drm/tegra: Allocate resources at probe time

Since the .init() and .exit() functions are executed whenever the DRM
driver is loaded or unloaded, care must be taken not to use them for
resource allocation. Otherwise deferred probing cannot be used, since
the .init() and .exit() are not run at probe time. Similarly the code
that frees resources must be run at .remove() time. If it is run from
the .exit() function, it can release resources multiple times.

To handle this more consistently, rename the tegra_output_parse_dt()
function to tegra_output_probe() and introduce tegra_output_remove()
which can be used to free output-related resources.
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/dc.c

@@ -1191,6 +1191,12 @@ static int tegra_dc_remove(struct platform_device *pdev)
 		return err;
 	}
 
+	err = tegra_dc_rgb_remove(dc);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to remove RGB output: %d\n", err);
+		return err;
+	}
+
 	clk_disable_unprepare(dc->clk);
 
 	return 0;

drivers/gpu/drm/tegra/drm.h

@@ -236,11 +236,13 @@ void drm_host1x_exit(struct drm_driver *driver, struct host1x_device *device);
 
 /* from rgb.c */
 extern int tegra_dc_rgb_probe(struct tegra_dc *dc);
+extern int tegra_dc_rgb_remove(struct tegra_dc *dc);
 extern int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc);
 extern int tegra_dc_rgb_exit(struct tegra_dc *dc);
 
 /* from output.c */
-extern int tegra_output_parse_dt(struct tegra_output *output);
+extern int tegra_output_probe(struct tegra_output *output);
+extern int tegra_output_remove(struct tegra_output *output);
 extern int tegra_output_init(struct drm_device *drm, struct tegra_output *output);
 extern int tegra_output_exit(struct tegra_output *output);
 

drivers/gpu/drm/tegra/hdmi.c

@@ -1226,7 +1226,7 @@ static int tegra_hdmi_probe(struct platform_device *pdev)
 
 	hdmi->output.dev = &pdev->dev;
 
-	err = tegra_output_parse_dt(&hdmi->output);
+	err = tegra_output_probe(&hdmi->output);
 	if (err < 0)
 		return err;
 
@@ -1272,6 +1272,12 @@ static int tegra_hdmi_remove(struct platform_device *pdev)
 		return err;
 	}
 
+	err = tegra_output_remove(&hdmi->output);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to remove output: %d\n", err);
+		return err;
+	}
+
 	clk_unprepare(hdmi->clk_parent);
 	clk_unprepare(hdmi->clk);
 

drivers/gpu/drm/tegra/output.c

@@ -161,7 +161,7 @@ static irqreturn_t hpd_irq(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
-int tegra_output_parse_dt(struct tegra_output *output)
+int tegra_output_probe(struct tegra_output *output)
 {
 	enum of_gpio_flags flags;
 	struct device_node *ddc;
@@ -191,14 +191,6 @@ int tegra_output_parse_dt(struct tegra_output *output)
 	output->hpd_gpio = of_get_named_gpio_flags(output->of_node,
 						   "nvidia,hpd-gpio", 0,
 						   &flags);
-
-	return 0;
-}
-
-int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
-{
-	int connector, encoder, err;
-
 	if (gpio_is_valid(output->hpd_gpio)) {
 		unsigned long flags;
 
@@ -212,7 +204,8 @@ int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
 		err = gpio_to_irq(output->hpd_gpio);
 		if (err < 0) {
 			dev_err(output->dev, "gpio_to_irq(): %d\n", err);
-			goto free_hpd;
+			gpio_free(output->hpd_gpio);
+			return err;
 		}
 
 		output->hpd_irq = err;
@@ -225,12 +218,33 @@ int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
 		if (err < 0) {
 			dev_err(output->dev, "failed to request IRQ#%u: %d\n",
 				output->hpd_irq, err);
-			goto free_hpd;
+			gpio_free(output->hpd_gpio);
+			return err;
 		}
 
 		output->connector.polled = DRM_CONNECTOR_POLL_HPD;
 	}
 
+	return 0;
+}
+
+int tegra_output_remove(struct tegra_output *output)
+{
+	if (gpio_is_valid(output->hpd_gpio)) {
+		free_irq(output->hpd_irq, output);
+		gpio_free(output->hpd_gpio);
+	}
+
+	if (output->ddc)
+		put_device(&output->ddc->dev);
+
+	return 0;
+}
+
+int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
+{
+	int connector, encoder;
+
 	switch (output->type) {
 	case TEGRA_OUTPUT_RGB:
 		connector = DRM_MODE_CONNECTOR_LVDS;
@@ -261,22 +275,9 @@ int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
 	output->encoder.possible_crtcs = 0x3;
 
 	return 0;
-
-free_hpd:
-	gpio_free(output->hpd_gpio);
-
-	return err;
 }
 
 int tegra_output_exit(struct tegra_output *output)
 {
-	if (gpio_is_valid(output->hpd_gpio)) {
-		free_irq(output->hpd_irq, output);
-		gpio_free(output->hpd_gpio);
-	}
-
-	if (output->ddc)
-		put_device(&output->ddc->dev);
-
 	return 0;
 }

drivers/gpu/drm/tegra/rgb.c

@@ -147,7 +147,7 @@ int tegra_dc_rgb_probe(struct tegra_dc *dc)
 	rgb->output.dev = dc->dev;
 	rgb->output.of_node = np;
 
-	err = tegra_output_parse_dt(&rgb->output);
+	err = tegra_output_probe(&rgb->output);
 	if (err < 0)
 		return err;
 
@@ -174,6 +174,20 @@ int tegra_dc_rgb_probe(struct tegra_dc *dc)
 	return 0;
 }
 
+int tegra_dc_rgb_remove(struct tegra_dc *dc)
+{
+	int err;
+
+	if (!dc->rgb)
+		return 0;
+
+	err = tegra_output_remove(dc->rgb);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
 int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc)
 {
 	struct tegra_rgb *rgb = to_rgb(dc->rgb);