dm: core: Add a flag to control sequence numbering

At present we try to use the 'reg' property and device tree aliases to give
devices a sequence number. The 'reg' property is often actually a memory
address, so the sequence numbers thus-obtained are not useful. It would be
better if the devices were just sequentially numbered in that case. In fact
neither I2C nor SPI use this feature, so drop it.

Some devices need us to look up an alias to number them within the uclass.
Add a flag to control this, so it is not done unless it is needed.

Adjust the tests to test this new behaviour.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

drivers/core/device.c

@@ -53,24 +53,22 @@ int device_bind(struct udevice *parent, struct driver *drv, const char *name,
 	dev->driver = drv;
 	dev->uclass = uc;
 
-	/*
-	 * For some devices, such as a SPI or I2C bus, the 'reg' property
-	 * is a reasonable indicator of the sequence number. But if there is
-	 * an alias, we use that in preference. In any case, this is just
-	 * a 'requested' sequence, and will be resolved (and ->seq updated)
-	 * when the device is probed.
-	 */
 	dev->seq = -1;
-#ifdef CONFIG_OF_CONTROL
-	dev->req_seq = fdtdec_get_int(gd->fdt_blob, of_offset, "reg", -1);
-	if (!IS_ERR_VALUE(dev->req_seq))
-		dev->req_seq &= INT_MAX;
-	if (uc->uc_drv->name && of_offset != -1) {
-		fdtdec_get_alias_seq(gd->fdt_blob, uc->uc_drv->name, of_offset,
-				     &dev->req_seq);
-	}
-#else
 	dev->req_seq = -1;
+#ifdef CONFIG_OF_CONTROL
+	/*
+	 * Some devices, such as a SPI bus, I2C bus and serial ports are
+	 * numbered using aliases.
+	 *
+	 * This is just a 'requested' sequence, and will be
+	 * resolved (and ->seq updated) when the device is probed.
+	 */
+	if (uc->uc_drv->flags & DM_UC_FLAG_SEQ_ALIAS) {
+		if (uc->uc_drv->name && of_offset != -1) {
+			fdtdec_get_alias_seq(gd->fdt_blob, uc->uc_drv->name,
+					     of_offset, &dev->req_seq);
+		}
+	}
 #endif
 	if (!dev->platdata && drv->platdata_auto_alloc_size) {
 		dev->flags |= DM_FLAG_ALLOC_PDATA;

drivers/i2c/i2c-uclass.c

@@ -453,6 +453,7 @@ int i2c_post_bind(struct udevice *dev)
 UCLASS_DRIVER(i2c) = {
 	.id		= UCLASS_I2C,
 	.name		= "i2c",
+	.flags		= DM_UC_FLAG_SEQ_ALIAS,
 	.per_device_auto_alloc_size = sizeof(struct dm_i2c_bus),
 	.post_bind	= i2c_post_bind,
 	.post_probe	= i2c_post_probe,

drivers/serial/serial-uclass.c

@@ -297,6 +297,7 @@ static int serial_pre_remove(struct udevice *dev)
 UCLASS_DRIVER(serial) = {
 	.id		= UCLASS_SERIAL,
 	.name		= "serial",
+	.flags		= DM_UC_FLAG_SEQ_ALIAS,
 	.post_probe	= serial_post_probe,
 	.pre_remove	= serial_pre_remove,
 	.per_device_auto_alloc_size = sizeof(struct serial_dev_priv),

drivers/spi/spi-uclass.c

@@ -344,6 +344,7 @@ int spi_ofdata_to_platdata(const void *blob, int node,
 UCLASS_DRIVER(spi) = {
 	.id		= UCLASS_SPI,
 	.name		= "spi",
+	.flags		= DM_UC_FLAG_SEQ_ALIAS,
 	.post_bind	= spi_post_bind,
 	.post_probe	= spi_post_probe,
 	.per_device_auto_alloc_size = sizeof(struct dm_spi_bus),