On Thu, 1 Jan 2015 14:37:47 +0100
Michal Suchanek <[email protected]> wrote:

> Hello
> 
> On 30 December 2014 at 11:18, Siarhei Siamashka
> <[email protected]> wrote:
> > On Thu, 25 Dec 2014 11:59:55 +0100
> > Hans de Goede <[email protected]> wrote:
> >
> >> Hi,
> >>
> >> On 25-12-14 11:00, Chen-Yu Tsai wrote:
> >> > Hi,
> >> >
> >> > On Thu, Dec 25, 2014 at 3:06 AM, Hans de Goede <[email protected]> 
> >> > wrote:
> >> >> Enable the new LCD support on Ippo_q8h tablets.
> >> >>
> >> >> Signed-off-by: Hans de Goede <[email protected]>
> >> >> ---
> >> >>   configs/Ippo_q8h_v1_2_defconfig | 5 ++++-
> >> >>   configs/Ippo_q8h_v5_defconfig   | 5 ++++-
> >> >>   2 files changed, 8 insertions(+), 2 deletions(-)
> >> >>
> >> >> diff --git a/configs/Ippo_q8h_v1_2_defconfig 
> >> >> b/configs/Ippo_q8h_v1_2_defconfig
> >> >> index fefed32..c773f5f 100644
> >> >> --- a/configs/Ippo_q8h_v1_2_defconfig
> >> >> +++ b/configs/Ippo_q8h_v1_2_defconfig
> >> >> @@ -1,7 +1,10 @@
> >> >>   CONFIG_SPL=y
> >> >>   CONFIG_SYS_EXTRA_OPTIONS="CONS_INDEX=5"
> >> >>   CONFIG_FDTFILE="sun8i-a23-ippo-q8h-v1.2.dtb"
> >> >> -CONFIG_VIDEO=n
> >> >> +CONFIG_VIDEO_LCD_MODE="x:800,y:480,depth:18,pclk_khz:33000,le:16,ri:209,up:22,lo:22,hs:30,vs:1,sync:0,vmode:0"
> >> >> +CONFIG_VIDEO_LCD_POWER="PH7"
> >> >> +CONFIG_VIDEO_LCD_BL_EN="PH6"
> >> >> +CONFIG_VIDEO_LCD_BL_PWM="PH0"
> >> >>   CONFIG_USB_KEYBOARD=n
> >> >>   +S:CONFIG_ARM=y
> >> >>   +S:CONFIG_ARCH_SUNXI=y
> >> >> diff --git a/configs/Ippo_q8h_v5_defconfig 
> >> >> b/configs/Ippo_q8h_v5_defconfig
> >> >> index b8d3afe..ce4f0b8 100644
> >> >> --- a/configs/Ippo_q8h_v5_defconfig
> >> >> +++ b/configs/Ippo_q8h_v5_defconfig
> >> >> @@ -1,7 +1,10 @@
> >> >>   CONFIG_SPL=y
> >> >>   CONFIG_SYS_EXTRA_OPTIONS="CONS_INDEX=5"
> >> >>   CONFIG_FDTFILE="sun8i-a23-ippo-q8h-v5.dtb"
> >> >> -CONFIG_VIDEO=n
> >> >> +CONFIG_VIDEO_LCD_MODE="x:800,y:480,depth:18,pclk_khz:33000,le:16,ri:209,up:22,lo:22,hs:30,vs:1,sync:0,vmode:0"
> >> >
> >> > The display on my Q8H is a bit off to the left. With the simplefb
> >> > bindings from your kernel sunxi-wip branch, I get a nice console.
> >> > Though I've no way to type, at least I can tell my tablet is on. :)
> >> >
> >> > Could you briefly explain how to convert the values in the fex
> >> > file to the mode line here? It could also help others with
> >> > enabling display on their tablets.
> >>
> >> Ah yes, I used the slightly different timings from the olimex 7" lcd
> >> panel for olinuxino boards, and since those worked fine on my a23
> >> tablet I never adjusted things. Here is a translation table:
> >>
> >>
> >> CONFIG_VIDEO_LCD_MODE         fex value(s)
> >>
> >> x                             lcd_x
> >> y                             lcd_y
> >> depth:18                      lcd_frm = 1
> >> pclk_khz                      lcd_dclk_freq * 1000
> >> hs                            lcd_hv_hspw (with a minimum of 1)
> >> vs                            lcd_hv_vspw (with a minimum of 1)
> >> le                            lcd_hbp - hs
> >> ri                            lcd_ht - lcd_x - lcd_hbp
> >> up                            lcd_vbp - vs
> >>
> >> On sun4i/sun5i/sun7i:
> >> lo                            (lcd_vt / 2) - lcd_y - lcd_vbp
> >> On sun8i:
> >> lo                            lcd_vt - lcd_y - lcd_vbp
> >>
> >> sync                          0
> >> mode                          0
> >>
> >> I notice that the Ippo_q8h_v5 fex uses 0 for lcd_hv_hspw and lcd_hv_vspw, 
> >> which
> >> is not a valid value as the register value contains hspw - 1, so the 
> >> minimum is 1,
> >> and looking at a register dump under android with my A23 tablet the value 
> >> indeed
> >> should be 1.
> >
> > That's interesting. What would be the correct general formula for the
> > hs/vs values then? "max(lcd_hv_hspw, 1)" or maybe "lcd_hv_hspw + 1"?
> >
> > BTW, I have done a preliminary automatic conversion for all FEX
> > files from sunxi-boards, which enable lcd0 in fex. The results are
> > now available at the all the same http://linux-sunxi.org/LCD wiki page.
> > If "hs = lcd_hv_hspw + 1" is a better choice, then the whole table
> > probably needs to be re-generated.
> >
> > Also additional explanations about GPIO related options (what would be
> > the exact rules to interpret FEX?) and more details about "lcd_frm" and
> > "lcd_if" would help a lot to get a better understanding about what
> > still needs to be done to get LCD displays supported on all devices.
> >
> > If I understand it correctly, the kernel sources from the Allwinner SDK
> > contain the relevant code for handling the information from FEX, and
> > this code is the best reference. And it's more reliable to refer to
> > A23 SDK for interpreting the FEX files originally snatched from A23
> > devices, and likewise A31 SDK for A31 devices. For example, it is not
> > uncommon to see both 'lcd_pwm_used' and 'lcd_pwm_not_used' variables
> > defined in FEX. And sometimes the values of these variables even
> > contradict each other. So the fine details about the relative
> > priorities of these variables and other similar things might need
> > to be discovered for perfectly correct conversion.
> 
> FWIW this is fex file for q8h v1.0.

It's an A23 tablet, right? Could you please submit it as a patch for
sunxi-boards?
 
> I had some problem getting anything to boot on it since v1.0 does not
> seem to have an uart so this device is completely unsupported so far
> and the fex file is not posted anywhere.

Do you happen to have a MicroSD breakout board? It can be bought for
something like ~5 EUR at these places:
    http://store.r0ck.me/products/usd-breakout-board   
    http://www.exp-tech.de/sd-breakout-board

If you have it, then you can already get serial console. The whole
setup looks like this:
    http://linux-sunxi.org/File:MSI_Primo81_and_MicroSD_breakout.jpg

If you are interested, then I can provide instructions about how to
build u-boot with the serial console output through MicroSD breakout,
the kernel, and buildroot based initramfs for testing WLAN. All of
this is booted in FEL mode. Serial console is useful, because you
can see error messages (for example, a forgotten WLAN firmware blob
or any other problems) and interact with the system to debug them.
Finally, after WLAN is working properly, it is possible to boot from
the SD card and make the tablet connect to a WLAN access point
automatically. So that you can ssh login to it.

-- 
Best regards,
Siarhei Siamashka

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