[PATCH v2 2/3] drm/tidss: Power up attached PM domains on probe

[Swamil Jain <s-jain1@ti.com>]

From: Devarsh Thakkar <devarsht@ti.com>

Some SoC's such as AM62P have dedicated power domains
for OLDI which need to be powered on separately along
with display controller.

So during driver probe, power up all attached PM domains
enumerated in devicetree node for DSS.

This also prepares base to add display support for AM62P.

Signed-off-by: Devarsh Thakkar <devarsht@ti.com>
[j-choudhary@ti.com: fix PM call sequence causing kernel crash in OLDI]
Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>
Signed-off-by: Swamil Jain <s-jain1@ti.com>
---
 drivers/gpu/drm/tidss/tidss_drv.c | 88 +++++++++++++++++++++++++++++--
 drivers/gpu/drm/tidss/tidss_drv.h |  4 ++
 2 files changed, 89 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/tidss/tidss_drv.c b/drivers/gpu/drm/tidss/tidss_drv.c
index 1c8cc18bc53c..50158281715f 100644
--- a/drivers/gpu/drm/tidss/tidss_drv.c
+++ b/drivers/gpu/drm/tidss/tidss_drv.c
@@ -8,6 +8,7 @@
 #include <linux/of.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
+#include <linux/pm_domain.h>
 #include <linux/aperture.h>
 
 #include <drm/clients/drm_client_setup.h>
@@ -107,6 +108,72 @@ static const struct drm_driver tidss_driver = {
 	.minor			= 0,
 };
 
+static int tidss_detach_pm_domains(struct tidss_device *tidss)
+{
+	int i;
+
+	if (tidss->num_domains <= 1)
+		return 0;
+
+	for (i = 0; i < tidss->num_domains; i++) {
+		if (tidss->pd_link[i] && !IS_ERR(tidss->pd_link[i]))
+			device_link_del(tidss->pd_link[i]);
+		if (tidss->pd_dev[i] && !IS_ERR(tidss->pd_dev[i]))
+			dev_pm_domain_detach(tidss->pd_dev[i], true);
+		tidss->pd_dev[i] = NULL;
+		tidss->pd_link[i] = NULL;
+	}
+
+	return 0;
+}
+
+static int tidss_attach_pm_domains(struct tidss_device *tidss)
+{
+	struct device *dev = tidss->dev;
+	int i;
+	int ret;
+	struct platform_device *pdev = to_platform_device(dev);
+	struct device_node *np = pdev->dev.of_node;
+
+	tidss->num_domains = of_count_phandle_with_args(np, "power-domains",
+							"#power-domain-cells");
+	if (tidss->num_domains <= 1) {
+		dev_dbg(dev, "One or less power domains, no need to do attach domains\n");
+		return 0;
+	}
+
+	tidss->pd_dev = devm_kmalloc_array(dev, tidss->num_domains,
+					   sizeof(*tidss->pd_dev), GFP_KERNEL);
+	if (!tidss->pd_dev)
+		return -ENOMEM;
+
+	tidss->pd_link = devm_kmalloc_array(dev, tidss->num_domains,
+					    sizeof(*tidss->pd_link), GFP_KERNEL);
+	if (!tidss->pd_link)
+		return -ENOMEM;
+
+	for (i = 0; i < tidss->num_domains; i++) {
+		tidss->pd_dev[i] = dev_pm_domain_attach_by_id(dev, i);
+		if (IS_ERR(tidss->pd_dev[i])) {
+			ret = PTR_ERR(tidss->pd_dev[i]);
+			goto fail;
+		}
+
+		tidss->pd_link[i] = device_link_add(dev, tidss->pd_dev[i],
+						    DL_FLAG_STATELESS |
+						    DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE);
+		if (!tidss->pd_link[i]) {
+			ret = -EINVAL;
+			goto fail;
+		}
+	}
+
+	return 0;
+fail:
+	tidss_detach_pm_domains(tidss);
+	return ret;
+}
+
 static int tidss_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -129,15 +196,24 @@ static int tidss_probe(struct platform_device *pdev)
 
 	spin_lock_init(&tidss->irq_lock);
 
+	/* powering up associated OLDI domains */
+	ret = tidss_attach_pm_domains(tidss);
+	if (ret < 0) {
+		dev_err(dev, "failed to attach power domains %d\n", ret);
+		goto err_detach_pm_domains;
+	}
+
 	ret = dispc_init(tidss);
 	if (ret) {
 		dev_err(dev, "failed to initialize dispc: %d\n", ret);
-		return ret;
+		goto err_detach_pm_domains;
 	}
 
 	ret = tidss_oldi_init(tidss);
-	if (ret)
-		return dev_err_probe(dev, ret, "failed to init OLDI\n");
+	if (ret) {
+		dev_dbg(dev, "failed to init OLDI: %d\n", ret);
+		goto err_oldi_deinit;
+	}
 
 	pm_runtime_enable(dev);
 
@@ -203,8 +279,12 @@ static int tidss_probe(struct platform_device *pdev)
 	pm_runtime_dont_use_autosuspend(dev);
 	pm_runtime_disable(dev);
 
+err_oldi_deinit:
 	tidss_oldi_deinit(tidss);
 
+err_detach_pm_domains:
+	tidss_detach_pm_domains(tidss);
+
 	return ret;
 }
 
@@ -232,6 +312,8 @@ static void tidss_remove(struct platform_device *pdev)
 	/* devm allocated dispc goes away with the dev so mark it NULL */
 	dispc_remove(tidss);
 
+	tidss_detach_pm_domains(tidss);
+
 	dev_dbg(dev, "%s done\n", __func__);
 }
 
diff --git a/drivers/gpu/drm/tidss/tidss_drv.h b/drivers/gpu/drm/tidss/tidss_drv.h
index e1c1f41d8b4b..6eb17cb32043 100644
--- a/drivers/gpu/drm/tidss/tidss_drv.h
+++ b/drivers/gpu/drm/tidss/tidss_drv.h
@@ -41,6 +41,10 @@ struct tidss_device {
 	/* protects the irq masks field and irqenable/irqstatus registers */
 	spinlock_t irq_lock;
 	dispc_irq_t irq_mask;	/* enabled irqs */
+
+	int num_domains; /* Handle attached PM domains */
+	struct device **pd_dev;
+	struct device_link **pd_link;
 };
 
 #define to_tidss(__dev) container_of(__dev, struct tidss_device, ddev)