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Subject[PATCH v5 05/12] drm/sun4i: Force the mixer rate at 150MHz
Date
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 <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
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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