From 4d8aa2a3aa485c056ad488608c08a55201482127 Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Fri, 5 May 2023 13:25:27 +0200 Subject: clk: davinci: da8xx-cfgchip: Add a determine_rate hook The Davinci DA8xxx cfgchip "clk48" clock 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 candidates to trigger that parent change are either the assigned-clock-parents device tree property or 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. Similarly, it doesn't look like the device tree using that clock driver uses any of the assigned-clock properties on 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 latter case would be equivalent to setting the determine_rate implementation to clk_hw_determine_rate_no_reparent(). Indeed, if no determine_rate implementation is provided, clk_round_rate() (through clk_core_round_rate_nolock()) will call itself on the parent if CLK_SET_RATE_PARENT is set, and will not change the clock rate otherwise. And if it was an oversight, then we are at least explicit about our behavior now and it can be further refined down the line. Cc: David Lechner Cc: Sekhar Nori Acked-by: David Lechner Signed-off-by: Maxime Ripard Link: https://lore.kernel.org/r/20221018-clk-range-checks-fixes-v4-25-971d5077e7d2@cerno.tech Signed-off-by: Stephen Boyd --- drivers/clk/davinci/da8xx-cfgchip.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/clk/davinci') diff --git a/drivers/clk/davinci/da8xx-cfgchip.c b/drivers/clk/davinci/da8xx-cfgchip.c index 11fcf6f63336..1bbcc8e43bc5 100644 --- a/drivers/clk/davinci/da8xx-cfgchip.c +++ b/drivers/clk/davinci/da8xx-cfgchip.c @@ -565,6 +565,7 @@ static u8 da8xx_usb1_clk48_get_parent(struct clk_hw *hw) } static const struct clk_ops da8xx_usb1_clk48_ops = { + .determine_rate = clk_hw_determine_rate_no_reparent, .set_parent = da8xx_usb1_clk48_set_parent, .get_parent = da8xx_usb1_clk48_get_parent, }; -- cgit v1.2.3