reset/aspeed: Implement status callback

The I2C driver shares a reset line between buses, so allow it to test
the state of the reset line before resetting it.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Ryan Chen <ryan_chen@aspeedtech.com>
diff --git a/drivers/reset/reset-ast2600.c b/drivers/reset/reset-ast2600.c
index 985235a..1732a45 100644
--- a/drivers/reset/reset-ast2600.c
+++ b/drivers/reset/reset-ast2600.c
@@ -47,6 +47,22 @@
 	return 0;
 }
 
+static int ast2600_reset_status(struct reset_ctl *reset_ctl)
+{
+	struct ast2600_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+	struct ast2600_scu *scu = priv->scu;
+	int status;
+
+	debug("%s: reset_ctl->id: %lu\n", __func__, reset_ctl->id);
+
+	if (reset_ctl->id < 32)
+		status = BIT(reset_ctl->id) & readl(&scu->modrst_ctrl1);
+	else
+		status = BIT(reset_ctl->id - 32) & readl(&scu->modrst_ctrl2);
+
+	return !!status;
+}
+
 static int ast2600_reset_probe(struct udevice *dev)
 {
 	int rc;
@@ -78,6 +94,7 @@
 struct reset_ops ast2600_reset_ops = {
 	.rst_assert = ast2600_reset_assert,
 	.rst_deassert = ast2600_reset_deassert,
+	.rst_status = ast2600_reset_status,
 };
 
 U_BOOT_DRIVER(ast2600_reset) = {