[PATCH 22/27] drm/sun4i: Initialize registers in tcon-top driver
From: Jernej Skrabec <hidden>
Date: 2018-09-02 07:28:03
Also in:
dri-devel, linux-arm-kernel, 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 turns out that TCON TOP registers in H6 SoC have non-zero reset value. This may cause issues if bits are not changed during configuration. To prevent that, initialize registers to 0. Signed-off-by: Jernej Skrabec <redacted> --- drivers/gpu/drm/sun4i/sun8i_tcon_top.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/gpu/drm/sun4i/sun8i_tcon_top.c b/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
index 3040a79f298f..37158548b447 100644
--- a/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
+++ b/drivers/gpu/drm/sun4i/sun8i_tcon_top.c@@ -167,6 +167,13 @@ static int sun8i_tcon_top_bind(struct device *dev, struct device *master, goto err_assert_reset; } + /* + * At least on H6, some registers have some bits set by default + * which may cause issues. Clear them here. + */ + writel(0, regs + TCON_TOP_PORT_SEL_REG); + writel(0, regs + TCON_TOP_GATE_SRC_REG); + /* * TCON TOP has two muxes, which select parent clock for each TCON TV * channel clock. Parent could be either TCON TV or TVE clock. For now
--
2.18.0