[Buildroot] Fwd: Fwd: Fwd: [PATCH v3] linux: add fbtft kernel extension

Sun Jan 11 14:04:27 UTC 2015

Hello Lou,

On Sat, Jan 10, 2015 at 08:00:15PM -0600, Lou Crittenden wrote:
> Thanks for this info. I have some questions to ask:
> 
> I saw that you have updated your patch. What did you do to it?
>

The downloaded patch via the described command:

 $ wget -O v3-linux-add-fbtft-kernel-extension.patch https://patchwork.ozlabs.org/patch/425126/mbox/

was already my latest patch (Thomas did some changes on the committed patch, but
introduced a bug, see [1][2]), but the downloaded one is good ;-).

> Did you have to manually create the /etc/modules-load.d and /etc/modprobe.d
> folders and the text files you named in your setup? Mine didn't have those.
> I manually made the directories and text files as laid out but the device
> still didn't work.

Yes you have to create this two files with the described content (thats why I
wrote 'add', otherwiese it would be 'change' ;-) ).

But I do this advice 'blindly' because I own a different display device...

> 
> How did you build the fbtft drivers in your menuconfig: as add-on modules
> (with the option asterisked) or built-in (with the option checkmarked)?
>

I did enable the 'linux-menuconfig' SPI configs with 'y'/'*' (built in)
and the FB_TFT ones with 'm'/'M' (modules)...

Please do the following:
$ cd  build_rpi_001
$ grep -E "^CONFIG_SPI|^CONFIG_GPIO|^CONFIG_FB" build/linux-c256eb9968c8997dce47350d2075e42f1b3991d3/.config

Output should be like the following:
CONFIG_SPI=y
CONFIG_SPI_MASTER=y
CONFIG_SPI_BCM2708=y
CONFIG_GPIO_DEVRES=y
CONFIG_GPIOLIB=y
CONFIG_FB=y
CONFIG_FB_CFB_FILLRECT=y
CONFIG_FB_CFB_COPYAREA=y
CONFIG_FB_CFB_IMAGEBLIT=y
CONFIG_FB_SYS_FILLRECT=y
CONFIG_FB_SYS_COPYAREA=y
CONFIG_FB_SYS_IMAGEBLIT=y
CONFIG_FB_SYS_FOPS=y
CONFIG_FB_DEFERRED_IO=y
CONFIG_FB_BACKLIGHT=y
CONFIG_FB_BCM2708=y
CONFIG_FB_TFT=y
CONFIG_FB_TFT_ILI9340=m
CONFIG_FB_TFT_FBTFT_DEVICE=m

Please send your output...

> I couldn't find a "waveshare32b" model in any driver list, so I'm using the
> "flexfb" module that my factory image uses. Still no go.

There is now waveshare32b module, only the fbtft_device module (a helper module for
the various displays). If you load btft_device by hand,e.g.:

$ insmod fbtft_device name=waveshare32b

you give your display type via the module parameter 'name=waveshare32b'

> 
> What I've done thus far:
> I used lsmod on the flexfb.ko, and while the command goes through fine
> without error, but nothing happens with the display (what am I missing
> parameters wise?). I then ran dd if=/dev/urandom of=/dev/fb1. Nothing.

flexfb is the 'old' universal module, you have to give a lot of parameters
for your device, the way via fbtft_device is a shortcut/helper for this
(and added recently to fbtft for your device [3]), see file
build/linux-c256eb9968c8997dce47350d2075e42f1b3991d3/drivers/video/fbtft/fbtft_device.c:

1012         }, {
1013                 .name = "waveshare32b",
1014                 .spi = &(struct spi_board_info) {
1015                         .modalias = "fb_ili9340",
1016                         .max_speed_hz = 48000000,
1017                         .mode = SPI_MODE_0,
1018                         .platform_data = &(struct fbtft_platform_data) {
1019                                 .display = {
1020                                         .buswidth = 8,
1021                                         .backlight = 1,
1022                                         .init_sequence = waveshare32b_init_sequence,
1023                                 },
1024                                 .bgr = true,
1025                                 .gpios = (const struct fbtft_gpio []) {
1026                                         { "reset", 27 },
1027                                         { "dc", 22 },
1028                                         {},
1029                                 },
1030                         }
1031                 }
1032         }, {

> 
> I ran insmod /lib/modules/3.12.28/kernel/drivers/video/fbtft/ili9340.ko. It
> complains "cannot load module: no such file or directory" even if I use an
> absolute path where "ili9340.ko" is located.
> 

The module should be named 'fb_ili9340.ko'

> 
> I have my buildroot .config file in the attachments if you wish to take a
> look at my setup to compare and maybe edit/reupload.
>

The buildroot .config is o.k., both options are enabled:
BR2_LINUX_KERNEL_EXT_FBTFT=y
BR2_PACKAGE_FBTFT=y

One more try for remote debugging, please send the output of the
following commands from your buildroot build directory:

$ cd build_rpi_001
$ grep -E "^CONFIG_SPI|^CONFIG_GPIO|^CONFIG_FB" build/linux-c256eb9968c8997dce47350d2075e42f1b3991d3/.config
$ find target/lib/modules

And the output from the following commands from your Raspberry Pi device:

$ lsmod
$ cat /proc/cmdline
$ cat /etc/modules-load.d/fbtft.conf
$ cat /etc/modprobe.d/00-fbtft.conf
$ find /lib/modules
$ insmod fbtft_device name=waveshare32b
$ dmesg
$ ls -l /dev/fb*

Regards,
Peter

[1] http://lists.busybox.net/pipermail/buildroot/2015-January/117057.html
[2] http://lists.busybox.net/pipermail/buildroot/2015-January/117062.html
[3] https://github.com/notro/fbtft/commit/e67014490a9df34b9a4bf04e49c50254aebc10a8

> ---------- Forwarded message ----------
> From: Peter Seiderer <ps.report at gmx.net>
> Date: Wed, Jan 7, 2015 at 8:12 AM
> Subject: Aw: Fwd: Fwd: [Buildroot] [PATCH v3] linux: add fbtft kernel
> extension
> To: Lou Crittenden <loucrittenden63 at gmail.com>
> Cc: buildroot at busybox.net
> 
> 
> Hello Lou,
> 
> > Gesendet: Mittwoch, 07. Januar 2015 um 14:06 Uhr
> > Von: "Lou Crittenden" <loucrittenden63 at gmail.com>
> > An: buildroot at busybox.net, "Peter Seiderer" <ps.report at gmx.net>
> > Betreff: Fwd: Fwd: [Buildroot] [PATCH v3] linux: add fbtft kernel
> extension
> >
> > Alright, I have the buildroot built and a resultant bootable system, but
> the screen doesn't initialize. Did you have to
> > create an /etc/modules file and the corresponding /etc/init.d script to
> load the modules/drivers at boot or something?
> >
> 
> Sorry, forgot to mention this part in my 'instruction' e-mail (but a
> description was already included in [1]).
> 
> For your case the following configuration changes should be needed:
> 
> On the sd-card boot partition:
> - cmdline.txt: add 'fbcon=map:10 fbcon=font:VGA8x8'
> 
> On the sd-card root partition:
> - add /etc/modules-load.d/fbtft.conf with 'fbtft_device'
> - add /etc/modprobe.d/00-fbtft.conf with 'options fbtft_device
> name=waveshare32b'
> 
> If this works for you its fine, if not try to load the fbtft_device module
> via
> insmod and play with the module parameters....and take a look at the
> dmesg commnd output....on success a second frame buffer device /dev/fb1
> should
> be available (/dev/fb0 is the hdmi output)...
> 
> $ dd if=/dev/urandom of=/dev/fb1
> 
> should fill your waveshare device with random snow...
> 
> Or take a look at [2] and [3], seems similare displays...
> 
> Regards,
> Peter
> 
> 
> [1] http://lists.busybox.net/pipermail/buildroot/2014-December/116096.html
> [2] https://github.com/notro/rpi-firmware/issues/6
> [3]https://github.com/notro/fbtft/issues/215
> 
> >
> > ---------- Forwarded message ----------
> > From: Lou Crittenden <loucrittenden63 at gmail.com>
> > Date: Mon, Jan 5, 2015 at 5:03 PM
> > Subject: Re: Fwd: [Buildroot] [PATCH v3] linux: add fbtft kernel extension
> > To: Peter Seiderer <ps.report at gmx.net[ps.report at gmx.net]>,
> buildroot at busybox.net[buildroot at busybox.net]
> >
> >
> > Yes, I'm using a waveshare32b. I bought it from here:
> http://www.ebay.com/itm/331320440420[http://www.ebay.com/itm/331320440420]
> >
> > I didn't know this was an ili9340 device. I've tried looking up the
> controller type, but it's been difficult, as they are a
> > little sketchy. I was able to enable this screen in raspbmc through the
> use of the "flexfb" driver, as the factory raspbian
> > image also uses this driver. The touchscreen controller is an ads7846.