Re: [PATCH 2/2] 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>
---
 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);
 }
--

1.9.1


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