[PATCH v5 2/3] media: vsp1: Add support to deassert/assert reset line

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As the resets DT property is mandatory, and is present in all .dtsi
in mainline, add support to perform deassert/assert using reference
counted reset handle.

Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
Reviewed-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
v4->v5:
 * Added Rb tag from Geert
v3->v4:
 * Restored error check for pm_runtime_resume_and_get and calls
   assert() in case of failure.
v2->v3:
 * Added Rb tag from Philipp
 * If reset_control_deassert() failed, return ret directly. 
v1->v2:
 * Used reference counted reset handle to perform deassert/assert
RFC->v1:
 * Added reset support as separate patch
 * Moved rstc just after the bus_master field in struct vsp1_device
RFC:
 * https://patchwork.kernel.org/project/linux-renesas-soc/patch/20220112174612.10773-21-biju.das.jz@xxxxxxxxxxxxxx/
---
 drivers/media/platform/vsp1/vsp1.h     |  1 +
 drivers/media/platform/vsp1/vsp1_drv.c | 18 +++++++++++++++++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/vsp1/vsp1.h b/drivers/media/platform/vsp1/vsp1.h
index 37cf33c7e6ca..c5da829c79b5 100644
--- a/drivers/media/platform/vsp1/vsp1.h
+++ b/drivers/media/platform/vsp1/vsp1.h
@@ -79,6 +79,7 @@ struct vsp1_device {
 	void __iomem *mmio;
 	struct rcar_fcp_device *fcp;
 	struct device *bus_master;
+	struct reset_control *rstc;
 
 	struct vsp1_brx *brs;
 	struct vsp1_brx *bru;
diff --git a/drivers/media/platform/vsp1/vsp1_drv.c b/drivers/media/platform/vsp1/vsp1_drv.c
index 502c7d9d6890..699d7d985df4 100644
--- a/drivers/media/platform/vsp1/vsp1_drv.c
+++ b/drivers/media/platform/vsp1/vsp1_drv.c
@@ -16,6 +16,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 #include <linux/videodev2.h>
 
 #include <media/rcar-fcp.h>
@@ -569,7 +570,16 @@ static void vsp1_mask_all_interrupts(struct vsp1_device *vsp1)
  */
 int vsp1_device_get(struct vsp1_device *vsp1)
 {
-	return pm_runtime_resume_and_get(vsp1->dev);
+	int ret = reset_control_deassert(vsp1->rstc);
+
+	if (ret < 0)
+		return ret;
+
+	ret = pm_runtime_resume_and_get(vsp1->dev);
+	if (ret < 0)
+		reset_control_assert(vsp1->rstc);
+
+	return ret;
 }
 
 /*
@@ -581,6 +591,7 @@ int vsp1_device_get(struct vsp1_device *vsp1)
 void vsp1_device_put(struct vsp1_device *vsp1)
 {
 	pm_runtime_put_sync(vsp1->dev);
+	reset_control_assert(vsp1->rstc);
 }
 
 /* -----------------------------------------------------------------------------
@@ -827,6 +838,11 @@ static int vsp1_probe(struct platform_device *pdev)
 	if (irq < 0)
 		return irq;
 
+	vsp1->rstc = devm_reset_control_get_shared(&pdev->dev, NULL);
+	if (IS_ERR(vsp1->rstc))
+		return dev_err_probe(&pdev->dev, PTR_ERR(vsp1->rstc),
+				     "failed to get reset ctrl\n");
+
 	/* FCP (optional). */
 	fcp_node = of_parse_phandle(pdev->dev.of_node, "renesas,fcp", 0);
 	if (fcp_node) {
-- 
2.17.1




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