[U-Boot] [PATCH 0/3] sunxi: Enable VGA output on Hummingbird A31
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(-)
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
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; }
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();
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_LCDdefault ""---help---Set the enable pin for the external VGA DAC. This takes a stringin the
format understood by sunxi_name_to_gpio, e.g. PH1 for pin 1 ofport 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();
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
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
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
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(-)
participants (2)
-
Chen-Yu Tsai -
Hans de Goede