Add support for clock gate hysteresis control.  For now, if it's
defined for a clock, it's enabled.
Signed-off-by: NAlex Elder <elder@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Add support for CCU policy engine control, and also for setting the
mask bits for bus clocks that require a policy change to get
activated.  This includes adding validity checking framework for
CCUs, to validate the policy fields if defined.
Signed-off-by: NAlex Elder <elder@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Rather than "manually" setting up each CCU's clock entries at run
time, define a flexible array of generic Kona clock structures
within the CCU structure itself.  Each of these entries contains
generic kona clock information (like its CCU pointer and clock
framework initialization data).  Each also has a pointer to a
structure contianing clock type-dependent initialization data
(like register definitions).

Since we'll iterate over these arrays we need to be sure they have
slots for all potential clock index values.  (E.g. for the root CCU
we must have at least BCM281XX_ROOT_CCU_CLOCK_COUNT slots.)  To
ensure this we always define an extra entry and fill it using the
special initializer LAST_KONA_CLK.

Just about everything we need to know about a clock can be defined
statically.  As a result, kona_clk_setup() can be changed to take
just a kona_clk structure as its argument, and peri_clk_setup() can
be simplified.  With the information pre-defined we are also able
to handle most clock setup genericially.  We can do away with the
CCU-specific callback functions that previously were needed to set
up the entries in CCU's clock array.

Move the definition of the ccu_data structure down in "clk-kona.h"
to avoid a forward dependency.
Signed-off-by: NAlex Elder <elder@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

We know up front how many CCU's we'll support, so there's no need to
allocate their data structures dynamically.  Define a macro
KONA_CCU_COMMON() to simplify the initialization of many of the
fields in a ccu_data structure.  Pass the address of a statically
defined CCU structure to kona_dt_ccu_setup() rather than having that
function allocate one.

We also know at build time how many clocks a given CCU will provide,
though the number of of them for each CCU is different.  Record the
number of clocks we need in the CCU's clk_onecell_data struct
(which is used when we register the CCU with the common clock code
as a clock provider).  Rename that struct field "clk_data" (because
"data" alone gets a little confusing).

Use the known clock count to move the allocation of each CCU's
clocks array into ccu_clks_setup() rather than having each CCU's
setup callback function do it.

(The real motivation behind all of this is that we'll be doing some
static initialization of some additional CCU-specific data soon.)
Signed-off-by: NAlex Elder <elder@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

As I developed the bcm281xx clock code I understood there were
restrictions on device tree "compatible" strings names, and as a
result "bcm11351" was used in places despite the part family being
more properly called "bcm281xx".  This can be a little confusing.

In some cases I went to far and things using "bcm11351" when that
was not necessary.

This patch remedies this.  It renames the symbol used to define the
"compatible" string (but not its value) so it uses "BCM281XX".
Similarly, the name names provided to the CLK_OF_DECLARE() macro
are changed, hoping to minimize the number of places that the
confusing "11351" string is used.
Signed-off-by: NAlex Elder <elder@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Use the init_data.name field to hold the name of a Kona clock rather
than duplicating it.
Signed-off-by: NAlex Elder <elder@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Don't let a failure of ccu_wait_bit() go unnoticed.
Signed-off-by: NAlex Elder <elder@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

The Broadcom Kona clock code, as originally written, made use of
unnamed union and struct fields.  This is a feature present in C11,
and is a GNU extension otherwise.  It worked very well for me.

Unfortunately, Russell King reported that this feature was not
supported in a build environment he used, which meant attempting
to build this code failed spectacularly.

Add names to these unnamed fields, and update the code accordingly.
Reported-by: NRussell King <linux@arm.linux.org.uk>
Tested-by: NMarkus Mayer <markus.mayer@linaro.org>
Signed-off-by: NAlex Elder <elder@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Add the CLK_IGNORE_UNUSED flag when setting up a peripheral clock.
This prevents unused clocks from getting disabled, and by doing
this we can use the common clock code even before we've resolved
all the spots that need to get a reference to their clock.
Signed-off-by: NAlex Elder <elder@linaro.org>
Reviewed-by: NMatt Porter <mporter@linaro.org>
Acked-by: NMike Turquette <mturquette@linaro.org>
Signed-off-by: NMatt Porter <mporter@linaro.org>

Add code for device tree support of clocks in the BCM281xx family of
SoCs.  Machines in this family use peripheral clocks implemented by
"Kona" clock control units (CCUs).  (Other Broadcom SoC families use
Kona style CCUs as well, but support for them is not yet upstream.)

A BCM281xx SoC has multiple CCUs, each of which manages a set of
clocks on the SoC.  A Kona peripheral clock is composite clock that
may include a gate, a parent clock multiplexor, and zero, one
or two dividers.  There is a variety of gate types, and many gates
implement hardware-managed gating (often called "auto-gating").
Most dividers divide their input clock signal by an integer value
(one or more).  There are also "fractional" dividers which allow
division by non-integer values.  To accomodate such dividers,
clock rates and dividers are generally maintained by the code in
"scaled" form, which allows integer and fractional dividers to
be handled in a uniform way.

If present, the gate for a Kona peripheral clock must be enabled
when a change is made to its multiplexor or one of its dividers.
Additionally, dividers and multiplexors have trigger registers which
must be used whenever the divider value or selected parent clock is
changed.  The same trigger is often used for a divider and
multiplexor, and a BCM281xx peripheral clock occasionally has two
triggers.

The gate, dividers, and parent clock selector are treated in this
code as "components" of a peripheral clock.  Their functionality is
implemented directly--e.g. the common clock framework gate
implementation is not used for a Kona peripheral clock gate.  (This
has being considered though, and the intention is to evolve this
code to leverage common code as much as possible.)

The source code is divided into three general portions:

    drivers/clk/bcm/clk-kona.h
    drivers/clk/bcm/clk-kona.c
        These implement the basic Kona clock functionality,
        including the clk_ops methods and various routines to
        manipulate registers and interpret their values.  This
        includes some functions used to set clocks to a desired
        initial state (though this feature is only partially
        implemented here).

    drivers/clk/bcm/clk-kona-setup.c
        This contains generic run-time initialization code for
        data structures representing Kona CCUs and clocks.  This
        encapsulates the clock structure initialization that can't
        be done statically.  Note that there is a great deal of
        validity-checking code here, making explicit certain
        assumptions in the code.   This is mostly useful for adding
        new clock definitions and could possibly be disabled for
        production use.

    drivers/clk/bcm/clk-bcm281xx.c
        This file defines the specific CCUs used by BCM281XX family
        SoCs, as well as the specific clocks implemented by each.
        It declares a device tree clock match entry for each CCU
        defined.

    include/dt-bindings/clock/bcm281xx.h
        This file defines the selector (index) values used to
        identify a particular clock provided by a CCU.  It consists
        entirely of C preprocessor constants, to be used by both the
        C source and device tree source files.
Signed-off-by: NAlex Elder <elder@linaro.org>
Reviewed-by: NTim Kryger <tim.kryger@linaro.org>
Reviewed-by: NMatt Porter <mporter@linaro.org>
Acked-by: NMike Turquette <mturquette@linaro.org>
Signed-off-by: NMatt Porter <mporter@linaro.org>