spi/pl022: Devicetree support w/o platform data

Even with devicetree support, we needed platform data to provide some data,
leading to mixed device tree and platform data. This patch makes it possible to
provide all that information via device tree. Now, the data must be provided
via platform data _or_ device tree completely.

Only in case of DMA where a callback specification is necessary (dma_filter()),
platform data is the only option.

Signed-off-by: Roland Stigge <stigge@antcom.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

Documentation/devicetree/bindings/spi/spi_pl022.txt

@@ -10,6 +10,13 @@ Optional properties:
 - cs-gpios : should specify GPIOs used for chipselects.
   The gpios will be referred to as reg = <index> in the SPI child nodes.
   If unspecified, a single SPI device without a chip select can be used.
+- pl022,autosuspend-delay : delay in ms following transfer completion before
+			    the runtime power management system suspends the
+			    device. A setting of 0 indicates no delay and the
+                            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)
+
 
 SPI slave nodes must be children of the SPI master node and can
 contain the following properties.

drivers/spi/spi-pl022.c

@@ -2029,6 +2029,34 @@ static void pl022_cleanup(struct spi_device *spi)
 	kfree(chip);
 }
 
+static struct pl022_ssp_controller *
+pl022_platform_data_dt_get(struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	struct pl022_ssp_controller *pd;
+	u32 tmp;
+
+	if (!np) {
+		dev_err(dev, "no dt node defined\n");
+		return NULL;
+	}
+
+	pd = devm_kzalloc(dev, sizeof(struct pl022_ssp_controller), GFP_KERNEL);
+	if (!pd) {
+		dev_err(dev, "cannot allocate platform data memory\n");
+		return NULL;
+	}
+
+	pd->bus_id = -1;
+	of_property_read_u32(np, "num-cs", &tmp);
+	pd->num_chipselect = tmp;
+	of_property_read_u32(np, "pl022,autosuspend-delay",
+			     &pd->autosuspend_delay);
+	pd->rt = of_property_read_bool(np, "pl022,rt");
+
+	return pd;
+}
+
 static int __devinit
 pl022_probe(struct amba_device *adev, const struct amba_id *id)
 {
@@ -2041,18 +2069,19 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id)
 
 	dev_info(&adev->dev,
 		 "ARM PL022 driver, device ID: 0x%08x\n", adev->periphid);
-	if (platform_info == NULL) {
-		dev_err(&adev->dev, "probe - no platform data supplied\n");
+	if (!platform_info && IS_ENABLED(CONFIG_OF))
+		platform_info = pl022_platform_data_dt_get(dev);
+
+	if (!platform_info) {
+		dev_err(dev, "probe: no platform data defined\n");
 		status = -ENODEV;
 		goto err_no_pdata;
 	}
 
 	if (platform_info->num_chipselect) {
 		num_cs = platform_info->num_chipselect;
-	} else if (IS_ENABLED(CONFIG_OF)) {
-		of_property_read_u32(np, "num-cs", &num_cs);
 	} else {
-		dev_err(&adev->dev, "probe: no chip select defined\n");
+		dev_err(dev, "probe: no chip select defined\n");
 		status = -ENODEV;
 		goto err_no_pdata;
 	}