[RFC PATCH 02/10] dma-engine: sun4i: Add has_reset option to quirk

[Mesih Kilinc]

Allwinner suniv F1C100s has a reset bit for DMA in CCU. Sun4i do not
has this bit but in order to support suniv we need to add it. So add
support for reset bit.

Signed-off-by: Mesih Kilinc <mesihkilinc@xxxxxxxxx>
---
 drivers/dma/sun4i-dma.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/dma/sun4i-dma.c b/drivers/dma/sun4i-dma.c
index e86b424..d267ff9 100644
--- a/drivers/dma/sun4i-dma.c
+++ b/drivers/dma/sun4i-dma.c
@@ -18,6 +18,7 @@
 #include <linux/of_dma.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 
@@ -153,6 +154,7 @@ struct sun4i_dma_config {
 	u8 ddma_drq_sdram;
 
 	u8 max_burst;
+	bool has_reset;
 };
 
 struct sun4i_dma_pchan {
@@ -201,6 +203,7 @@ struct sun4i_dma_dev {
 	int				irq;
 	spinlock_t			lock;
 	const struct sun4i_dma_config *cfg;
+	struct reset_control *rst;
 };
 
 static struct sun4i_dma_dev *to_sun4i_dma_dev(struct dma_device *dev)
@@ -1198,6 +1201,15 @@ static int sun4i_dma_probe(struct platform_device *pdev)
 		return PTR_ERR(priv->clk);
 	}
 
+	if(priv->cfg->has_reset) {
+		priv->rst = devm_reset_control_get_exclusive(&pdev->dev,
+							       NULL);
+		if (IS_ERR(priv->rst)) {
+			dev_err(&pdev->dev, "Failed to get reset control\n");
+			return PTR_ERR(priv->rst);
+		}
+	}
+
 	platform_set_drvdata(pdev, priv);
 	spin_lock_init(&priv->lock);
 
@@ -1268,6 +1280,16 @@ static int sun4i_dma_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	/* Deassert the reset control */
+	if (priv->rst) {
+		ret = reset_control_deassert(priv->rst);
+		if (ret) {
+			dev_err(&pdev->dev,
+				"Failed to deassert the reset control\n");
+			goto err_clk_disable;
+		}
+	}
+
 	/*
 	 * Make sure the IRQs are all disabled and accounted for. The bootloader
 	 * likes to leave these dirty
@@ -1339,6 +1361,7 @@ static struct sun4i_dma_config sun4i_a10_dma_cfg = {
 	.ddma_drq_sdram		= SUN4I_DDMA_DRQ_TYPE_SDRAM,
 
 	.max_burst		= SUN4I_MAX_BURST,
+	.has_reset		= false,
 };
 
 static const struct of_device_id sun4i_dma_match[] = {
-- 
2.7.4