clk: kirkwood: Fix a clocking boot regression

Since a few kernel releases the Pogoplug 4 has crashed like this
during boot:

Unable to handle kernel NULL pointer dereference at virtual address 00000002
(...)
[<c04116ec>] (strlen) from [<c00ead80>] (kstrdup+0x1c/0x4c)
[<c00ead80>] (kstrdup) from [<c04591d8>] (__clk_register+0x44/0x37c)
[<c04591d8>] (__clk_register) from [<c04595ec>] (clk_hw_register+0x20/0x44)
[<c04595ec>] (clk_hw_register) from [<c045bfa8>] (__clk_hw_register_mux+0x198/0x1e4)
[<c045bfa8>] (__clk_hw_register_mux) from [<c045c050>] (clk_register_mux_table+0x5c/0x6c)
[<c045c050>] (clk_register_mux_table) from [<c0acf3e0>] (kirkwood_clk_muxing_setup.constprop.0+0x13c/0x1ac)
[<c0acf3e0>] (kirkwood_clk_muxing_setup.constprop.0) from [<c0aceae0>] (of_clk_init+0x12c/0x214)
[<c0aceae0>] (of_clk_init) from [<c0ab576c>] (time_init+0x20/0x2c)
[<c0ab576c>] (time_init) from [<c0ab3d18>] (start_kernel+0x3dc/0x56c)
[<c0ab3d18>] (start_kernel) from [<00000000>] (0x0)
Code: e3130020 1afffffb e12fff1e c08a1078 (e5d03000)

This is because the "powersave" mux clock 0 was provided in an unterminated
array, which is required by the loop in the driver:

/* Count, allocate, and register clock muxes */
for (n = 0; desc[n].name;)
n++;

Here n will go out of bounds and then call clk_register_mux() on random
memory contents after the mux clock.

Fix this by terminating the array with a blank entry.

Fixes: 105299381d87 ("cpufreq: kirkwood: use the powersave multiplexer")
Cc: stable@vger.kernel.org
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: Gregory CLEMENT <gregory.clement@bootlin.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210814235514.403426-1-linus.walleij@linaro.org
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: kirkwood: Add support for MV98DX1135

The 98DX1135 is a switch chip with an integrated CPU. This is similar to
the 98DX4122 except that the core clock speed is fixed to 166Mhz.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: kirkwood: fix refcount leak in kirkwood_clk_init()

The of_find_compatible_node() returns a node pointer with refcount
incremented, but there is the lack of use of the of_node_put() when
done. Add the missing of_node_put() to release the refcount.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Reviewed-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Fixes: 58d516ae95cb ("clk: mvebu: kirkwood: maintain clock init order")
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: mvebu: use SPDX-License-Identifier

Convert the remaining files to SPDX license description.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: move the common clock's to_clk_*(_hw) macros to clk-provider.h

to_clk_*(_hw) macros have been repeatedly defined in many places.
This patch moves all the to_clk_*(_hw) definitions in the common
clock framework to public header clk-provider.h, and drop the local
definitions.

Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

cpufreq: kirkwood: use the powersave multiplexer

The powersave clock acts like a multiplexer for the cpu, selecting
either the clock signal derived from the cpu pll or from the ddr clock.
This patch changes powersave from a gate clock to a mux clock to better
reflect this behavior.

This is a cleaner approach whereby the frequency of the cpu always
matches the rate of powersave_clk. The cpufreq driver for the kirkwood
platform no longer must parse this behavior out of various calls to
clk_enable and clk_disable, but can instead simply select the parent cpu
it wants when changing rate. Likewise when requesting the cpu rate we
need only query powersave_clk's rate through the usual call to
clk_get_rate.

The new clock data and corresponding changes to the cpufreq driver are
combined into this single commit to avoid a git bisect issue where this
cpufreq driver fails to work properly between the commit that updates
the kirkwood clock driver and the commit that changes how the cpufreq
driver uses that clock.

Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

clk: mvebu: powersave clock is a multiplexer

Kirkwood is unique among the mvebu SoCs for having a clock multiplexer
that feeds into the cpu. This multiplexer can select either the cpu pll
or the ddr clock as its input signal, allowing for a choice between
performance and power savings.

This patch introduces the code needed to register the clock multiplexer
on Kirkwood SoCs but does not include the clock data to actually
register the clock. That will be done in a follow-up patch which is
necessary to prevent breaking git bisect.

Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

clk: mvebu: kirkwood: maintain clock init order

Init order of CLK_OF_DECLARE'd drivers depends on compile order.
Unfortunately, clk_of_init does not allow drivers to return errors,
e.g. -EPROBE_DEFER if parent clocks have not been registered, yet.

To avoid init order woes for MVEBU clock drivers, we take care of
proper init order ourselves. This patch joins core-clk and gating-clk
init to maintain proper init order.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

clk: kirkwood: Fix incorrect placement of __initconst

__initconst should be placed between the variable name and equal
sign for the variable to be placed in the intended section.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Gregory Clement <gregory.clement@free-electrons.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

clk: mvebu: add Kirkwood SoC-centric clock init

This is moving core clock and clock gating init for Kirkwood to its
own file and adds a Kconfig option. Also init functions are added and
declared so they get called on of_clk_init.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>