[PATCH] serial: samsung: Fixed wrong comparison for baudclk_rate

[PATCH] serial: samsung: Fixed wrong comparison for baudclk_rate

[Kyoungil Kim]

port->baudclk_rate should be compared to the rate of port->baudclk,
because port->baudclk_rate was assigned as the rate of port->baudclk previously.
So to check that the current baudclk rate is same as previous rate,
the target of comparison sholud be the rate of port->baudclk.

Signed-off-by: Jun-Ho, Yoon <junho78.yoon@samsung.com>
Signed-off-by: Kyoungil Kim <ki0351.kim@samsung.com>	
---
 drivers/tty/serial/samsung.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index d8b0aee..c4867ea 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -1014,10 +1014,10 @@ static int s3c24xx_serial_cpufreq_transition(struct notifier_block *nb,
 	 * a disturbance in the clock-rate over the change.
 	 */
 
-	if (IS_ERR(port->clk))
+	if (IS_ERR_OR_NULL(port->baudclk))
 		goto exit;
 
-	if (port->baudclk_rate == clk_get_rate(port->clk))
+	if (port->baudclk_rate == clk_get_rate(port->baudclk))
 		goto exit;
 
 	if (val == CPUFREQ_PRECHANGE) {
-- 
1.7.1

Re: [PATCH] serial: samsung: Fixed wrong comparison for baudclk_rate

[Russell King - ARM Linux]

On Tue, May 15, 2012 at 07:13:28PM +0900, Kyoungil Kim wrote:
> port->baudclk_rate should be compared to the rate of port->baudclk,
> because port->baudclk_rate was assigned as the rate of port->baudclk previously.
> So to check that the current baudclk rate is same as previous rate,
> the target of comparison sholud be the rate of port->baudclk.
> 
> Signed-off-by: Jun-Ho, Yoon <junho78.yoon@samsung.com>
> Signed-off-by: Kyoungil Kim <ki0351.kim@samsung.com>	
> ---
>  drivers/tty/serial/samsung.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
> index d8b0aee..c4867ea 100644
> --- a/drivers/tty/serial/samsung.c
> +++ b/drivers/tty/serial/samsung.c
> @@ -1014,10 +1014,10 @@ static int s3c24xx_serial_cpufreq_transition(struct notifier_block *nb,
>  	 * a disturbance in the clock-rate over the change.
>  	 */
>  
> -	if (IS_ERR(port->clk))
> +	if (IS_ERR_OR_NULL(port->baudclk))

NAK.  See my previous emails on the validity of clk_get() return values.

RE: [PATCH] serial: samsung: Fixed wrong comparison for baudclk_rate

[Kyoungil Kim]

Russell King wrote:
> On Tue, May 15, 2012 at 07:13:28PM +0900, Kyoungil Kim wrote:
> > port->baudclk_rate should be compared to the rate of port->baudclk,
> > because port->baudclk_rate was assigned as the rate of port->baudclk previously.
> > So to check that the current baudclk rate is same as previous rate,
> > the target of comparison sholud be the rate of port->baudclk.
> >
> > Signed-off-by: Jun-Ho, Yoon <junho78.yoon@samsung.com>
> > Signed-off-by: Kyoungil Kim <ki0351.kim@samsung.com>
> > ---
> >  drivers/tty/serial/samsung.c |    4 ++--
> >  1 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
> > index d8b0aee..c4867ea 100644
> > --- a/drivers/tty/serial/samsung.c
> > +++ b/drivers/tty/serial/samsung.c
> > @@ -1014,10 +1014,10 @@ static int s3c24xx_serial_cpufreq_transition(struct notifier_block *nb,
> >  	 * a disturbance in the clock-rate over the change.
> >  	 */
> >
> > -	if (IS_ERR(port->clk))
> > +	if (IS_ERR_OR_NULL(port->baudclk))
> 
> NAK.  See my previous emails on the validity of clk_get() return values.

I read your previous emails, but I don't understand.
Could you explain more details, please?

Re: [PATCH] serial: samsung: Fixed wrong comparison for baudclk_rate

[Russell King - ARM Linux]

On Tue, May 15, 2012 at 08:52:39PM +0900, Kyoungil Kim wrote:
> Russell King wrote:
> > On Tue, May 15, 2012 at 07:13:28PM +0900, Kyoungil Kim wrote:
> > > port->baudclk_rate should be compared to the rate of port->baudclk,
> > > because port->baudclk_rate was assigned as the rate of port->baudclk previously.
> > > So to check that the current baudclk rate is same as previous rate,
> > > the target of comparison sholud be the rate of port->baudclk.
> > >
> > > Signed-off-by: Jun-Ho, Yoon <junho78.yoon@samsung.com>
> > > Signed-off-by: Kyoungil Kim <ki0351.kim@samsung.com>
> > > ---
> > >  drivers/tty/serial/samsung.c |    4 ++--
> > >  1 files changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
> > > index d8b0aee..c4867ea 100644
> > > --- a/drivers/tty/serial/samsung.c
> > > +++ b/drivers/tty/serial/samsung.c
> > > @@ -1014,10 +1014,10 @@ static int s3c24xx_serial_cpufreq_transition(struct notifier_block *nb,
> > >  	 * a disturbance in the clock-rate over the change.
> > >  	 */
> > >
> > > -	if (IS_ERR(port->clk))
> > > +	if (IS_ERR_OR_NULL(port->baudclk))
> > 
> > NAK.  See my previous emails on the validity of clk_get() return values.
> 
> I read your previous emails, but I don't understand.
> Could you explain more details, please?

Drivers are only allowed to assume that IS_ERR() values for clocks are
invalid.  Everything else they should not concern themselves with.