Thread (39 messages) 39 messages, 5 authors, 2017-12-02
STALE3159d
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[PATCH v2 05/18] drm/sun4i: Force the mixer rate at 150MHz

From: Maxime Ripard <hidden>
Date: 2017-11-27 15:43:15
Also in: dri-devel, linux-clk, lkml
Subsystem: drm driver for allwinner de2 and de3 engine, drm drivers, drm drivers and misc gpu patches, drm drivers for allwinner a10, the rest · Maintainers: Chen-Yu Tsai, David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Linus Torvalds

It seems like the mixer can only run properly when clocked at 150MHz. In
order to have something more robust than simply a fire-and-forget
assigned-clocks-rate, let's put that in the code.

Signed-off-by: Maxime Ripard <redacted>
---
 drivers/gpu/drm/sun4i/sun8i_mixer.c | 7 +++++++
 1 file changed, 7 insertions(+)
diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.c b/drivers/gpu/drm/sun4i/sun8i_mixer.c
index cb193c5f1686..c0cdccf772a2 100644
--- a/drivers/gpu/drm/sun4i/sun8i_mixer.c
+++ b/drivers/gpu/drm/sun4i/sun8i_mixer.c
@@ -315,6 +315,13 @@ static int sun8i_mixer_bind(struct device *dev, struct device *master,
 	}
 	clk_prepare_enable(mixer->mod_clk);
 
+	/*
+	 * It seems that we need to enforce that rate for whatever
+	 * reason for the mixer to be functional. Make sure it's the
+	 * case.
+	 */
+	clk_set_rate(mixer->mod_clk, 150000000);
+
 	list_add_tail(&mixer->engine.list, &drv->engine_list);
 
 	/* Reset the registers */
-- 
git-series 0.9.1
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