On 11/7/23 21:01, Uwe Kleine-König wrote:
On Tue, Nov 07, 2023 at 10:17:43AM +0100, Uwe Kleine-König wrote:
On today's platforms the benefit of platform_driver_probe() isn't that
relevant any more. It allows to drop some code after booting (or module
loading) for .probe() and discard the .remove() function completely if
the driver is built-in. This typically saves a few 100k.

The downside of platform_driver_probe() is that the driver cannot be
bound and unbound at runtime which is ancient and also slightly
complicates testing. There are also thoughts to deprecate
platform_driver_probe() because it adds some complexity in the driver
core for little gain. Also many drivers don't use it correctly. This
driver for example misses to mark the driver struct with __refdata which
is needed to suppress a (W=1) modpost warning:

        WARNING: modpost: drivers/video/fbdev/atmel_lcdfb: section mismatch in 
reference: atmel_lcdfb_driver+0x4 (section: .data) -> atmel_lcdfb_remove 
(section: .exit.text)

Signed-off-by: Uwe Kleine-König <u.kleine-koe...@pengutronix.de>
---
  drivers/video/fbdev/atmel_lcdfb.c | 9 +++++----
  1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/video/fbdev/atmel_lcdfb.c 
b/drivers/video/fbdev/atmel_lcdfb.c
index a908db233409..b218731ef732 100644
--- a/drivers/video/fbdev/atmel_lcdfb.c
+++ b/drivers/video/fbdev/atmel_lcdfb.c
@@ -1017,7 +1017,7 @@ static int atmel_lcdfb_of_init(struct atmel_lcdfb_info 
*sinfo)
        return ret;
  }

-static int __init atmel_lcdfb_probe(struct platform_device *pdev)
+static int atmel_lcdfb_probe(struct platform_device *pdev)
  {
        struct device *dev = &pdev->dev;
        struct fb_info *info;
@@ -1223,7 +1223,7 @@ static int __init atmel_lcdfb_probe(struct 
platform_device *pdev)
        return ret;
  }

-static int __exit atmel_lcdfb_remove(struct platform_device *pdev)
+static int atmel_lcdfb_remove(struct platform_device *pdev)
  {
        struct device *dev = &pdev->dev;
        struct fb_info *info = dev_get_drvdata(dev);
@@ -1301,7 +1301,8 @@ static int atmel_lcdfb_resume(struct platform_device 
*pdev)
  #endif

  static struct platform_driver atmel_lcdfb_driver = {
-       .remove         = __exit_p(atmel_lcdfb_remove),
+       .probe          = atmel_lcdfb_probe,
+       .remove         = atmel_lcdfb_remove,
        .suspend        = atmel_lcdfb_suspend,
        .resume         = atmel_lcdfb_resume,
        .driver         = {
@@ -1310,7 +1311,7 @@ static struct platform_driver atmel_lcdfb_driver = {
        },
  };

-module_platform_driver_probe(atmel_lcdfb_driver, atmel_lcdfb_probe);
+module_platform_driver(atmel_lcdfb_driver, );

Argh, the , must be removed. I had this in my working copy but forgot to
squash it into this commit. Sorry!

Can you squash in the following please?:

Sure.
I fixed it up in the git tree.

Thanks!
Helge

diff --git a/drivers/video/fbdev/atmel_lcdfb.c 
b/drivers/video/fbdev/atmel_lcdfb.c
index 0531d6f6dcc5..88c75ae7d315 100644
--- a/drivers/video/fbdev/atmel_lcdfb.c
+++ b/drivers/video/fbdev/atmel_lcdfb.c
@@ -1308,8 +1308,7 @@ static struct platform_driver atmel_lcdfb_driver = {
                .of_match_table = atmel_lcdfb_dt_ids,
        },
  };
-
-module_platform_driver(atmel_lcdfb_driver, );
+module_platform_driver(atmel_lcdfb_driver);

  MODULE_DESCRIPTION("AT91 LCD Controller framebuffer driver");
  MODULE_AUTHOR("Nicolas Ferre <nicolas.fe...@atmel.com>");

Best regards
Uwe


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