[PATCH] ARM: dts: am437x-sk-evm: Reduce i2c0 bus speed for tps65218

[Tony Lindgren]

* Keerthy <j-keerthy at ti.com> [160614 23:18]:
> From: Dave Gerlach <d-gerlach at ti.com>
> 
> 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.

Applying into omap-for-v4.7/fixes thanks.

Tony