On 06/19/2012 07:56 AM, Tony Lindgren wrote: > Hi, > > Below is the pinctrl-single patch updated with hopefully all the Stephen's > comments addressed. The binding still needs to be looked at, see relevant > parts of the discussion below. ... > From: Tony Lindgren <tony@xxxxxxxxxxx> > Date: Wed, 6 Jun 2012 04:18:18 -0700 > Subject: [PATCH] pinctrl: Add one-register-per-pin type device tree based pinctrl driver > > Add one-register-per-pin type device tree based pinctrl driver. > > Currently this driver only works on omap2+ series of processors, > where there is either an 8 or 16-bit padconf register for each pin. > Support for other similar pinmux controllers can be added. > > Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx> > > diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-single.txt b/Documentation/devicetree/bindings/pinctrl/pinctrl-single.txt > new file mode 100644 > index 0000000..929254c > --- /dev/null > +++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-single.txt > @@ -0,0 +1,106 @@ > +One-register-per-pin type device tree based pinctrl driver > + > +Required properties: > +- compatible : "pinctrl-single" > + > +- reg : offset and length of the register set for the mux registers > + > +- pinctrl-single,register-width : pinmux register access width in bits > + > +- pinctrl-single,function-mask : mask of allowed pinmux function bits > + in the pinmux register > + > +- pinctrl-single,pinconf-mask : mask of allowed pinconf bits in the > + pinmux register; this gets combined with pinconf mask but is a separate > + mask to allow the option of setting pinconf separatately from the > + function Given that this binding doesn't allow describing pin configuration at present, I would simply remove all mention of that property in the binding documentation. It can be added back if/when that feature is added. Any future driver using this binding can refuse to allow pin configuration if that property is missing. > +- pinctrl-single,function-off : function off mode for disabled state if > + available and same for all registers; if not, use a value larger than > + function-mask to ignore disabling of registers Rather than requiring an invalid value in this property, shouldn't the lack of a valid function-off value be represented by the property not being present in the DT? > +This driver assumes that there is only one register for each pin, > +and uses the common pinctrl bindings as specified in the pinctrl-bindings.txt > +document in this directory. At this point in the file, I think you need to mention that you're switching from describing the top-level device node to describing pin configuration nodes. > +The pinctrl register offsets and default values are specified as pairs I thought we were going to remove "default" here? > +using pinctrl-single,pins. For example, setting a pin for a device > +could be done with: > + > + pinctrl-single,pins = <0xdc 0x118>; > + > +Where 0xdc is the offset from the pinctrl register base address for the > +device pinctrl register, and 0x118 contains the desired value of the > +pinctrl register. See the device example and static board pins example > +below for more information. There should be some explanation only the portion of this value covered by the pinctrl-single,function-mask value is updated in the register. > +This driver tries to avoid understanding pin and function names because of > +the extra bloat they would cause especially in the case of a large number > +of pins. This driver just sets what is specified for the board in the .dts file. > +Further user space debugging tools can be developed to decipher the pin and > +function names using debugfs. There shouldn't be any discussion of a driver here; the binding is a HW description. > +Example: I only reviewed the binding document, not the code. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
