| Message ID | 20170322142754.30888-3-chris.brandt@renesas.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
On Wed, Mar 22, 2017 at 10:27:49AM -0400, Chris Brandt wrote: > rtc-sh is an RTC for SuperH and RZ/A SoCs. Please work on the subject. It's a bit brief. "dt-bindings: rtc: " is the preferred prefix. > > Signed-off-by: Chris Brandt <chris.brandt@renesas.com> > --- > v2: > * added interrupt-names and clock-names > * clocks now include counting sources > * changed 'is a RTC' to 'is an RTC' in commit message > --- > Documentation/devicetree/bindings/rtc/rtc-sh.txt | 29 ++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > create mode 100644 Documentation/devicetree/bindings/rtc/rtc-sh.txt > > diff --git a/Documentation/devicetree/bindings/rtc/rtc-sh.txt b/Documentation/devicetree/bindings/rtc/rtc-sh.txt > new file mode 100644 > index 0000000..adbb8af > --- /dev/null > +++ b/Documentation/devicetree/bindings/rtc/rtc-sh.txt > @@ -0,0 +1,29 @@ > +* Real Time Clock for Renesas SH and ARM SoCs > + > +Required properties: > +- compatible: Should be "renesas,r7s72100-rtc" and "renesas,sh-rtc" as a > + fallback. > +- reg: physical base address and length of memory mapped region. > +- interrupts: 3 interrupts for alarm, period, and carry. > +- interrupt-names: The interrupts should be labeled as "alarm", "period", and > + "carry". > +- clocks: The functional clock source for the RTC controller must be listed > + first (if exists). Additionally, potential clock counting sources are to be > + listed. > +- clock-names: The functional clock must be labeled as "fck". Other clocks > + may be named in accordance to the SoC hardware manuals. > + > + > +Example: > +rtc: rtc@fcff1000 { > + compatible = "renesas,r7s72100-rtc", "renesas,sh-rtc"; > + reg = <0xfcff1000 0x2e>; > + interrupts = <GIC_SPI 276 IRQ_TYPE_EDGE_RISING > + GIC_SPI 277 IRQ_TYPE_EDGE_RISING > + GIC_SPI 278 IRQ_TYPE_EDGE_RISING>; > + interrupt-names = "alarm", "period", "carry"; > + clocks = <&mstp6_clks R7S72100_CLK_RTC>, <&rtc_x1_clk>, > + <&rtc_x3_clk>, <&extal_clk>; > + clock-names = "fck", "rtc_x1", "rtc_x3", "extal"; > + power-domains = <&cpg_clocks>; Not documented. Rob
Hi Rob, On Wed, Mar 29, 2017 at 3:24 AM, Rob Herring <robh@kernel.org> wrote: > On Wed, Mar 22, 2017 at 10:27:49AM -0400, Chris Brandt wrote: >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/rtc/rtc-sh.txt >> @@ -0,0 +1,29 @@ >> +* Real Time Clock for Renesas SH and ARM SoCs >> + >> +Required properties: >> +- compatible: Should be "renesas,r7s72100-rtc" and "renesas,sh-rtc" as a >> + fallback. >> +- reg: physical base address and length of memory mapped region. >> +- interrupts: 3 interrupts for alarm, period, and carry. >> +- interrupt-names: The interrupts should be labeled as "alarm", "period", and >> + "carry". >> +- clocks: The functional clock source for the RTC controller must be listed >> + first (if exists). Additionally, potential clock counting sources are to be >> + listed. >> +- clock-names: The functional clock must be labeled as "fck". Other clocks >> + may be named in accordance to the SoC hardware manuals. >> + >> + >> +Example: >> +rtc: rtc@fcff1000 { >> + compatible = "renesas,r7s72100-rtc", "renesas,sh-rtc"; >> + reg = <0xfcff1000 0x2e>; >> + interrupts = <GIC_SPI 276 IRQ_TYPE_EDGE_RISING >> + GIC_SPI 277 IRQ_TYPE_EDGE_RISING >> + GIC_SPI 278 IRQ_TYPE_EDGE_RISING>; >> + interrupt-names = "alarm", "period", "carry"; >> + clocks = <&mstp6_clks R7S72100_CLK_RTC>, <&rtc_x1_clk>, >> + <&rtc_x3_clk>, <&extal_clk>; >> + clock-names = "fck", "rtc_x1", "rtc_x3", "extal"; >> + power-domains = <&cpg_clocks>; > > Not documented. "power-domains" is a platform property. All hardware components need power. All synchronous hardware components need a clock. Most hardware components have a reset signal. Whether these are exposed and can be controlled depends on the platform/SoC. So documenting them in each and every device binding looks overkill to me. I think this is something to be addressed by devicetree-specification (which doesn't handle clocks, power-domains, resets yet). If you prefer, the property can be removed from the example, though. Thanks! Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On Wednesday, March 29, 2017, Geert Uytterhoeven wrote: > >> +Example: > >> +rtc: rtc@fcff1000 { > >> + compatible = "renesas,r7s72100-rtc", "renesas,sh-rtc"; > >> + reg = <0xfcff1000 0x2e>; > >> + interrupts = <GIC_SPI 276 IRQ_TYPE_EDGE_RISING > >> + GIC_SPI 277 IRQ_TYPE_EDGE_RISING > >> + GIC_SPI 278 IRQ_TYPE_EDGE_RISING>; > >> + interrupt-names = "alarm", "period", "carry"; > >> + clocks = <&mstp6_clks R7S72100_CLK_RTC>, <&rtc_x1_clk>, > >> + <&rtc_x3_clk>, <&extal_clk>; > >> + clock-names = "fck", "rtc_x1", "rtc_x3", "extal"; > >> + power-domains = <&cpg_clocks>; > > > > Not documented. > > "power-domains" is a platform property. > > All hardware components need power. > All synchronous hardware components need a clock. > Most hardware components have a reset signal. > > Whether these are exposed and can be controlled depends on the > platform/SoC. > So documenting them in each and every device binding looks overkill to me. > I think this is something to be addressed by devicetree-specification > (which doesn't handle clocks, power-domains, resets yet). > > If you prefer, the property can be removed from the example, though. I'll go ahead and pull it out (since I have to update the commit title anyway as per Rob's request) Besides...it's probably the most least important part of the example ;) Thanks, Chris
On Wed, Mar 29, 2017 at 1:49 AM, Geert Uytterhoeven <geert@linux-m68k.org> wrote: > Hi Rob, > > On Wed, Mar 29, 2017 at 3:24 AM, Rob Herring <robh@kernel.org> wrote: >> On Wed, Mar 22, 2017 at 10:27:49AM -0400, Chris Brandt wrote: >>> --- /dev/null >>> +++ b/Documentation/devicetree/bindings/rtc/rtc-sh.txt >>> @@ -0,0 +1,29 @@ >>> +* Real Time Clock for Renesas SH and ARM SoCs >>> + >>> +Required properties: >>> +- compatible: Should be "renesas,r7s72100-rtc" and "renesas,sh-rtc" as a >>> + fallback. >>> +- reg: physical base address and length of memory mapped region. >>> +- interrupts: 3 interrupts for alarm, period, and carry. >>> +- interrupt-names: The interrupts should be labeled as "alarm", "period", and >>> + "carry". >>> +- clocks: The functional clock source for the RTC controller must be listed >>> + first (if exists). Additionally, potential clock counting sources are to be >>> + listed. >>> +- clock-names: The functional clock must be labeled as "fck". Other clocks >>> + may be named in accordance to the SoC hardware manuals. >>> + >>> + >>> +Example: >>> +rtc: rtc@fcff1000 { >>> + compatible = "renesas,r7s72100-rtc", "renesas,sh-rtc"; >>> + reg = <0xfcff1000 0x2e>; >>> + interrupts = <GIC_SPI 276 IRQ_TYPE_EDGE_RISING >>> + GIC_SPI 277 IRQ_TYPE_EDGE_RISING >>> + GIC_SPI 278 IRQ_TYPE_EDGE_RISING>; >>> + interrupt-names = "alarm", "period", "carry"; >>> + clocks = <&mstp6_clks R7S72100_CLK_RTC>, <&rtc_x1_clk>, >>> + <&rtc_x3_clk>, <&extal_clk>; >>> + clock-names = "fck", "rtc_x1", "rtc_x3", "extal"; >>> + power-domains = <&cpg_clocks>; >> >> Not documented. > > "power-domains" is a platform property. > > All hardware components need power. > All synchronous hardware components need a clock. > Most hardware components have a reset signal. And we document clocks and reset for every binding. > Whether these are exposed and can be controlled depends on the platform/SoC. > So documenting them in each and every device binding looks overkill to me. > I think this is something to be addressed by devicetree-specification (which > doesn't handle clocks, power-domains, resets yet). It's a question of validation. How do I validate power-domains is a valid property for a given compatible? What if it is required, but not present? Any node can have it? So it is valid for memory and chosen nodes, an i2c device, an LCD panel, etc? > If you prefer, the property can be removed from the example, though. If it is valid, then I don't want it removed. Rob
Hi Rob, On Tue, Apr 4, 2017 at 4:29 PM, Rob Herring <robh@kernel.org> wrote: > On Wed, Mar 29, 2017 at 1:49 AM, Geert Uytterhoeven > <geert@linux-m68k.org> wrote: >> On Wed, Mar 29, 2017 at 3:24 AM, Rob Herring <robh@kernel.org> wrote: >>> On Wed, Mar 22, 2017 at 10:27:49AM -0400, Chris Brandt wrote: >>>> --- /dev/null >>>> +++ b/Documentation/devicetree/bindings/rtc/rtc-sh.txt >>>> +Example: >>>> +rtc: rtc@fcff1000 { >>>> + compatible = "renesas,r7s72100-rtc", "renesas,sh-rtc"; >>>> + reg = <0xfcff1000 0x2e>; >>>> + interrupts = <GIC_SPI 276 IRQ_TYPE_EDGE_RISING >>>> + GIC_SPI 277 IRQ_TYPE_EDGE_RISING >>>> + GIC_SPI 278 IRQ_TYPE_EDGE_RISING>; >>>> + interrupt-names = "alarm", "period", "carry"; >>>> + clocks = <&mstp6_clks R7S72100_CLK_RTC>, <&rtc_x1_clk>, >>>> + <&rtc_x3_clk>, <&extal_clk>; >>>> + clock-names = "fck", "rtc_x1", "rtc_x3", "extal"; >>>> + power-domains = <&cpg_clocks>; >>> >>> Not documented. >> >> "power-domains" is a platform property. >> >> All hardware components need power. >> All synchronous hardware components need a clock. >> Most hardware components have a reset signal. > > And we document clocks and reset for every binding. Then we'll have to add lots of them ;-) Usually these are documented only if the user (the driver) cares about them, and/or if there are multiple of the same type. E.g. - The driver needs to know or control a clock frequency, - The driver needs to enable/disable a clock, - The driver needs to know or control one or more voltages, - ... It's not that devices without documented regulators, power-domains, or clocks properties no longer consume power or don't run from a clock. These are just not described in DT, as deemed unimportant. But on some platforms, they may become important. >> Whether these are exposed and can be controlled depends on the platform/SoC. >> So documenting them in each and every device binding looks overkill to me. >> I think this is something to be addressed by devicetree-specification (which >> doesn't handle clocks, power-domains, resets yet). > > It's a question of validation. How do I validate power-domains is a > valid property for a given compatible? What if it is required, but not With platform property, I mean that it depends on the platform, not on the compatible value of the device. For a generic compatible value ("renesas,sh-srtc") you cannot know, as it depends on the actual SoC the (same) RTC device is part of. For an SoC-specific compatible value ("renesas,r7s72100-rtc"), you could know from the compatible value (an r7s72100 SoC must have r7s72100 clocks, and the r7s72100 clock domain, cfr. Documentation/devicetree/bindings/clock/renesas,rz-cpg-clocks.txt). However. the SoC-specific compatible values exist only as a workaround for not knowing the exact version of the IP cores. > present? Any node can have it? So it is valid for memory and chosen > nodes, an i2c device, an LCD panel, etc? It's not valid for a chosen node ;-) It can be valid for memory (or the memory-controller; oops, the memory node is not a child of the memory-controller node), i2c devices, LCD panels, ... depending on the platform. Consider e.g. i2c devices. I can add a GPIO-controlled MOSFET bank to my board, to enable power to individual i2c devices, and abstract that as a power-controller in DT. Suddenly I have to add power-domains properties to the individual i2c device nodes, while the i2c devices itself haven't changed, and thus keep the same compatible values. Should I now document the power-domains property in the i2c devices' DT binding documents? On Linux, the drivers won't care, as the platform-specific things are handled transparently by Runtime PM. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
diff --git a/Documentation/devicetree/bindings/rtc/rtc-sh.txt b/Documentation/devicetree/bindings/rtc/rtc-sh.txt new file mode 100644 index 0000000..adbb8af --- /dev/null +++ b/Documentation/devicetree/bindings/rtc/rtc-sh.txt @@ -0,0 +1,29 @@ +* Real Time Clock for Renesas SH and ARM SoCs + +Required properties: +- compatible: Should be "renesas,r7s72100-rtc" and "renesas,sh-rtc" as a + fallback. +- reg: physical base address and length of memory mapped region. +- interrupts: 3 interrupts for alarm, period, and carry. +- interrupt-names: The interrupts should be labeled as "alarm", "period", and + "carry". +- clocks: The functional clock source for the RTC controller must be listed + first (if exists). Additionally, potential clock counting sources are to be + listed. +- clock-names: The functional clock must be labeled as "fck". Other clocks + may be named in accordance to the SoC hardware manuals. + + +Example: +rtc: rtc@fcff1000 { + compatible = "renesas,r7s72100-rtc", "renesas,sh-rtc"; + reg = <0xfcff1000 0x2e>; + interrupts = <GIC_SPI 276 IRQ_TYPE_EDGE_RISING + GIC_SPI 277 IRQ_TYPE_EDGE_RISING + GIC_SPI 278 IRQ_TYPE_EDGE_RISING>; + interrupt-names = "alarm", "period", "carry"; + clocks = <&mstp6_clks R7S72100_CLK_RTC>, <&rtc_x1_clk>, + <&rtc_x3_clk>, <&extal_clk>; + clock-names = "fck", "rtc_x1", "rtc_x3", "extal"; + power-domains = <&cpg_clocks>; +};
rtc-sh is an RTC for SuperH and RZ/A SoCs. Signed-off-by: Chris Brandt <chris.brandt@renesas.com> --- v2: * added interrupt-names and clock-names * clocks now include counting sources * changed 'is a RTC' to 'is an RTC' in commit message --- Documentation/devicetree/bindings/rtc/rtc-sh.txt | 29 ++++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 Documentation/devicetree/bindings/rtc/rtc-sh.txt