linux-kernel - [PATCH] tty: serial: meson: Request the register region in meson_uart

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Date:   Mon, 10 Jan 2022 16:26:13 +0800
From:   Yu Tu <yu.tu@...ogic.com>
To:     <linux-serial@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-amlogic@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>
CC:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Jiri Slaby <jirislaby@...nel.org>,
        Neil Armstrong <narmstrong@...libre.com>,
        Kevin Hilman <khilman@...libre.com>,
        Jerome Brunet <jbrunet@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Yu Tu <yu.tu@...ogic.com>
Subject: [PATCH] tty: serial: meson: Request the register region in meson_uart_probe()

This simplifies resetting the UART controller during probe and will make
it easier to integrate the common clock code which will require the
registers at probe time as well.

Signed-off-by: Yu Tu <yu.tu@...ogic.com>
---
 drivers/tty/serial/meson_uart.c | 24 ++++++------------------
 1 file changed, 6 insertions(+), 18 deletions(-)

diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c
index c9a37602ffd0..99efe62a1507 100644
--- a/drivers/tty/serial/meson_uart.c
+++ b/drivers/tty/serial/meson_uart.c
@@ -397,24 +397,11 @@ static int meson_uart_verify_port(struct uart_port *port,
 
 static void meson_uart_release_port(struct uart_port *port)
 {
-	devm_iounmap(port->dev, port->membase);
-	port->membase = NULL;
-	devm_release_mem_region(port->dev, port->mapbase, port->mapsize);
+	/* nothing to do */
 }
 
 static int meson_uart_request_port(struct uart_port *port)
 {
-	if (!devm_request_mem_region(port->dev, port->mapbase, port->mapsize,
-				     dev_name(port->dev))) {
-		dev_err(port->dev, "Memory region busy\n");
-		return -EBUSY;
-	}
-
-	port->membase = devm_ioremap(port->dev, port->mapbase,
-					     port->mapsize);
-	if (!port->membase)
-		return -ENOMEM;
-
 	return 0;
 }
 
@@ -728,6 +715,10 @@ static int meson_uart_probe(struct platform_device *pdev)
 	if (!port)
 		return -ENOMEM;
 
+	port->membase = devm_ioremap_resource(&pdev->dev, res_mem);
+	if (IS_ERR(port->membase))
+		return PTR_ERR(port->membase);
+
 	ret = meson_uart_probe_clocks(pdev, port);
 	if (ret)
 		return ret;
@@ -749,10 +740,7 @@ static int meson_uart_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, port);
 
 	/* reset port before registering (and possibly registering console) */
-	if (meson_uart_request_port(port) >= 0) {
-		meson_uart_reset(port);
-		meson_uart_release_port(port);
-	}
+	meson_uart_reset(port);
 
 	ret = uart_add_one_port(&meson_uart_driver, port);
 	if (ret)

base-commit: b3a9e3b9622ae10064826dccb4f7a52bd88c7407
prerequisite-patch-id: 97a514f3447511cb204179ce03ae99dc1d5902d9
-- 
2.33.1