| Message ID | 1465971211-15994-1-git-send-email-j-keerthy@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wednesday 15 June 2016 11:43 AM, Keerthy wrote: > From: Dave Gerlach <d-gerlach@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. I will resend with proper $Subject. Sorry for the noise. Please ignore this patch. > > Signed-off-by: Dave Gerlach <d-gerlach@ti.com> > Signed-off-by: Nishanth Menon <nm@ti.com> > Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com> > Signed-off-by: Aparna Balasubramanian <aparnab@ti.com> > Signed-off-by: Keerthy <j-keerthy@ti.com> > --- > arch/arm/boot/dts/am437x-sk-evm.dts | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm/boot/dts/am437x-sk-evm.dts b/arch/arm/boot/dts/am437x-sk-evm.dts > index 18a3445..5f67001 100644 > --- a/arch/arm/boot/dts/am437x-sk-evm.dts > +++ b/arch/arm/boot/dts/am437x-sk-evm.dts > @@ -490,7 +490,7 @@ > status = "okay"; > pinctrl-names = "default"; > pinctrl-0 = <&i2c0_pins>; > - clock-frequency = <400000>; > + clock-frequency = <100000>; > > tps@24 { > compatible = "ti,tps65218"; >
diff --git a/arch/arm/boot/dts/am437x-sk-evm.dts b/arch/arm/boot/dts/am437x-sk-evm.dts index 18a3445..5f67001 100644 --- a/arch/arm/boot/dts/am437x-sk-evm.dts +++ b/arch/arm/boot/dts/am437x-sk-evm.dts @@ -490,7 +490,7 @@ status = "okay"; pinctrl-names = "default"; pinctrl-0 = <&i2c0_pins>; - clock-frequency = <400000>; + clock-frequency = <100000>; tps@24 { compatible = "ti,tps65218";