[PATCH 2/2] dmaengine: zynqmp_dma: Add per-channel reset support

[Golla Nagendra]

Versal Gen 2 and Versal Net SoCs expose a dedicated reset line per
ZDMA channel, replacing the earlier approach where a single reset
was shared across all channels. Add reset handling in the channel
probe path using device_reset_optional() to trigger a reset pulse
on the channel during initialization.

Platforms without per-channel reset continue to work unaffected
since device_reset_optional() returns 0 when no reset is specified.

Signed-off-by: Golla Nagendra <nagendra.golla at amd.com>
---
 drivers/dma/xilinx/zynqmp_dma.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
index f6a812e49ddc..51c831760372 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -18,6 +18,7 @@
 #include <linux/clk.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 
 #include "../dmaengine.h"
 
@@ -916,6 +917,11 @@ static int zynqmp_dma_chan_probe(struct zynqmp_dma_device *zdev,
 	if (IS_ERR(chan->regs))
 		return PTR_ERR(chan->regs);
 
+	err = device_reset_optional(&pdev->dev);
+	if (err)
+		return dev_err_probe(&pdev->dev, err,
+				     "failed to reset channel\n");
+
 	chan->bus_width = ZYNQMP_DMA_BUS_WIDTH_64;
 	chan->dst_burst_len = ZYNQMP_DMA_MAX_DST_BURST_LEN;
 	chan->src_burst_len = ZYNQMP_DMA_MAX_SRC_BURST_LEN;
-- 
2.43.0