[PATCH 1/2] tty: serial: provide devm_uart_add_one_port()

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>

Provide a devres variant of uart_add_one_port() that removes the managed
port at device detach.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
---
 .../driver-api/driver-model/devres.rst        |  3 ++
 drivers/tty/serial/serial_core.c              | 48 +++++++++++++++++++
 include/linux/serial_core.h                   |  6 +++
 3 files changed, 57 insertions(+)

diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index 56082265e8e5..5d07a8c1eadb 100644
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst
@@ -436,6 +436,9 @@ RTC
 SERDEV
   devm_serdev_device_open()
 
+SERIAL
+  devm_uart_add_one_port()
+
 SLAVE DMA ENGINE
   devm_acpi_dma_controller_register()
 
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 179ee199df34..44cdb8aa80a4 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -3217,6 +3217,54 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
 }
 EXPORT_SYMBOL(uart_remove_one_port);
 
+struct uart_port_devres {
+	struct uart_driver *drv;
+	struct uart_port *port;
+};
+
+static void devm_uart_remove_one_port(struct device *dev, void *data)
+{
+	struct uart_port_devres *res = data;
+
+	uart_remove_one_port(res->drv, res->port);
+}
+
+/**
+ * devm_uart_add_one_port - managed variant of uart_register_driver()
+ * @dev: managed device
+ * @drv: pointer to the uart low level driver structure for this port
+ * @uport: uart port structure to use for this port.
+ *
+ * Context: task context, might sleep
+ *
+ * This is a devres wrapper around uart_add_one_port(). It allows the driver
+ * @drv to register its own uart_port structure with the core driver. The port
+ * will be unregistered on driver detach.
+ */
+int devm_uart_add_one_port(struct device *dev,
+			   struct uart_driver *drv, struct uart_port *port)
+{
+	struct uart_port_devres *res;
+	int ret;
+
+	res = devres_alloc(devm_uart_remove_one_port, sizeof(*res), GFP_KERNEL);
+	if (!res)
+		return -1;
+
+	ret = uart_add_one_port(drv, port);
+	if (ret) {
+		devres_free(res);
+		return -1;
+	}
+
+	res->drv = drv;
+	res->port = port;
+	devres_add(dev, res);
+
+	return 0;
+}
+EXPORT_SYMBOL(devm_uart_add_one_port);
+
 /**
  * uart_match_port - are the two ports equivalent?
  * @port1: first port
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index d657f2a42a7b..d0911f04706e 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -771,6 +771,12 @@ int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
 bool uart_match_port(const struct uart_port *port1,
 		const struct uart_port *port2);
 
+/*
+ * UART devres
+ */
+int devm_uart_add_one_port(struct device *dev,
+			   struct uart_driver *drv, struct uart_port *port);
+
 /*
  * Power Management
  */
-- 
2.37.2