memory: aemif: add support for board files

Currently aemif is supported in two places separately. By the platform
driver in drivers/memory and by a hand crafted driver in mach-davinci.

We want to drop the latter but also keep the legacy mode. Add support
for board files to the aemif driver.

The new structure in platform data currently only contains the chip
select number, since currently existing users don't require anything
else, but it can be extended in the future.

While extending the platform data struct, add kernel docs describing
its members.

Signed-off-by: Bartosz Golaszewski <[e-mail]>
Signed-off-by: Santosh Shilimkar <[e-mail]>

drivers/memory/ti-aemif.c

···
 	struct aemif_platform_data *pdata;
 	struct of_dev_auxdata *dev_lookup;
 
-	if (np == NULL)
-		return 0;
-
 	aemif = devm_kzalloc(dev, sizeof(*aemif), GFP_KERNEL);
 	if (!aemif)
 		return -ENOMEM;
···
 
 	aemif->clk_rate = clk_get_rate(aemif->clk) / MSEC_PER_SEC;
 
-	if (of_device_is_compatible(np, "ti,da850-aemif"))
+	if (np && of_device_is_compatible(np, "ti,da850-aemif"))
 		aemif->cs_offset = 2;
+	else if (pdata)
+		aemif->cs_offset = pdata->cs_offset;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	aemif->base = devm_ioremap_resource(dev, res);
···
 		goto error;
 	}
 
-	/*
-	 * For every controller device node, there is a cs device node that
-	 * describe the bus configuration parameters. This functions iterate
-	 * over these nodes and update the cs data array.
-	 */
-	for_each_available_child_of_node(np, child_np) {
-		ret = of_aemif_parse_abus_config(pdev, child_np);
-		if (ret < 0)
-			goto error;
+	if (np) {
+		/*
+		 * For every controller device node, there is a cs device node
+		 * that describe the bus configuration parameters. This
+		 * functions iterate over these nodes and update the cs data
+		 * array.
+		 */
+		for_each_available_child_of_node(np, child_np) {
+			ret = of_aemif_parse_abus_config(pdev, child_np);
+			if (ret < 0)
+				goto error;
+		}
+	} else if (pdata && pdata->num_abus_data > 0) {
+		for (i = 0; i < pdata->num_abus_data; i++, aemif->num_cs++) {
+			aemif->cs_data[i].cs = pdata->abus_data[i].cs;
+			aemif_get_hw_params(pdev, i);
+		}
 	}
 
 	for (i = 0; i < aemif->num_cs; i++) {
···
 	}
 
 	/*
-	 * Create a child devices explicitly from here to
-	 * guarantee that the child will be probed after the AEMIF timing
-	 * parameters are set.
+	 * Create a child devices explicitly from here to guarantee that the
+	 * child will be probed after the AEMIF timing parameters are set.
 	 */
-	for_each_available_child_of_node(np, child_np) {
-		ret = of_platform_populate(child_np, NULL, dev_lookup, dev);
-		if (ret < 0)
-			goto error;
+	if (np) {
+		for_each_available_child_of_node(np, child_np) {
+			ret = of_platform_populate(child_np, NULL,
+						   dev_lookup, dev);
+			if (ret < 0)
+				goto error;
+		}
+	} else {
+		for (i = 0; i < pdata->num_sub_devices; i++) {
+			pdata->sub_devices[i].dev.parent = dev;
+			ret = platform_device_register(&pdata->sub_devices[i]);
+			if (ret) {
+				dev_warn(dev, "Error register sub device %s\n",
+					 pdata->sub_devices[i].name);
+			}
+		}
 	}
 
 	return 0;

include/linux/platform_data/ti-aemif.h

···
 
 #include <linux/of_platform.h>
 
+/**
+ * struct aemif_abus_data - Async bus configuration parameters.
+ *
+ * @cs - Chip-select number.
+ */
+struct aemif_abus_data {
+	u32 cs;
+};
+
+/**
+ * struct aemif_platform_data - Data to set up the TI aemif driver.
+ *
+ * @dev_lookup: of_dev_auxdata passed to of_platform_populate() for aemif
+ *              subdevices.
+ * @cs_offset: Lowest allowed chip-select number.
+ * @abus_data: Array of async bus configuration entries.
+ * @num_abus_data: Number of abus entries.
+ * @sub_devices: Array of platform subdevices.
+ * @num_sub_devices: Number of subdevices.
+ */
 struct aemif_platform_data {
 	struct of_dev_auxdata *dev_lookup;
+	u32 cs_offset;
+	struct aemif_abus_data *abus_data;
+	size_t num_abus_data;
+	struct platform_device *sub_devices;
+	size_t num_sub_devices;
 };
 
 #endif /* __TI_DAVINCI_AEMIF_DATA_H__ */