Thread (20 messages) 20 messages, 3 authors, 2018-01-05
STALE3090d REVIEWED: 1 (0M)
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[PATCH v5 05/12] drm/sun4i: Force the mixer rate at 150MHz

From: Maxime Ripard <hidden>
Date: 2017-12-21 11:05:33
Also in: dri-devel, linux-devicetree, 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.

Reviewed-by: Chen-Yu Tsai <redacted>
Signed-off-by: Maxime Ripard <redacted>
---
 drivers/gpu/drm/sun4i/sun8i_mixer.c | 10 ++++++++++
 drivers/gpu/drm/sun4i/sun8i_mixer.h |  3 +++
 2 files changed, 13 insertions(+)
diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.c b/drivers/gpu/drm/sun4i/sun8i_mixer.c
index 29ceeb016d72..3a610a87cbd2 100644
--- a/drivers/gpu/drm/sun4i/sun8i_mixer.c
+++ b/drivers/gpu/drm/sun4i/sun8i_mixer.c
@@ -398,6 +398,15 @@ static int sun8i_mixer_bind(struct device *dev, struct device *master,
 		ret = PTR_ERR(mixer->mod_clk);
 		goto err_disable_bus_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.
+	 */
+	if (mixer->cfg->mod_rate)
+		clk_set_rate(mixer->mod_clk, mixer->cfg->mod_rate);
+
 	clk_prepare_enable(mixer->mod_clk);
 
 	list_add_tail(&mixer->engine.list, &drv->engine_list);
@@ -474,6 +483,7 @@ static const struct sun8i_mixer_cfg sun8i_v3s_mixer_cfg = {
 	.ui_num = 1,
 	.scaler_mask = 0x3,
 	.ccsc = 0,
+	.mod_rate = 150000000,
 };
 
 static const struct of_device_id sun8i_mixer_of_table[] = {
diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.h b/drivers/gpu/drm/sun4i/sun8i_mixer.h
index bc58040a88f9..f34e70c42adf 100644
--- a/drivers/gpu/drm/sun4i/sun8i_mixer.h
+++ b/drivers/gpu/drm/sun4i/sun8i_mixer.h
@@ -121,12 +121,15 @@ struct de2_fmt_info {
  *	Set value to 0 if this is first mixer or second mixer with VEP support.
  *	Set value to 1 if this is second mixer without VEP support. Other values
  *	are invalid.
+ * @mod_rate: module clock rate that needs to be set in order to have
+ *	a functional block.
  */
 struct sun8i_mixer_cfg {
 	int		vi_num;
 	int		ui_num;
 	int		scaler_mask;
 	int		ccsc;
+	unsigned long	mod_rate;
 };
 
 struct sun8i_mixer {
-- 
git-series 0.9.1
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