Re: [PATCH v2 25/29] drm: sun4i: add quirks for TCON TOP

[Maxime Ripard <maxime.ripard@bootlin.com>]

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On Mon, Oct 08, 2018 at 06:50:44PM +0800, Chen-Yu Tsai wrote:
> On Mon, Oct 8, 2018 at 6:20 PM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
> >
> > On Mon, Oct 08, 2018 at 05:06:45PM +0800, Chen-Yu Tsai wrote:
> > > On Mon, Oct 8, 2018 at 4:51 PM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
> > > >
> > > > On Sun, Oct 07, 2018 at 11:39:01AM +0200, Jernej Skrabec wrote:
> > > > > From: Icenowy Zheng <icenowy@aosc.io>
> > > > >
> > > > > Some SoCs, such as H6, doesn't have a full-featured TCON TOP.
> > > > >
> > > > > Add quirks support for TCON TOP.
> > > > >
> > > > > Currently the presence of TCON_TV1 and DSI is controlled via the quirks
> > > > > structure.
> > > > >
> > > > > Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
> > > > > ---
> > > > >  drivers/gpu/drm/sun4i/sun8i_tcon_top.c | 43 ++++++++++++++++++++------
> > > > >  1 file changed, 34 insertions(+), 9 deletions(-)
> > > > >
> > > > > diff --git a/drivers/gpu/drm/sun4i/sun8i_tcon_top.c b/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
> > > > > index 37158548b447..ed13233cad88 100644
> > > > > --- a/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
> > > > > +++ b/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
> > > > > @@ -9,11 +9,17 @@
> > > > >  #include <linux/component.h>
> > > > >  #include <linux/device.h>
> > > > >  #include <linux/module.h>
> > > > > +#include <linux/of_device.h>
> > > > >  #include <linux/of_graph.h>
> > > > >  #include <linux/platform_device.h>
> > > > >
> > > > >  #include "sun8i_tcon_top.h"
> > > > >
> > > > > +struct sun8i_tcon_top_quirks {
> > > > > +     bool has_tcon_tv1;
> > > > > +     bool has_dsi;
> > > > > +};
> > > > > +
> > > > >  static bool sun8i_tcon_top_node_is_tcon_top(struct device_node *node)
> > > > >  {
> > > > >       return !!of_match_node(sun8i_tcon_top_of_table, node);
> > > > > @@ -121,10 +127,13 @@ static int sun8i_tcon_top_bind(struct device *dev, struct device *master,
> > > > >       struct platform_device *pdev = to_platform_device(dev);
> > > > >       struct clk_hw_onecell_data *clk_data;
> > > > >       struct sun8i_tcon_top *tcon_top;
> > > > > +     const struct sun8i_tcon_top_quirks *quirks;
> > > > >       struct resource *res;
> > > > >       void __iomem *regs;
> > > > >       int ret, i;
> > > > >
> > > > > +     quirks = of_device_get_match_data(&pdev->dev);
> > > > > +
> > > > >       tcon_top = devm_kzalloc(dev, sizeof(*tcon_top), GFP_KERNEL);
> > > > >       if (!tcon_top)
> > > > >               return -ENOMEM;
> > > > > @@ -187,15 +196,23 @@ static int sun8i_tcon_top_bind(struct device *dev, struct device *master,
> > > > >                                            &tcon_top->reg_lock,
> > > > >                                            TCON_TOP_TCON_TV0_GATE, 0);
> > > > >
> > > > > -     clk_data->hws[CLK_TCON_TOP_TV1] =
> > > > > -             sun8i_tcon_top_register_gate(dev, "tcon-tv1", regs,
> > > > > -                                          &tcon_top->reg_lock,
> > > > > -                                          TCON_TOP_TCON_TV1_GATE, 1);
> > > > > +     if (quirks->has_tcon_tv1) {
> > > > > +             clk_data->hws[CLK_TCON_TOP_TV1] =
> > > > > +                     sun8i_tcon_top_register_gate(dev, "tcon-tv1", regs,
> > > > > +                                                  &tcon_top->reg_lock,
> > > > > +                                                  TCON_TOP_TCON_TV1_GATE, 1);
> > > > > +     } else {
> > > > > +             clk_data->hws[CLK_TCON_TOP_TV1] = NULL;
> > > > > +     }
> > > > >
> > > > > -     clk_data->hws[CLK_TCON_TOP_DSI] =
> > > > > -             sun8i_tcon_top_register_gate(dev, "dsi", regs,
> > > > > -                                          &tcon_top->reg_lock,
> > > > > -                                          TCON_TOP_TCON_DSI_GATE, 2);
> > > > > +     if (quirks->has_dsi) {
> > > > > +             clk_data->hws[CLK_TCON_TOP_DSI] =
> > > > > +                     sun8i_tcon_top_register_gate(dev, "dsi", regs,
> > > > > +                                                  &tcon_top->reg_lock,
> > > > > +                                                  TCON_TOP_TCON_DSI_GATE, 2);
> > > > > +     } else {
> > > > > +             clk_data->hws[CLK_TCON_TOP_DSI] = NULL;
> > > >
> > > > clk_data has been kzalloc'd so its content is already NULL.
> > > >
> > > > And you shouldn't have brackets for single line blocks.
> > > >
> > > > with that fixed,
> > >
> > > FYI checkpatch.pl complains if you use brackets for the if block
> > > but not for the else block. They should be matching.
> >
> > Checkpatch might not warn on this, but
> > https://www.kernel.org/doc/Documentation/process/coding-style.rst,
> > section 3 is pretty clear on whether we should use them or not.
> 
> Right. What I'm pointing out what checkpatch.pl complains about is
> shown in the second last example in section 3:
> 
>     This does not apply if only one branch of a conditional statement
> is a single
>     statement; in the latter case use braces in both branches:
> 
> Which is where I think your comment on "shouldn't have brackets for
> single line blocks"
> is pointing in the opposite direction.

I think we have a communication failure :)

The two blocks above are single line blocks, even though the line is
wrapped. So whether or not there is an else condition or not doesn't
matter, you shouldn't have braces at all.

Maxime

-- 
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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