[PATCH v3 1/3] serial: 8250_em: Use dev_err_probe()

[Biju Das <biju.das.jz@xxxxxxxxxxxxxx>]

This patch simplifies probe() function by using dev_err_probe()
instead of dev_err in probe().

While at it, remove the unused header file slab.h and added a
local variable 'dev' to replace '&pdev->dev' in probe().

Also replace devm_clk_get->devm_clk_get_enabled and updated the
clk handling in probe() and remove().

Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
v2->v3:
 * Dropped sclk from priv.
 * Dropped unneeded clk_disable_unprepare from remove().
 * Retained Rb tags from Geert and Andy as the changes are trivial.
v1->v2:
 * replaced devm_clk_get->devm_clk_get_enabled() and updated clk
   handling in probe().
 * Added Rb tag from Geert.
---
 drivers/tty/serial/8250/8250_em.c | 33 +++++++++++--------------------
 1 file changed, 12 insertions(+), 21 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_em.c b/drivers/tty/serial/8250/8250_em.c
index f8e99995eee9..9781bf73ed0c 100644
--- a/drivers/tty/serial/8250/8250_em.c
+++ b/drivers/tty/serial/8250/8250_em.c
@@ -13,7 +13,6 @@
 #include <linux/serial_reg.h>
 #include <linux/platform_device.h>
 #include <linux/clk.h>
-#include <linux/slab.h>
 
 #include "8250.h"
 
@@ -21,7 +20,6 @@
 #define UART_DLM_EM 10
 
 struct serial8250_em_priv {
-	struct clk *sclk;
 	int line;
 };
 
@@ -79,8 +77,10 @@ static void serial8250_em_serial_dl_write(struct uart_8250_port *up, int value)
 static int serial8250_em_probe(struct platform_device *pdev)
 {
 	struct serial8250_em_priv *priv;
+	struct device *dev = &pdev->dev;
 	struct uart_8250_port up;
 	struct resource *regs;
+	struct clk *sclk;
 	int irq, ret;
 
 	irq = platform_get_irq(pdev, 0);
@@ -88,31 +88,26 @@ static int serial8250_em_probe(struct platform_device *pdev)
 		return irq;
 
 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!regs) {
-		dev_err(&pdev->dev, "missing registers\n");
-		return -EINVAL;
-	}
+	if (!regs)
+		return dev_err_probe(dev, -EINVAL, "missing registers\n");
 
-	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
-	priv->sclk = devm_clk_get(&pdev->dev, "sclk");
-	if (IS_ERR(priv->sclk)) {
-		dev_err(&pdev->dev, "unable to get clock\n");
-		return PTR_ERR(priv->sclk);
-	}
+	sclk = devm_clk_get_enabled(dev, "sclk");
+	if (IS_ERR(sclk))
+		return dev_err_probe(dev, PTR_ERR(sclk), "unable to get clock\n");
 
 	memset(&up, 0, sizeof(up));
 	up.port.mapbase = regs->start;
 	up.port.irq = irq;
 	up.port.type = PORT_UNKNOWN;
 	up.port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_IOREMAP;
-	up.port.dev = &pdev->dev;
+	up.port.dev = dev;
 	up.port.private_data = priv;
 
-	clk_prepare_enable(priv->sclk);
-	up.port.uartclk = clk_get_rate(priv->sclk);
+	up.port.uartclk = clk_get_rate(sclk);
 
 	up.port.iotype = UPIO_MEM32;
 	up.port.serial_in = serial8250_em_serial_in;
@@ -121,11 +116,8 @@ static int serial8250_em_probe(struct platform_device *pdev)
 	up.dl_write = serial8250_em_serial_dl_write;
 
 	ret = serial8250_register_8250_port(&up);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "unable to register 8250 port\n");
-		clk_disable_unprepare(priv->sclk);
-		return ret;
-	}
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "unable to register 8250 port\n");
 
 	priv->line = ret;
 	platform_set_drvdata(pdev, priv);
@@ -137,7 +129,6 @@ static int serial8250_em_remove(struct platform_device *pdev)
 	struct serial8250_em_priv *priv = platform_get_drvdata(pdev);
 
 	serial8250_unregister_port(priv->line);
-	clk_disable_unprepare(priv->sclk);
 	return 0;
 }
 
-- 
2.25.1