[PATCH v2 1/6] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"

[PATCH v2 1/6] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"

[Arnd Bergmann]

This reverts commit d72d391c126e, which tried to remove dead code but
left the driver in a useless state when the main 8250 driver is a
loadable module. This would normally result in a link error, but
as the entire drivers/tty/serial/8250/ directory is only entered
when CONFIG_SERIAL_8250 is set, we never notice that the driver does
not get built in this configuration.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: d72d391c126e ("drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular")
---
 drivers/tty/serial/8250/8250_mtk.c | 35 ++++++++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 0e590b233f03..78883ca64ddd 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -16,7 +16,7 @@
  */
 #include <linux/clk.h>
 #include <linux/io.h>
-#include <linux/init.h>
+#include <linux/module.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
@@ -245,6 +245,23 @@ static int mtk8250_probe(struct platform_device *pdev)
 	return 0;
 }
 
+static int mtk8250_remove(struct platform_device *pdev)
+{
+	struct mtk8250_data *data = platform_get_drvdata(pdev);
+
+	pm_runtime_get_sync(&pdev->dev);
+
+	serial8250_unregister_port(data->line);
+
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+
+	if (!pm_runtime_status_suspended(&pdev->dev))
+		mtk8250_runtime_suspend(&pdev->dev);
+
+	return 0;
+}
+
 #ifdef CONFIG_PM_SLEEP
 static int mtk8250_suspend(struct device *dev)
 {
@@ -275,18 +292,18 @@ static const struct of_device_id mtk8250_of_match[] = {
 	{ .compatible = "mediatek,mt6577-uart" },
 	{ /* Sentinel */ }
 };
+MODULE_DEVICE_TABLE(of, mtk8250_of_match);
 
 static struct platform_driver mtk8250_platform_driver = {
 	.driver = {
-		.name			= "mt6577-uart",
-		.pm			= &mtk8250_pm_ops,
-		.of_match_table		= mtk8250_of_match,
-		.suppress_bind_attrs	= true,
-
+		.name		= "mt6577-uart",
+		.pm		= &mtk8250_pm_ops,
+		.of_match_table	= mtk8250_of_match,
 	},
 	.probe			= mtk8250_probe,
+	.remove			= mtk8250_remove,
 };
-builtin_platform_driver(mtk8250_platform_driver);
+module_platform_driver(mtk8250_platform_driver);
 
 #ifdef CONFIG_SERIAL_8250_CONSOLE
 static int __init early_mtk8250_setup(struct earlycon_device *device,
@@ -302,3 +319,7 @@ static int __init early_mtk8250_setup(struct earlycon_device *device,
 
 OF_EARLYCON_DECLARE(mtk8250, "mediatek,mt6577-uart", early_mtk8250_setup);
 #endif
+
+MODULE_AUTHOR("Matthias Brugger");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Mediatek 8250 serial port driver");
-- 
2.7.0

Re: [PATCH v2 1/6] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"

[Paul Gortmaker]

[[PATCH v2 1/6] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"] On 11/02/2016 (Thu 16:41) Arnd Bergmann wrote:

> This reverts commit d72d391c126e, which tried to remove dead code but
> left the driver in a useless state when the main 8250 driver is a

Am I misunderstanding something?  The commit didn't cause the driver to
be in a useless state for 8250=m.  But rather isn't that it was a
pre-existing condition, independent of the change to 8250_mtk.c to
remove the dead code in d72d391c126e?

Since the commit did not touch Kconfig or Makefile, I can't see how it
could cause some new useless state that did not already exist, and hence
the "Fixes:" tag is invalid as well.

Paul.
--

> loadable module. This would normally result in a link error, but
> as the entire drivers/tty/serial/8250/ directory is only entered
> when CONFIG_SERIAL_8250 is set, we never notice that the driver does
> not get built in this configuration.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Fixes: d72d391c126e ("drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular")
> ---
>  drivers/tty/serial/8250/8250_mtk.c | 35 ++++++++++++++++++++++++++++-------
>  1 file changed, 28 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
> index 0e590b233f03..78883ca64ddd 100644
> --- a/drivers/tty/serial/8250/8250_mtk.c
> +++ b/drivers/tty/serial/8250/8250_mtk.c
> @@ -16,7 +16,7 @@
>   */
>  #include <linux/clk.h>
>  #include <linux/io.h>
> -#include <linux/init.h>
> +#include <linux/module.h>
>  #include <linux/of_irq.h>
>  #include <linux/of_platform.h>
>  #include <linux/platform_device.h>
> @@ -245,6 +245,23 @@ static int mtk8250_probe(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static int mtk8250_remove(struct platform_device *pdev)
> +{
> +	struct mtk8250_data *data = platform_get_drvdata(pdev);
> +
> +	pm_runtime_get_sync(&pdev->dev);
> +
> +	serial8250_unregister_port(data->line);
> +
> +	pm_runtime_disable(&pdev->dev);
> +	pm_runtime_put_noidle(&pdev->dev);
> +
> +	if (!pm_runtime_status_suspended(&pdev->dev))
> +		mtk8250_runtime_suspend(&pdev->dev);
> +
> +	return 0;
> +}
> +
>  #ifdef CONFIG_PM_SLEEP
>  static int mtk8250_suspend(struct device *dev)
>  {
> @@ -275,18 +292,18 @@ static const struct of_device_id mtk8250_of_match[] = {
>  	{ .compatible = "mediatek,mt6577-uart" },
>  	{ /* Sentinel */ }
>  };
> +MODULE_DEVICE_TABLE(of, mtk8250_of_match);
>  
>  static struct platform_driver mtk8250_platform_driver = {
>  	.driver = {
> -		.name			= "mt6577-uart",
> -		.pm			= &mtk8250_pm_ops,
> -		.of_match_table		= mtk8250_of_match,
> -		.suppress_bind_attrs	= true,
> -
> +		.name		= "mt6577-uart",
> +		.pm		= &mtk8250_pm_ops,
> +		.of_match_table	= mtk8250_of_match,
>  	},
>  	.probe			= mtk8250_probe,
> +	.remove			= mtk8250_remove,
>  };
> -builtin_platform_driver(mtk8250_platform_driver);
> +module_platform_driver(mtk8250_platform_driver);
>  
>  #ifdef CONFIG_SERIAL_8250_CONSOLE
>  static int __init early_mtk8250_setup(struct earlycon_device *device,
> @@ -302,3 +319,7 @@ static int __init early_mtk8250_setup(struct earlycon_device *device,
>  
>  OF_EARLYCON_DECLARE(mtk8250, "mediatek,mt6577-uart", early_mtk8250_setup);
>  #endif
> +
> +MODULE_AUTHOR("Matthias Brugger");
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Mediatek 8250 serial port driver");
> -- 
> 2.7.0
> 

Re: [PATCH v2 1/6] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"

[Arnd Bergmann]

On Thursday 11 February 2016 11:00:22 Paul Gortmaker wrote:
> [[PATCH v2 1/6] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"] On 11/02/2016 (Thu 16:41) Arnd Bergmann wrote:
> 
> > This reverts commit d72d391c126e, which tried to remove dead code but
> > left the driver in a useless state when the main 8250 driver is a
> 
> Am I misunderstanding something?  The commit didn't cause the driver to
> be in a useless state for 8250=m.  But rather isn't that it was a
> pre-existing condition, independent of the change to 8250_mtk.c to
> remove the dead code in d72d391c126e?
> 
> Since the commit did not touch Kconfig or Makefile, I can't see how it
> could cause some new useless state that did not already exist, and hence
> the "Fixes:" tag is invalid as well.

My wording may have been bad here. What I meant to say is that it
was broken before the patch, and still broken after the patch.

The Fixes tag was meant to just be a reference to the commit I'm
reverting.

	Arnd

Re: [PATCH v2 1/6] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"

[Paul Gortmaker]

[Re: [PATCH v2 1/6] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"] On 11/02/2016 (Thu 17:06) Arnd Bergmann wrote:

> On Thursday 11 February 2016 11:00:22 Paul Gortmaker wrote:
> > [[PATCH v2 1/6] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"] On 11/02/2016 (Thu 16:41) Arnd Bergmann wrote:
> > 
> > > This reverts commit d72d391c126e, which tried to remove dead code but
> > > left the driver in a useless state when the main 8250 driver is a
> > 
> > Am I misunderstanding something?  The commit didn't cause the driver to
> > be in a useless state for 8250=m.  But rather isn't that it was a
> > pre-existing condition, independent of the change to 8250_mtk.c to
> > remove the dead code in d72d391c126e?
> > 
> > Since the commit did not touch Kconfig or Makefile, I can't see how it
> > could cause some new useless state that did not already exist, and hence
> > the "Fixes:" tag is invalid as well.
> 
> My wording may have been bad here. What I meant to say is that it
> was broken before the patch, and still broken after the patch.

OK, no problem. I just didn't want Greg/Jiri to think I was sending them
broken commits.   Will need a v3 to get rid of the extra module.h
anyway, so that gives you a chance to reword.

> 
> The Fixes tag was meant to just be a reference to the commit I'm
> reverting.

Yeah, but since the stable people trigger off of that, and since the
revert doesn't really fix anything, that is probably best removed.
The stable trees don't need the revert.

Thanks,
Paul.

Re: [PATCH v2 1/6] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"

[Arnd Bergmann]

On Thursday 11 February 2016 11:28:52 Paul Gortmaker wrote:
> [Re: [PATCH v2 1/6] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"] On 11/02/2016 (Thu 17:06) Arnd Bergmann wrote:
> 
> > On Thursday 11 February 2016 11:00:22 Paul Gortmaker wrote:
> > > [[PATCH v2 1/6] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"] On 11/02/2016 (Thu 16:41) Arnd Bergmann wrote:
> > > 
> > > > This reverts commit d72d391c126e, which tried to remove dead code but
> > > > left the driver in a useless state when the main 8250 driver is a
> > > 
> > > Am I misunderstanding something?  The commit didn't cause the driver to
> > > be in a useless state for 8250=m.  But rather isn't that it was a
> > > pre-existing condition, independent of the change to 8250_mtk.c to
> > > remove the dead code in d72d391c126e?
> > > 
> > > Since the commit did not touch Kconfig or Makefile, I can't see how it
> > > could cause some new useless state that did not already exist, and hence
> > > the "Fixes:" tag is invalid as well.
> > 
> > My wording may have been bad here. What I meant to say is that it
> > was broken before the patch, and still broken after the patch.
> 
> OK, no problem. I just didn't want Greg/Jiri to think I was sending them
> broken commits.   Will need a v3 to get rid of the extra module.h
> anyway, so that gives you a chance to reword.

Sure.

> > 
> > The Fixes tag was meant to just be a reference to the commit I'm
> > reverting.
> 
> Yeah, but since the stable people trigger off of that, and since the
> revert doesn't really fix anything, that is probably best removed.
> The stable trees don't need the revert.

Yes, good point.

	Arnd

[PATCH v2 3/6] serial: 8250/mediatek: mark PM functions as __maybe_unused

[Arnd Bergmann]

The mtk8250_runtime_suspend function is not used when runtime PM is
disabled, so we get a warning about an unused function:

drivers/tty/serial/8250/8250_mtk.c:119:12: error: 'mtk8250_runtime_suspend' defined but not used [-Werror=unused-function]
 static int mtk8250_runtime_suspend(struct device *dev)

This marks all the PM functions as __maybe_unused to avoid the warning,
and removes the #ifdef around the PM_SLEEP functions for consistency.

Signed-off-by: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
Acked-by: Matthias Brugger <matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/tty/serial/8250/8250_mtk.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 78883ca64ddd..6ecc6e3e82dc 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -116,7 +116,7 @@ mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
 		tty_termios_encode_baud_rate(termios, baud, baud);
 }
 
-static int mtk8250_runtime_suspend(struct device *dev)
+static int __maybe_unused mtk8250_runtime_suspend(struct device *dev)
 {
 	struct mtk8250_data *data = dev_get_drvdata(dev);
 
@@ -126,7 +126,7 @@ static int mtk8250_runtime_suspend(struct device *dev)
 	return 0;
 }
 
-static int mtk8250_runtime_resume(struct device *dev)
+static int __maybe_unused mtk8250_runtime_resume(struct device *dev)
 {
 	struct mtk8250_data *data = dev_get_drvdata(dev);
 	int err;
@@ -262,8 +262,7 @@ static int mtk8250_remove(struct platform_device *pdev)
 	return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
-static int mtk8250_suspend(struct device *dev)
+static int __maybe_unused mtk8250_suspend(struct device *dev)
 {
 	struct mtk8250_data *data = dev_get_drvdata(dev);
 
@@ -272,7 +271,7 @@ static int mtk8250_suspend(struct device *dev)
 	return 0;
 }
 
-static int mtk8250_resume(struct device *dev)
+static int __maybe_unused mtk8250_resume(struct device *dev)
 {
 	struct mtk8250_data *data = dev_get_drvdata(dev);
 
@@ -280,7 +279,6 @@ static int mtk8250_resume(struct device *dev)
 
 	return 0;
 }
-#endif /* CONFIG_PM_SLEEP */
 
 static const struct dev_pm_ops mtk8250_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(mtk8250_suspend, mtk8250_resume)
-- 
2.7.0

[PATCH v2 5/6] serial: 8250/mediatek: fix building with SERIAL_8250=m

[Arnd Bergmann]

The Mediatek 8250 driver has a 'bool' Kconfig symbol, but that
breaks when SERIAL_8250 is a loadable module:

drivers/tty/built-in.o: In function `mtk8250_set_termios':
:(.text+0x1bee8): undefined reference to `serial8250_do_set_termios'
:(.text+0x1bf10): undefined reference to `uart_get_baud_rate'
:(.text+0x1c09c): undefined reference to `uart_get_divisor'
drivers/tty/built-in.o: In function `mtk8250_do_pm':
:(.text+0x1c0d0): undefined reference to `serial8250_do_pm'
drivers/tty/built-in.o: In function `mtk8250_probe':
:(.text+0x1c2e4): undefined reference to `serial8250_register_8250_port'
serial/8250/8250_mtk.c:287:242: error: data definition has no type or storage class [-Werror]
serial/8250/8250_mtk.c:287:122: error: 'mtk8250_platform_driver_init' defined but not used [-Werror=unused-function]

This changes the symbol to a 'tristate', so the dependency on
SERIAL_8250 also works when that is set to 'm'.
To actually build the driver, we also need to include <linux/module.h>.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/tty/serial/8250/8250_mtk.c | 3 ++-
 drivers/tty/serial/8250/Kconfig    | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 6ecc6e3e82dc..55be90c1d85e 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/serial_8250.h>
@@ -303,7 +304,7 @@ static struct platform_driver mtk8250_platform_driver = {
 };
 module_platform_driver(mtk8250_platform_driver);
 
-#ifdef CONFIG_SERIAL_8250_CONSOLE
+#if defined(CONFIG_SERIAL_8250_CONSOLE) && !defined(MODULE)
 static int __init early_mtk8250_setup(struct earlycon_device *device,
 					const char *options)
 {
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 67ad6b0d595b..6ae0fae4f796 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -370,7 +370,7 @@ config SERIAL_8250_LPC18XX
 	  serial port, say Y to this option. If unsure, say Y.
 
 config SERIAL_8250_MT6577
-	bool "Mediatek serial port support"
+	tristate "Mediatek serial port support"
 	depends on SERIAL_8250 && ARCH_MEDIATEK
 	help
 	  If you have a Mediatek based board and want to use the
-- 
2.7.0

Re: [PATCH v2 5/6] serial: 8250/mediatek: fix building with SERIAL_8250=m

[Paul Gortmaker]

[[PATCH v2 5/6] serial: 8250/mediatek: fix building with SERIAL_8250=m] On 11/02/2016 (Thu 16:41) Arnd Bergmann wrote:

> The Mediatek 8250 driver has a 'bool' Kconfig symbol, but that
> breaks when SERIAL_8250 is a loadable module:
> 
> drivers/tty/built-in.o: In function `mtk8250_set_termios':
> :(.text+0x1bee8): undefined reference to `serial8250_do_set_termios'
> :(.text+0x1bf10): undefined reference to `uart_get_baud_rate'
> :(.text+0x1c09c): undefined reference to `uart_get_divisor'
> drivers/tty/built-in.o: In function `mtk8250_do_pm':
> :(.text+0x1c0d0): undefined reference to `serial8250_do_pm'
> drivers/tty/built-in.o: In function `mtk8250_probe':
> :(.text+0x1c2e4): undefined reference to `serial8250_register_8250_port'
> serial/8250/8250_mtk.c:287:242: error: data definition has no type or storage class [-Werror]
> serial/8250/8250_mtk.c:287:122: error: 'mtk8250_platform_driver_init' defined but not used [-Werror=unused-function]
> 
> This changes the symbol to a 'tristate', so the dependency on
> SERIAL_8250 also works when that is set to 'm'.
> To actually build the driver, we also need to include <linux/module.h>.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/tty/serial/8250/8250_mtk.c | 3 ++-
>  drivers/tty/serial/8250/Kconfig    | 2 +-
>  2 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
> index 6ecc6e3e82dc..55be90c1d85e 100644
> --- a/drivers/tty/serial/8250/8250_mtk.c
> +++ b/drivers/tty/serial/8250/8250_mtk.c
> @@ -19,6 +19,7 @@
>  #include <linux/module.h>
>  #include <linux/of_irq.h>
>  #include <linux/of_platform.h>
> +#include <linux/module.h>

Something isn't right here ; I can see module.h three lines up in the
context.  Guessing your addition of the revert makes this addition no
longer required...

P.
--

>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/serial_8250.h>
> @@ -303,7 +304,7 @@ static struct platform_driver mtk8250_platform_driver = {
>  };
>  module_platform_driver(mtk8250_platform_driver);
>  
> -#ifdef CONFIG_SERIAL_8250_CONSOLE
> +#if defined(CONFIG_SERIAL_8250_CONSOLE) && !defined(MODULE)
>  static int __init early_mtk8250_setup(struct earlycon_device *device,
>  					const char *options)
>  {
> diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
> index 67ad6b0d595b..6ae0fae4f796 100644
> --- a/drivers/tty/serial/8250/Kconfig
> +++ b/drivers/tty/serial/8250/Kconfig
> @@ -370,7 +370,7 @@ config SERIAL_8250_LPC18XX
>  	  serial port, say Y to this option. If unsure, say Y.
>  
>  config SERIAL_8250_MT6577
> -	bool "Mediatek serial port support"
> +	tristate "Mediatek serial port support"
>  	depends on SERIAL_8250 && ARCH_MEDIATEK
>  	help
>  	  If you have a Mediatek based board and want to use the
> -- 
> 2.7.0
> 

Re: [PATCH v2 5/6] serial: 8250/mediatek: fix building with SERIAL_8250=m

[Arnd Bergmann]

On Thursday 11 February 2016 11:04:38 you wrote:
> > diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
> > index 6ecc6e3e82dc..55be90c1d85e 100644
> > --- a/drivers/tty/serial/8250/8250_mtk.c
> > +++ b/drivers/tty/serial/8250/8250_mtk.c
> > @@ -19,6 +19,7 @@
> >  #include <linux/module.h>
> >  #include <linux/of_irq.h>
> >  #include <linux/of_platform.h>
> > +#include <linux/module.h>
> 
> Something isn't right here ; I can see module.h three lines up in the
> context.  Guessing your addition of the revert makes this addition no
> longer required...
> 

Ok, thanks for noticing this. Also, I really should know my alphabet
at this point. I saw that the headers were sorted alphabetically and
thought I had added it in the right place, which would have worked fine
after the revert. Oh well.

	Arnd

Re: [PATCH v2 5/6] serial: 8250/mediatek: fix building with SERIAL_8250=m

[Matthias Brugger]

On 11/02/16 16:41, Arnd Bergmann wrote:
> The Mediatek 8250 driver has a 'bool' Kconfig symbol, but that
> breaks when SERIAL_8250 is a loadable module:
>
> drivers/tty/built-in.o: In function `mtk8250_set_termios':
> :(.text+0x1bee8): undefined reference to `serial8250_do_set_termios'
> :(.text+0x1bf10): undefined reference to `uart_get_baud_rate'
> :(.text+0x1c09c): undefined reference to `uart_get_divisor'
> drivers/tty/built-in.o: In function `mtk8250_do_pm':
> :(.text+0x1c0d0): undefined reference to `serial8250_do_pm'
> drivers/tty/built-in.o: In function `mtk8250_probe':
> :(.text+0x1c2e4): undefined reference to `serial8250_register_8250_port'
> serial/8250/8250_mtk.c:287:242: error: data definition has no type or storage class [-Werror]
> serial/8250/8250_mtk.c:287:122: error: 'mtk8250_platform_driver_init' defined but not used [-Werror=unused-function]
>
> This changes the symbol to a 'tristate', so the dependency on
> SERIAL_8250 also works when that is set to 'm'.
> To actually build the driver, we also need to include <linux/module.h>.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---

Acked-by: Matthias Brugger <matthias.bgg@gmail.com>

Re: [PATCH v2 5/6] serial: 8250/mediatek: fix building with SERIAL_8250=m

[Masahiro Yamada]

Hi Arnd,


2016-02-12 0:41 GMT+09:00 Arnd Bergmann <arnd@arndb.de>:
> The Mediatek 8250 driver has a 'bool' Kconfig symbol, but that
> breaks when SERIAL_8250 is a loadable module:
>
> drivers/tty/built-in.o: In function `mtk8250_set_termios':
> :(.text+0x1bee8): undefined reference to `serial8250_do_set_termios'
> :(.text+0x1bf10): undefined reference to `uart_get_baud_rate'
> :(.text+0x1c09c): undefined reference to `uart_get_divisor'
> drivers/tty/built-in.o: In function `mtk8250_do_pm':
> :(.text+0x1c0d0): undefined reference to `serial8250_do_pm'
> drivers/tty/built-in.o: In function `mtk8250_probe':
> :(.text+0x1c2e4): undefined reference to `serial8250_register_8250_port'
> serial/8250/8250_mtk.c:287:242: error: data definition has no type or storage class [-Werror]
> serial/8250/8250_mtk.c:287:122: error: 'mtk8250_platform_driver_init' defined but not used [-Werror=unused-function]
>
> This changes the symbol to a 'tristate', so the dependency on
> SERIAL_8250 also works when that is set to 'm'.
> To actually build the driver, we also need to include <linux/module.h>.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/tty/serial/8250/8250_mtk.c | 3 ++-
>  drivers/tty/serial/8250/Kconfig    | 2 +-
>  2 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
> index 6ecc6e3e82dc..55be90c1d85e 100644
> --- a/drivers/tty/serial/8250/8250_mtk.c
> +++ b/drivers/tty/serial/8250/8250_mtk.c
> @@ -19,6 +19,7 @@
>  #include <linux/module.h>
>  #include <linux/of_irq.h>
>  #include <linux/of_platform.h>
> +#include <linux/module.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/serial_8250.h>
> @@ -303,7 +304,7 @@ static struct platform_driver mtk8250_platform_driver = {
>  };
>  module_platform_driver(mtk8250_platform_driver);
>
> -#ifdef CONFIG_SERIAL_8250_CONSOLE
> +#if defined(CONFIG_SERIAL_8250_CONSOLE) && !defined(MODULE)
>  static int __init early_mtk8250_setup(struct earlycon_device *device,
>                                         const char *options)
>  {


As mentioned in 4/6, this hunk might become unneeded if
https://patchwork.kernel.org/patch/8289231/
is accepted.



-- 
Best Regards
Masahiro Yamada