[PATCH 4/5] dmaengine: stm32-dma: Add support for STM32 DMAMUX

[M'boumba Cedric Madianga]

This patch adds support for STM32 DMAMUX.
When the STM32 DMA controller is behind a STM32 DMAMUX the request line
number has not to be handled by DMA but DMAMUX.

Signed-off-by: M'boumba Cedric Madianga <cedric.madianga at gmail.com>
---
 drivers/dma/stm32-dma.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c
index 786fc8f..3bf2893 100644
--- a/drivers/dma/stm32-dma.c
+++ b/drivers/dma/stm32-dma.c
@@ -179,6 +179,7 @@ struct stm32_dma_device {
 	struct clk *clk;
 	struct reset_control *rst;
 	bool mem2mem;
+	bool dmamux;
 	struct stm32_dma_chan chan[STM32_DMA_MAX_CHANNELS];
 };
 
@@ -968,10 +969,14 @@ static void stm32_dma_desc_free(struct virt_dma_desc *vdesc)
 static void stm32_dma_set_config(struct stm32_dma_chan *chan,
 			  struct stm32_dma_cfg *cfg)
 {
+	struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
+
 	stm32_dma_clear_reg(&chan->chan_reg);
 
 	chan->chan_reg.dma_scr = cfg->stream_config & STM32_DMA_SCR_CFG_MASK;
-	chan->chan_reg.dma_scr |= STM32_DMA_SCR_REQ(cfg->request_line);
+
+	if (!dmadev->dmamux)
+		chan->chan_reg.dma_scr |= STM32_DMA_SCR_REQ(cfg->request_line);
 
 	/* Enable Interrupts  */
 	chan->chan_reg.dma_scr |= STM32_DMA_SCR_TEIE | STM32_DMA_SCR_TCIE;
@@ -998,8 +1003,8 @@ static struct dma_chan *stm32_dma_of_xlate(struct of_phandle_args *dma_spec,
 	cfg.stream_config = dma_spec->args[2];
 	cfg.threshold = dma_spec->args[3];
 
-	if ((cfg.channel_id >= STM32_DMA_MAX_CHANNELS) ||
-	    (cfg.request_line >= STM32_DMA_MAX_REQUEST_ID)) {
+	if ((!dmadev->dmamux && cfg.request_line >= STM32_DMA_MAX_REQUEST_ID) ||
+	    (cfg.channel_id >= STM32_DMA_MAX_CHANNELS)) {
 		dev_err(dev, "Bad channel and/or request id\n");
 		return NULL;
 	}
@@ -1058,6 +1063,8 @@ static int stm32_dma_probe(struct platform_device *pdev)
 	dmadev->mem2mem = of_property_read_bool(pdev->dev.of_node,
 						"st,mem2mem");
 
+	dmadev->dmamux = of_property_read_bool(pdev->dev.of_node, "st,dmamux");
+
 	dmadev->rst = devm_reset_control_get(&pdev->dev, NULL);
 	if (!IS_ERR(dmadev->rst)) {
 		reset_control_assert(dmadev->rst);
-- 
1.9.1