1 files changed, 39 insertions, 1 deletions

diff --git a/drivers/mtd/nand/raw/denali_dt.c b/drivers/mtd/nand/raw/denali_dt.c
index 699255fb2dd8..f08740ae282b 100644
--- a/drivers/mtd/nand/raw/denali_dt.c
+++ b/drivers/mtd/nand/raw/denali_dt.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/clk.h>
+#include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/ioport.h>
@@ -14,6 +15,7 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/reset.h>
 
 #include "denali.h"
 
@@ -22,6 +24,8 @@ struct denali_dt {
 	struct clk *clk;	/* core clock */
 	struct clk *clk_x;	/* bus interface clock */
 	struct clk *clk_ecc;	/* ECC circuit clock */
+	struct reset_control *rst;	/* core reset */
+	struct reset_control *rst_reg;	/* register reset */
 };
 
 struct denali_dt_data {
@@ -157,6 +161,14 @@ static int denali_dt_probe(struct platform_device *pdev)
 	if (IS_ERR(dt->clk_ecc))
 		return PTR_ERR(dt->clk_ecc);
 
+	dt->rst = devm_reset_control_get_optional_shared(dev, "nand");
+	if (IS_ERR(dt->rst))
+		return PTR_ERR(dt->rst);
+
+	dt->rst_reg = devm_reset_control_get_optional_shared(dev, "reg");
+	if (IS_ERR(dt->rst_reg))
+		return PTR_ERR(dt->rst_reg);
+
 	ret = clk_prepare_enable(dt->clk);
 	if (ret)
 		return ret;
@@ -172,10 +184,30 @@ static int denali_dt_probe(struct platform_device *pdev)
 	denali->clk_rate = clk_get_rate(dt->clk);
 	denali->clk_x_rate = clk_get_rate(dt->clk_x);
 
-	ret = denali_init(denali);
+	/*
+	 * Deassert the register reset, and the core reset in this order.
+	 * Deasserting the core reset while the register reset is asserted
+	 * will cause unpredictable behavior in the controller.
+	 */
+	ret = reset_control_deassert(dt->rst_reg);
 	if (ret)
 		goto out_disable_clk_ecc;
 
+	ret = reset_control_deassert(dt->rst);
+	if (ret)
+		goto out_assert_rst_reg;
+
+	/*
+	 * When the reset is deasserted, the initialization sequence is kicked
+	 * (bootstrap process). The driver must wait until it finished.
+	 * Otherwise, it will result in unpredictable behavior.
+	 */
+	usleep_range(200, 1000);
+
+	ret = denali_init(denali);
+	if (ret)
+		goto out_assert_rst;
+
 	for_each_child_of_node(dev->of_node, np) {
 		ret = denali_dt_chip_init(denali, np);
 		if (ret) {
@@ -190,6 +222,10 @@ static int denali_dt_probe(struct platform_device *pdev)
 
 out_remove_denali:
 	denali_remove(denali);
+out_assert_rst:
+	reset_control_assert(dt->rst);
+out_assert_rst_reg:
+	reset_control_assert(dt->rst_reg);
 out_disable_clk_ecc:
 	clk_disable_unprepare(dt->clk_ecc);
 out_disable_clk_x:
@@ -205,6 +241,8 @@ static int denali_dt_remove(struct platform_device *pdev)
 	struct denali_dt *dt = platform_get_drvdata(pdev);
 
 	denali_remove(&dt->controller);
+	reset_control_assert(dt->rst);
+	reset_control_assert(dt->rst_reg);
 	clk_disable_unprepare(dt->clk_ecc);
 	clk_disable_unprepare(dt->clk_x);
 	clk_disable_unprepare(dt->clk);