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Ixora V1.0A and V1.1A HDMI DDC issues with Apalis TK1 V1.0A/B and V1.1A Workaround Patches

 
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This article describes in greater details the patches required to work around the Ixora V1.0A and V1.1A HDMI DDC issues with Apalis TK1 V1.0A/B and V1.1A hardware revisions.

The HDMI DDC/EDID aka SCL/SDA pins need to be connected to the proper TK1 SoC DDC/EDID I2C bus.

As follows a summary of the HDMI DDC/EDID signal side:

Nexperia IP4791CZ12 Pin Nexperia IP4791CZ12 Function Ixora Resistor Array Ixora V1.1A X19 Pin Ixora V1.1A X19 Function
2 SCL_IN RA11A 36 LVDS SDA
3 SDA_IN RA11B 38 LVDS SCL

As follows a summary of the TK1 SoC DDC/EDID side:

Apalis X1 Pin Apalis Function TK1 SoC Ball Apalis V1.0/V1.1 Ixora Resistor Array Ixora V1.0/V1.1
5 GPIO3 DDC_SCL RA1B X27-15
7 GPIO4 DDC_SDA RA1A X27-16

For reference the TK1 SoC ball to GPIO name as well as number assignment of above-mentioned pins:

TK1 SoC Ball TK1 SoC GPIO GPIO Number
DDC_SCL GPIO3_PV.04 172
DDC_SDA GPIO3_PV.05 173

Patches for Apalis TK1 V1.0A, V1.0B and V1.1A Modules

Make sure DDC/EDID pin muxing is proper (default since BSP 2.8b2):

http://git.toradex.com/cgit/linux-toradex.git/diff/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-pinmux.dtsi?h=toradex_tk1_l4t_r21.6&id=722035cfcd7e238000eafa5803e26072433371c8
diff --git a/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-pinmux.dtsi b/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-pinmux.dtsi index 8d4ff4e..5c9ba71 100644 --- a/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-pinmux.dtsi +++ b/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-pinmux.dtsi @@ -119,14 +119,14 @@ /* Apalis GPIO */ ddc_scl_pv4 { nvidia,pins = "ddc_scl_pv4"; - nvidia,function = "rsvd2"; + nvidia,function = "i2c4"; nvidia,pull = <TEGRA_PIN_PULL_NONE>; nvidia,tristate = <TEGRA_PIN_DISABLE>; nvidia,enable-input = <TEGRA_PIN_ENABLE>; }; ddc_sda_pv5 { nvidia,pins = "ddc_sda_pv5"; - nvidia,function = "rsvd2"; + nvidia,function = "i2c4"; nvidia,pull = <TEGRA_PIN_PULL_NONE>; nvidia,tristate = <TEGRA_PIN_DISABLE>; nvidia,enable-input = <TEGRA_PIN_ENABLE>;

Make sure GPIOs are not conflicting:

diff --git a/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-gpio.dtsi b/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-gpio.dtsi index 100e344..f0882c5 100644 --- a/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-gpio.dtsi +++ b/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-gpio.dtsi @@ -17,9 +17,11 @@ TEGRA_GPIO(K, 7) TEGRA_GPIO(N, 7) TEGRA_GPIO(O, 5) + TEGRA_GPIO(T, 5) + TEGRA_GPIO(T, 6) TEGRA_GPIO(V, 3) - TEGRA_GPIO(V, 4) - TEGRA_GPIO(V, 5) + /* TEGRA_GPIO(V, 4) */ + /* TEGRA_GPIO(V, 5) */ TEGRA_GPIO(W, 3) TEGRA_GPIO(W, 5) TEGRA_GPIO(BB, 0)

Make sure DDC/EDID aka I2C3 enables rcv-sel (default in upcoming BSP 2.8b3):

http://git.toradex.com/cgit/linux-toradex.git/commit/?h=toradex_tk1_l4t_r21.6-next&id=4193bdbf4e88ef304304a011271bdd14b45dea35
diff --git a/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-pinmux.dtsi b/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-pinmux.dtsi index 52e35ca..8cf7cdc 100644 --- a/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-pinmux.dtsi +++ b/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-pinmux.dtsi @@ -123,6 +123,7 @@ nvidia,pull = <TEGRA_PIN_PULL_NONE>; nvidia,tristate = <TEGRA_PIN_DISABLE>; nvidia,enable-input = <TEGRA_PIN_ENABLE>; + nvidia,rcv-sel = <TEGRA_PIN_ENABLE>; }; ddc_sda_pv5 { nvidia,pins = "ddc_sda_pv5"; @@ -130,6 +131,7 @@ nvidia,pull = <TEGRA_PIN_PULL_NONE>; nvidia,tristate = <TEGRA_PIN_DISABLE>; nvidia,enable-input = <TEGRA_PIN_ENABLE>; + nvidia,rcv-sel = <TEGRA_PIN_ENABLE>; }; pex_l0_rst_n_pdd1 { nvidia,pins = "pex_l0_rst_n_pdd1";

Make sure proper I2C bus is used for DDC/EDID

Before 2.8b1:

diff --git a/arch/arm/mach-tegra/board-apalis-tk1-panel.c b/arch/arm/mach-tegra/board-apalis-tk1- panel.c index 9ee23e7..fda57d1 100644 --- a/arch/arm/mach-tegra/board-apalis-tk1-panel.c +++ b/arch/arm/mach-tegra/board-apalis-tk1-panel.c @@ -378,7 +378,7 @@ static struct tegra_dc_out apalis_tk1_disp2_out = { .parent_clk = "pll_d", #endif /* CONFIG_TEGRA_HDMI_PRIMARY */ - .ddc_bus = 1, + .ddc_bus = 3, .hotplug_gpio = apalis_tk1_hdmi_hpd, .hdmi_out = &apalis_tk1_hdmi_out,

starting with 2.8b1:

--- a/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-displays.dtsi +++ b/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-displays.dtsi @@ -209,7 +209,7 @@ }; }; - hdmi_ddc: i2c@7000c400 { + hdmi_ddc: i2c@7000c700 { clock-frequency = <10000>; };