linux/drivers/clk/st
Maxime Ripard 36f8a30c0f clk: st: flexgen: Switch to determine_rate
The ST Flexgen 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-v4-62-971d5077e7d2@cerno.tech
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2023-06-08 18:39:35 -07:00
..
clk-flexgen.c clk: st: flexgen: Switch to determine_rate 2023-06-08 18:39:35 -07:00
clkgen-fsyn.c clk: st: Fix memory leak in st_of_quadfs_setup() 2022-12-07 18:27:11 -08:00
clkgen-mux.c clk: st: Hold reference returned by of_get_parent() 2022-08-19 14:34:44 -07:00
clkgen-pll.c clk: st: clkgen-pll: embed soc clock outputs within compatible data 2021-06-27 19:53:39 -07:00
clkgen.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00