[PATCH 2/3] phy: mediatek: phy-mtk-mipi-dsi: Reorder and stop implicit header inclusion

[Chen-Yu Tsai]

On Thu, Jan 6, 2022 at 4:48 PM Chunfeng Yun <chunfeng.yun at mediatek.com> wrote:
>
> On Mon, 2022-01-03 at 15:53 +0100, AngeloGioacchino Del Regno wrote:
> > All the headers for phy-mtk-mipi-{dsi,dsi-mt8173,dsi-mt8183}.c were
> > included from phy-mtk-mipi-dsi.h, but this isn't optimal: in order to
> > increase readability and sensibly reduce build times, the inclusions
> > should be done per-file, also avoiding to include unused headers and
> > should not be implicit.
> >
> > For this reason, move the inclusions to each file and remove unused
> > ones.
> >
> > Signed-off-by: AngeloGioacchino Del Regno <
> > angelogioacchino.delregno at collabora.com>
> > ---
> >  drivers/phy/mediatek/phy-mtk-mipi-dsi-mt8173.c |  4 ++++
> >  drivers/phy/mediatek/phy-mtk-mipi-dsi-mt8183.c |  4 ++++
> >  drivers/phy/mediatek/phy-mtk-mipi-dsi.c        |  7 +++++++
> >  drivers/phy/mediatek/phy-mtk-mipi-dsi.h        | 10 ++--------
> >  4 files changed, 17 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/phy/mediatek/phy-mtk-mipi-dsi-mt8173.c
> > b/drivers/phy/mediatek/phy-mtk-mipi-dsi-mt8173.c
> > index 95a0d9a3cca7..59f028da9d3e 100644
> > --- a/drivers/phy/mediatek/phy-mtk-mipi-dsi-mt8173.c
> > +++ b/drivers/phy/mediatek/phy-mtk-mipi-dsi-mt8173.c
> > @@ -4,7 +4,11 @@
> >   * Author: jitao.shi <jitao.shi at mediatek.com>
> >   */
> >
> > +#include <linux/clk-provider.h>
> > +#include <linux/delay.h>
> > +#include <linux/module.h>
> >  #include <linux/regmap.h>
> > +#include <linux/phy/phy.h>
> >  #include "phy-mtk-mipi-dsi.h"
> >
> >  #define MIPITX_DSI_CON               0x00
> > diff --git a/drivers/phy/mediatek/phy-mtk-mipi-dsi-mt8183.c
> > b/drivers/phy/mediatek/phy-mtk-mipi-dsi-mt8183.c
> > index 01b59527669e..6c6b192485ba 100644
> > --- a/drivers/phy/mediatek/phy-mtk-mipi-dsi-mt8183.c
> > +++ b/drivers/phy/mediatek/phy-mtk-mipi-dsi-mt8183.c
> > @@ -4,7 +4,11 @@
> >   * Author: jitao.shi <jitao.shi at mediatek.com>
> >   */
> >
> > +#include <linux/clk-provider.h>
> > +#include <linux/delay.h>
> > +#include <linux/module.h>
> >  #include <linux/regmap.h>
> > +#include <linux/phy/phy.h>
> >  #include "phy-mtk-mipi-dsi.h"
> >
> >  #define MIPITX_LANE_CON              0x000c
> > diff --git a/drivers/phy/mediatek/phy-mtk-mipi-dsi.c
> > b/drivers/phy/mediatek/phy-mtk-mipi-dsi.c
> > index 51b1b1d4ad38..6f7425b0bf5b 100644
> > --- a/drivers/phy/mediatek/phy-mtk-mipi-dsi.c
> > +++ b/drivers/phy/mediatek/phy-mtk-mipi-dsi.c
> > @@ -3,7 +3,14 @@
> >   * Copyright (c) 2015 MediaTek Inc.
> >   */
> >
> > +#include <linux/clk.h>
> > +#include <linux/clk-provider.h>
> > +#include <linux/module.h>
> > +#include <linux/nvmem-consumer.h>
> > +#include <linux/of_device.h>
> > +#include <linux/platform_device.h>
> >  #include <linux/regmap.h>
> > +#include <linux/phy/phy.h>
> >  #include "phy-mtk-mipi-dsi.h"
> >
> >  inline struct mtk_mipi_tx *mtk_mipi_tx_from_clk_hw(struct clk_hw
> > *hw)
> > diff --git a/drivers/phy/mediatek/phy-mtk-mipi-dsi.h
> > b/drivers/phy/mediatek/phy-mtk-mipi-dsi.h
> > index 8d32e9027a15..4eb5fc91e083 100644
> > --- a/drivers/phy/mediatek/phy-mtk-mipi-dsi.h
> > +++ b/drivers/phy/mediatek/phy-mtk-mipi-dsi.h
> > @@ -7,16 +7,10 @@
> >  #ifndef _MTK_MIPI_TX_H
> >  #define _MTK_MIPI_TX_H
> >
> > -#include <linux/clk.h>
> >  #include <linux/clk-provider.h>
> > -#include <linux/delay.h>
> > -#include <linux/io.h>
> > -#include <linux/module.h>
> > -#include <linux/nvmem-consumer.h>
> > -#include <linux/of_device.h>
> > -#include <linux/platform_device.h>
> > +#include <linux/types.h>
> > +#include <linux/regmap.h>
> >  #include <linux/phy/phy.h>
> > -#include <linux/slab.h>
> >
> I don't think it's good idea to move the common headers into .c files

Header files should be included directly by the file that uses facilities
provided by said header file. Required ones should not be transitively
included through other header files, as that introduces a subtle dependency.

Also, needlessly including header files in places that aren't using them
increases build time. See the 2000+ patch series from Ingo Molnar [1]
increasing build performance by cleaning up header files.

ChenYu

[1] https://lwn.net/ml/linux-kernel/YdIfz+LMewetSaEB@gmail.com/

> >  struct mtk_mipitx_data {
> >       const u32 mppll_preserve;
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