powerpc/83xx: gianfar_ptp: select 1588 clock source through dts file
Currently IEEE 1588 timer reference clock source is determined through hard-coded value in gianfar_ptp driver. This patch allows to select ptp clock source by means of device tree file node. For instance: fsl,cksel = <0>; for using external (TSEC_TMR_CLK input) high precision timer reference clock. Other acceptable values: <1> : eTSEC system clock <2> : eTSEC1 transmit clock <3> : RTC clock input When this attribute isn't used, eTSEC system clock will serve as IEEE 1588 timer reference clock. Signed-off-by: Aida Mynzhasova <aida.mynzhasova@skitlab.ru> Acked-by: Kumar Gala <galak@codeaurora.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -86,6 +86,7 @@ General Properties:
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Clock Properties:
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- fsl,cksel Timer reference clock source.
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- fsl,tclk-period Timer reference clock period in nanoseconds.
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- fsl,tmr-prsc Prescaler, divides the output clock.
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- fsl,tmr-add Frequency compensation value.
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@ -97,7 +98,7 @@ Clock Properties:
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clock. You must choose these carefully for the clock to work right.
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Here is how to figure good values:
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TimerOsc = system clock MHz
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TimerOsc = selected reference clock MHz
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tclk_period = desired clock period nanoseconds
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NominalFreq = 1000 / tclk_period MHz
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FreqDivRatio = TimerOsc / NominalFreq (must be greater that 1.0)
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@ -114,6 +115,20 @@ Clock Properties:
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Pulse Per Second (PPS) signal, since this will be offered to the PPS
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subsystem to synchronize the Linux clock.
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Reference clock source is determined by the value, which is holded
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in CKSEL bits in TMR_CTRL register. "fsl,cksel" property keeps the
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value, which will be directly written in those bits, that is why,
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according to reference manual, the next clock sources can be used:
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<0> - external high precision timer reference clock (TSEC_TMR_CLK
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input is used for this purpose);
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<1> - eTSEC system clock;
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<2> - eTSEC1 transmit clock;
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<3> - RTC clock input.
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When this attribute is not used, eTSEC system clock will serve as
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IEEE 1588 timer reference clock.
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Example:
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ptp_clock@24E00 {
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@ -121,6 +136,7 @@ Example:
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reg = <0x24E00 0xB0>;
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interrupts = <12 0x8 13 0x8>;
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interrupt-parent = < &ipic >;
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fsl,cksel = <1>;
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fsl,tclk-period = <10>;
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fsl,tmr-prsc = <100>;
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fsl,tmr-add = <0x999999A4>;
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@ -452,7 +452,9 @@ static int gianfar_ptp_probe(struct platform_device *dev)
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err = -ENODEV;
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etsects->caps = ptp_gianfar_caps;
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etsects->cksel = DEFAULT_CKSEL;
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if (get_of_u32(node, "fsl,cksel", &etsects->cksel))
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etsects->cksel = DEFAULT_CKSEL;
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if (get_of_u32(node, "fsl,tclk-period", &etsects->tclk_period) ||
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get_of_u32(node, "fsl,tmr-prsc", &etsects->tmr_prsc) ||
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