serial: samsung: Remove NULL checking for baud clock

PATCH New Kyoungil Kim 3 participants 4 messages May 24, 2012 – Jun 20, 2012

Subsystems (2)

Arm Samsung Exynos TTY layer and serial drivers

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Kyoungil Kim

author

2012-05-24 08:39 UTC #0 lore raw

PATCH 1/2 serial: samsung: Remove NULL checking for baud clock

Kyoungil Kim wrote:

I missed following.

Russell King suggested:

As I said, drivers have no business interpreting anything but IS_ERR(clk) as being an error. They should not make any other assumptions.

Quoted 103 lines

Signed-off-by Kyoungil Kim <[email protected]>

---
 drivers/tty/serial/samsung.c |   21 ++++++++++++---------
 1 files changed, 12 insertions(+), 9 deletions(-)

drivers/tty/serial/samsung.c +12 ~~-10~~

index d8b0aee..5668538 100644
@@ -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;
--

1.7.1

Kukjin Kim

2012-06-19 08:52 UTC #1 lore raw

PATCH 1/2 serial: samsung: Remove NULL checking for baud clock

Quoted 18 lines · Kyoungil Kim

Kyoungil Kim wrote:
I missed following.
Russell King suggested:
As I said, drivers have no business interpreting anything but IS_ERR(clk) as being an error. They should not make any other assumptions.
Suggested-by Russell King <[email protected]>
Quoted 5 lines
Signed-off-by Kyoungil Kim <[email protected]>
---
 drivers/tty/serial/samsung.c |   21 ++++++++++++---------
 1 files changed, 12 insertions(+), 9 deletions(-)

Quoted 5 lines

drivers/tty/serial/samsung.c static void s3c24xx_serial_pm(struct uart_port
Quoted 5 lines
drivers/tty/serial/samsung.c +0 -0
index d8b0aee..5668538 100644
@@ -529,7 +529,7 @@ static void s3c24xx_serial_pm(struct uart_port

*port,

Quoted 10 lines

unsigned int level,

drivers/tty/serial/samsung.c static void s3c24xx_serial_pm(struct uart_port

Quoted 9 lines

drivers/tty/serial/samsung.c +1 -1

 	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,

Quoted 85 lines

unsigned int level,

drivers/tty/serial/samsung.c static unsigned int s3c24xx_serial_getclk(struct

Quoted 9 lines

drivers/tty/serial/samsung.c +1 -1

 	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,

drivers/tty/serial/samsung.c static unsigned int s3c24xx_serial_getclk(struct

Quoted 8 lines

drivers/tty/serial/samsung.c +0 -1

 	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,

drivers/tty/serial/samsung.c static void s3c24xx_serial_set_termios(struct

Quoted 9 lines

drivers/tty/serial/samsung.c +1 -1

 		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,

drivers/tty/serial/samsung.c static void s3c24xx_serial_set_termios(struct

Quoted 9 lines

drivers/tty/serial/samsung.c +1 -1

 {
 	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,

drivers/tty/serial/samsung.c static void s3c24xx_serial_set_termios(struct

Quoted 9 lines

drivers/tty/serial/samsung.c +1 -1

 	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,

drivers/tty/serial/samsung.c static ssize_t s3c24xx_serial_show_clksrc(struct

Quoted 12 lines

drivers/tty/serial/samsung.c +2 -2

 	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,

drivers/tty/serial/samsung.c static int s3c24xx_serial_probe(struct

Quoted 10 lines

drivers/tty/serial/samsung.c +3 -0

 	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)

drivers/tty/serial/samsung.c s3c24xx_serial_get_options(struct uart_port *port,

Quoted 8 lines

drivers/tty/serial/samsung.c +1 -0

 		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,

Quoted 2 lines

drivers/tty/serial/samsung.c +0 -0
 		sprintf(clk_name, "clk_uart_baud%d", clk_sel);
 

Quoted 8 lines

drivers/tty/serial/samsung.c +1 -2

 		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;
--

1.7.1

Looks ok to me, will apply.
Thanks.

Best regards,
Kgene.
--
Kukjin Kim <[email protected]>, Senior Engineer, SW Solution Development Team, Samsung Electronics Co., Ltd.

Kukjin Kim

2012-06-20 04:28 UTC #2 lore raw

PATCH 1/2 serial: samsung: Remove NULL checking for baud clock

In reply to Kyoungil Kim

Quoted 10 lines · Kukjin Kim

Quoted 8 lines · Kyoungil Kim
Kyoungil Kim wrote:
I missed following.
Russell King suggested:
As I said, drivers have no business interpreting anything but

IS_ERR(clk)

Quoted 114 lines

Quoted 11 lines
as being an error. They should not make any other assumptions.
Suggested-by Russell King <[email protected]>
Review
Quoted 6 lines
Signed-off-by Kyoungil Kim <[email protected]>
---
 drivers/tty/serial/samsung.c |   21 ++++++++++++---------
 1 files changed, 12 insertions(+), 9 deletions(-)
(quoted diff) +0 -0
b/drivers/tty/serial/samsung.c
Quoted 4 lines
drivers/tty/serial/samsung.c static void s3c24xx_serial_pm(struct uart_port
Quoted 4 lines
index d8b0aee..5668538 100644
drivers/tty/serial/samsung.c +0 -0
@@ -529,7 +529,7 @@ static void s3c24xx_serial_pm(struct uart_port
*port,
Quoted 10 lines
unsigned int level,
drivers/tty/serial/samsung.c static void s3c24xx_serial_pm(struct uart_port
Quoted 9 lines
drivers/tty/serial/samsung.c +1 -1
 	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,
Quoted 74 lines
unsigned int level,
drivers/tty/serial/samsung.c static unsigned int s3c24xx_serial_getclk(struct
Quoted 9 lines
drivers/tty/serial/samsung.c +1 -1
 	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,
drivers/tty/serial/samsung.c static unsigned int s3c24xx_serial_getclk(struct
Quoted 8 lines
drivers/tty/serial/samsung.c +0 -1
 	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,
drivers/tty/serial/samsung.c static void s3c24xx_serial_set_termios(struct
Quoted 9 lines
drivers/tty/serial/samsung.c +1 -1
 		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,
drivers/tty/serial/samsung.c static void s3c24xx_serial_set_termios(struct
Quoted 9 lines
drivers/tty/serial/samsung.c +1 -1
 {
 	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,
drivers/tty/serial/samsung.c static void s3c24xx_serial_set_termios(struct
Quoted 9 lines
drivers/tty/serial/samsung.c +1 -1
 	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,
drivers/tty/serial/samsung.c static ssize_t s3c24xx_serial_show_clksrc(struct
Quoted 12 lines
drivers/tty/serial/samsung.c +2 -2
 	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,
drivers/tty/serial/samsung.c static int s3c24xx_serial_probe(struct
Quoted 10 lines
drivers/tty/serial/samsung.c +3 -0
 	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)
Quoted 8 lines
drivers/tty/serial/samsung.c s3c24xx_serial_get_options(struct uart_port
Quoted 8 lines
drivers/tty/serial/samsung.c +1 -0
 		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,
Quoted 3 lines
int *baud,
Quoted 2 lines
drivers/tty/serial/samsung.c +0 -0
 		sprintf(clk_name, "clk_uart_baud%d", clk_sel);
 

Quoted 12 lines

Quoted 8 lines
Quoted 8 lines
drivers/tty/serial/samsung.c +1 -2
 		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;
--
1.7.1
Looks ok to me, will apply.
Thanks.

(Cc'ed Greg)

I think, would be better if Greg could pick this up in his tree.

Acked-by Kukjin Kim <[email protected]>

Thanks.

Best regards,
Kgene.
--
Kukjin Kim <[email protected]>, Senior Engineer, SW Solution Development Team, Samsung Electronics Co., Ltd.

Greg KH

maintainer

2012-06-20 23:50 UTC #3 lore raw

PATCH 1/2 serial: samsung: Remove NULL checking for baud clock

Quoted 138 lines · Kukjin Kim

Quoted 10 lines · Kukjin Kim
Quoted 8 lines · Kyoungil Kim
Kyoungil Kim wrote:
I missed following.
Russell King suggested:
As I said, drivers have no business interpreting anything but
IS_ERR(clk)
Quoted 114 lines
Quoted 11 lines
as being an error. They should not make any other assumptions.
Suggested-by Russell King <[email protected]>
Review
Quoted 6 lines
Signed-off-by Kyoungil Kim <[email protected]>
---
 drivers/tty/serial/samsung.c |   21 ++++++++++++---------
 1 files changed, 12 insertions(+), 9 deletions(-)
(quoted diff) +0 -0
b/drivers/tty/serial/samsung.c
Quoted 4 lines
drivers/tty/serial/samsung.c static void s3c24xx_serial_pm(struct uart_port
Quoted 4 lines
index d8b0aee..5668538 100644
drivers/tty/serial/samsung.c +0 -0
@@ -529,7 +529,7 @@ static void s3c24xx_serial_pm(struct uart_port
*port,
Quoted 10 lines
unsigned int level,
drivers/tty/serial/samsung.c static void s3c24xx_serial_pm(struct uart_port
Quoted 9 lines
drivers/tty/serial/samsung.c +1 -1
 	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,
Quoted 74 lines
unsigned int level,
drivers/tty/serial/samsung.c static unsigned int s3c24xx_serial_getclk(struct
Quoted 9 lines
drivers/tty/serial/samsung.c +1 -1
 	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,
drivers/tty/serial/samsung.c static unsigned int s3c24xx_serial_getclk(struct
Quoted 8 lines
drivers/tty/serial/samsung.c +0 -1
 	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,
drivers/tty/serial/samsung.c static void s3c24xx_serial_set_termios(struct
Quoted 9 lines
drivers/tty/serial/samsung.c +1 -1
 		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,
drivers/tty/serial/samsung.c static void s3c24xx_serial_set_termios(struct
Quoted 9 lines
drivers/tty/serial/samsung.c +1 -1
 {
 	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,
drivers/tty/serial/samsung.c static void s3c24xx_serial_set_termios(struct
Quoted 9 lines
drivers/tty/serial/samsung.c +1 -1
 	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,
drivers/tty/serial/samsung.c static ssize_t s3c24xx_serial_show_clksrc(struct
Quoted 12 lines
drivers/tty/serial/samsung.c +2 -2
 	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,
drivers/tty/serial/samsung.c static int s3c24xx_serial_probe(struct
Quoted 10 lines
drivers/tty/serial/samsung.c +3 -0
 	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)
Quoted 8 lines
drivers/tty/serial/samsung.c s3c24xx_serial_get_options(struct uart_port
Quoted 8 lines
drivers/tty/serial/samsung.c +1 -0
 		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,
Quoted 3 lines
int *baud,
Quoted 2 lines
drivers/tty/serial/samsung.c +0 -0
 		sprintf(clk_name, "clk_uart_baud%d", clk_sel);
 
Quoted 12 lines
Quoted 8 lines
Quoted 8 lines
drivers/tty/serial/samsung.c +1 -2
 		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;
--
1.7.1
Looks ok to me, will apply.
Thanks.

Quoted 5 lines

(Cc'ed Greg)
I think, would be better if Greg could pick this up in his tree.
Acked-by Kukjin Kim <[email protected]>

It's already there :)