dma-engine: sun4i: Add has_reset option to quirk

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 <[e-mail]>
[ csokas.bence: Rebased and addressed comments ]
Signed-off-by: Csókás Bence <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/sun4i-dma.c

···
 #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>
 
···
 	u8 ddma_drq_sdram;
 
 	u8 max_burst;
+	bool has_reset;
 };
 
 struct sun4i_dma_pchan {
···
 	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)
···
 		return PTR_ERR(priv->clk);
 	}
 
+	if (priv->cfg->has_reset) {
+		priv->rst = devm_reset_control_get_exclusive_deasserted(&pdev->dev, NULL);
+		if (IS_ERR(priv->rst))
+			return dev_err_probe(&pdev->dev, PTR_ERR(priv->rst),
+					     "Failed to get reset control\n");
+	}
+
 	platform_set_drvdata(pdev, priv);
 	spin_lock_init(&priv->lock);
 
···
 	.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[] = {