[U-Boot] [PATCH 0/3] sunxi: Enable VGA output on Hummingbird A31

[U-Boot] [PATCH 0/3] sunxi: Enable VGA output on Hummingbird A31

[Chen-Yu Tsai]

Hi Hans, Ian,

This series enables the VGA output on the Hummingbird A31. The VGA output
is driven from LCD0, through an external DAC that's powered up by toggling
pin PH25.

Patch 1 allows selecting CONFIG_VIDEO_VGA_VIA_LCD on sun6i and sun8i.
These 2 platforms do not have builtin TV encoders, and some vendor may
use an external DAC to support VGA.

Patch 2 adds support for toggling a GPIO pin as part of the video init
sequence to power up the DAC

Patch 3 updates the Hummingbird A31 defconfig to enable VGA output.

I have one question about the VGA_VIA_LCD code in general. The color depth
is forced to 18. Is this necessary? Can we make it configurable? I haven't
tried displaying pictures so I don't know if it makes a visible difference.

Also with the VGA output on my Hummingbird A31, I get greenish flashing
pixels where it should be black, like in and between characters. Once
booted in to the kernel this disappears, and I get a nice console with
simplefb. Kind of weird.


Cheers
ChenYu


Chen-Yu Tsai (3):
  sunxi: video: Allow external DACs for VGA on platforms without TV
    encoders
  sunxi: video: Add support for external DAC enable pin
  sunxi: Hummingbird_A31_defconfig: Enable VGA output through external
    DAC

 board/sunxi/Kconfig               | 10 +++++++++-
 configs/Hummingbird_A31_defconfig |  2 ++
 drivers/video/sunxi_display.c     | 18 ++++++++++++++++++
 3 files changed, 29 insertions(+), 1 deletion(-)

-- 
2.1.4

[U-Boot] [PATCH 1/3] sunxi: video: Allow external DACs for VGA on platforms without TV encoders

[Chen-Yu Tsai]

Using an external DAC for VGA output was available on sun5i. Since
some other SoCs don't have a builtin TV encoder, but might have
use for a VGA output, enable the option for the platforms that
don't have TV encoders.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 board/sunxi/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/board/sunxi/Kconfig b/board/sunxi/Kconfig
index 882db33..bce270e 100644
--- a/board/sunxi/Kconfig
+++ b/board/sunxi/Kconfig
@@ -308,7 +308,7 @@ config VIDEO_VGA
 
 config VIDEO_VGA_VIA_LCD
 	boolean "VGA via LCD controller support"
-	depends on VIDEO && MACH_SUN5I
+	depends on VIDEO && (MACH_SUN5I || MACH_SUN6I || MACH_SUN8I)
 	default n
 	---help---
 	Say Y here to add support for external DACs connected to the parallel
-- 
2.1.4

[U-Boot] [PATCH 2/3] sunxi: video: Add support for external DAC enable pin

[Chen-Yu Tsai]

The external DAC for VGA output might have either a power or reset
control pin that needs to be pulled up, as is the case on the
Hummingbird A31.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 board/sunxi/Kconfig           |  8 ++++++++
 drivers/video/sunxi_display.c | 18 ++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/board/sunxi/Kconfig b/board/sunxi/Kconfig
index bce270e..e9a6b3c 100644
--- a/board/sunxi/Kconfig
+++ b/board/sunxi/Kconfig
@@ -315,6 +315,14 @@ config VIDEO_VGA_VIA_LCD
 	LCD interface driving a VGA connector, such as found on the
 	Olimex A13 boards.
 
+config VIDEO_VGA_EXTERNAL_DAC_EN
+	string "LCD panel power enable pin"
+	depends on VIDEO_VGA_VIA_LCD
+	default ""
+	---help---
+	Set the enable pin for the external VGA DAC. This takes a string in the
+	format understood by sunxi_name_to_gpio, e.g. PH1 for pin 1 of port H.
+
 config VIDEO_LCD_MODE
 	string "LCD panel timing details"
 	depends on VIDEO
diff --git a/drivers/video/sunxi_display.c b/drivers/video/sunxi_display.c
index 47d820d..1052af2 100644
--- a/drivers/video/sunxi_display.c
+++ b/drivers/video/sunxi_display.c
@@ -813,6 +813,23 @@ static void sunxi_drc_init(void)
 #endif
 }
 
+#ifdef CONFIG_VIDEO_VGA_VIA_LCD
+static void sunxi_vga_external_dac_enable(void)
+{
+	int pin;
+
+	/*
+	 * Start with backlight disabled to avoid the screen flashing to
+	 * white while the lcd inits.
+	 */
+	pin = sunxi_name_to_gpio(CONFIG_VIDEO_VGA_EXTERNAL_DAC_EN);
+	if (pin != -1) {
+		gpio_request(pin, "vga_enable");
+		gpio_direction_output(pin, 1);
+	}
+}
+#endif /* CONFIG_VIDEO_VGA_VIA_LCD */
+
 static void sunxi_engines_init(void)
 {
 	sunxi_composer_init();
@@ -860,6 +877,7 @@ static void sunxi_mode_set(const struct ctfb_res_modes *mode,
 		sunxi_lcdc_tcon0_mode_set(mode);
 		sunxi_composer_enable();
 		sunxi_lcdc_enable();
+		sunxi_vga_external_dac_enable();
 #endif
 		break;
 	}
-- 
2.1.4

[U-Boot] [PATCH 3/3] sunxi: Hummingbird_A31_defconfig: Enable VGA output through external DAC

[Chen-Yu Tsai]

The Hummingbird A31 uses an external DAC connected to the LCD0 outputs
for the on board VGA output. The DAC has a power control that's toggled
by GPIO.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 configs/Hummingbird_A31_defconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/configs/Hummingbird_A31_defconfig b/configs/Hummingbird_A31_defconfig
index 93820ab..8896999 100644
--- a/configs/Hummingbird_A31_defconfig
+++ b/configs/Hummingbird_A31_defconfig
@@ -1,6 +1,8 @@
 CONFIG_SPL=y
 CONFIG_SYS_EXTRA_OPTIONS="USB_EHCI,SUNXI_GMAC,RGMII,MACPWR=SUNXI_GPA(21)"
 CONFIG_FDTFILE="sun6i-a31-hummingbird.dtb"
+CONFIG_VIDEO_VGA_VIA_LCD=y
+CONFIG_VIDEO_VGA_EXTERNAL_DAC_EN="PH25"
 +S:CONFIG_ARM=y
 +S:CONFIG_ARCH_SUNXI=y
 +S:CONFIG_MACH_SUN6I=y
-- 
2.1.4

[U-Boot] [PATCH 0/3] sunxi: Enable VGA output on Hummingbird A31

[Hans de Goede]

Hi,

On 12-01-15 11:02, Chen-Yu Tsai wrote:
> Hi Hans, Ian,
>
> This series enables the VGA output on the Hummingbird A31. The VGA output
> is driven from LCD0, through an external DAC that's powered up by toggling
> pin PH25.

Thanks for working on this!

> Patch 1 allows selecting CONFIG_VIDEO_VGA_VIA_LCD on sun6i and sun8i.
> These 2 platforms do not have builtin TV encoders, and some vendor may
> use an external DAC to support VGA.
>
> Patch 2 adds support for toggling a GPIO pin as part of the video init
> sequence to power up the DAC
>
> Patch 3 updates the Hummingbird A31 defconfig to enable VGA output.
>
> I have one question about the VGA_VIA_LCD code in general. The color depth
> is forced to 18. Is this necessary?

Depends on the DAC-s you're using, so far this was only used with Olinuxino
boards which use 6 bits dacs. If your board has 8 bit dacs then we should
make this configurable. Note that all this does is enable dithering to avoid
color gradients becoming ugly with 6 bits dacs, but with 8 bit dacs we should
disable the dithering (which is done when depth == 24).

> Can we make it configurable? I haven't
> tried displaying pictures so I don't know if it makes a visible difference.
>
> Also with the VGA output on my Hummingbird A31, I get greenish flashing
> pixels where it should be black, like in and between characters. Once
> booted in to the kernel this disappears, and I get a nice console with
> simplefb. Kind of weird.

Weird indeed, could it be that the DAC-s need some power-supply setup which
u-boot does not set up, but your axp221 kernel code does setup ?

Regards,

Hans

[U-Boot] [PATCH 2/3] sunxi: video: Add support for external DAC enable pin

[Hans de Goede]

Hi,

On 12-01-15 11:02, Chen-Yu Tsai wrote:
> The external DAC for VGA output might have either a power or reset
> control pin that needs to be pulled up, as is the case on the
> Hummingbird A31.
>
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
>   board/sunxi/Kconfig           |  8 ++++++++
>   drivers/video/sunxi_display.c | 18 ++++++++++++++++++
>   2 files changed, 26 insertions(+)
>
> diff --git a/board/sunxi/Kconfig b/board/sunxi/Kconfig
> index bce270e..e9a6b3c 100644
> --- a/board/sunxi/Kconfig
> +++ b/board/sunxi/Kconfig
> @@ -315,6 +315,14 @@ config VIDEO_VGA_VIA_LCD
>   	LCD interface driving a VGA connector, such as found on the
>   	Olimex A13 boards.
>
> +config VIDEO_VGA_EXTERNAL_DAC_EN
> +	string "LCD panel power enable pin"
> +	depends on VIDEO_VGA_VIA_LCD
> +	default ""
> +	---help---
> +	Set the enable pin for the external VGA DAC. This takes a string in the
> +	format understood by sunxi_name_to_gpio, e.g. PH1 for pin 1 of port H.
> +
>   config VIDEO_LCD_MODE
>   	string "LCD panel timing details"
>   	depends on VIDEO
> diff --git a/drivers/video/sunxi_display.c b/drivers/video/sunxi_display.c
> index 47d820d..1052af2 100644
> --- a/drivers/video/sunxi_display.c
> +++ b/drivers/video/sunxi_display.c
> @@ -813,6 +813,23 @@ static void sunxi_drc_init(void)
>   #endif
>   }
>
> +#ifdef CONFIG_VIDEO_VGA_VIA_LCD
> +static void sunxi_vga_external_dac_enable(void)
> +{
> +	int pin;
> +
> +	/*
> +	 * Start with backlight disabled to avoid the screen flashing to
> +	 * white while the lcd inits.
> +	 */

This comment seems wrong, copy & paste error ?

Let me know if you agree that it is wrong, then I'll drop it before applying
the series, not need to resend.

Regards,

Hans


> +	pin = sunxi_name_to_gpio(CONFIG_VIDEO_VGA_EXTERNAL_DAC_EN);
> +	if (pin != -1) {
> +		gpio_request(pin, "vga_enable");
> +		gpio_direction_output(pin, 1);
> +	}
> +}
> +#endif /* CONFIG_VIDEO_VGA_VIA_LCD */
> +
>   static void sunxi_engines_init(void)
>   {
>   	sunxi_composer_init();
> @@ -860,6 +877,7 @@ static void sunxi_mode_set(const struct ctfb_res_modes *mode,
>   		sunxi_lcdc_tcon0_mode_set(mode);
>   		sunxi_composer_enable();
>   		sunxi_lcdc_enable();
> +		sunxi_vga_external_dac_enable();
>   #endif
>   		break;
>   	}
>

[U-Boot] [PATCH 2/3] sunxi: video: Add support for external DAC enable pin

[Chen-Yu Tsai]

On Mon, Jan 12, 2015 at 6:19 PM, Hans de Goede <hdegoede@redhat.com> wrote:
> Hi,
>
>
> On 12-01-15 11:02, Chen-Yu Tsai wrote:
>>
>> The external DAC for VGA output might have either a power or reset
>> control pin that needs to be pulled up, as is the case on the
>> Hummingbird A31.
>>
>> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
>> ---
>>   board/sunxi/Kconfig           |  8 ++++++++
>>   drivers/video/sunxi_display.c | 18 ++++++++++++++++++
>>   2 files changed, 26 insertions(+)
>>
>> diff --git a/board/sunxi/Kconfig b/board/sunxi/Kconfig
>> index bce270e..e9a6b3c 100644
>> --- a/board/sunxi/Kconfig
>> +++ b/board/sunxi/Kconfig
>> @@ -315,6 +315,14 @@ config VIDEO_VGA_VIA_LCD
>>         LCD interface driving a VGA connector, such as found on the
>>         Olimex A13 boards.
>>
>> +config VIDEO_VGA_EXTERNAL_DAC_EN
>> +       string "LCD panel power enable pin"
>> +       depends on VIDEO_VGA_VIA_LCD
>> +       default ""
>> +       ---help---
>> +       Set the enable pin for the external VGA DAC. This takes a string
>> in the
>> +       format understood by sunxi_name_to_gpio, e.g. PH1 for pin 1 of
>> port H.
>> +
>>   config VIDEO_LCD_MODE
>>         string "LCD panel timing details"
>>         depends on VIDEO
>> diff --git a/drivers/video/sunxi_display.c b/drivers/video/sunxi_display.c
>> index 47d820d..1052af2 100644
>> --- a/drivers/video/sunxi_display.c
>> +++ b/drivers/video/sunxi_display.c
>> @@ -813,6 +813,23 @@ static void sunxi_drc_init(void)
>>   #endif
>>   }
>>
>> +#ifdef CONFIG_VIDEO_VGA_VIA_LCD
>> +static void sunxi_vga_external_dac_enable(void)
>> +{
>> +       int pin;
>> +
>> +       /*
>> +        * Start with backlight disabled to avoid the screen flashing to
>> +        * white while the lcd inits.
>> +        */
>
>
> This comment seems wrong, copy & paste error ?
>
> Let me know if you agree that it is wrong, then I'll drop it before applying
> the series, not need to resend.

Yes it's a copy & paste error. Please drop it.

Thanks!

ChenYu

> Regards,
>
> Hans
>
>
>
>> +       pin = sunxi_name_to_gpio(CONFIG_VIDEO_VGA_EXTERNAL_DAC_EN);
>> +       if (pin != -1) {
>> +               gpio_request(pin, "vga_enable");
>> +               gpio_direction_output(pin, 1);
>> +       }
>> +}
>> +#endif /* CONFIG_VIDEO_VGA_VIA_LCD */
>> +
>>   static void sunxi_engines_init(void)
>>   {
>>         sunxi_composer_init();
>> @@ -860,6 +877,7 @@ static void sunxi_mode_set(const struct ctfb_res_modes
>> *mode,
>>                 sunxi_lcdc_tcon0_mode_set(mode);
>>                 sunxi_composer_enable();
>>                 sunxi_lcdc_enable();
>> +               sunxi_vga_external_dac_enable();
>>   #endif
>>                 break;
>>         }
>>
>

[U-Boot] [PATCH 0/3] sunxi: Enable VGA output on Hummingbird A31

[Chen-Yu Tsai]

Hi,

On Mon, Jan 12, 2015 at 6:18 PM, Hans de Goede <hdegoede@redhat.com> wrote:
> Hi,
>
> On 12-01-15 11:02, Chen-Yu Tsai wrote:
>>
>> Hi Hans, Ian,
>>
>> This series enables the VGA output on the Hummingbird A31. The VGA output
>> is driven from LCD0, through an external DAC that's powered up by toggling
>> pin PH25.
>
>
> Thanks for working on this!
>
>> Patch 1 allows selecting CONFIG_VIDEO_VGA_VIA_LCD on sun6i and sun8i.
>> These 2 platforms do not have builtin TV encoders, and some vendor may
>> use an external DAC to support VGA.
>>
>> Patch 2 adds support for toggling a GPIO pin as part of the video init
>> sequence to power up the DAC
>>
>> Patch 3 updates the Hummingbird A31 defconfig to enable VGA output.
>>
>> I have one question about the VGA_VIA_LCD code in general. The color depth
>> is forced to 18. Is this necessary?
>
>
> Depends on the DAC-s you're using, so far this was only used with Olinuxino
> boards which use 6 bits dacs. If your board has 8 bit dacs then we should
> make this configurable. Note that all this does is enable dithering to avoid
> color gradients becoming ugly with 6 bits dacs, but with 8 bit dacs we
> should
> disable the dithering (which is done when depth == 24).

OK. The Hummingbird uses all 24 bits. The DAC is actually 30 bits.
First I need to get some sort of full color display setup running.
Then I'll do the config options.

>> Can we make it configurable? I haven't
>> tried displaying pictures so I don't know if it makes a visible
>> difference.
>>
>> Also with the VGA output on my Hummingbird A31, I get greenish flashing
>> pixels where it should be black, like in and between characters. Once
>> booted in to the kernel this disappears, and I get a nice console with
>> simplefb. Kind of weird.
>
>
> Weird indeed, could it be that the DAC-s need some power-supply setup which
> u-boot does not set up, but your axp221 kernel code does setup ?

There's just the regulator that's enabled in u-boot. And I'm not running an
AXP221 enabled kernel either. Hence the weirdness. :|


Regards
ChenYu

[U-Boot] [PATCH 0/3] sunxi: Enable VGA output on Hummingbird A31

[Hans de Goede]

Hi,

On 12-01-15 11:02, Chen-Yu Tsai wrote:
> Hi Hans, Ian,
>
> This series enables the VGA output on the Hummingbird A31. The VGA output
> is driven from LCD0, through an external DAC that's powered up by toggling
> pin PH25.
>
> Patch 1 allows selecting CONFIG_VIDEO_VGA_VIA_LCD on sun6i and sun8i.
> These 2 platforms do not have builtin TV encoders, and some vendor may
> use an external DAC to support VGA.
>
> Patch 2 adds support for toggling a GPIO pin as part of the video init
> sequence to power up the DAC
>
> Patch 3 updates the Hummingbird A31 defconfig to enable VGA output.
>
> I have one question about the VGA_VIA_LCD code in general. The color depth
> is forced to 18. Is this necessary? Can we make it configurable? I haven't
> tried displaying pictures so I don't know if it makes a visible difference.
>
> Also with the VGA output on my Hummingbird A31, I get greenish flashing
> pixels where it should be black, like in and between characters. Once
> booted in to the kernel this disappears, and I get a nice console with
> simplefb. Kind of weird.
>
>
> Cheers
> ChenYu

Thanks, applied to u-boot-sunxi/next (with the discussed fix), while at
it I've also fixed the whitespace errors you pointed out in
<CAGb2v65Y26fTjcoOcWUZLG0+BR+UrWJ4HCL5d1V7ovn6TA6WTw@mail.gmail.com>

Regards,

Hans

>
>
> Chen-Yu Tsai (3):
>    sunxi: video: Allow external DACs for VGA on platforms without TV
>      encoders
>    sunxi: video: Add support for external DAC enable pin
>    sunxi: Hummingbird_A31_defconfig: Enable VGA output through external
>      DAC
>
>   board/sunxi/Kconfig               | 10 +++++++++-
>   configs/Hummingbird_A31_defconfig |  2 ++
>   drivers/video/sunxi_display.c     | 18 ++++++++++++++++++
>   3 files changed, 29 insertions(+), 1 deletion(-)
>