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authorMaxime Ripard <maxime@cerno.tech>2020-01-07 17:59:56 +0100
committerMaxime Ripard <maxime@cerno.tech>2020-01-08 09:13:47 +0100
commit451debe55715acafdcacba6a879e6ccb8eca23ce (patch)
tree7f7044c4b815eeccefa44e9549e5d097d7812453
parentf66ff55a9bd06855f9c6b8f29d8760f77bfe43c2 (diff)
drm/sun4i: backend: Make sure we enforce the clock rate
The backend needs to run at 300MHz to be functional. This was done so far using assigned-clocks in the device tree, but that is easy to forget, and doesn't provide any other guarantee than the rate is going to be roughly the one requested at probe time. Therefore it's pretty fragile, so let's just use the exclusive clock API to enforce it. Reviewed-by: Chen-Yu Tsai <wens@csie.org> Signed-off-by: Maxime Ripard <maxime@cerno.tech> Link: https://patchwork.freedesktop.org/patch/msgid/20200107165957.672435-1-maxime@cerno.tech
-rw-r--r--drivers/gpu/drm/sun4i/sun4i_backend.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
index 4e29f4fe4a05..072ea113e6be 100644
--- a/drivers/gpu/drm/sun4i/sun4i_backend.c
+++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
@@ -856,6 +856,13 @@ static int sun4i_backend_bind(struct device *dev, struct device *master,
ret = PTR_ERR(backend->mod_clk);
goto err_disable_bus_clk;
}
+
+ ret = clk_set_rate_exclusive(backend->mod_clk, 300000000);
+ if (ret) {
+ dev_err(dev, "Couldn't set the module clock frequency\n");
+ goto err_disable_bus_clk;
+ }
+
clk_prepare_enable(backend->mod_clk);
backend->ram_clk = devm_clk_get(dev, "ram");
@@ -932,6 +939,7 @@ static int sun4i_backend_bind(struct device *dev, struct device *master,
err_disable_ram_clk:
clk_disable_unprepare(backend->ram_clk);
err_disable_mod_clk:
+ clk_rate_exclusive_put(backend->mod_clk);
clk_disable_unprepare(backend->mod_clk);
err_disable_bus_clk:
clk_disable_unprepare(backend->bus_clk);
@@ -952,6 +960,7 @@ static void sun4i_backend_unbind(struct device *dev, struct device *master,
sun4i_backend_free_sat(dev);
clk_disable_unprepare(backend->ram_clk);
+ clk_rate_exclusive_put(backend->mod_clk);
clk_disable_unprepare(backend->mod_clk);
clk_disable_unprepare(backend->bus_clk);
reset_control_assert(backend->reset);