clk: renesas: div6: Implement range checking

Consider the minimum and maximum clock rates imposed by clock users when
calculating the most appropriate clock rate in the .determine_rate()
callback.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/35ceb262c71f1b2e9864a39bde9dafd78b2981f4.1617281699.git.geert+renesas@glider.be

clk: renesas: div6: Consider all parents for requested rate

Currently the .determine_rate() callback considers only the current
parent clock, limiting the range of achievable clock rates on DIV6
clocks with multiple parents, as found on SH/R-Mobile SoCs.

Extend the callback to consider all available parent clocks.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/60e639692b462f99e0b6ab868c3675b3d97dbdb0.1617281699.git.geert+renesas@glider.be

clk: renesas: div6: Switch to .determine_rate()

As the .round_rate() callback returns a long clock rate, it cannot
return clock rates that do not fit in signed long, but do fit in
unsigned long. Hence switch the DIV6 clocks on SH/R-Mobile and R-Car
SoCs from the old .round_rate() callback to the newer .determine_rate()
callback, which does not suffer from this limitation.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/7fd8c45cd8bf5c6d928ca69c8b669be35b93de09.1617281699.git.geert+renesas@glider.be

clk: renesas: div6: Simplify src mask handling

Simplify the handling of the register bits to select the parent clock,
by storing a bitmask instead of separate shift and width values.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/5f05a5110d222ce5a113e683fe2aa726f4100b73.1617281699.git.geert+renesas@glider.be

clk: renesas: div6: Use clamp() instead of clamp_t()

As "div" is already "unsigned int", adding "U" suffixes to the constants
"1" and "64" allows us to replace the call to clamp_t() by a call to
clamp(). This removes hidden casts, and thus helps the compiler doing a
better job at type-checking.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/2670c1e3c82a245666578cbbd1fb20d37932fd8e.1617281699.git.geert+renesas@glider.be

clk: renesas: Zero init clk_init_data

As clk_core_populate_parent_map() checks clk_init_data.num_parents
first, and checks clk_init_data.parent_names[] before
clk_init_data.parent_data[] and clk_init_data.parent_hws[], leaving the
latter uninitialized doesn't do harm for now. However, it is better to
play it safe, and initialize all clk_init_data structures to zeroes, to
avoid any current and future members containing uninitialized data.

Remove a few explicit zero initializers, which are now superfluous.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20210326105434.1574796-1-geert+renesas@glider.be

clk: renesas: div6: Combine clock-private and parent array allocation

Make div6_clock.parents[] a flexible array member, and use the new
struct_size() helper, to combine the allocation of the clock-private
structure and array of parent clocks.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>

clk: renesas: Remove usage of CLK_IS_BASIC

This flag doesn't look to be used by any code, just set in various clk
init structures and then never tested again. Remove it from these
drivers as it doesn't provide any benefit.

Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: <linux-renesas-soc@vger.kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: renesas: use SPDX identifier for Renesas drivers

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: Convert to using %pOFn instead of device_node.name

In preparation to remove the node name pointer from struct device_node,
convert printf users to use the %pOFn format specifier.

Cc: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: linux-clk@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-renesas-soc@vger.kernel.org
Cc: linux-omap@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: renesas: div6: Always use readl()/writel()

On arm32/arm64, there is no reason to use the (soon deprecated)
clk_readl()/clk_writel(). Hence use the generic readl()/writel()
instead.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>

clk: renesas: div6: Restore clock state during resume

On R-Car Gen3 systems, PSCI system suspend powers down the SoC, losing
clock configuration. Register an (optional) notifier to restore the
DIV6 clock state during system resume.

As DIV6 clocks can be picky w.r.t. modifying multiple register fields at
once, restore is not implemented by blindly restoring the register
value, but by using the existing cpg_div6_clock_{en,dis}able() helpers.

Note that this does not yet support DIV6 clocks with multiple parents,
which do not exist on R-Car Gen3 SoCs.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

clk: renesas: div6: Document fields used for parent selection

Add the missing documentation for the fields in struct div6_clock
related to parent selection for DIV6 clocks with selectable parents, as
found in R/SH-Mobile SoCs.

Fixes: c6d67fb037f4eaaf ("clk: shmobile: div6: support selectable-input clocks")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

clk: renesas: move drivers to renesas directory

This is part of an ongoing process to migrate from ARCH_SHMOBILE to
ARCH_RENESAS the motivation for which being that RENESAS seems to be a more
appropriate name than SHMOBILE for the majority of Renesas ARM based SoCs.

Along with the above mentioned Kconfig changes it seems appropriate
to also rename directories that only hold drivers for such SoCs.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>