* [PATCH] serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_termios() @ 2016-03-14 0:41 Chanwoo Choi 2016-03-25 0:10 ` Chanwoo Choi 0 siblings, 1 reply; 4+ messages in thread From: Chanwoo Choi @ 2016-03-14 0:41 UTC (permalink / raw) To: gregkh, jslaby Cc: k.kozlowski, kgene, linux-serial, linux-kernel, linux-samsung-soc, Chanwoo Choi This patch fixes the broken serial log when changing the clock source of uart device. Before disabling the original clock source, this patch enables the new clock source to protect the clock off state for a split second. Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> --- drivers/tty/serial/samsung.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c index d72cd736bdc6..80d59dbfebba 100644 --- a/drivers/tty/serial/samsung.c +++ b/drivers/tty/serial/samsung.c @@ -1265,13 +1265,13 @@ static void s3c24xx_serial_set_termios(struct uart_port *port, if (ourport->baudclk != clk) { s3c24xx_serial_setsource(port, clk_sel); + clk_prepare_enable(clk); + if (!IS_ERR(ourport->baudclk)) { clk_disable_unprepare(ourport->baudclk); ourport->baudclk = ERR_PTR(-EINVAL); } - clk_prepare_enable(clk); - ourport->baudclk = clk; ourport->baudclk_rate = clk ? clk_get_rate(clk) : 0; } -- 1.9.1 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_termios() 2016-03-14 0:41 [PATCH] serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_termios() Chanwoo Choi @ 2016-03-25 0:10 ` Chanwoo Choi 2016-03-25 8:14 ` Marek Szyprowski 0 siblings, 1 reply; 4+ messages in thread From: Chanwoo Choi @ 2016-03-25 0:10 UTC (permalink / raw) To: gregkh, jslaby Cc: k.kozlowski, kgene, linux-serial, linux-kernel, linux-samsung-soc, Robert Baldyga (SRPOL) Hi Robert, I send following patch to fix the broken serial log of Exynos SoC. As I knew, you also knew this issue. If possible, could you review or test this patch? Best Regards, Chanwoo Choi On 2016년 03월 14일 09:41, Chanwoo Choi wrote: > This patch fixes the broken serial log when changing the clock source > of uart device. Before disabling the original clock source, this patch > enables the new clock source to protect the clock off state for a split second. > > Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> > --- > drivers/tty/serial/samsung.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c > index d72cd736bdc6..80d59dbfebba 100644 > --- a/drivers/tty/serial/samsung.c > +++ b/drivers/tty/serial/samsung.c > @@ -1265,13 +1265,13 @@ static void s3c24xx_serial_set_termios(struct uart_port *port, > if (ourport->baudclk != clk) { > s3c24xx_serial_setsource(port, clk_sel); > > + clk_prepare_enable(clk); > + > if (!IS_ERR(ourport->baudclk)) { > clk_disable_unprepare(ourport->baudclk); > ourport->baudclk = ERR_PTR(-EINVAL); > } > > - clk_prepare_enable(clk); > - > ourport->baudclk = clk; > ourport->baudclk_rate = clk ? clk_get_rate(clk) : 0; > } > ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_termios() 2016-03-25 0:10 ` Chanwoo Choi @ 2016-03-25 8:14 ` Marek Szyprowski 2016-03-25 8:22 ` Chanwoo Choi 0 siblings, 1 reply; 4+ messages in thread From: Marek Szyprowski @ 2016-03-25 8:14 UTC (permalink / raw) To: Chanwoo Choi, gregkh, jslaby Cc: k.kozlowski, kgene, linux-serial, linux-kernel, linux-samsung-soc, Robert Baldyga (SRPOL) Dear Chanwoo, On 2016-03-25 01:10, Chanwoo Choi wrote: > Hi Robert, > > I send following patch to fix the broken serial log of Exynos SoC. > As I knew, you also knew this issue. > If possible, could you review or test this patch? Robert no longer works for Samsung, so I'm afraid that he won't be able to test this patch. > Best Regards, > Chanwoo Choi > > On 2016년 03월 14일 09:41, Chanwoo Choi wrote: >> This patch fixes the broken serial log when changing the clock source >> of uart device. Before disabling the original clock source, this patch >> enables the new clock source to protect the clock off state for a split second. >> >> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> >> --- >> drivers/tty/serial/samsung.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c >> index d72cd736bdc6..80d59dbfebba 100644 >> --- a/drivers/tty/serial/samsung.c >> +++ b/drivers/tty/serial/samsung.c >> @@ -1265,13 +1265,13 @@ static void s3c24xx_serial_set_termios(struct uart_port *port, >> if (ourport->baudclk != clk) { >> s3c24xx_serial_setsource(port, clk_sel); >> >> + clk_prepare_enable(clk); >> + IMHO clk_prepare_enable() should be moved before s3c24xx_serial_setsource() to be really sure that there will be no period of hw operating with disabled baud clock. Could you check if it works for you? >> if (!IS_ERR(ourport->baudclk)) { >> clk_disable_unprepare(ourport->baudclk); >> ourport->baudclk = ERR_PTR(-EINVAL); >> } >> >> - clk_prepare_enable(clk); >> - >> ourport->baudclk = clk; >> ourport->baudclk_rate = clk ? clk_get_rate(clk) : 0; >> } Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_termios() 2016-03-25 8:14 ` Marek Szyprowski @ 2016-03-25 8:22 ` Chanwoo Choi 0 siblings, 0 replies; 4+ messages in thread From: Chanwoo Choi @ 2016-03-25 8:22 UTC (permalink / raw) To: Marek Szyprowski, gregkh, jslaby Cc: k.kozlowski, kgene, linux-serial, linux-kernel, linux-samsung-soc, Robert Baldyga (SRPOL) Dear Marek, On 2016년 03월 25일 17:14, Marek Szyprowski wrote: > Dear Chanwoo, > > On 2016-03-25 01:10, Chanwoo Choi wrote: >> Hi Robert, >> >> I send following patch to fix the broken serial log of Exynos SoC. >> As I knew, you also knew this issue. >> If possible, could you review or test this patch? > > Robert no longer works for Samsung, so I'm afraid that he won't be able to test > this patch. Ah. Thanks for your reply. > >> Best Regards, >> Chanwoo Choi >> >> On 2016년 03월 14일 09:41, Chanwoo Choi wrote: >>> This patch fixes the broken serial log when changing the clock source >>> of uart device. Before disabling the original clock source, this patch >>> enables the new clock source to protect the clock off state for a split second. >>> >>> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> >>> --- >>> drivers/tty/serial/samsung.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c >>> index d72cd736bdc6..80d59dbfebba 100644 >>> --- a/drivers/tty/serial/samsung.c >>> +++ b/drivers/tty/serial/samsung.c >>> @@ -1265,13 +1265,13 @@ static void s3c24xx_serial_set_termios(struct uart_port *port, >>> if (ourport->baudclk != clk) { >>> s3c24xx_serial_setsource(port, clk_sel); >>> + clk_prepare_enable(clk); >>> + > > IMHO clk_prepare_enable() should be moved before s3c24xx_serial_setsource() to be > really sure that there will be no period of hw operating with disabled baud clock. > Could you check if it works for you? Yes. I tested it without any problem. But, as you commented, clk_prepare_enable() should be called before s3c24xx_serial_setsource(). I'll modify it. > >>> if (!IS_ERR(ourport->baudclk)) { >>> clk_disable_unprepare(ourport->baudclk); >>> ourport->baudclk = ERR_PTR(-EINVAL); >>> } >>> - clk_prepare_enable(clk); >>> - >>> ourport->baudclk = clk; >>> ourport->baudclk_rate = clk ? clk_get_rate(clk) : 0; >>> } > > Best regards Best Regards, Chanwoo Choi ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-03-25 8:22 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2016-03-14 0:41 [PATCH] serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_termios() Chanwoo Choi 2016-03-25 0:10 ` Chanwoo Choi 2016-03-25 8:14 ` Marek Szyprowski 2016-03-25 8:22 ` Chanwoo Choi
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