linux-kernel - [PATCH 1/1] clk: meson: meson8b: make the CCF use the glitch-free "mali" mux

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Date:   Sun, 15 Dec 2019 22:01:53 +0100
From:   Martin Blumenstingl <martin.blumenstingl@...glemail.com>
To:     linux-amlogic@...ts.infradead.org, jbrunet@...libre.com,
        narmstrong@...libre.com
Cc:     mturquette@...libre.com, sboyd@...nel.org,
        linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Subject: [PATCH 1/1] clk: meson: meson8b: make the CCF use the glitch-free "mali" mux

The Mali clock tree should not be updated while the clock is running.
Enforce this by setting CLK_SET_RATE_GATE on the "mali_0" and "mali_1"
gates. This makes the CCF switch to the "mali_1" tree when "mali_0" is
currently active and vice versa which is exactly what the vendor driver
does when updating the frequency of the mali clock.

This fixes a potential hang when changing the GPU frequency at runtime.

Fixes: 74e1f2521f16ff ("clk: meson: meson8b: add the GPU clock tree")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@...glemail.com>
---
 drivers/clk/meson/meson8b.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/meson/meson8b.c b/drivers/clk/meson/meson8b.c
index 3408297bff65..6b13084eebf5 100644
--- a/drivers/clk/meson/meson8b.c
+++ b/drivers/clk/meson/meson8b.c
@@ -1838,7 +1838,7 @@ static struct clk_regmap meson8b_mali_0 = {
 			&meson8b_mali_0_div.hw
 		},
 		.num_parents = 1,
-		.flags = CLK_SET_RATE_PARENT,
+		.flags = CLK_SET_RATE_GATE | CLK_SET_RATE_PARENT,
 	},
 };
 
@@ -1893,7 +1893,7 @@ static struct clk_regmap meson8b_mali_1 = {
 			&meson8b_mali_1_div.hw
 		},
 		.num_parents = 1,
-		.flags = CLK_SET_RATE_PARENT,
+		.flags = CLK_SET_RATE_GATE | CLK_SET_RATE_PARENT,
 	},
 };
 
-- 
2.24.1