linux-kernel - [RESEND PATCH 1/2] tty: serial: provide devm_uart_add_one

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Message-Id: <20221229161948.594102-2-brgl@bgdev.pl>
Date:   Thu, 29 Dec 2022 17:19:47 +0100
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jirislaby@...nel.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Vinod Koul <vkoul@...nel.org>, Alex Elder <elder@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-serial@...r.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [RESEND PATCH 1/2] tty: serial: provide devm_uart_add_one_port()

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

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

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
 .../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 4249eb4239e0..1d79053070f5 100644
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst
@@ -448,6 +448,9 @@ RTC
 SERDEV
   devm_serdev_device_open()
 
+SERIAL
+  devm_uart_add_one_port()
+
 SLAVE DMA ENGINE
   devm_acpi_dma_controller_register()
   devm_acpi_dma_controller_free()
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index b9fbbee598b8..996aa73705f8 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 fd59f600094a..3c86b751e3b6 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -857,6 +857,12 @@ 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