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Subject[PATCH 1/3] apalis_t30/tk1, colibri_t20/t30: fix i2c bus frequencies
Date
From: Marcel Ziswiler <marcel.ziswiler@toradex.com>

Use a faster speed of 400 kbit/s for regular I2C busses.

Use a slower speed of 10 kbit/s for DDC/EDID to improve reliability.

Use a slower speed of 100 kbit/s for power I2C to be within specs of
the LM95245 temperature sensor.

While at it further annotate I2C pin usage.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>

---

arch/arm/boot/dts/tegra124-apalis-eval.dts | 5 ++---
arch/arm/boot/dts/tegra124-apalis.dtsi | 2 +-
arch/arm/boot/dts/tegra20-colibri-512.dtsi | 16 +++++++++++-----
arch/arm/boot/dts/tegra30-apalis-eval.dts | 2 +-
arch/arm/boot/dts/tegra30-apalis.dtsi | 2 +-
arch/arm/boot/dts/tegra30-colibri-eval-v3.dts | 2 +-
arch/arm/boot/dts/tegra30-colibri.dtsi | 2 +-
7 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/arch/arm/boot/dts/tegra124-apalis-eval.dts b/arch/arm/boot/dts/tegra124-apalis-eval.dts
index ecffcd115fa7..66b6c45ee865 100644
--- a/arch/arm/boot/dts/tegra124-apalis-eval.dts
+++ b/arch/arm/boot/dts/tegra124-apalis-eval.dts
@@ -105,7 +105,7 @@
*/
i2c@7000c000 {
status = "okay";
- clock-frequency = <100000>;
+ clock-frequency = <400000>;

pcie-switch@58 {
compatible = "plx,pex8605";
@@ -124,7 +124,6 @@
*/
hdmi_ddc: i2c@7000c400 {
status = "okay";
- clock-frequency = <100000>;
};

/*
@@ -133,7 +132,7 @@
*/
i2c@7000c500 {
status = "okay";
- clock-frequency = <100000>;
+ clock-frequency = <400000>;
};

/* I2C4 (DDC): unused */
diff --git a/arch/arm/boot/dts/tegra124-apalis.dtsi b/arch/arm/boot/dts/tegra124-apalis.dtsi
index 5d9b18ef5af6..7aef8928e115 100644
--- a/arch/arm/boot/dts/tegra124-apalis.dtsi
+++ b/arch/arm/boot/dts/tegra124-apalis.dtsi
@@ -1579,7 +1579,7 @@
};

hdmi_ddc: i2c@7000c400 {
- clock-frequency = <100000>;
+ clock-frequency = <10000>;
};

/* PWR_I2C: power I2C to audio codec, PMIC and temperature sensor */
diff --git a/arch/arm/boot/dts/tegra20-colibri-512.dtsi b/arch/arm/boot/dts/tegra20-colibri-512.dtsi
index 813ae34edd6a..5c202b3e3bb1 100644
--- a/arch/arm/boot/dts/tegra20-colibri-512.dtsi
+++ b/arch/arm/boot/dts/tegra20-colibri-512.dtsi
@@ -213,21 +213,27 @@
GPIO_ACTIVE_HIGH>;
};

+ /*
+ * GEN1_I2C: I2C_SDA/SCL on SODIMM pin 194/196 (e.g. RTC on carrier
+ * board)
+ */
i2c@7000c000 {
clock-frequency = <400000>;
};

+ /* DDC_SCL/SDA on X3 pin 15/16 (e.g. display EDID) */
i2c_ddc: i2c@7000c400 {
- clock-frequency = <100000>;
+ clock-frequency = <10000>;
};

- i2c@7000c500 {
- clock-frequency = <400000>;
- };
+ /* GEN2_I2C: unused */

+ /* CAM/GEN3_I2C: used as EXT_IO1/2 GPIOs on SODIMM pin 133/127 */
+
+ /* PWR_I2C: power I2C to PMIC and temperature sensor (On-module) */
i2c@7000d000 {
status = "okay";
- clock-frequency = <400000>;
+ clock-frequency = <100000>;

pmic: tps6586x@34 {
compatible = "ti,tps6586x";
diff --git a/arch/arm/boot/dts/tegra30-apalis-eval.dts b/arch/arm/boot/dts/tegra30-apalis-eval.dts
index 07b945b0391a..fdca527a2248 100644
--- a/arch/arm/boot/dts/tegra30-apalis-eval.dts
+++ b/arch/arm/boot/dts/tegra30-apalis-eval.dts
@@ -79,7 +79,7 @@
*/
i2c@7000c000 {
status = "okay";
- clock-frequency = <100000>;
+ clock-frequency = <400000>;

pcie-switch@58 {
compatible = "plx,pex8605";
diff --git a/arch/arm/boot/dts/tegra30-apalis.dtsi b/arch/arm/boot/dts/tegra30-apalis.dtsi
index bfb7913c0657..676a4c4b1512 100644
--- a/arch/arm/boot/dts/tegra30-apalis.dtsi
+++ b/arch/arm/boot/dts/tegra30-apalis.dtsi
@@ -437,7 +437,7 @@
};

hdmiddc: i2c@7000c700 {
- clock-frequency = <100000>;
+ clock-frequency = <10000>;
};

/*
diff --git a/arch/arm/boot/dts/tegra30-colibri-eval-v3.dts b/arch/arm/boot/dts/tegra30-colibri-eval-v3.dts
index b307feb7c330..8c62833197e5 100644
--- a/arch/arm/boot/dts/tegra30-colibri-eval-v3.dts
+++ b/arch/arm/boot/dts/tegra30-colibri-eval-v3.dts
@@ -56,7 +56,7 @@
*/
i2c@7000c000 {
status = "okay";
- clock-frequency = <100000>;
+ clock-frequency = <400000>;

/* M41T0M6 real time clock on carrier board */
rtc@68 {
diff --git a/arch/arm/boot/dts/tegra30-colibri.dtsi b/arch/arm/boot/dts/tegra30-colibri.dtsi
index 139bfa028b04..1f77273521bf 100644
--- a/arch/arm/boot/dts/tegra30-colibri.dtsi
+++ b/arch/arm/boot/dts/tegra30-colibri.dtsi
@@ -215,7 +215,7 @@
};

hdmiddc: i2c@7000c700 {
- clock-frequency = <100000>;
+ clock-frequency = <10000>;
};

/*
--
2.14.3
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