spi: pl022: use generic DMA slave configuration if possible

With the new OF DMA binding, it is possible to completely avoid the
need for platform_data for configuring a DMA channel. In cases where the
platform has already been converted, calling dma_request_slave_channel
should get all the necessary information from the device tree.

Like the patch that converts the dw_dma controller, this is completely
untested and is looking for someone to try it out.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: spi-devel-general@lists.sourceforge.net
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Vinod Koul <vinod.koul@linux.intel.com>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: linux-arm-kernel@lists.infradead.org

diff --git a/Documentation/devicetree/bindings/spi/spi_pl022.txt b/Documentation/devicetree/bindings/spi/spi_pl022.txt
index f158fd31cfda71a3ab69984c54cbeab3fa22bc61..22ed6797216d70e3ddcf6f30e40a07d7ea559f1d 100644 (file)
--- a/Documentation/devicetree/bindings/spi/spi_pl022.txt
+++ b/Documentation/devicetree/bindings/spi/spi_pl022.txt
@@ -16,6 +16,11 @@ Optional properties:
                             device will be suspended immediately
 - pl022,rt : indicates the controller should run the message pump with realtime
              priority to minimise the transfer latency on the bus (boolean)
+- dmas : Two or more DMA channel specifiers following the convention outlined
+         in bindings/dma/dma.txt
+- dma-names: Names for the dma channels, if present. There must be at
+            least one channel named "tx" for transmit and named "rx" for
+             receive.
 
 
 SPI slave nodes must be children of the SPI master node and can
@@ -32,3 +37,34 @@ contain the following properties.
 - pl022,wait-state : Microwire interface: Wait state
 - pl022,duplex : Microwire interface: Full/Half duplex
 
+
+Example:
+
+       spi@e0100000 {
+               compatible = "arm,pl022", "arm,primecell";
+               reg = <0xe0100000 0x1000>;
+               #address-cells = <1>;
+               #size-cells = <0>;
+               interrupts = <0 31 0x4>;
+               dmas = <&dma-controller 23 1>,
+                       <&dma-controller 24 0>;
+               dma-names = "rx", "tx";
+
+               m25p80@1 {
+                       compatible = "st,m25p80";
+                       reg = <1>;
+                       spi-max-frequency = <12000000>;
+                       spi-cpol;
+                       spi-cpha;
+                       pl022,hierarchy = <0>;
+                       pl022,interface = <0>;
+                       pl022,slave-tx-disable;
+                       pl022,com-mode = <0x2>;
+                       pl022,rx-level-trig = <0>;
+                       pl022,tx-level-trig = <0>;
+                       pl022,ctrl-len = <0x11>;
+                       pl022,wait-state = <0>;
+                       pl022,duplex = <0>;
+               };
+       };
+       

diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c
index b0fe393c882ced538ef9f098daf885a736796469..371cc66f1a0e9d4abfce97b8ee5fe3466cb28ad3 100644 (file)
--- a/drivers/spi/spi-pl022.c
+++ b/drivers/spi/spi-pl022.c
@@ -1139,6 +1139,35 @@ err_no_rxchan:
        return -ENODEV;
 }
 
+static int pl022_dma_autoprobe(struct pl022 *pl022)
+{
+       struct device *dev = &pl022->adev->dev;
+
+       /* automatically configure DMA channels from platform, normally using DT */
+       pl022->dma_rx_channel = dma_request_slave_channel(dev, "rx");
+       if (!pl022->dma_rx_channel)
+               goto err_no_rxchan;
+
+       pl022->dma_tx_channel = dma_request_slave_channel(dev, "tx");
+       if (!pl022->dma_tx_channel)
+               goto err_no_txchan;
+
+       pl022->dummypage = kmalloc(PAGE_SIZE, GFP_KERNEL);
+       if (!pl022->dummypage)
+               goto err_no_dummypage;
+
+       return 0;
+
+err_no_dummypage:
+       dma_release_channel(pl022->dma_tx_channel);
+       pl022->dma_tx_channel = NULL;
+err_no_txchan:
+       dma_release_channel(pl022->dma_rx_channel);
+       pl022->dma_rx_channel = NULL;
+err_no_rxchan:
+       return -ENODEV;
+}
+               
 static void terminate_dma(struct pl022 *pl022)
 {
        struct dma_chan *rxchan = pl022->dma_rx_channel;
@@ -1167,6 +1196,11 @@ static inline int configure_dma(struct pl022 *pl022)
        return -ENODEV;
 }
 
+static inline int pl022_dma_autoprobe(struct pl022 *pl022)
+{
+       return 0;
+}
+
 static inline int pl022_dma_probe(struct pl022 *pl022)
 {
        return 0;
@@ -2226,8 +2260,13 @@ static int pl022_probe(struct amba_device *adev, const struct amba_id *id)
                goto err_no_irq;
        }
 
-       /* Get DMA channels */
-       if (platform_info->enable_dma) {
+       /* Get DMA channels, try autoconfiguration first */
+       status = pl022_dma_autoprobe(pl022);
+
+       /* If that failed, use channels from platform_info */
+       if (status == 0)
+               platform_info->enable_dma = 1;
+       else if (platform_info->enable_dma) {
                status = pl022_dma_probe(pl022);
                if (status != 0)
                        platform_info->enable_dma = 0;