crawling my way through the DTS files for the BBB and i ran across
this in am33xx.dtsi:
epwmss1: epwmss@48302000 {
compatible = "ti,am33xx-pwmss";
reg = <0x48302000 0x10>;
ti,hwmods = "epwmss1";
#address-cells = <1>;
#size-cells = <1>;
status = "disabled";
ranges = <0x48302100 0x48302100 0x80 /* ECAP */
0x48302180 0x48302180 0x80 /* EQEP */
0x48302200 0x48302200 0x80>; /* EHRPWM */
ecap1: ecap@48302100 {
compatible = "ti,am33xx-ecap";
#pwm-cells = <3>;
reg = <0x48302100 0x80>;
interrupts = <47>;
interrupt-names = "ecap1";
ti,hwmods = "ecap1";
status = "disabled";
};
ehrpwm1: ehrpwm@48302200 {
compatible = "ti,am33xx-ehrpwm";
#pwm-cells = <3>;
reg = <0x48302200 0x80>;
ti,hwmods = "ehrpwm1";
status = "disabled";
};
};
first question ... should there be a node definition for "eqep"?
after all, the second triplet in "ranges" is commented with "EQEP",
but there is no associated child node for that. i would have expected
one.
also, based on my understanding of "ranges", the above definition
seems to be simply mapping the child address space directly back to
the parent address space; i.e., no translation is required. so what is
the point? wouldn't the same thing be achieved with a simple:
ranges;
which specifies that the two address spaces are identical and no
address translation is required?
or does the above also restrict the mapping to specifically the
ranges listed there?
rday
--
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Robert P. J. Day Ottawa, Ontario, CANADA
http://crashcourse.ca
Twitter: http://twitter.com/rpjday
LinkedIn: http://ca.linkedin.com/in/rpjday
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