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path: root/Documentation/devicetree/bindings/clock/ti-clkctrl.txt
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2022-04-11dt-bindings: clock: ti: Add clock-output-names for clockctrlTony Lindgren1-1/+3
This allows us to use clock-output-names for the clockctrl instance name instead of relying on a custom compatible or non-standard node names. Cc: Stephen Boyd <sboyd@kernel.org> Cc: Tero Kristo <kristo@kernel.org> Signed-off-by: Tony Lindgren <tony@atomide.com> Acked-by: Rob Herring <robh@kernel.org> Message-Id: <20220203112337.19821-2-tony@atomide.com>
2020-01-20clk: ti: clkctrl: Fix hidden dependency to node nameTony Lindgren1-3/+8
We currently have a hidden dependency to the device tree node name for the clkctrl clocks. Instead of using standard node name like "clock", we must use "l4-per-clkctrl" type naming so the clock driver can find the associated clock domain. Further, if "clk" is specified for a clock node name, the driver sets TI_CLK_CLKCTRL_COMPAT flag that uses different logic for the clock name based on the parent node name for the all the clkctrl clocks for the SoC. If the clock node naming dependency is not understood, the related clockdomain is not found, or a wrong one can get used if a clock manager has multiple clock domains. As each clkctrl instance represents a single clock domain, let's allow using domain specific compatible names to specify the clock domain. This simplifies things and removes the hidden dependency to the node name. And then later on, after the node names have been standardized, we can drop the related code for parsing the node names. Let's also update the binding to use standard "clock" node naming instead of "clk" and add the missing description for reg. Cc: devicetree@vger.kernel.org Cc: Rob Herring <robh+dt@kernel.org> Signed-off-by: Tony Lindgren <tony@atomide.com> Acked-by: Rob Herring <robh@kernel.org> Acked-by: Stephen Boyd <sboyd@kernel.org> Signed-off-by: Tero Kristo <t-kristo@ti.com>
2017-06-15Documentation: dt-bindings: Add binding documentation for TI clkctrl clocksTony Lindgren1-0/+56
Texas Instruments omap variant SoCs starting with omap4 have a clkctrl clock controller instance for each interconnect target module. The clkctrl controls functional and interface clocks for the module. The clkctrl clocks are currently handled by arch/arm/mach-omap2 hwmod code. With this binding and a related clock device driver we can start moving the clkctrl clock handling to live in drivers/clk/ti. Note that this binding allows keeping the clockdomain related parts out of drivers/clock. The CLKCTCTRL and DYNAMICDEP registers can be handled by a separate driver in drivers/soc/ti and genpd. If the clockdomain driver needs to know it's clocks, we can just set the the clkctrl device instances to be children of the related clockdomain device. Each clkctrl clock can have multiple optional gate clocks, and multiple optional mux clocks. To represent this in device tree, it seems that it is best done using four clock cells #clock-cells = <2> property. The reasons for using #clock-cells = <2> are: 1. We need to specify the clkctrl offset from the instance base. Otherwise we end up with a large number of device tree nodes that need to be patched when new clocks are discovered in a clkctrl clock with minor hardware revision changes for example 2. On omap5 CM_L3INIT_USB_HOST_HS_CLKCTRL has ten OPTFCLKEN bits. So we need to use a separate cell for optional gate clocks to avoid address space conflicts There is probably no need to list input clocks for each clkctrl clock instance in the binding. If we want to add them, the standard clocks binding can be used for that. For hardware reference, see omap4430 TRM "Table 3-1312. L4PER_CM2 Registers Mapping Summary" for example. It shows one instance of a clkctrl clock controller with multiple clkctrl registers. Cc: Paul Walmsley <paul@pwsan.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Tero Kristo <t-kristo@ti.com>