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Message-ID: <5197DBCA.8050708@prisktech.co.nz>
Date: Sun, 19 May 2013 07:51:38 +1200
From: Tony Prisk <linux@...sktech.co.nz>
To: Alexey Charkov <alchark@...il.com>
CC: VT8500/WM8505 Linux Kernel
<vt8500-wm8505-linux-kernel@...glegroups.com>,
Florian Tobias Schandinat <FlorianSchandinat@....de>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
tomi.valkeinen@...com,
"linux-fbdev@...r.kernel.org" <linux-fbdev@...r.kernel.org>
Subject: Re: [PATCH 4/4] fb: vt8500: Add VGA output support to wm8505fb driver.
On 19/05/13 01:28, Alexey Charkov wrote:
> 2013/5/18 Tony Prisk <linux@...sktech.co.nz>:
>> The APC8750 does not support an LCD panel, but provides a VGA connector.
>> This patch adds support for the VGA interface, and defines an optional
>> devicetree property to specify the output interface. The default if not
>> specified is LCD for backward compatibility.
>>
>> Signed-off-by: Tony Prisk <linux@...sktech.co.nz>
>> ---
>> .../devicetree/bindings/video/wm,wm8505-fb.txt | 5 ++++
>> drivers/video/wm8505fb.c | 31 ++++++++++++++++++--
>> 2 files changed, 34 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/video/wm,wm8505-fb.txt b/Documentation/devicetree/bindings/video/wm,wm8505-fb.txt
>> index 601416c..9f1d648 100644
>> --- a/Documentation/devicetree/bindings/video/wm,wm8505-fb.txt
>> +++ b/Documentation/devicetree/bindings/video/wm,wm8505-fb.txt
>> @@ -7,6 +7,10 @@ Required properties:
>> - bits-per-pixel : bit depth of framebuffer (16 or 32)
>> - clocks : phandle to DVO clock
>>
>> +Optional properties:
>> +- output-interface : the interface the fb should output on. Valid values are
>> + "lcd" or "vga". If not specified, the default is "lcd".
>> +
>> Required subnodes:
>> - display-timings: see display-timing.txt for information
>>
>> @@ -17,6 +21,7 @@ Example:
>> reg = <0xd8051700 0x200>;
>> bits-per-pixel = <16>;
>> clocks = <&clkdvo>;
>> + output-interface = "vga";
>>
>> display-timings {
>> native-mode = <&timing0>;
>> diff --git a/drivers/video/wm8505fb.c b/drivers/video/wm8505fb.c
>> index f8bffc2..d1f7f33 100644
>> --- a/drivers/video/wm8505fb.c
>> +++ b/drivers/video/wm8505fb.c
>> @@ -130,12 +130,17 @@
>>
>> #define to_wm8505fb_info(__info) container_of(__info, \
>> struct wm8505fb_info, fb)
>> +
>> +#define INTERFACE_LCD 1
>> +#define INTERFACE_VGA 2
>> +
>> struct wm8505fb_info {
>> struct fb_info fb;
>> void __iomem *regbase;
>> unsigned int contrast;
>> struct device *dev;
>> struct clk *clk_dvo;
>> + int interface;
>> };
>>
>>
>> @@ -158,7 +163,11 @@ static int wm8505fb_init_hw(struct fb_info *info)
>> * 0x31C sets the correct color mode (RGB565) for WM8650
>> * Bit 8+9 (0x300) are ignored on WM8505 as reserved
>> */
>> - writel(0x31c, fbi->regbase + REG_GOVRH_YUVRGB);
>> + if (fbi->interface == INTERFACE_VGA)
>> + writel(0x338, fbi->regbase + REG_GOVRH_YUVRGB);
>> + else
>> + writel(0x31c, fbi->regbase + REG_GOVRH_YUVRGB);
>> +
>> writel(1, fbi->regbase + REG_GOVRH_DVO_PIX);
> Tony,
>
> Would it be possible to also define known bit offsets for those
> registers, while you are at this? It would probably reduce the black
> magic quite a bit :)
On my list of things to do :)
>> /* Virtual buffer size */
>> @@ -167,7 +176,12 @@ static int wm8505fb_init_hw(struct fb_info *info)
>>
>> /* black magic ;) */
>> writel(0xf, fbi->regbase + REG_GOVRH_FHI);
>> - writel(4, fbi->regbase + REG_GOVRH_DVO_SET);
>> +
>> + if (fbi->interface == INTERFACE_VGA)
>> + writel(0xe, fbi->regbase + REG_GOVRH_DVO_SET);
>> + else
>> + writel(4, fbi->regbase + REG_GOVRH_DVO_SET);
> I don't remember if HDMI is yet another option for this register or
> not... If it is, it would probably warrant defining fbi->interface as
> an enum and changing this if-else into a switch statement to let the
> compiler add its checks/warnings.
This register defines the h/v syncpolarity and enable/disable for DVO.
>
>> writel(1, fbi->regbase + REG_GOVRH_MIF);
>> writel(1, fbi->regbase + REG_GOVRH_REG_STS);
>>
>> @@ -194,11 +208,15 @@ static int wm8505fb_set_timing(struct fb_info *info)
>> writel(h_end, fbi->regbase + REG_GOVRH_ACTPX_END);
>> writel(h_all, fbi->regbase + REG_GOVRH_H_ALLPXL);
>> writel(h_sync, fbi->regbase + REG_GOVRH_HDMI_HSYNW);
>> + if (fbi->interface == INTERFACE_VGA)
>> + writel(h_sync, fbi->regbase + REG_GOVRH_VGA_HSYNW);
> Will it misbehave on LCD if you write to the VGA register unconditionally?
Don't know - wouldn't imagine so. I will test it and see.
>
>> writel(v_start, fbi->regbase + REG_GOVRH_ACTLN_BG);
>> writel(v_end, fbi->regbase + REG_GOVRH_ACTLN_END);
>> writel(v_all, fbi->regbase + REG_GOVRH_V_ALLLN);
>> writel(v_sync, fbi->regbase + REG_GOVRH_HDMI_VBISW);
>> + if (fbi->interface == INTERFACE_VGA)
>> + writel(info->var.pixclock, fbi->regbase + REG_GOVRH_VGA_VSYNW);
> Same here. I would assume that setting the pixclock should not hurt
> LCD, which would then simplify the code a little.
>
> Thanks,
> Alexey
Regards
Tony Prisk
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