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| author | Paul Kocialkowski <paul.kocialkowski@bootlin.com> | 2019-01-31 14:25:50 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-03-13 14:03:21 -0700 |
| commit | 2b34bef88a2ee48936997c77bc0b04149cac39ca (patch) | |
| tree | abbd7b70d14d3204c7aa292370d5f63e651514b2 | |
| parent | dcab2483a1a3eff37411377202837d8a473d885f (diff) | |
| download | linux-2b34bef88a2ee48936997c77bc0b04149cac39ca.tar.gz linux-2b34bef88a2ee48936997c77bc0b04149cac39ca.tar.bz2 linux-2b34bef88a2ee48936997c77bc0b04149cac39ca.zip | |
drm/sun4i: tcon: Prepare and enable TCON channel 0 clock at init
[ Upstream commit b14e945bda8ae227d1bf2b1837c0c4a61721cd1a ]
When initializing clocks, a reference to the TCON channel 0 clock is
obtained. However, the clock is never prepared and enabled later.
Switching from simplefb to DRM actually disables the clock (that was
usually configured by U-Boot) because of that.
On the V3s, this results in a hang when writing to some mixer registers
when switching over to DRM from simplefb.
Fix this by preparing and enabling the clock when initializing other
clocks. Waiting for sun4i_tcon_channel_enable to enable the clock is
apparently too late and results in the same mixer register access hang.
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190131132550.26355-1-paul.kocialkowski@bootlin.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/gpu/drm/sun4i/sun4i_tcon.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c index 7b909d814d38..095bd6b4ae80 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c @@ -371,6 +371,7 @@ static int sun4i_tcon_init_clocks(struct device *dev, dev_err(dev, "Couldn't get the TCON channel 0 clock\n"); return PTR_ERR(tcon->sclk0); } + clk_prepare_enable(tcon->sclk0); if (tcon->quirks->has_channel_1) { tcon->sclk1 = devm_clk_get(dev, "tcon-ch1"); @@ -385,6 +386,7 @@ static int sun4i_tcon_init_clocks(struct device *dev, static void sun4i_tcon_free_clocks(struct sun4i_tcon *tcon) { + clk_disable_unprepare(tcon->sclk0); clk_disable_unprepare(tcon->clk); } |