Add core support to allow clock implementations to select the best
parent clock when rounding a rate, e.g. the one which can provide the
closest clock rate to that requested. This is by way of adding a new
clock op, determine_rate(), which is like round_rate() but has an extra
parameter to allow the clock implementation to optionally select a
different parent clock. The core then takes care of reparenting the
clock when setting the rate.
The parent change takes place with the help of some new private data
members. struct clk::new_parent specifies a clock's new parent (NULL
indicates no change), and struct clk::new_child specifies a clock's new
child (whose new_parent member points back to it). The purpose of these
are to allow correct walking of the future tree for notifications prior
to actually reparenting any clocks, specifically to skip child clocks
who are being reparented to another clock (they will be notified via the
new parent), and to include any new child clock. These pointers are set
by clk_calc_subtree(), and the new_child pointer gets cleared when a
child is actually reparented to avoid duplicate POST_RATE_CHANGE
notifications.
Each place where round_rate() is called, determine_rate() is checked
first and called in preference. This restructures a few of the call
sites to simplify the logic into if/else blocks.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Add a table lookup feature to the mux clock. Also allow arbitrary masks
instead of the width. This will be used by some clocks on Tegra114. Also
adapt the tegra periph clk because it uses struct clk_mux directly.
Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Most platforms end up using a mix of basic clock types and
some which use clk_hw_foo struct for filling in custom platform
information when the clocks don't fit into basic types supported.
In platform code, its useful to know if a clock is using a basic
type or clk_hw_foo, which helps platforms know if they can
safely use to_clk_hw_foo to derive the clk_hw_foo pointer from
clk_hw.
Mark all basic clocks with a CLK_IS_BASIC flag.
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Some divider clks do not have any obvious relationship
between the divider and the value programmed in the
register. For instance, say a value of 1 could signify divide
by 6 and a value of 2 could signify divide by 4 etc.
Also there are dividers where not all values possible
based on the bitfield width are valid. For instance
a 3 bit wide bitfield can be used to program a value
from 0 to 7. However its possible that only 0 to 4
are valid values.
All these cases need the platform code to pass a simple
table of divider/value tuple, so the framework knows
the exact value to be written based on the divider
calculation and can also do better error checking.
This patch adds support for such rate table based
dividers and as part of the support adds a new
registration function 'clk_register_divider_table()'
and a new macro for static definition
'DEFINE_CLK_DIVIDER_TABLE'.
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Having fixed factors/dividers in hardware is a common pattern, so
add a basic clock type doing this. It basically describes a fixed
factor clock using a nominator and a denominator.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Viresh Kumar <viresh.kumar@st.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
[mturquette@linaro.org: constify parent_names in static init macro]
[mturquette@linaro.org: copy/paste bug from mux in static init macro]
[mturquette@linaro.org: fix error handling in clk_register_fixed_factor]
[mturquette@linaro.org: improve division accuracy; thanks to Saravana]
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Create a struct clk_init_data to hold all data that needs to be passed from
the platfrom specific driver to the common clock framework during clock
registration. Add a pointer to this struct inside clk_hw.
This has several advantages:
* Completely hides struct clk from many clock platform drivers and static
clock initialization code that don't care for static initialization of
the struct clks.
* For platforms that want to do complete static initialization, it removed
the need to directly mess with the struct clk's fields while still
allowing to statically allocate struct clk. This keeps the code more
future proof even if they include clk-private.h.
* Simplifies the generic clk_register() function and allows adding optional
fields in the future without modifying the function signature.
* Simplifies the static initialization of clocks on all platforms by
removing the need for forward delcarations or convoluted macros.
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
[mturquette@linaro.org: kept DEFINE_CLK_* macros and __clk_init]
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergman <arnd.bergmann@linaro.org>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Shawn Guo <shawn.guo@freescale.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Jamie Iles <jamie@jamieiles.com>
Cc: Richard Zhao <richard.zhao@linaro.org>
Cc: Saravana Kannan <skannan@codeaurora.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Amit Kucheria <amit.kucheria@linaro.org>
Cc: Deepak Saxena <dsaxena@linaro.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
parent name array is now expected to be const char *, make
the relevent changes in the clk macros which define
default clock types.
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
All macros used for creating different kind of clocks have similar code for
initializing struct clk. This patch removes those redundant lines and create
another macro DEFINE_CLK.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
This patch cleans up clk_register and solves a few bugs by teaching
clk_register and __clk_init to return error codes (instead of just NULL)
to better align with the existing clk.h api.
Along with that change this patch also introduces a new behavior whereby
clk_register copies the parent_names array, thus allowing platforms to
declare their parent_names arrays as __initdata.
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Drivers should be able to declare their arrays of parent names as const
so the APIs need to accept const arguments.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
[mturquette@linaro.org: constified gate]
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Besides the static initialization, the clk_ops of basic clks could
also be used by particular clk type being subclass of the basic clks.
For example, clk_busy_divider has the same clk_ops as clk_divider,
except it has to wait for a busy bit before return success with
.set_rate. clk_busy_divider will somehow reuse clk_ops of clk_divider.
Since clk-provider.h is included by clk-private.h, it's safe to move
those clk_ops declaration of basic clks form clk-private.h into
clk-provider.h, so that implementation of clks like clk_busy_divider
above do not need to include clk-private.h to access those clk_ops.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
The clk_ops of basic clks should have "const" to match the definition
in "struct clk" and clk_register prototype.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Many platforms support simple gateable clocks, fixed-rate clocks,
adjustable divider clocks and multi-parent multiplexer clocks.
This patch introduces basic clock types for the above-mentioned hardware
which share some common characteristics.
Based on original work by Jeremy Kerr and contribution by Jamie Iles.
Dividers and multiplexor clocks originally contributed by Richard Zhao &
Sascha Hauer.
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Mike Turquette <mturquette@ti.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergman <arnd.bergmann@linaro.org>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Shawn Guo <shawn.guo@freescale.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Jamie Iles <jamie@jamieiles.com>
Cc: Richard Zhao <richard.zhao@linaro.org>
Cc: Saravana Kannan <skannan@codeaurora.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Amit Kucheria <amit.kucheria@linaro.org>
Cc: Deepak Saxena <dsaxena@linaro.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The common clock framework defines a common struct clk useful across
most platforms as well as an implementation of the clk api that drivers
can use safely for managing clocks.
The net result is consolidation of many different struct clk definitions
and platform-specific clock framework implementations.
This patch introduces the common struct clk, struct clk_ops and an
implementation of the well-known clock api in include/clk/clk.h.
Platforms may define their own hardware-specific clock structure and
their own clock operation callbacks, so long as it wraps an instance of
struct clk_hw.
See Documentation/clk.txt for more details.
This patch is based on the work of Jeremy Kerr, which in turn was based
on the work of Ben Herrenschmidt.
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Mike Turquette <mturquette@ti.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Rob Herring <rob.herring <at> calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Arnd Bergman <arnd.bergmann@linaro.org>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Shawn Guo <shawn.guo@freescale.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Richard Zhao <richard.zhao@linaro.org>
Cc: Saravana Kannan <skannan@codeaurora.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Amit Kucheria <amit.kucheria@linaro.org>
Cc: Deepak Saxena <dsaxena@linaro.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
