ata: arasan: remove the need for platform_data

This adds a complete DT binding for the arasan device driver. There is
currently only one user, which is the spear13xx platform, so we don't
actually have to parse all the properties until another user comes in,
but this does use the generic DMA binding to find the DMA channel.

The patch is untested so far and is part of a series to convert
the spear platform over to use the generic DMA binding, so it
should stay with the rest of the series.

Signed-off-by: Arnd Bergmann <[e-mail]>
Acked-by: Viresh Kumar <[e-mail]>
Cc: Vinod Koul <[e-mail]>
Cc: Jeff Garzik <[e-mail]>
Cc: [e-mail]

Documentation/devicetree/bindings/ata/pata-arasan.txt

···
 - interrupt-parent: Should be the phandle for the interrupt controller
   that services interrupts for this device
 - interrupt: Should contain the CF interrupt number
+- clock-frequency: Interface clock rate, in Hz, one of
+       25000000
+       33000000
+       40000000
+       50000000
+       66000000
+       75000000
+      100000000
+      125000000
+      150000000
+      166000000
+      200000000
+
+Optional properties:
+- arasan,broken-udma: if present, UDMA mode is unusable
+- arasan,broken-mwdma: if present, MWDMA mode is unusable
+- arasan,broken-pio: if present, PIO mode is unusable
+- dmas: one DMA channel, as described in bindings/dma/dma.txt
+  required unless both UDMA and MWDMA mode are broken
+- dma-names: the corresponding channel name, must be "data"
 
 Example:
 
···
 		reg = <0xfc000000 0x1000>;
 		interrupt-parent = <&vic1>;
 		interrupts = <12>;
+		dmas = <&dma-controller 23>;
+		dma-names = "data";
 	};

drivers/ata/pata_arasan_cf.c

···
 	struct dma_chan *dma_chan;
 	/* Mask for DMA transfers */
 	dma_cap_mask_t mask;
-	/* dma channel private data */
-	void *dma_priv;
 	/* DMA transfer work */
 	struct work_struct work;
 	/* DMA delayed finish work */
···
 static int cf_init(struct arasan_cf_dev *acdev)
 {
 	struct arasan_cf_pdata *pdata = dev_get_platdata(acdev->host->dev);
+	unsigned int if_clk;
 	unsigned long flags;
 	int ret = 0;
 
···
 
 	spin_lock_irqsave(&acdev->host->lock, flags);
 	/* configure CF interface clock */
-	writel((pdata->cf_if_clk <= CF_IF_CLK_200M) ? pdata->cf_if_clk :
-			CF_IF_CLK_166M, acdev->vbase + CLK_CFG);
+	/* TODO: read from device tree */
+	if_clk = CF_IF_CLK_166M;
+	if (pdata && pdata->cf_if_clk <= CF_IF_CLK_200M)
+		if_clk = pdata->cf_if_clk;
+
+	writel(if_clk, acdev->vbase + CLK_CFG);
 
 	writel(TRUE_IDE_MODE | CFHOST_ENB, acdev->vbase + OP_MODE);
 	cf_interrupt_enable(acdev, CARD_DETECT_IRQ, 1);
···
 	struct arasan_cf_dev *acdev = (struct arasan_cf_dev *) dev;
 
 	complete(&acdev->dma_completion);
-}
-
-static bool filter(struct dma_chan *chan, void *slave)
-{
-	chan->private = slave;
-	return true;
 }
 
 static inline void dma_complete(struct arasan_cf_dev *acdev)
···
 
 	/* request dma channels */
 	/* dma_request_channel may sleep, so calling from process context */
-	acdev->dma_chan = dma_request_channel(acdev->mask, filter,
-			acdev->dma_priv);
+	acdev->dma_chan = dma_request_slave_channel(acdev->host->dev, "data");
 	if (!acdev->dma_chan) {
 		dev_err(acdev->host->dev, "Unable to get dma_chan\n");
 		goto chan_request_fail;
···
 	struct ata_host *host;
 	struct ata_port *ap;
 	struct resource *res;
+	u32 quirk;
 	irq_handler_t irq_handler = NULL;
 	int ret = 0;
 
···
 		return -ENOMEM;
 	}
 
+	if (pdata)
+		quirk = pdata->quirk;
+	else
+		quirk = CF_BROKEN_UDMA; /* as it is on spear1340 */
+
 	/* if irq is 0, support only PIO */
 	acdev->irq = platform_get_irq(pdev, 0);
 	if (acdev->irq)
 		irq_handler = arasan_cf_interrupt;
 	else
-		pdata->quirk |= CF_BROKEN_MWDMA | CF_BROKEN_UDMA;
+		quirk |= CF_BROKEN_MWDMA | CF_BROKEN_UDMA;
 
 	acdev->pbase = res->start;
 	acdev->vbase = devm_ioremap_nocache(&pdev->dev, res->start,
···
 	INIT_WORK(&acdev->work, data_xfer);
 	INIT_DELAYED_WORK(&acdev->dwork, delayed_finish);
 	dma_cap_set(DMA_MEMCPY, acdev->mask);
-	acdev->dma_priv = pdata->dma_priv;
 
 	/* Handle platform specific quirks */
-	if (pdata->quirk) {
-		if (pdata->quirk & CF_BROKEN_PIO) {
+	if (quirk) {
+		if (quirk & CF_BROKEN_PIO) {
 			ap->ops->set_piomode = NULL;
 			ap->pio_mask = 0;
 		}
-		if (pdata->quirk & CF_BROKEN_MWDMA)
+		if (quirk & CF_BROKEN_MWDMA)
 			ap->mwdma_mask = 0;
-		if (pdata->quirk & CF_BROKEN_UDMA)
+		if (quirk & CF_BROKEN_UDMA)
 			ap->udma_mask = 0;
 	}
 	ap->flags |= ATA_FLAG_PIO_POLLING | ATA_FLAG_NO_ATAPI;

include/linux/pata_arasan_cf_data.h

···
 	#define CF_BROKEN_PIO			(1)
 	#define CF_BROKEN_MWDMA			(1 << 1)
 	#define CF_BROKEN_UDMA			(1 << 2)
-	/* This is platform specific data for the DMA controller */
-	void *dma_priv;
 };
 
 static inline void