On 29.11.2018 19:24, Thierry Reding wrote:
> From: Thierry Reding <treding@xxxxxxxxxx>
>
> The display architecture on Tegra186 and Tegra194 requires that there be
> some valid clock on all domains before accessing any display register. A
> further requirement is that in addition to the host1x, hub, disp and dsc
> clocks, all the head clocks (pclk0-2 on Tegra186 or pclk0-3 on Tegra194)
> must also be enabled.
>
> Implement this logic within the display hub driver to ensure the clocks
> are always enabled at the right time.
>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
> Changes in v2:
> - reverse order in which clocks are disabled for symmetry
> - don't leak child device tree node
>
And here is a variant that uses bulk-API, it looks nicer to me. Don't you think so?
diff --git a/drivers/gpu/drm/tegra/hub.c b/drivers/gpu/drm/tegra/hub.c
index 6112d9042979..d597de7d0de4 100644
--- a/drivers/gpu/drm/tegra/hub.c
+++ b/drivers/gpu/drm/tegra/hub.c
@@ -742,6 +742,7 @@ static const struct host1x_client_ops tegra_display_hub_ops = {
static int tegra_display_hub_probe(struct platform_device *pdev)
{
+ struct device_node *child = NULL;
struct tegra_display_hub *hub;
unsigned int i;
int err;
@@ -801,6 +802,29 @@ static int tegra_display_hub_probe(struct platform_device *pdev)
return err;
}
+ hub->num_heads = of_get_child_count(pdev->dev.of_node);
+
+ hub->clk_heads = devm_kcalloc(&pdev->dev, hub->num_heads,
+ sizeof(*hub->clk_heads), GFP_KERNEL);
+ if (!hub->clk_heads)
+ return -ENOMEM;
+
+ for (i = 0; i < hub->num_heads; i++) {
+ child = of_get_next_child(pdev->dev.of_node, child);
+
+ hub->clk_heads[i].id = "dc";
+ hub->clk_heads[i].clk = devm_get_clk_from_child(&pdev->dev,
+ child, "dc");
+ if (IS_ERR(hub->clk_heads[i].clk)) {
+ dev_err(&pdev->dev, "failed to get clock for head %u\n",
+ i);
+ of_node_put(child);
+ return PTR_ERR(hub->clk_heads[i].clk);
+ }
+ }
+
+ of_node_put(child);
+
/* XXX: enable clock across reset? */
err = reset_control_assert(hub->rst);
if (err < 0)
@@ -846,6 +870,7 @@ static int __maybe_unused tegra_display_hub_suspend(struct device *dev)
if (err < 0)
return err;
+ clk_bulk_disable_unprepare(hub->num_heads, hub->clk_heads);
clk_disable_unprepare(hub->clk_hub);
clk_disable_unprepare(hub->clk_dsc);
clk_disable_unprepare(hub->clk_disp);
@@ -870,12 +895,18 @@ static int __maybe_unused tegra_display_hub_resume(struct device *dev)
if (err < 0)
goto disable_dsc;
- err = reset_control_deassert(hub->rst);
+ err = clk_bulk_prepare_enable(hub->num_heads, hub->clk_heads);
if (err < 0)
goto disable_hub;
+ err = reset_control_deassert(hub->rst);
+ if (err < 0)
+ goto disable_heads;
+
return 0;
+disable_heads:
+ clk_bulk_disable_unprepare(hub->num_heads, hub->clk_heads);
disable_hub:
clk_disable_unprepare(hub->clk_hub);
disable_dsc:
diff --git a/drivers/gpu/drm/tegra/hub.h b/drivers/gpu/drm/tegra/hub.h
index 6696a85fc1f2..40866765ef0d 100644
--- a/drivers/gpu/drm/tegra/hub.h
+++ b/drivers/gpu/drm/tegra/hub.h
@@ -49,6 +49,9 @@ struct tegra_display_hub {
struct clk *clk_hub;
struct reset_control *rst;
+ unsigned int num_heads;
+ struct clk_bulk_data *clk_heads;
+
const struct tegra_display_hub_soc *soc;
struct tegra_windowgroup *wgrps;
};
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