[PATCH v3] soc: ti: smartreflex: Use platform_get_irq_optional() to get the interrupt

[Lad Prabhakar]

platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.

In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq_optional().

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj at bp.renesas.com>
---
v2->v3
* Switch back to platform_get_irq_optional()
* Only print error in case of error, and not when interrupt is missing.

v1->v2
* Updated commit message
* Drop check for IRQ0
* Switched to using platform_get_irq() so that the probe won't
  fail silently as requested by Nishanth.

v1:
* https://www.spinics.net/lists/arm-kernel/msg942549.html
---
 drivers/soc/ti/smartreflex.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/soc/ti/smartreflex.c b/drivers/soc/ti/smartreflex.c
index b5b2fa538d5c..e2e3eb3db4cc 100644
--- a/drivers/soc/ti/smartreflex.c
+++ b/drivers/soc/ti/smartreflex.c
@@ -819,7 +819,7 @@ static int omap_sr_probe(struct platform_device *pdev)
 {
 	struct omap_sr *sr_info;
 	struct omap_sr_data *pdata = pdev->dev.platform_data;
-	struct resource *mem, *irq;
+	struct resource *mem;
 	struct dentry *nvalue_dir;
 	int i, ret = 0;
 
@@ -844,7 +844,14 @@ static int omap_sr_probe(struct platform_device *pdev)
 	if (IS_ERR(sr_info->base))
 		return PTR_ERR(sr_info->base);
 
-	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	ret = platform_get_irq_optional(pdev, 0);
+	if (ret < 0 && ret != -ENXIO) {
+		dev_err(&pdev->dev, "%s: failed to get IRQ resource\n", __func__);
+		return ret;
+	}
+	if (ret > 0)
+		sr_info->irq = ret;
+	ret = 0;
 
 	sr_info->fck = devm_clk_get(pdev->dev.parent, "fck");
 	if (IS_ERR(sr_info->fck))
@@ -870,9 +877,6 @@ static int omap_sr_probe(struct platform_device *pdev)
 	sr_info->autocomp_active = false;
 	sr_info->ip_type = pdata->ip_type;
 
-	if (irq)
-		sr_info->irq = irq->start;
-
 	sr_set_clk_length(sr_info);
 
 	list_add(&sr_info->node, &sr_list);
-- 
2.17.1