Thread (13 messages) 13 messages, 3 authors, 2016-02-29

Re: [PATCH 2/2] clk: ti: Add support for dm814x ADPLL

From: Tony Lindgren <tony@atomide.com>
Date: 2016-02-17 17:39:52
Also in: linux-arm-kernel, linux-omap

* Michael Turquette [off-list ref] [160216 17:32]:
Quoting Tony Lindgren (2016-02-12 13:20:09)
quoted
- Split the device tree binding into a separate patch as requested
  by Mike for his conditional ack of the binding
Just to make life fun for you, the clk tree is once more merging DT
bindings descriptions and headers. You don't need to merge the patches,
it doesn't matter to me, but just as a heads up for the future.
OK :)
quoted
--- /dev/null
+++ b/drivers/clk/ti/Kconfig
@@ -0,0 +1,6 @@
+config COMMON_CLK_TI_ADPLL
+       tristate "Clock driver for dm814x ADPLL"
+       depends on ARCH_OMAP2PLUS
+       default y if SOC_TI81XX
Can we add COMPILE_TEST here?
Good idea, will add.
quoted
+static int ti_adpll_init_inputs(struct ti_adpll_data *d)
+{
+       const char *error = "need at least %i inputs";
+       struct clk *clock;
+       int nr_inputs;
+
+       nr_inputs = of_clk_get_parent_count(d->np);
+       if (nr_inputs < d->c->nr_max_inputs) {
+               dev_err(d->dev, error, nr_inputs);
+               return -EINVAL;
+       }
+       of_clk_parent_fill(d->np, d->parent_names, nr_inputs);
+
+       clock = devm_clk_get(d->dev, d->parent_names[0]);
+       if (IS_ERR(clock)) {
+               dev_err(d->dev, "could not get clkinp\n");
+               return PTR_ERR(clock);
+       }
+       d->parent_clocks[TI_ADPLL_CLKINP] = clock;
+
+       clock = devm_clk_get(d->dev, d->parent_names[1]);
+       if (IS_ERR(clock)) {
+               dev_err(d->dev, "could not get clkinpulow clock\n");
+               return PTR_ERR(clock);
+       }
+       d->parent_clocks[TI_ADPLL_CLKINPULOW] = clock;
Are the clock parents known at compile-time? Can we just put that data
in C instead of whatever is going on here?
No they can be board specific depending how the inputs for
clkin, clkinpulow and clkinphif are wired.
...
quoted
+int __init dm814x_adpll_enable_init_clocks(void)
+{
+       int i, err;
+
+       if (!timer_clocks_initialized)
+               return -ENODEV;
+
+       for (i = 0; i < ARRAY_SIZE(init_clocks); i++) {
+               struct clk *clock;
+
+               clock = clk_get(NULL, init_clocks[i]);
+               if (WARN(IS_ERR(clock), "could not find init clock %s\n",
+                        init_clocks[i]))
+                       continue;
+               err = clk_prepare_enable(clock);
+               if (WARN(err, "could not enable init clock %s\n",
+                        init_clocks[i]))
+                       continue;
We have a shiny new series that provides a standard way to do this:

http://lkml.kernel.org/r/[ref]
OK nice, so tagging the MPU and DDR clocks with CLK_IS_CRITICAL or
"clock-critical" should allow removing this code. I think in this
case I still need to set CLK_IS_CRITICAL as the clock is output 1
of the dts defined clock and does not have a separate dts node.

I can update when those patches hit Linux next, or I can do a
follow-up patch later on if we want to avoid the dependency
here. Which do you prefer?

Regards,

Tony
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