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authorDave Gerlach <d-gerlach@ti.com>2021-07-16 09:07:30 -0700
committerSasha Levin <sashal@kernel.org>2021-08-26 08:37:49 -0400
commitcc770cec14cf7cbba01013d5a0c4b9a993def7b8 (patch)
tree653ffd3da93b5a80ebc669bf53060671164c634e /arch
parent0eee458057c0132e5ddaa1b6fe2080b1b6668ec0 (diff)
ARM: dts: am43x-epos-evm: Reduce i2c0 bus speed for tps65218
[ Upstream commit 20a6b3fd8e2e2c063b25fbf2ee74d86b898e5087 ] Based on the latest timing specifications for the TPS65218 from the data sheet, http://www.ti.com/lit/ds/symlink/tps65218.pdf, document SLDS206 from November 2014, we must change the i2c bus speed to better fit within the minimum high SCL time required for proper i2c transfer. When running at 400khz, measurements show that SCL spends 0.8125 uS/1.666 uS high/low which violates the requirement for minimum high period of SCL provided in datasheet Table 7.6 which is 1 uS. Switching to 100khz gives us 5 uS/5 uS high/low which both fall above the minimum given values for 100 khz, 4.0 uS/4.7 uS high/low. Without this patch occasionally a voltage set operation from the kernel will appear to have worked but the actual voltage reflected on the PMIC will not have updated, causing problems especially with cpufreq that may update to a higher OPP without actually raising the voltage on DCDC2, leading to a hang. Signed-off-by: Dave Gerlach <d-gerlach@ti.com> Signed-off-by: Kevin Hilman <khilman@baylibre.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/boot/dts/am43x-epos-evm.dts2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/boot/dts/am43x-epos-evm.dts b/arch/arm/boot/dts/am43x-epos-evm.dts
index a74b09f17a1a..e7cd99793bc6 100644
--- a/arch/arm/boot/dts/am43x-epos-evm.dts
+++ b/arch/arm/boot/dts/am43x-epos-evm.dts
@@ -411,7 +411,7 @@
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&i2c0_pins>;
- clock-frequency = <400000>;
+ clock-frequency = <100000>;
tps65218: tps65218@24 {
reg = <0x24>;