[PATCH 5.15.y] tty: serial: fsl_lpuart: fixup error path in lpuart_probe()

[PATCH 5.15.y] tty: serial: fsl_lpuart: fixup error path in lpuart_probe()

[Rasmus Villemoes]

When 7c7f9bc986e6 ("serial: Deassert Transmit Enable on probe in
driver-specific way") got backported to 5.15.y, there known as
b079d3775237, this hunk was accidentally left out. So if the "goto
failed_get_rs485;" is hit, the cleanup will do uart_remove_one_port()
despite uart_add_one_port() not having been called.

Add the missing hunk.

Fixes: b079d3775237 ("serial: Deassert Transmit Enable on probe in driver-specific way")
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---

Not quite sure how to submit patches for a specific -stable series
only, or if the Fixes tag is appropriate and correct. Please let me
know if you'd have preferred anything different.

drivers/tty/serial/fsl_lpuart.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 595430aedc0d..fc311df9f1c9 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -2784,9 +2784,9 @@ static int lpuart_probe(struct platform_device *pdev)
 	return 0;
 
 failed_irq_request:
-failed_get_rs485:
 	uart_remove_one_port(&lpuart_reg, &sport->port);
 failed_attach_port:
+failed_get_rs485:
 failed_reset:
 	lpuart_disable_clks(sport);
 	return ret;

base-commit: fd6d66840b4269da4e90e1ea807ae3197433bc66
-- 
2.37.2

[PATCH 5.15.y v2] serial: fixup backport of "serial: Deassert Transmit Enable on probe in driver-specific way"

[Rasmus Villemoes]

When 7c7f9bc986e6 ("serial: Deassert Transmit Enable on probe in
driver-specific way") got backported to 5.15.y, there known as
b079d3775237, some hunks were accidentally left out.

In fsl_lpuart.c, this amounts to uart_remove_one_port() being called
in an error path despite uart_add_one_port() not having been called.

In serial_core.c, it is possible that the omission in
uart_suspend_port() is harmless, but the backport did have the
corresponding hunk in uart_resume_port(), it runs counter to the
original commit's intention of

  Skip any invocation of ->set_mctrl() if RS485 is enabled.

and it's certainly better to be aligned with upstream.

Fixes: b079d3775237 ("serial: Deassert Transmit Enable on probe in driver-specific way")
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---

v2: Also amend uart_suspend_port(), update commit log accordingly.

 drivers/tty/serial/fsl_lpuart.c  | 2 +-
 drivers/tty/serial/serial_core.c | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 595430aedc0d..fc311df9f1c9 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -2784,9 +2784,9 @@ static int lpuart_probe(struct platform_device *pdev)
 	return 0;
 
 failed_irq_request:
-failed_get_rs485:
 	uart_remove_one_port(&lpuart_reg, &sport->port);
 failed_attach_port:
+failed_get_rs485:
 failed_reset:
 	lpuart_disable_clks(sport);
 	return ret;
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 5f8f0a90ce55..45b721abaa2f 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2225,7 +2225,8 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
 
 		spin_lock_irq(&uport->lock);
 		ops->stop_tx(uport);
-		ops->set_mctrl(uport, 0);
+		if (!(uport->rs485.flags & SER_RS485_ENABLED))
+			ops->set_mctrl(uport, 0);
 		ops->stop_rx(uport);
 		spin_unlock_irq(&uport->lock);
 

base-commit: 5827ddaf4534c52d31dd464679a186b41810ef76
-- 
2.37.2

Re: [PATCH 5.15.y v2] serial: fixup backport of "serial: Deassert Transmit Enable on probe in driver-specific way"

[Dominique Martinet]

Rasmus Villemoes wrote on Thu, Dec 22, 2022 at 12:44:14PM +0100:
> When 7c7f9bc986e6 ("serial: Deassert Transmit Enable on probe in
> driver-specific way") got backported to 5.15.y, there known as
> b079d3775237, some hunks were accidentally left out.
> 
> In fsl_lpuart.c, this amounts to uart_remove_one_port() being called
> in an error path despite uart_add_one_port() not having been called.
> 
> In serial_core.c, it is possible that the omission in
> uart_suspend_port() is harmless, but the backport did have the
> corresponding hunk in uart_resume_port(), it runs counter to the
> original commit's intention of
> 
>   Skip any invocation of ->set_mctrl() if RS485 is enabled.
> 
> and it's certainly better to be aligned with upstream.
> 
> Fixes: b079d3775237 ("serial: Deassert Transmit Enable on probe in driver-specific way")
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>

Thank you!
I've confirmed both hunks are part of the original patch; I'm not quite
sure why we missed them...

Reviewed-by: Dominique MARTINET <dominique.martinet@atmark-techno.com>


This doesn't apply cleanly to 5.10 because 5.10 did not get
401fb66a3 ("fsl_lpuart: Don't enable interrupts too early") backported,
I think it makes sense to take as well so I'll send a backport of these
two patches for 5.10

-- 
Dominique

Re: [PATCH 5.15.y v2] serial: fixup backport of "serial: Deassert Transmit Enable on probe in driver-specific way"

[Greg Kroah-Hartman]

On Thu, Dec 22, 2022 at 12:44:14PM +0100, Rasmus Villemoes wrote:
> When 7c7f9bc986e6 ("serial: Deassert Transmit Enable on probe in
> driver-specific way") got backported to 5.15.y, there known as
> b079d3775237, some hunks were accidentally left out.
> 
> In fsl_lpuart.c, this amounts to uart_remove_one_port() being called
> in an error path despite uart_add_one_port() not having been called.
> 
> In serial_core.c, it is possible that the omission in
> uart_suspend_port() is harmless, but the backport did have the
> corresponding hunk in uart_resume_port(), it runs counter to the
> original commit's intention of
> 
>   Skip any invocation of ->set_mctrl() if RS485 is enabled.
> 
> and it's certainly better to be aligned with upstream.
> 
> Fixes: b079d3775237 ("serial: Deassert Transmit Enable on probe in driver-specific way")
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> ---
> 
> v2: Also amend uart_suspend_port(), update commit log accordingly.

Now queued up, thanks.

greg k-h