bcmdev;
+	u32 speed;
+	int err;
+
+	bcmdev = devm_kzalloc(&serdev->dev, sizeof(*bcmdev), GFP_KERNEL);
+	if (!bcmdev)
+		return -ENOMEM;
+
+	bcmdev->hu.serdev = serdev;
+	serdev_device_set_drvdata(serdev, bcmdev);
+
+	err = of_property_read_u32(serdev->dev.of_node, "max-speed", &speed);
+	if (!err)
+		bcmdev->hu.oper_speed = speed;
+
+	return hci_uart_register_device(&bcmdev->hu, &bcm_proto);
+}

+
+static void bcm_serdev_remove(struct serdev_device *serdev)
+{
+	struct bcm_bt_device *bcmdev = serdev_device_get_drvdata(serdev);
+
+	hci_uart_unregister_device(&bcmdev->hu);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id bcm_bluetooth_of_match[] = {
+	{ .compatible = "brcm,bcm43438-bt" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, bcm_bluetooth_of_match);
+#endif
+
+static struct serdev_device_driver bcm_serdev_driver = {
+	.probe = bcm_serdev_probe,
+	.remove = bcm_serdev_remove,
+	.driver = {
+		.name = "hci_uart_bcm",
+		.of_match_table = of_match_ptr(bcm_bluetooth_of_match),
+	},
+};
+
int __init bcm_init(void)
{
+	/* For now, we need to keep both platform device
+	 * driver (ACPI generated) and serdev driver (DT).
+	 */
	platform_driver_register(&bcm_driver);
+	serdev_device_driver_register(&bcm_serdev_driver);

	return hci_uart_register_proto(&bcm_proto);
}

@@ -913,6 +986,7 @@ int __init bcm_init(void)

int __exit bcm_deinit(void)
{
	platform_driver_unregister(&bcm_driver);
+	serdev_device_driver_unregister(&bcm_serdev_driver);

	return hci_uart_unregister_proto(&bcm_proto);
}