Re: [PATCH v3] of: Add videomode helper

[Steffen Trumtrar <s.trumtrar@pengutronix.de>]

On Mon, Sep 17, 2012 at 06:35:43PM +0000, Tabi Timur-B04825 wrote:
> On Fri, Sep 14, 2012 at 11:24 AM, Steffen Trumtrar
> <s.trumtrar@pengutronix.de> wrote:
> 
> > +/* FIXME */
> > +static u32 of_video_get_value(struct mode_property *prop)
> > +{
> > +       return (prop->min >= prop->typ) ? prop->min : prop->typ;
> > +}
> > +
> > +/* read property into new mode_property */
> > +static int of_video_parse_property(struct device_node *np, char *name,
> > +                               struct mode_property *result)
> > +{
> > +       struct property *prop;
> > +       int length;
> > +       int cells;
> > +       int ret;
> > +
> > +       prop = of_find_property(np, name, &length);
> > +       if (!prop)
> > +               return -EINVAL;
> > +
> > +       cells = length / sizeof(u32);
> > +
> > +       memset(result, 0, sizeof(*result));
> > +
> > +       ret = of_property_read_u32_array(np, name, &result->min, cells);
> > +       of_video_get_value(result);
> 
> What's the point of calling of_video_get_value() here?  It doesn't do anything.
> 

You're right. That definitely does not belong there.

> > +       return ret;
> > +}
> > +
> > +int videomode_to_display_mode(struct display *disp, struct drm_display_mode *dmode, int index)
> > +{
> > +       struct videomode *vm;
> > +
> > +        memset(dmode, 0, sizeof(*dmode));
> 
> Indentation problem.
> 

Okay.
> > +int of_get_video_mode(struct device_node *np, struct display *disp)
> > +{
> > +       struct device_node *display_np;
> > +       struct device_node *mode_np;
> > +       struct device_node *modes_np;
> > +       char *default_mode;
> > +
> > +       int ret = 0;
> > +
> > +       memset(disp, 0, sizeof(*disp));
> > +       disp->modes = kmalloc(sizeof(struct videomode*), GFP_KERNEL);
> > +       if (!np)
> > +               return -EINVAL;
> > +
> > +       display_np = of_parse_phandle(np, "display", 0);
> > +
> > +       if (!display_np)
> > +               return -EINVAL;
> > +
> > +       of_property_read_u32(display_np, "width-mm", &disp->width_mm);
> > +       of_property_read_u32(display_np, "height-mm", &disp->height_mm);
> > +
> > +       mode_np = of_parse_phandle(np, "default-mode", 0);
> > +
> > +       if (!mode_np)
> > +               mode_np = of_find_node_by_name(np, "mode");
> > +
> > +       if (!mode_np)
> > +               return -EINVAL;
> > +
> > +       default_mode = (char *)mode_np->full_name;
> > +
> > +       modes_np = of_find_node_by_name(np, "modes");
> > +       for_each_child_of_node(modes_np, mode_np) {
> > +               struct videomode *vm;
> 
> Blank line after variable declarations, please.
> 
> > +               vm = kmalloc(sizeof(struct videomode), GFP_KERNEL);
> > +               disp->modes[disp->num_modes] = kmalloc(sizeof(struct videomode*), GFP_KERNEL);
> 
> Are you sure this is right?
> 
I implemented disp->modes as "struct videomode** modes". So I guess the first
kmalloc is wrong. Right?!

> > +               ret |= of_video_parse_property(mode_np, "hback-porch", &vm->hback_porch);
> > +               ret |= of_video_parse_property(mode_np, "hfront-porch", &vm->hfront_porch);
> > +               ret |= of_video_parse_property(mode_np, "hactive", &vm->hactive);
> > +               ret |= of_video_parse_property(mode_np, "hsync-len", &vm->hsync_len);
> > +               ret |= of_video_parse_property(mode_np, "vback-porch", &vm->vback_porch);
> > +               ret |= of_video_parse_property(mode_np, "vfront-porch", &vm->vfront_porch);
> > +               ret |= of_video_parse_property(mode_np, "vactive", &vm->vactive);
> > +               ret |= of_video_parse_property(mode_np, "vsync-len", &vm->vsync_len);
> > +               ret |= of_video_parse_property(mode_np, "clock", &vm->clock);
> > +
> > +               if (ret)
> > +                       return -EINVAL;
> > +
> > +               vm->hah = of_property_read_bool(mode_np, "hsync-active-high");
> > +               vm->vah = of_property_read_bool(mode_np, "vsync-active-high");
> > +               vm->interlaced = of_property_read_bool(mode_np, "interlaced");
> > +               vm->doublescan = of_property_read_bool(mode_np, "doublescan");
> > +
> > +               if (strcmp(default_mode,mode_np->full_name) = 0) {
> > +                       printk("%s: default_node = %d\n", __func__, disp->num_modes);
> 
> Please use a KERN_ macro here, or a pr_xxx function.  Even better
> would be to use a dev_xxx function.
> 
> In general, I'd like to see more error reporting of bad device tree
> properties, to help debugging.
> 

Okay. Actually, the printk also was not supposed to be in the final patch.
I can fix that and add some dev_xxx.

> > +                       disp->default_mode = disp->num_modes;
> > +               }
> > +
> > +               disp->modes[disp->num_modes] = vm;
> 
> Isn't this a memory leak?
> 

I think I get you. I will fix that.

> > +               disp->num_modes++;
> > +       }
> > +       of_node_put(display_np);
> > +
> > +       return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(of_get_video_mode);
> 

Thank you for your review.

Regards,
Steffen

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