From c80ac50cbb378a4029129a596251747386e3c8e9 Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Fri, 25 Feb 2022 15:35:28 +0100 Subject: clk: Always set the rate on clk_set_range_rate When we change a clock minimum or maximum using clk_set_rate_range(), clk_set_min_rate() or clk_set_max_rate(), the current code will only trigger a new rate change if the rate is outside of the new boundaries. However, a clock driver might want to always keep the clock rate to one of its boundary, for example the minimum to keep the power consumption as low as possible. Since they don't always get called though, clock providers don't have the opportunity to implement this behaviour. Let's trigger a clk_set_rate() on the previous requested rate every time clk_set_rate_range() is called. That way, providers that care about the new boundaries have a chance to adjust the rate, while providers that don't care about those new boundaries will return the same rate than before, which will be ignored by clk_set_rate() and won't result in a new rate change. Suggested-by: Stephen Boyd Signed-off-by: Maxime Ripard Link: https://lore.kernel.org/r/20220225143534.405820-7-maxime@cerno.tech Signed-off-by: Stephen Boyd --- drivers/clk/clk.c | 45 +++++++++++++++++++++++---------------------- 1 file changed, 23 insertions(+), 22 deletions(-) (limited to 'drivers/clk/clk.c') diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index c15ee5070f52..9bc8bf434b94 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -2373,28 +2373,29 @@ int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max) goto out; } - rate = clk_core_get_rate_nolock(clk->core); - if (rate < min || rate > max) { - /* - * FIXME: - * We are in bit of trouble here, current rate is outside the - * the requested range. We are going try to request appropriate - * range boundary but there is a catch. It may fail for the - * usual reason (clock broken, clock protected, etc) but also - * because: - * - round_rate() was not favorable and fell on the wrong - * side of the boundary - * - the determine_rate() callback does not really check for - * this corner case when determining the rate - */ - - rate = clamp(clk->core->req_rate, min, max); - ret = clk_core_set_rate_nolock(clk->core, rate); - if (ret) { - /* rollback the changes */ - clk->min_rate = old_min; - clk->max_rate = old_max; - } + /* + * Since the boundaries have been changed, let's give the + * opportunity to the provider to adjust the clock rate based on + * the new boundaries. + * + * We also need to handle the case where the clock is currently + * outside of the boundaries. Clamping the last requested rate + * to the current minimum and maximum will also handle this. + * + * FIXME: + * There is a catch. It may fail for the usual reason (clock + * broken, clock protected, etc) but also because: + * - round_rate() was not favorable and fell on the wrong + * side of the boundary + * - the determine_rate() callback does not really check for + * this corner case when determining the rate + */ + rate = clamp(clk->core->req_rate, min, max); + ret = clk_core_set_rate_nolock(clk->core, rate); + if (ret) { + /* rollback the changes */ + clk->min_rate = old_min; + clk->max_rate = old_max; } out: -- cgit v1.2.3-58-ga151