serial: mxs-auart: move to use generic DMA helper

With the generic DMA device tree helper supported by mxs-dma driver,
client devices only need to call dma_request_slave_channel() for
requesting a DMA channel from dmaengine.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

2 files changed, 11 insertions, 57 deletions

diff --git a/Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt b/Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt
index 273a8d5b3300..2c00ec64628e 100644
--- a/Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt
+++ b/Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt
@@ -5,20 +5,18 @@ Required properties:
   imx23 and imx28.
 - reg : Address and length of the register set for the device
 - interrupts : Should contain the auart interrupt numbers
-
-Optional properties:
-- fsl,auart-dma-channel : The DMA channels, the first is for RX, the other
-                is for TX. If you add this property, it also means that you
-                will enable the DMA support for the auart.
-                Note: due to the hardware bug in imx23(see errata : 2836),
-                only the imx28 can enable the DMA support for the auart.
+- dmas: DMA specifier, consisting of a phandle to DMA controller node
+  and AUART DMA channel ID.
+  Refer to dma.txt and fsl-mxs-dma.txt for details.
+- dma-names: "rx" for RX channel, "tx" for TX channel.
 
 Example:
 auart0: serial@8006a000 {
         compatible = "fsl,imx28-auart", "fsl,imx23-auart";
         reg = <0x8006a000 0x2000>;
-        interrupts = <112 70 71>;
-        fsl,auart-dma-channel = <8 9>;
+        interrupts = <112>;
+        dmas = <&dma_apbx 8>, <&dma_apbx 9>;
+        dma-names = "rx", "tx";
 };
 
 Note: Each auart port should have an alias correctly numbered in "aliases"
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index d549fe1fa42a..269a27caff33 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -35,7 +35,7 @@
 #include <linux/pinctrl/consumer.h>
 #include <linux/of_device.h>
 #include <linux/dma-mapping.h>
-#include <linux/fsl/mxs-dma.h>
+#include <linux/dmaengine.h>
 
 #include <asm/cacheflush.h>
 
@@ -148,11 +148,6 @@ struct mxs_auart_port {
         struct device *dev;
 
         /* for DMA */
-        struct mxs_dma_data dma_data;
-        int dma_channel_rx, dma_channel_tx;
-        int dma_irq_rx, dma_irq_tx;
-        int dma_channel;
-
         struct scatterlist tx_sgl;
         struct dma_chan *tx_dma_chan;
         void *tx_dma_buf;
@@ -440,20 +435,6 @@ static u32 mxs_auart_get_mctrl(struct uart_port *u)
         return mctrl;
 }
 
-static bool mxs_auart_dma_filter(struct dma_chan *chan, void *param)
-{
-        struct mxs_auart_port *s = param;
-
-        if (!mxs_dma_is_apbx(chan))
-                return false;
-
-        if (s->dma_channel == chan->chan_id) {
-                chan->private = &s->dma_data;
-                return true;
-        }
-        return false;
-}
-
 static int mxs_auart_dma_prep_rx(struct mxs_auart_port *s);
 static void dma_rx_callback(void *arg)
 {
@@ -545,21 +526,11 @@ static void mxs_auart_dma_exit(struct mxs_auart_port *s)
 
 static int mxs_auart_dma_init(struct mxs_auart_port *s)
 {
-        dma_cap_mask_t mask;
-
         if (auart_dma_enabled(s))
                 return 0;
 
-        /* We do not get the right DMA channels. */
-        if (s->dma_channel_rx == -1 || s->dma_channel_tx == -1)
-                return -EINVAL;
-
         /* init for RX */
-        dma_cap_zero(mask);
-        dma_cap_set(DMA_SLAVE, mask);
-        s->dma_channel = s->dma_channel_rx;
-        s->dma_data.chan_irq = s->dma_irq_rx;
-        s->rx_dma_chan = dma_request_channel(mask, mxs_auart_dma_filter, s);
+        s->rx_dma_chan = dma_request_slave_channel(s->dev, "rx");
         if (!s->rx_dma_chan)
                 goto err_out;
         s->rx_dma_buf = kzalloc(UART_XMIT_SIZE, GFP_KERNEL | GFP_DMA);
@@ -567,9 +538,7 @@ static int mxs_auart_dma_init(struct mxs_auart_port *s)
                 goto err_out;
 
         /* init for TX */
-        s->dma_channel = s->dma_channel_tx;
-        s->dma_data.chan_irq = s->dma_irq_tx;
-        s->tx_dma_chan = dma_request_channel(mask, mxs_auart_dma_filter, s);
+        s->tx_dma_chan = dma_request_slave_channel(s->dev, "tx");
         if (!s->tx_dma_chan)
                 goto err_out;
         s->tx_dma_buf = kzalloc(UART_XMIT_SIZE, GFP_KERNEL | GFP_DMA);
@@ -1020,7 +989,6 @@ static int serial_mxs_probe_dt(struct mxs_auart_port *s,
                 struct platform_device *pdev)
 {
         struct device_node *np = pdev->dev.of_node;
-        u32 dma_channel[2];
         int ret;
 
         if (!np)
@@ -1034,20 +1002,8 @@ static int serial_mxs_probe_dt(struct mxs_auart_port *s,
         }
         s->port.line = ret;
 
-        s->dma_irq_rx = platform_get_irq(pdev, 1);
-        s->dma_irq_tx = platform_get_irq(pdev, 2);
+        s->flags |= MXS_AUART_DMA_CONFIG;
 
-        ret = of_property_read_u32_array(np, "fsl,auart-dma-channel",
-                                        dma_channel, 2);
-        if (ret == 0) {
-                s->dma_channel_rx = dma_channel[0];
-                s->dma_channel_tx = dma_channel[1];
-
-                s->flags |= MXS_AUART_DMA_CONFIG;
-        } else {
-                s->dma_channel_rx = -1;
-                s->dma_channel_tx = -1;
-        }
         return 0;
 }