On Wed, 04 Dec 2019, Geert Uytterhoeven wrote: > Hi Lee, > > On Wed, Dec 4, 2019 at 9:38 AM Lee Jones <lee.jones@xxxxxxxxxx> wrote: > > On Tue, 03 Dec 2019, Geert Uytterhoeven wrote: > > > On Tue, Dec 3, 2019 at 7:58 PM Chris Brandt <Chris.Brandt@xxxxxxxxxxx> wrote: > > > > On Tue, Dec 3, 2019, Geert Uytterhoeven wrote: > > > > > > + reg = <0x3fefa000 0x100>, <0x18000000 > > > > > > + 0x4000000>; > > > > > > > > > > The second region conflicts with the XIP flash@18000000 in > > > > > arch/arm/boot/dts/r7s72100-gr-peach.dts. > > > > > Yes, I know it is the same device ;-) > > > > > > > > Is that just an FYI?? Or do you have some suggestion?? > > > > > > Can the flash subnode be compatible with "mtd-rom", even if the parent node > > > is kept disabled? > > > > > > > > > + clock-critical = <4>; /* spibsc0 */ > > > > > > > > > > Iff we go this clock-critical route, I think this should be specified in the > > > > > board-specific .dts instead of in the SoC-specific .dtsi. > > > > > > > > OK, that's fine. It makes more sense to be in the .dts because it's a board > > > > design decision. I will remove it from the patch. > > > > > > > > The one 'tricky' thing is that the <4> is the index into the number of clocks. > > > > > > > > So in the Renesas BSP where it includes the VDC5 LCD controllers, > > > > > > > > clock-output-names = "i2c0", "i2c1", "i2c2", "i2c3", "vdc50", "vdc51", "spibsc0", "spibsc1"; > > > > > > > > the <4> needs to become a <6>. > > > > > > Unless you pass "clkidx" instead of "i" to of_clk_detect_critical() in [1], > > > and use "clock-critical = <R7S72100_CLK_SPIBSC0>" in DT? > > > > > > Unfortunately the exact semantics of clock-critical were never documented. > > > Lee? > > > > /** > > * of_clk_detect_critical() - set CLK_IS_CRITICAL flag from Device Tree > > * @np: Device node pointer associated with clock provider > > * @index: clock index > > * @flags: pointer to top-level framework flags > > * > > * Detects if the clock-critical property exists and, if so, sets the > > * corresponding CLK_IS_CRITICAL flag. > > * > > * Do not use this function. It exists only for legacy Device Tree > > * bindings, such as the one-clock-per-node style that are outdated. > > * Those bindings typically put all clock data into .dts and the Linux > > * driver has no clock data, thus making it impossible to set this flag > > * correctly from the driver. Only those drivers may call > > * of_clk_detect_critical from their setup functions. > > * > > * Return: error code or zero on success > > */ > > > > If this meets the criteria, the API is pretty simple/self > > explanatory. What are you having trouble with? > > What exactly is the "index" parameter? This value is matched against > the values of the "clock-critical" (array) property, but it is described > nowhere in the DT bindings. > stih407-clock.dtsi seems to assume this value is an index into the > clock-output-names array? > Can we use it as a value of "clock-indices" instead? of_clk_detect_critical(), the consumer of the device tree property 'clock-critical', is a helper. Neither deliver any auto-magical functionality. Simply providing an index into the property will not do anything useful. It's up to the vendor's clock driver to handle. The vendor driver can call of_clk_detect_critical() with *any* index it sees fit. If it matches a number listed in the 'clock-critical' array, the CLK_IS_CRITICAL flag is set in the flags pointed to by the 3rd function parameter. Take a look at some of the call sites in drivers/clk/st/* for further clarification. > > > Thanks! > > > > > > [1] "[PATCH 1/6] clk: renesas: mstp: Add critical clock from device > > > tree support" > > > https://lore.kernel.org/linux-renesas-soc/20191203034519.5640-2-chris.brandt@xxxxxxxxxxx/ > > Gr{oetje,eeting}s, > > Geert > -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog
