[How-to] BB-View on latest Debian

Perfect timing, I was just about to start looking for what pieces I need to extract in order to get the 4.3" BB-View working on a vanilla 3.13 kernel. Looks like you've identified the interesting pieces for me

When you say the touch screen is different from the standard TI 4 wire interface, how did you work that out ?  Did you find schematics for the BB-View anywhere ?

From the Angstrom source download, a diff between BB-BONE-LCD4-01-00A1.dts & BB-VIEW-LCD4-01-00A0.dts is interesting, there's a couple of differences in the pins used for LEDs & keys along with differences in numbers of leds & keys.

Other than that, there's one extra pin used for "LCD DISEN" in BB-BONE-LCD4-01-00A1.dts and for the BB-VIEW there's this

ti,touch-type = <1>;

in the LCD7 ones the BB-VIEW has that as 2

Not exactly sure what that does just yet, but it's obviously some hint to the driver to configure something a certain way. Otherwise the driver and pins used appear to be identical.  Perhaps it's a place to start looking for the problem though.

If you do a diff between the ti_am335x_tsc.c files, you will see the changes. It appears to use bits 9 and 10 (STEPCONFIG_XNP and YPN) for sequencing, instead of the usual bits 7 and 8.

Modifications to Debian original ti_am335x_tsc.c:

I added the two new bit definitions to the config_pins array assignment on line 38. I then changed line 98 from switch(wi_order) to switch(i), so that it would assume XP, XN, YP, and YN from array position in the dts file. The fun part is trying to figure out which combination of dts "ti,wire-config" values and changes to lines 180 and 187 will result in a working touchscreen.

I think I focused too much on just the changed lines and not the relationship between the lines that didn't change, especially between lines 178 to 198. I will look into that today.

Louis

Well, the recompile seems unavoidable due to the way the charge bits are used. I have made changes to the stock touchscreen drivers, to add a hook for the BB-View, but also to keep compatibility with other displays. I will see if I can get someone to include them in the next kernel patch.

For some reason, the xinput_calibrator is not working properly with the values being returned by the tsc. Manually modify your /etc/pointercal.xinput file, on the bbb, to the following, to get it close:

xinput set-int-prop "ti-tsc" "Evdev Axis Calibration" 32 3953 130 366 3832; xinput set-int-prop "ti-tsc" "Evdev Axes Swap" 8 1;

If you want to test out the kernel modules on your own, here are the diffs:

diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c

index ed83043..69bc5d9 100644

--- a/drivers/input/touchscreen/ti_am335x_tsc.c

+++ b/drivers/input/touchscreen/ti_am335x_tsc.c

@@ -50,6 +50,7 @@ struct titsc {

  unsigned int x_plate_resistance;

  bool pen_down;

  int coordinate_readouts;

+ int charge_mode;

  u32 config_inp[4];

  u32 bit_xp, bit_xn, bit_yp, bit_yn;

  u32 inp_xp, inp_xn, inp_yp, inp_yn;

@@ -176,16 +177,23 @@ static void titsc_step_config(struct titsc *ts_dev)

  /* Charge step configuration */

  config = ts_dev->bit_xp | ts_dev->bit_yn |

  STEPCHARGE_RFP_XPUL | STEPCHARGE_RFM_XNUR |

- STEPCHARGE_INM_AN1 | STEPCHARGE_INP(ts_dev->inp_yp);

+ STEPCHARGE_INM_AN1;

+

+ if (ts_dev->charge_mode == 1)

+ config |= STEPCHARGE_INP(ts_dev->inp_xn);

+ else

+ config |= STEPCHARGE_INP(ts_dev->inp_yp);

 

  titsc_writel(ts_dev, REG_CHARGECONFIG, config);

  titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY);

 

  /* coordinate_readouts * 2 … coordinate_readouts * 2 + 2 is for Z */

- config = STEPCONFIG_MODE_HWSYNC |

- STEPCONFIG_AVG_16 | ts_dev->bit_yp |

- ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |

- STEPCONFIG_INP(ts_dev->inp_xp);

+ config = STEPCONFIG_MODE_HWSYNC | STEPCONFIG_AVG_16 |

+ STEPCONFIG_INM_ADCREFM | STEPCONFIG_INP(ts_dev->inp_xp);

+ if (ts_dev->charge_mode == 1)

+ config |= STEPCONFIG_YPN | STEPCONFIG_XNP;

+ else

+ config |= ts_dev->bit_yp | ts_dev->bit_xn;

  titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);

  titsc_writel(ts_dev, REG_STEPDELAY(end_step),

  STEPCONFIG_OPENDLY);

@@ -372,6 +380,11 @@ static int titsc_parse_dt(struct ti_tscadc_dev *tscadc_dev,

  if (err < 0)

  return err;

 

+ err = of_property_read_u32(node, "ti,charge-mode",

+ &ts_dev->charge_mode);

+ if (err < 0)

+ ts_dev->charge_mode = 0;

+

  return of_property_read_u32_array(node, "ti,wire-config",

  ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));

}

@@ -389,6 +402,7 @@ static int titsc_parse_pdata(struct ti_tscadc_dev *tscadc_dev,

  pdata->tsc_init->x_plate_resistance;

  ts_dev->coordinate_readouts =

  pdata->tsc_init->coordinate_readouts;

+ ts_dev->charge_mode = pdata->tsc_init->charge_mode;

  memcpy(ts_dev->config_inp, pdata->tsc_init->wire_config,

  sizeof(pdata->tsc_init->wire_config));

  return 0;

diff --git a/firmware/Makefile b/firmware/Makefile

index e45d10b..f18b95a 100644

--- a/firmware/Makefile

+++ b/firmware/Makefile

@@ -189,6 +189,7 @@ fw-shipped-$(CONFIG_CAPE_BEAGLEBONE) += \

  BB-BONE-RST-00A0.dtbo \

  BB-BONE-RST2-00A0.dtbo \

  BB-BONE-CAM3-01-00A2.dtbo \

+ BB-VIEW-LCD7-01-00A0.dtbo \

  BB-BONE-CAM-VVDN-00A0.dtbo \

  TT3201-001-01.dtbo \

  BB-BONE-SERL-03-00A1.dtbo \

diff --git a/include/linux/input/ti_am335x_tsc.h b/include/linux/input/ti_am335x_tsc.h

index c0bf08b..278125a 100644

--- a/include/linux/input/ti_am335x_tsc.h

+++ b/include/linux/input/ti_am335x_tsc.h

@@ -30,6 +30,7 @@ struct tsc_data {

  int x_plate_resistance;

  int coordinate_readouts;

  int wire_config[10];

+ int charge_mode;

};

 

#endif

diff --git a/firmware/capes/BB-VIEW-LCD7-01-00A0.dts b/firmware/capes/BB-VIEW-LCD7-01-00A0.dts

index f506a15..9370327 100755

--- a/firmware/capes/BB-VIEW-LCD7-01-00A0.dts

+++ b/firmware/capes/BB-VIEW-LCD7-01-00A0.dts

@@ -158,7 +158,7 @@

  ti,wires = <4>;

  ti,x-plate-resistance = <200>;

  ti,coordinate-readouts = <5>;

- ti,touch-type = <2>;

+ ti,charge-mode = <1>;

  ti,wire-config = <0x00 0x11 0x22 0x33>;

  };

Haven't got as far as looking at the touch screen parts yet...

Question for you though.. if you set the brightness to something like 50 do you get an audible high pitched whine from the display ?  I have an LCD4, just wondering if your LCD7 does the same..

Yes, I have heard it with the CircuitCo 7 inch screens, and a quick test with the BB-View 7 proves it does it too.

I modified the BB-View dts file, line 141, to read:

pwms = <&ehrpwm1 0 32768 0>;

and the noise is gone.....

After what seems like way too long fighting with devicetree... It's alive !

ts_calibrate is of course giving me a pile of crap, so your patches to the touchscreen driver are next on the list.

I should also say here that I'm not using the beaglebone kernels, I'm using mainline.. Gave up with the mess that's going into the beagle kernels a while ago.

The TI folks doing the mainline devicetree development for am3359 (and omap in general) and the beagleboard folks are heading off in two totally different directions, the differences are significant at this point.

Very good. Just curious if you boot up in the proper color mode, or if you wait until X starts up like I do?

I don't have X installed, the tux logo has correct colours and that's just a jpg displayed with http://repo.or.cz/w/fbv.git

I'd like to say I did something interesting to make it so, but I've not knowingly done so.

The dt definition fro the panel is this:

/* Embest 4.3 inch LCD cape: */

panel {

        compatible = "ti,tilcdc,panel";

        pinctrl-names = "default";

        pinctrl-0 = <&bb_view_lcd_cape_pins>;

        status="okay";

        panel-info {

                ac-bias         = <255>;

                ac-bias-intrpt  = <0>; 

                dma-burst-sz    = <16>;

                bpp             = <32>;

                fdd             = <0x80>;

                tft-alt-mode    = <0>;  

                stn-565-mode    = <0>;  

                mono-8bit-mode  = <0>;  

                sync-edge       = <0>;  

                sync-ctrl       = <1>;  

                raster-order    = <0>;  

                fifo-th         = <0>;  

        };

        display-timings {

                native-mode = <&timing0>;

                timing0: 480x272 {

                        hactive         = <480>;

                        vactive         = <272>;

                        hback-porch     = <44>;

                        hfront-porch    = <9>; 

                        hsync-len       = <5>; 

                        vback-porch     = <13>;

                        vfront-porch    = <4>; 

                        vsync-len       = <10>;

                        clock-frequency = <9000000>;

                        hsync-active    = <0>;

                        vsync-active    = <0>;

                };

        };

};

don't think I changed anything in that part from what was in the angstrom definition.