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From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
To: sboyd@kernel.org
Cc: heiko@sntech.de, knaerzche@gmail.com,
	linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org,
	martin.blumenstingl@googlemail.com
Subject: [PATCH] clk: composite: Also consider .determine_rate for rate + mux composites
Date: Fri, 15 Oct 2021 14:05:59 +0200	[thread overview]
Message-ID: <20211015120559.3515645-1-martin.blumenstingl@googlemail.com> (raw)
In-Reply-To: <163425193558.1688384.15520943968787313145@swboyd.mtv.corp.google.com>

Commit 69a00fb3d69706 ("clk: divider: Implement and wire up
.determine_rate by default") switches clk_divider_ops to implement
.determine_rate by default. This breaks composite clocks with multiple
parents because clk-composite.c does not use the special handling for
mux + divider combinations anymore (that was restricted to rate clocks
which only implement .round_rate, but not .determine_rate).

Alex reports:
  This breaks lot of clocks for Rockchip which intensively uses
  composites,  i.e. those clocks will always stay at the initial parent,
  which in some cases  is the XTAL clock and I strongly guess it is the
  same for other platforms,  which use composite clocks having more than
  one parent (e.g. mediatek, ti ...)

  Example (RK3399)
  clk_sdio is set (initialized) with XTAL (24 MHz) as parent in u-boot.
  It will always stay at this parent, even if the mmc driver sets a rate
  of  200 MHz (fails, as the nature of things), which should switch it
  to   any of its possible parent PLLs defined in
  mux_pll_src_cpll_gpll_npll_ppll_upll_24m_p (see clk-rk3399.c)  - which
  never happens.

Restore the original behavior by changing the priority of the conditions
inside clk-composite.c. Now the special rate + mux case (with rate_ops
having a .round_rate - which is still the case for the default
clk_divider_ops) is preferred over rate_ops which have .determine_rate
defined (and not further considering the mux).

Fixes: 69a00fb3d69706 ("clk: divider: Implement and wire up .determine_rate by default")
Reported-by: Alex Bee <knaerzche@gmail.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
Re-sending this as inline patch instead of attaching it.

 drivers/clk/clk-composite.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c
index 0506046a5f4b..510a9965633b 100644
--- a/drivers/clk/clk-composite.c
+++ b/drivers/clk/clk-composite.c
@@ -58,11 +58,8 @@ static int clk_composite_determine_rate(struct clk_hw *hw,
 	long rate;
 	int i;
 
-	if (rate_hw && rate_ops && rate_ops->determine_rate) {
-		__clk_hw_set_clk(rate_hw, hw);
-		return rate_ops->determine_rate(rate_hw, req);
-	} else if (rate_hw && rate_ops && rate_ops->round_rate &&
-		   mux_hw && mux_ops && mux_ops->set_parent) {
+	if (rate_hw && rate_ops && rate_ops->round_rate &&
+	    mux_hw && mux_ops && mux_ops->set_parent) {
 		req->best_parent_hw = NULL;
 
 		if (clk_hw_get_flags(hw) & CLK_SET_RATE_NO_REPARENT) {
@@ -107,6 +104,9 @@ static int clk_composite_determine_rate(struct clk_hw *hw,
 
 		req->rate = best_rate;
 		return 0;
+	} else if (rate_hw && rate_ops && rate_ops->determine_rate) {
+		__clk_hw_set_clk(rate_hw, hw);
+		return rate_ops->determine_rate(rate_hw, req);
 	} else if (mux_hw && mux_ops && mux_ops->determine_rate) {
 		__clk_hw_set_clk(mux_hw, hw);
 		return mux_ops->determine_rate(mux_hw, req);
-- 
2.33.0


  reply	other threads:[~2021-10-15 12:06 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-02 22:51 [PATCH v1 0/6] clk: switch dividers to .determine_rate Martin Blumenstingl
2021-07-02 22:51 ` [PATCH v1 1/6] clk: divider: Implement and wire up .determine_rate by default Martin Blumenstingl
2021-08-06  1:10   ` Stephen Boyd
2021-10-14  9:55   ` Alex Bee
2021-10-14 12:11     ` Martin Blumenstingl
2021-10-14 21:34       ` Martin Blumenstingl
2021-10-14 22:52         ` Stephen Boyd
2021-10-15 12:05           ` Martin Blumenstingl [this message]
2021-10-15 21:27             ` [PATCH] clk: composite: Also consider .determine_rate for rate + mux composites Stephen Boyd
2021-11-01 20:19             ` Guillaume Tucker
2021-11-01 20:58               ` Martin Blumenstingl
2021-11-01 21:59                 ` Robin Murphy
2021-11-01 22:11                   ` Robin Murphy
2021-11-01 22:41                     ` Alex Bee
2021-11-02  7:58                       ` Guillaume Tucker
2021-11-02 21:40                         ` LABBE Corentin
2021-10-15 19:14         ` [PATCH v1 1/6] clk: divider: Implement and wire up .determine_rate by default Alex Bee
2021-10-15 21:31           ` Stephen Boyd
2021-07-02 22:51 ` [PATCH v1 2/6] clk: imx: clk-divider-gate: Switch to clk_divider.determine_rate Martin Blumenstingl
2021-07-19 10:43   ` Abel Vesa
2021-07-29 11:30   ` Abel Vesa
2021-07-02 22:51 ` [PATCH v1 3/6] clk: bcm2835: " Martin Blumenstingl
2021-07-05  6:57   ` Marek Szyprowski
2021-08-06  1:10   ` Stephen Boyd
2021-07-02 22:51 ` [PATCH v1 4/6] clk: stm32f4: " Martin Blumenstingl
2021-08-06  1:10   ` Stephen Boyd
2021-07-02 22:51 ` [PATCH v1 5/6] clk: stm32h7: " Martin Blumenstingl
2021-08-06  1:10   ` Stephen Boyd
2021-07-02 22:51 ` [PATCH v1 6/6] clk: stm32mp1: " Martin Blumenstingl
2021-08-06  1:10   ` Stephen Boyd
2021-08-03 19:32 ` [PATCH v1 0/6] clk: switch dividers to .determine_rate Martin Blumenstingl
2021-08-03 20:16   ` Stephen Boyd

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