[RFC PATCH] component: Add common helpers for compare/release functions

[Yong Wu]

On Fri, 2022-01-28 at 23:24 +0100, Daniel Vetter wrote:
> On Fri, Jan 28, 2022 at 04:11:01PM +0800, Yong Wu wrote:
> > The component requires the compare/release functions, there are so
> > many
> > copy in current kernel. Just define three common helpers for them.
> > No functional change.
> > 
> > Signed-off-by: Yong Wu <yong.wu at mediatek.com>
> > ---
> > Base on v5.17-rc1
> > ---
> >  .../gpu/drm/arm/display/komeda/komeda_drv.c    |  5 -----
> >  drivers/gpu/drm/arm/hdlcd_drv.c                |  7 +------
> >  drivers/gpu/drm/armada/armada_drv.c            |  5 -----
> >  drivers/gpu/drm/drm_of.c                       |  8 +-------
> >  drivers/gpu/drm/etnaviv/etnaviv_drv.c          |  7 -------
> >  drivers/gpu/drm/exynos/exynos_drm_drv.c        |  5 -----
> >  .../gpu/drm/hisilicon/kirin/kirin_drm_drv.c    |  5 -----
> >  drivers/gpu/drm/imx/imx-drm-core.c             |  4 ++--
> >  drivers/gpu/drm/ingenic/ingenic-drm-drv.c      |  5 -----
> >  drivers/gpu/drm/mcde/mcde_drv.c                |  7 +------
> >  drivers/gpu/drm/mediatek/mtk_drm_drv.c         |  5 -----
> >  drivers/gpu/drm/meson/meson_drv.c              |  8 --------
> >  drivers/gpu/drm/msm/msm_drv.c                  |  9 ---------
> >  drivers/gpu/drm/omapdrm/dss/dss.c              |  8 +-------
> >  drivers/gpu/drm/rockchip/rockchip_drm_drv.c    |  5 -----
> >  drivers/gpu/drm/sti/sti_drv.c                  |  5 -----
> >  drivers/gpu/drm/sun4i/sun4i_drv.c              |  9 ---------
> >  drivers/gpu/drm/vc4/vc4_drv.c                  |  5 -----
> >  drivers/iommu/mtk_iommu.h                      | 10 ----------
> >  drivers/power/supply/ab8500_charger.c          |  8 +-------
> >  drivers/video/fbdev/omap2/omapfb/dss/dss.c     |  8 +-------
> >  include/linux/component.h                      | 18
> > ++++++++++++++++++
> >  sound/soc/codecs/wcd938x.c                     | 16 ++----------
> > ----
> 
> Seems like a neat idea. Please add kerneldoc for the new functions
> you're
> adding (bonus point for an example in there) and make sure it all
> renders
> correctly in

OK, I will add it.

> 
> $ make htmldoc

sorry, I still need some time to run this in my environment.

> 
> Also please split up the patch series per-driver and add the
> maintainers
> to each patches' Cc: list. With that I think this should be ready for
> merging.

In the orignal idea, I thought the name compare_of/release_of was
enough, thus I squashed them into one patch, otherwise, it may cause
build fail due to redefinition when bisecting.

From Jani, It's better to add a namespace for the function name,
something like comp_ or component_?

If the function name is changed, then I could split them. A question:
The biggest change are in DRM, and all of these patches will go
together. Maybe all the DRM parts could be in one patch, to avoid so
many small patches, is this ok? or We'd better create a patch per a drm
driver.

In the end, then the code should be something like:

--- a/drivers/base/component.c
+++ b/drivers/base/component.c
@@ -287,6 +287,24 @@ static void take_down_master(struct master
*master)
        }
 }

+int component_compare_of(struct device *dev, void *data)
+{
+       return device_match_of_node(dev, data);
+}
+EXPORT_SYMBOL_GPL(component_compare_of);
+
+void component_release_of(struct device *dev, void *data)
+{
+       of_node_put(data);
+}
+EXPORT_SYMBOL_GPL(component_release_of);

> 
> Cheers, Daniel
> 
> >  23 files changed, 28 insertions(+), 144 deletions(-)

> > diff --git a/include/linux/component.h b/include/linux/component.h
> > index 16de18f473d7..5a7468ea827c 100644
> > --- a/include/linux/component.h
> > +++ b/include/linux/component.h
> > @@ -2,6 +2,8 @@
> >  #ifndef COMPONENT_H
> >  #define COMPONENT_H
> >  
> > +#include <linux/device.h>
> > +#include <linux/of.h>
> >  #include <linux/stddef.h>
> >  
> >  
> > @@ -82,6 +84,22 @@ struct component_master_ops {
> >  	void (*unbind)(struct device *master);
> >  };
> >  
> > +/* A set common helpers for compare/release functions */
> > +static inline int compare_of(struct device *dev, void *data)
> > +{
> > +	return dev->of_node == data;
> > +}
> > +
> > +static inline void release_of(struct device *dev, void *data)
> > +{
> > +	of_node_put(data);
> > +}
> > +
> > +static inline int compare_dev(struct device *dev, void *data)
> > +{
> > +	return dev == data;
> > +}
> > +
> >  void component_master_del(struct device *,
> >  	const struct component_master_ops *);
> 
>