serial: samsung: Remove NULL checking for baud clock

Signed-off-by: Kyoungil Kim <ki0351.kim@samsung.com>
Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/samsung.c

@@ -529,7 +529,7 @@ static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level,
 
 	switch (level) {
 	case 3:
-		if (!IS_ERR(ourport->baudclk) && ourport->baudclk != NULL)
+		if (!IS_ERR(ourport->baudclk))
 			clk_disable(ourport->baudclk);
 
 		clk_disable(ourport->clk);
@@ -538,7 +538,7 @@ static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level,
 	case 0:
 		clk_enable(ourport->clk);
 
-		if (!IS_ERR(ourport->baudclk) && ourport->baudclk != NULL)
+		if (!IS_ERR(ourport->baudclk))
 			clk_enable(ourport->baudclk);
 
 		break;
@@ -604,7 +604,6 @@ static unsigned int s3c24xx_serial_getclk(struct s3c24xx_uart_port *ourport,
 	char clkname[MAX_CLK_NAME_LENGTH];
 	int calc_deviation, deviation = (1 << 30) - 1;
 
-	*best_clk = NULL;
 	clk_sel = (ourport->cfg->clk_sel) ? ourport->cfg->clk_sel :
 			ourport->info->def_clk_sel;
 	for (cnt = 0; cnt < info->num_clks; cnt++) {
@@ -613,7 +612,7 @@ static unsigned int s3c24xx_serial_getclk(struct s3c24xx_uart_port *ourport,
 
 		sprintf(clkname, "clk_uart_baud%d", cnt);
 		clk = clk_get(ourport->port.dev, clkname);
-		if (IS_ERR_OR_NULL(clk))
+		if (IS_ERR(clk))
 			continue;
 
 		rate = clk_get_rate(clk);
@@ -684,7 +683,7 @@ static void s3c24xx_serial_set_termios(struct uart_port *port,
 {
 	struct s3c2410_uartcfg *cfg = s3c24xx_port_to_cfg(port);
 	struct s3c24xx_uart_port *ourport = to_ourport(port);
-	struct clk *clk = NULL;
+	struct clk *clk = ERR_PTR(-EINVAL);
 	unsigned long flags;
 	unsigned int baud, quot, clk_sel = 0;
 	unsigned int ulcon;
@@ -705,7 +704,7 @@ static void s3c24xx_serial_set_termios(struct uart_port *port,
 	quot = s3c24xx_serial_getclk(ourport, baud, &clk, &clk_sel);
 	if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
 		quot = port->custom_divisor;
-	if (!clk)
+	if (IS_ERR(clk))
 		return;
 
 	/* check to see if we need  to change clock source */
@@ -713,9 +712,9 @@ static void s3c24xx_serial_set_termios(struct uart_port *port,
 	if (ourport->baudclk != clk) {
 		s3c24xx_serial_setsource(port, clk_sel);
 
-		if (ourport->baudclk != NULL && !IS_ERR(ourport->baudclk)) {
+		if (!IS_ERR(ourport->baudclk)) {
 			clk_disable(ourport->baudclk);
-			ourport->baudclk  = NULL;
+			ourport->baudclk = ERR_PTR(-EINVAL);
 		}
 
 		clk_enable(clk);
@@ -1160,6 +1159,9 @@ static ssize_t s3c24xx_serial_show_clksrc(struct device *dev,
 	struct uart_port *port = s3c24xx_dev_to_port(dev);
 	struct s3c24xx_uart_port *ourport = to_ourport(port);
 
+	if (IS_ERR(ourport->baudclk))
+		return -EINVAL;
+
 	return snprintf(buf, PAGE_SIZE, "* %s\n", ourport->baudclk->name);
 }
 
@@ -1200,6 +1202,7 @@ static int s3c24xx_serial_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
+	ourport->baudclk = ERR_PTR(-EINVAL);
 	ourport->info = ourport->drv_data->info;
 	ourport->cfg = (pdev->dev.platform_data) ?
 			(struct s3c2410_uartcfg *)pdev->dev.platform_data :
@@ -1387,7 +1390,7 @@ s3c24xx_serial_get_options(struct uart_port *port, int *baud,
 		sprintf(clk_name, "clk_uart_baud%d", clk_sel);
 
 		clk = clk_get(port->dev, clk_name);
-		if (!IS_ERR(clk) && clk != NULL)
+		if (!IS_ERR(clk))
 			rate = clk_get_rate(clk);
 		else
 			rate = 1;