clk: axi-clkgen: Switch to determine_rate

The AXI clkgen clocks implements a mux with a set_parent hook, but
doesn't provide a determine_rate implementation.

This is a bit odd, since set_parent() is there to, as its name implies,
change the parent of a clock. However, the most likely candidate to
trigger that parent change is a call to clk_set_rate(), with
determine_rate() figuring out which parent is the best suited for a
given rate.

The other trigger would be a call to clk_set_parent(), but it's far less
used, and it doesn't look like there's any obvious user for that clock.

So, the set_parent hook is effectively unused, possibly because of an
oversight. However, it could also be an explicit decision by the
original author to avoid any reparenting but through an explicit call to
clk_set_parent().

The driver does implement round_rate() though, which means that we can
change the rate of the clock, but we will never get to change the
parent.

However, It's hard to tell whether it's been done on purpose or not.

Since we'll start mandating a determine_rate() implementation, let's
convert the round_rate() implementation to a determine_rate(), which
will also make the current behavior explicit. And if it was an
oversight, the clock behaviour can be adjusted later on.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20221018-clk-range-checks-fixes-v4-50-971d5077e7d2@cerno.tech
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: axi-clkgen: Use managed `of_clk_add_hw_provider()`

Use the managed `devm_of_clk_add_hw_provider()` instead of
`of_clk_add_hw_provider()`. This makes sure the provider gets automatically
removed on unbind and allows to completely eliminate the drivers `remove()`
callback.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20230410014502.27929-1-lars@metafoo.de
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: axi-clkgen: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230312161512.2715500-7-u.kleine-koenig@pengutronix.de
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: axi-clkgen: use devm_platform_ioremap_resource() short-hand

No major functional change. Noticed while checking the driver code that
this could be used.
Saves two lines.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210201151245.21845-5-alexandru.ardelean@analog.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: clk-axiclkgen: add ZynqMP PFD and VCO limits

For ZynqMP (Ultrascale) the PFD and VCO limits are different. In order to
support these, this change adds a compatible string (i.e.
'adi,zynqmp-axi-clkgen-2.00.a') which will take into account for these
limits and apply them.

Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Signed-off-by: Mathias Tausen <mta@gomspace.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210201151245.21845-3-alexandru.ardelean@analog.com
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: axi-clkgen: move the OF table at the bottom of the file

The change is mostly cosmetic. No functional changes.
Since the driver now uses of_device_get_match_data() to obtain some driver
specific info, there is no need to define the OF table before the probe
function.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201203074037.26940-2-alexandru.ardelean@analog.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: axi-clkgen: wrap limits in a struct and keep copy on the state object

Up until the these limits were global/hard-coded, since they are typically
limits of the fabric.

However, since this is an FPGA generated clock, this may run on setups
where one clock is on a fabric, and another one synthesized on another
fabric connected via PCIe (or some other inter-connect, and then these
limits need to be adjusted for each instance of the AXI CLKGEN.

This change wraps the current constants in 'axi_clkgen_limits' struct and
the 'axi_clkgen' instance keeps a copy of these limits, which is
initialized at probe from the default limits.

The limits are stored on the device-tree OF table, so that we can adjust
them via the compatible string.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201203074037.26940-1-alexandru.ardelean@analog.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: axi-clkgen: Set power bits for fractional mode

Using the fractional dividers requires some additional power bits to be
set.

The fractional power bits are not documented and the current heuristic
for setting them seems be insufficient for some cases. Just always set all
the fractional power bits when in fractional mode.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201001085948.21412-2-alexandru.ardelean@analog.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: axi-clkgen: Add support for fractional dividers

The axi-clkgen has (optional) fractional dividers on the output clock
divider and feedback clock divider path. Utilizing the fractional dividers
allows for a better resolution of the output clock, being able to
synthesize more frequencies.

Rework the driver support to support the fractional register fields, both
for setting a new rate as well as reading back the current rate from the
hardware.

For setting the rate if no perfect divider settings were found in
non-fractional mode try again in fractional mode and see if better settings
can be found. This appears to be the recommended mode of operation.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201001085948.21412-1-alexandru.ardelean@analog.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 177

Based on 1 normalized pattern(s):

licensed under the gpl 2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 135 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528170026.071193225@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

clk: axi-clkgen: Round closest in round_rate() and recalc_rate()

To minimize the rounding error round to the closest integer when
calculating the result in the recalc_rate() and set_rate() callbacks.

Also in order to improve precision multiply first and then divide.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

clk: axi-clkgen: Correctly handle nocount bit in recalc_rate()

If the nocount bit is set the divider is bypassed and the settings for the
divider count should be ignored and a divider value of 1 should be assumed.
Handle this correctly in the driver recalc_rate() callback.

While the driver sets up the part so that the read back dividers values
yield the correct result the power-on reset settings of the part might not
reflect this and hence calling e.g. clk_get_rate() without prior calls to
clk_set_rate() will yield the wrong result.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

clk: axi-clkgen: Migrate to clk_hw based OF and registration APIs

Now that we have clk_hw based provider APIs to register clks, we
can get rid of struct clk pointers while registering clks in
these drivers, allowing us to move closer to a clear split of
consumer and provider clk APIs.

Cc: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

clk: axi-clkgen: Remove sometimes impossible check

The size of unsigned long on 64-bit architectures is equal to the
size of u64, so this check is impossible there. This throws off
static checkers:

drivers/clk/clk-axi-clkgen.c:331 axi_clkgen_recalc_rate() warn:
impossible condition '(tmp > (~0)) => (0-u64max > u64max)'

Let's change this code to use min_t() instead so that we
get the same effect on architectures where sizeof(unsigned long)
doesn't equal sizeof(u64).

Cc: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

clk: axi-clkgen: Add multi-parent support

The clock generator has two clock inputs that can be used as the reference
clock. Add support for switching between them at runtime.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

clk: axi-clkgen: Remove version 1 support

Version 1 of the axi-clkgen core has not been used in new designs for over
two years now. This is a soft peripheral used in FPGAs and anybody who has
updated their kernel to the latest version will also have updated the
bitstream containing the clock generator. So it should be safe to drop
support for this now.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

clk: axi-clkgen: Remove clk.h include

Clock provider drivers generally shouldn't include clk.h because
it's the consumer API. Remove the include here because this is a
provider driver.

Cc: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

clk: Remove .owner field for driver

There is no need to init .owner field.

Based on the patch from Peter Griffin <peter.griffin@linaro.org>
"mmc: remove .owner field for drivers using module_platform_driver"

This patch removes the superflous .owner field for drivers which
use the module_platform_driver API, as this is overriden in
platform_driver_register anyway."

Signed-off-by: Kiran Padwal <kiran.padwal@smartplayin.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

clk: axi-clkgen: Add support for v2

This patch adds support for the new v2 version of the axi-clkgen core.
Unfortunately the method of accessing the registers is quite different on v2,
while the content still stays largely the same. So the patch adds a small
abstraction layer which implements the specific read and write functions for v1
and v2 in callback functions.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>

clk: Add axi-clkgen driver

This driver adds support for the AXI clkgen pcore to the common clock framework.
The AXI clkgen pcore is a AXI front-end to the MMCM_ADV frequency synthesizer
commonly found in Xilinx FPGAs.

The AXI clkgen pcore is used in Analog Devices' reference designs targeting
Xilinx FPGAs.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mike Turquette <mturquette@linaro.org>