clk: Treat NULL as dummy clocks ...

NULL pointers should be treated as dummy clocks as done in the kernel.
Using a not fully filled in clk * array for of_clk_add_provider may result
in NULL clks. When these are passed into the clk framework we should not
crash.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: move of_clk_get_parent_name() to common clk code ...

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

treewide: fix signedness mixups in printf format specifiers ...

This most likely doesn't fix any real bugs, but it's the
right thing to do and reduces the noise level with static
checkers.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: Add parent round/set rate for mux and gate ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: implement clk_round_rate ...

Instead of returning just the current rate implement clk_round_rate
properly.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: add of_clk_init and CLK_OF_DECLARE macro ...

This add barebox versions of of_clk_init for parsing and registering
clock providers from DT. Also, a macro CLK_OF_DECLARE is added, that
allows to put init callbacks into its own section that can be linked
in the binary.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: of: introduce of_clk_src_simple_get ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: add clock lookup from devicetree ...

Taken from the Linuxkernel with some small adjustments for barebox.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: add prototype for clk_is_enabled ...

On MXS we need to poll the busy bit when changing a clock rate, but only
when the parent clocks are enabled. This exposes the already present
function clk_is_enabled which is suitable for this job.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: fix warning: no previous prototype for 'clk_is_enabled' ...

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: Add is_enabled callback ...

This allows us to better detect whether a clk is enabled or not.

- If we can ask a clk, ask it. If it's enabled, go on and ask parents
- If we can't ask it, but it can be enabled, depend on the enable_count.
  if it's positive, go on and ask parents
- If we can't ask it and it cannot be enabled, assume it is enabled
  and ask parents.

This makes the CLK_ALWAYS_ENABLED unnecessary, since the fixed clk now
always returns 1 in its is_enabled callback.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

commands: clk_dump: denote always enabled clocks ...

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: add always enabled clocks ...

Current barebox clk framework allow disable any clock
and there is no means to prevent that.

But there are the clocks that can't be disabled
by software at all.

This patch allow registration of a clock immune to clk_disable().

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: check for invalid clocks ...

Checking for invalid clocks on function entry allows users
to for example do a clk_set_rate(clk_lookup("myclk"), x) without
checking for validity of the result of clk_lookup first.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: initial common clk support ...

This adds barebox common clk support loosely based on the Kernel common
clk support. differences are:

- barebox does not need prepare/unprepare
- no parent rate propagation for set_rate
- struct clk is not really encapsulated from the drivers

Along with the clk support we have support for some basic clk building
blocks:

- clk-fixed
- clk-fixed-factor
- clk-mux
- clk-divider

clk-fixed and clk-fixed-factor are completely generic, clk-mux and clk-divider
are currently the way i.MX muxes/dividers are implemented.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>