For those clk gates which hold share count, since its is_enabled
callback is only checking the share count rather than reading
the hardware register setting, in the late phase of kernel bootup,
the clk_disable_unused action will NOT handle the scenario of
share_count is 0 but the hardware setting is enabled, actually,
U-Boot normally enables all clk gates, then those shared clk gates
will be always enabled until they are used by some modules.

So the problem would be: when kernel boot up, the usecount cat
from clk tree is 0, but the clk gates actually is enabled in
hardware register, it will confuse user and bring unnecessary power
consumption.

This patch adds .disable_unused callback and using hardware register
check for .is_enabled callback of shared nodes to handle such scenario
in late phase of kernel boot up, then the hardware status will match the
clk tree info.
Signed-off-by: NAnson Huang <b20788@freescale.com>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>

Commit 63288b72 ("ARM: imx: fix shared gate clock") attempted to fix
an issue with particular enable/disable sequence from two shared gate
clocks.  But unfortunately, while it partially fixed the issue, it also
did something wrong in .is_enabled() function hook.  In case of shared
gate, the function shouldn't really query the hardware state via
share_count, because the function is trying to query the enabling state
of the clock in question, not the hardware state which is shared by
multiple clocks.

Fix the issue by returning the enable_count of the clock itself which is
maintained by clock core, in case it's a clock sharing hardware gate
with others.  As the result, the initialization of share_count per
hardware state is not needed now.  So remove it.
Reported-by: NFabio Estevam <fabio.estevam@freescale.com>
Fixes: 63288b72 ("ARM: imx: fix shared gate clock")
Cc: <stable@vger.kernel.org>
Signed-off-by: NShawn Guo <shawn.guo@freescale.com>
Tested-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NOlof Johansson <olof@lixom.net>

Let's say clock A and B are two gate clocks that share the same register
bit in hardware.  Therefore they are registered as shared gate clocks
with imx_clk_gate2_shared().

In a scenario that only clock A is enabled by clk_enable(A) while B is
not used, the shared gate will be unexpectedly disabled in hardware.
It happens because clk_enable(A) increments the share_count from 0 to 1,
while clock B is unused to clock core, and therefore the core function
will just disable B by calling clk->ops->disable() directly.  The
consequence of that call is share_count is decremented to 0 and the gate
is disabled in hardware, even though clock A is still in use.

The patch fixes the issue by initializing the share_count per hardware
state and returns enable state per share_count from .is_enabled() hook,
in case it's a shared gate.

While at it, add a check in clk_gate2_disable() to ensure it's never
called with a zero share_count.
Reported-by: NFabio Estevam <fabio.estevam@freescale.com>
Fixes: f9f28cdf ("ARM: imx: add shared gate clock support")
Signed-off-by: NShawn Guo <shawn.guo@freescale.com>
Tested-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NOlof Johansson <olof@lixom.net>

It's quite common on i.MX that one gate bit controls the gating of
multiple clocks, i.e. this is a shared gate.  The patch adds the
function imx_clk_gate2_shared() for such case.  The clocks controlled
by the same gate bits should call this function with a pointer to a
single share count variable, so that the gate bits will only be
operated on the first enabling and the last disabling of these shared
gate clocks.

Thanks to Gerhard Sittig <gsi@denx.de> for this idea.
Signed-off-by: NShawn Guo <shawn.guo@freescale.com>

The imx specific clk_gate2 always has a valid lock with the clock.  So
the validation on gate->lock is not really needed.  Remove it.
Signed-off-by: NShawn Guo <shawn.guo@freescale.com>

The imx clk-gate2 driver implements an i.MX specific gate clock, which
has two bits controlling the gate states.  While this is a completely
separate gate driver from the common clk-gate one, it reuses the common
clk_gate structure.  Such reusing makes the extending of clk_gate2
clumsy.  Let's define struct clk_gate2 on our own to make the driver
independent of the common clk-gate one, and ease the clk_gate2 extending
at a later time.
Signed-off-by: NShawn Guo <shawn.guo@freescale.com>

For ccm clock gate, both 2b'11 and 2b'01 should be treated
as clock enabled, see below description in CCM, whenver CPU
trys to check clock gate's status, system will be in run mode.

2b'00: clock is off during all modes;
2b'01: clock is on in run mode, but off in wait and stop mode;
2b'10: Not applicable;
2b'11: clock is on during all modes, except stop mode.
Signed-off-by: NAnson Huang <b20788@freescale.com>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>

Fix the following sparse warning:

arch/arm/mach-imx/clk-gate2.c:86:12: warning: symbol 'clk_register_gate2' was not declared. Should it be static?
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>

The error-valued pointer clk is used for the arg of kfree, it should be
kfree(gate) if clk_register() return ERR_PTR().

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>

This gate consists of two bits:

0b00: clk disabled
0b01: clk enabled in run mode and disabled in sleep mode
0b11: clk enabled

Currently only disabled and enabled are supported. As it's unlikely
that we find something like this in another SoC create a i.MX specific
clk helper for this.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>

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: NSaravana Kannan <skannan@codeaurora.org>
[mturquette@linaro.org: kept DEFINE_CLK_* macros and __clk_init]
Signed-off-by: NMike 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>

This patch tries to remove duplicate code for clk_gate clocks. This creates
another routine clk_gate_endisable() which will take care of enable/disable
clock with knowledge of CLK_GATE_SET_TO_DISABLE flag.

It works on following logic:

For enabling clock, enable = 1
	set2dis = 1	-> clear bit	-> set = 0
	set2dis = 0	-> set bit	-> set = 1

For disabling clock, enable = 0
	set2dis = 1	-> set bit	-> set = 1
	set2dis = 0	-> clear bit	-> set = 0

So, result is always: enable xor set2dis.
Signed-off-by: NViresh Kumar <viresh.kumar@st.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

This patch is the basic clk version of 'clk: core: copy parent_names &
return error codes'.

The registration functions are changed to allow the core code to copy
the array of strings and allow platforms to declare those arrays as
__initdata.

This patch also converts all of the basic clk registration functions to
return error codes which better aligns them with the existing clk.h api.
Signed-off-by: NMike 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: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

It makes no sense to have EXPORT_SYMBOL_GPL on static functions.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NMike 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: NMike Turquette <mturquette@linaro.org>
Signed-off-by: NMike Turquette <mturquette@ti.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Tested-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: NRob 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: NArnd Bergmann <arnd@arndb.de>