[PATCH] drm/sun4i: tcon: Initialize regmap after enabling bus clocks

Chen-Yu Tsai
2016-11-16T09:37:32Z

If we attempt to read/write the TCON registers before the bus clock
is enabled, those accesses get ignored.

In practice this almost never occurs because U-boot had already enabled
the bus clock as part of its firmware provided framebuffer (simplefb).

Fixes: 9026e0d122ac ("drm: Add Allwinner A10 Display Engine support")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---

I was looking around the DRM driver and noticed this sequence was off.

---
drivers/gpu/drm/sun4i/sun4i_tcon.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index c6afb2448655..8c2db65ea229 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -506,16 +506,16 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master,
return ret;
}

- ret = sun4i_tcon_init_regmap(dev, tcon);
+ ret = sun4i_tcon_init_clocks(dev, tcon);
if (ret) {
- dev_err(dev, "Couldn't init our TCON regmap\n");
+ dev_err(dev, "Couldn't init our TCON clocks\n");
goto err_assert_reset;
}

- ret = sun4i_tcon_init_clocks(dev, tcon);
+ ret = sun4i_tcon_init_regmap(dev, tcon);
if (ret) {
- dev_err(dev, "Couldn't init our TCON clocks\n");
- goto err_assert_reset;
+ dev_err(dev, "Couldn't init our TCON regmap\n");
+ goto err_free_clocks;
}

ret = sun4i_tcon_init_irq(dev, tcon);
--
2.10.2