Bluetooth: hci_bcm: Retrieve UART speed from ACPI

Parse platform_device's ACPI to retrieve UART init speed.
When BCM device is open, check if its TTY has same parent as one of the
platform devices saved. If yes, use platform_device's init speed.
Signed-off-by: Frederic Danis <frederic.danis@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/hci_bcm.c

@@ -49,6 +49,8 @@ struct bcm_device {
 
 	struct clk		*clk;
 	bool			clk_enabled;
+
+	u32			init_speed;
 };
 
 struct bcm_data {
@@ -167,6 +169,7 @@ static int bcm_open(struct hci_uart *hu)
 		 */
 		if (hu->tty->dev->parent == dev->pdev->dev.parent) {
 			bcm->dev = dev;
+			hu->init_speed = dev->init_speed;
 			break;
 		}
 	}
@@ -324,11 +327,29 @@ static const struct acpi_gpio_mapping acpi_bcm_default_gpios[] = {
 	{ },
 };
 
+static int bcm_resource(struct acpi_resource *ares, void *data)
+{
+	struct bcm_device *dev = data;
+
+	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
+		struct acpi_resource_uart_serialbus *sb;
+
+		sb = &ares->data.uart_serial_bus;
+		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_UART)
+			dev->init_speed = sb->default_baud_rate;
+	}
+
+	/* Always tell the ACPI core to skip this resource */
+	return 1;
+}
+
 static int bcm_acpi_probe(struct bcm_device *dev)
 {
 	struct platform_device *pdev = dev->pdev;
 	const struct acpi_device_id *id;
 	struct gpio_desc *gpio;
+	struct acpi_device *adev;
+	LIST_HEAD(resources);
 	int ret;
 
 	id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
@@ -368,6 +389,13 @@ static int bcm_acpi_probe(struct bcm_device *dev)
 		return -EINVAL;
 	}
 
+	/* Retrieve UART ACPI info */
+	adev = ACPI_COMPANION(&dev->pdev->dev);
+	if (!adev)
+		return 0;
+
+	acpi_dev_get_resources(adev, &resources, bcm_resource, dev);
+
 	return 0;
 }