linux-kernel - [PATCH] clk: meson: g12a: mark fclk_div2 as CLK_IGNORE

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Date:   Fri, 28 Aug 2020 15:07:07 +0200
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-clk@...r.kernel.org
Cc:     Marek Szyprowski <m.szyprowski@...sung.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Jerome Brunet <jbrunet@...libre.com>,
        Kevin Hilman <khilman@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Subject: [PATCH] clk: meson: g12a: mark fclk_div2 as CLK_IGNORE_UNUSED

Add CLK_IGNORE_UNUSED flag to the "fclk_div2" clock to fix boot hang on
the Hardkernel's Odroid N2 board (with bootloader booted from SD card and
kernel loaded via FTFP).

It looks that this clock is disabled by the generic unused clocks
scanning code before it gets enabled by the meson-gx-mmc driver.

Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
---
Without this patch the only way to boot OdroidN2 board with mainline
kernel is to append clk_ignore_unused kernel parameter. I've build the
kernel from the default arm64's defconfig. The kernel is loaded via TFTP
using vendor's u-boot.
---
 drivers/clk/clk.c        | 5 +++++
 drivers/clk/meson/g12a.c | 1 +
 2 files changed, 6 insertions(+)

diff --git a/drivers/clk/meson/g12a.c b/drivers/clk/meson/g12a.c
index 9803d44bb157..4106b6231be4 100644
--- a/drivers/clk/meson/g12a.c
+++ b/drivers/clk/meson/g12a.c
@@ -298,6 +298,7 @@ static struct clk_regmap g12a_fclk_div2 = {
 			&g12a_fclk_div2_div.hw
 		},
 		.num_parents = 1,
+		.flags = CLK_IGNORE_UNUSED,
 	},
 };
 
-- 
2.17.1