Bluetooth: btmtkuart: add an implementation for boot-gpios property

Not every platform has the pinctrl device integrates the GPIO the function
such as MT7621 whose pinctrl and GPIO are separate hardware so the driver
adds additional boot-gpios to let the MT766[3,8]U can enter the proper boot
mode by gpiod for such platform.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 25 insertions, 9 deletions

diff --git a/drivers/bluetooth/btmtkuart.c b/drivers/bluetooth/btmtkuart.c
index f5dbeec8e274..1257149cfdc4 100644
--- a/drivers/bluetooth/btmtkuart.c
+++ b/drivers/bluetooth/btmtkuart.c
@@ -119,6 +119,7 @@ struct btmtkuart_dev {
 
         struct regulator *vcc;
         struct gpio_desc *reset;
+        struct gpio_desc *boot;
         struct pinctrl *pinctrl;
         struct pinctrl_state *pins_runtime;
         struct pinctrl_state *pins_boot;
@@ -911,6 +912,13 @@ static int btmtkuart_parse_dt(struct serdev_device *serdev)
                         return err;
                 }
 
+                bdev->boot = devm_gpiod_get_optional(&serdev->dev, "boot",
+                                                     GPIOD_OUT_LOW);
+                if (IS_ERR(bdev->boot)) {
+                        err = PTR_ERR(bdev->boot);
+                        return err;
+                }
+
                 bdev->pinctrl = devm_pinctrl_get(&serdev->dev);
                 if (IS_ERR(bdev->pinctrl)) {
                         err = PTR_ERR(bdev->pinctrl);
@@ -919,8 +927,10 @@ static int btmtkuart_parse_dt(struct serdev_device *serdev)
 
                 bdev->pins_boot = pinctrl_lookup_state(bdev->pinctrl,
                                                        "default");
-                if (IS_ERR(bdev->pins_boot)) {
+                if (IS_ERR(bdev->pins_boot) && !bdev->boot) {
                         err = PTR_ERR(bdev->pins_boot);
+                        dev_err(&serdev->dev,
+                                "Should assign RXD to LOW at boot stage\n");
                         return err;
                 }
 
@@ -996,8 +1006,14 @@ static int btmtkuart_probe(struct serdev_device *serdev)
         set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
 
         if (btmtkuart_is_standalone(bdev)) {
-                /* Switch to the specific pin state for the booting requires */
-                pinctrl_select_state(bdev->pinctrl, bdev->pins_boot);
+                if (bdev->boot) {
+                        gpiod_set_value_cansleep(bdev->boot, 1);
+                } else {
+                        /* Switch to the specific pin state for the booting
+                         * requires.
+                         */
+                        pinctrl_select_state(bdev->pinctrl, bdev->pins_boot);
+                }
 
                 /* Power on */
                 err = regulator_enable(bdev->vcc);
@@ -1017,6 +1033,10 @@ static int btmtkuart_probe(struct serdev_device *serdev)
                  * mode the device requires for UART transfers.
                  */
                 msleep(50);
+
+                if (bdev->boot)
+                        devm_gpiod_put(&serdev->dev, bdev->boot);
+
                 pinctrl_select_state(bdev->pinctrl, bdev->pins_runtime);
 
                 /* A standalone device doesn't depends on power domain on SoC,
@@ -1037,10 +1057,8 @@ static int btmtkuart_probe(struct serdev_device *serdev)
         return 0;
 
 err_regulator_disable:
-        if (btmtkuart_is_standalone(bdev))  {
-                pinctrl_select_state(bdev->pinctrl, bdev->pins_boot);
+        if (btmtkuart_is_standalone(bdev))
                 regulator_disable(bdev->vcc);
-        }
 
         return err;
 }
@@ -1050,10 +1068,8 @@ static void btmtkuart_remove(struct serdev_device *serdev)
         struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
         struct hci_dev *hdev = bdev->hdev;
 
-        if (btmtkuart_is_standalone(bdev))  {
-                pinctrl_select_state(bdev->pinctrl, bdev->pins_boot);
+        if (btmtkuart_is_standalone(bdev))
                 regulator_disable(bdev->vcc);
-        }
 
         hci_unregister_dev(hdev);
         hci_free_dev(hdev);