| Age | Commit message (Collapse) | Author |
|---|
|
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>
|
|
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>
|
|
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>
|
