[PATCHv5 05/31] CLK: TI: add support for OMAP gate clock
From: mark.rutland@arm.com (Mark Rutland)
Date: 2013-08-13 11:04:37
Also in:
linux-omap
On Fri, Aug 02, 2013 at 05:25:24PM +0100, Tero Kristo wrote:
quoted hunk ↗ jump to hunk
This node adds support for a clock node which allows control to the clockdomain enable / disable. Signed-off-by: Tero Kristo <redacted> --- .../devicetree/bindings/clock/ti/gate.txt | 41 ++++++++ arch/arm/mach-omap2/clock.h | 9 -- drivers/clk/ti/Makefile | 2 +- drivers/clk/ti/gate.c | 106 ++++++++++++++++++++ include/linux/clk/ti.h | 8 ++ 5 files changed, 156 insertions(+), 10 deletions(-) create mode 100644 Documentation/devicetree/bindings/clock/ti/gate.txt create mode 100644 drivers/clk/ti/gate.cdiff --git a/Documentation/devicetree/bindings/clock/ti/gate.txt b/Documentation/devicetree/bindings/clock/ti/gate.txt new file mode 100644 index 0000000..620a73d --- /dev/null +++ b/Documentation/devicetree/bindings/clock/ti/gate.txt@@ -0,0 +1,41 @@ +Binding for Texas Instruments gate clock. + +This binding uses the common clock binding[1]. This clock is +quite much similar to the basic gate-clock [2], however, +it supports a number of additional features. If no register +is provided for this clock, the code assumes that a clockdomain +will be controlled instead and the corresponding hw-ops for +that is used. + +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt +[2] Documentation/devicetree/bindings/clock/gate-clock.txt + +Required properties: +- compatible : shall be "ti,gate-clock" +- #clock-cells : from common clock binding; shall be set to 0 +- clocks : link to phandle of parent clock + +Optional properties: +- reg : base address for register controlling adjustable gate
Optional? That's odd. If I have a clock with registers, but don't specify the register, will it still work? i.e. are registerless clocks really compatible with clocks with registers?.
+- ti,enable-bit : bit shift for programming the clock gate
Why is this needed? Does the hardware vary wildly, or are several clocks sharing the same register(s)?
+- ti,dss-clk : use DSS hardware OPS for the clock +- ti,am35xx-clk : use AM35xx hardware OPS for the clock
Those last two sounds like the kind of thing that should be derived from the compatible string (e.g. ti,am35xx-gate-clock).
+- ti,clkdm-name : clockdomain to control this gate
As previously mentioned, I'm not a fan of this property. It would make more sense to describe the domain and have an explicit link to it (either nodes being children of the domain or having a phandle). [...]
+void __init of_omap_gate_clk_setup(struct device_node *node)
+{
+ struct clk *clk;
+ struct clk_init_data init = { 0 };
+ struct clk_hw_omap *clk_hw;
+ const char *clk_name = node->name;
+ int num_parents;
+ const char **parent_names = NULL;
+ int i;
+ u32 val;
+
+ clk_hw = kzalloc(sizeof(*clk_hw), GFP_KERNEL);
+ if (!clk_hw) {
+ pr_err("%s: could not allocate clk_hw_omap\n", __func__);
+ return;
+ }
+
+ clk_hw->hw.init = &init;
+
+ of_property_read_string(node, "clock-output-names", &clk_name);
+ of_property_read_string(node, "ti,clkdm-name", &clk_hw->clkdm_name);
+
+ init.name = clk_name;
+ init.flags = 0;
+
+ if (of_property_read_u32_index(node, "reg", 0, &val)) {
+ /* No register, clkdm control only */
+ init.ops = &omap_gate_clkdm_clk_ops;If they're truly compatible, you can just see if you can of_iomap, and if not, continue. Your reg values might be wider than 32 bits, and usig of_property_read_u32 to read this feels wrong.
+ } else {
+ init.ops = &omap_gate_clk_ops;
+ clk_hw->enable_reg = of_iomap(node, 0);
+ of_property_read_u32(node, "ti,enable-bit", &val);
+ clk_hw->enable_bit = val;What if of_property_read_u32 failed to read the "ti,enable-bit" property? One might not be present, it's marked as optional in the binding description.
+ + clk_hw->ops = &clkhwops_wait; + + if (of_property_read_bool(node, "ti,dss-clk")) + clk_hw->ops = &clkhwops_omap3430es2_dss_usbhost_wait; + + if (of_property_read_bool(node, "ti,am35xx-clk")) + clk_hw->ops = &clkhwops_am35xx_ipss_module_wait;
I really don't like this. I think this should be done based on the compatible string. Thanks, Mark.