RFC ARM LPC32xx AMBA apb_pclk changes

[Kevin Wells]

>> > This is a first cut at adding apb_pclk support for the AMBA bus driver.
>> >
>> > The temporary clock enable/disable wrappers around the amba_register
>> > function will no longer be needed. A "apb_pclk" con_id wasn't added,
>> > using only the matching device IDs used by the AMBA drivers. Because
>> > the AMBA driver attempts to turn off the LCD clock prior to exist, the
>> > workaround for the LCD clock enable needs to be handled with
>> > clk_enable so it will stay on after the AMBA driver disables it's clock.
>>
>> I think the clcd driver should be fixed not to do the first disable,
>> rather than work-around the problem like this.
>
> Something like this:
>
> diff --git a/drivers/video/amba-clcd.c b/drivers/video/amba-clcd.c
> index afe21e6..1c2c683 100644
> --- a/drivers/video/amba-clcd.c
> +++ b/drivers/video/amba-clcd.c
> @@ -80,7 +80,10 @@ static void clcdfb_disable(struct clcd_fb *fb)
>        /*
>         * Disable CLCD clock source.
>         */
> -       clk_disable(fb->clk);
> +       if (fb->clk_enabled) {
> +               fb->clk_enabled = false;
> +               clk_disable(fb->clk);
> +       }
>  }
>
>  static void clcdfb_enable(struct clcd_fb *fb, u32 cntl)
> @@ -88,7 +91,10 @@ static void clcdfb_enable(struct clcd_fb *fb, u32 cntl)
>        /*
>         * Enable the CLCD clock source.
>         */
> -       clk_enable(fb->clk);
> +       if (!fb->clk_enabled) {
> +               fb->clk_enabled = true;
> +               clk_enable(fb->clk);
> +       }
>
>        /*
>         * Bring up by first enabling..
> diff --git a/include/linux/amba/clcd.h b/include/linux/amba/clcd.h
> index ca16c38..be33b3a 100644
> --- a/include/linux/amba/clcd.h
> +++ b/include/linux/amba/clcd.h
> @@ -150,6 +150,7 @@ struct clcd_fb {
>        u16                     off_cntl;
>        u32                     clcd_cntl;
>        u32                     cmap[16];
> +       bool                    clk_enabled;
>  };
>
>  static inline void clcdfb_decode(struct clcd_fb *fb, struct clcd_regs *regs)
>
>

I'll get a patch for this change and the amba pclk changes for the
pl11x up a little later..thanks!