firmware: qcom: scm: Expose PAS command 10 as reset-controller

PAS command 10 is used to assert and deassert the MSS reset via
TrustZone, expose this as a reset-controller to mimic the direct
access case.

Cc: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>
diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index ec46c68..84330c5 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -21,6 +21,7 @@
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/clk.h>
+#include <linux/reset-controller.h>
 
 #include "qcom_scm.h"
 
@@ -29,6 +30,7 @@
 	struct clk *core_clk;
 	struct clk *iface_clk;
 	struct clk *bus_clk;
+	struct reset_controller_dev reset;
 };
 
 static struct qcom_scm *__scm;
@@ -283,6 +285,30 @@
 }
 EXPORT_SYMBOL(qcom_scm_pas_shutdown);
 
+static int qcom_scm_pas_reset_assert(struct reset_controller_dev *rcdev,
+				     unsigned long idx)
+{
+	if (idx != 0)
+		return -EINVAL;
+
+	return __qcom_scm_pas_mss_reset(__scm->dev, 1);
+}
+
+static int qcom_scm_pas_reset_deassert(struct reset_controller_dev *rcdev,
+				       unsigned long idx)
+{
+	if (idx != 0)
+		return -EINVAL;
+
+	return __qcom_scm_pas_mss_reset(__scm->dev, 0);
+}
+
+static const struct reset_control_ops qcom_scm_pas_reset_ops = {
+	.assert = qcom_scm_pas_reset_assert,
+	.deassert = qcom_scm_pas_reset_deassert,
+};
+
+
 static int qcom_scm_probe(struct platform_device *pdev)
 {
 	struct qcom_scm *scm;
@@ -316,6 +342,11 @@
 		}
 	}
 
+	scm->reset.ops = &qcom_scm_pas_reset_ops;
+	scm->reset.nr_resets = 1;
+	scm->reset.of_node = pdev->dev.of_node;
+	reset_controller_register(&scm->reset);
+
 	/* vote for max clk rate for highest performance */
 	ret = clk_set_rate(scm->core_clk, INT_MAX);
 	if (ret)