nvmem: rockchip-otp: Reset opt phy before access otp

It would be more stable to reset phy before use user interface to
access otp.

Change-Id: Icd5660db15f6da7bad0ef8d01970f88aeca369a2
Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com>

Author: finley1226

Documentation/devicetree/bindings/nvmem/rockchip-otp.txt

@@ -8,6 +8,9 @@ Required properties:
   - size-cells: must be set to 1.
   - clocks: Must contain an entry for each entry in clock-names.
   - clock-names: Should be "clk_opt", "pclk_otp" and "pclk_otp_phy".
+  - resets: Must contain an entry for each entry in reset-names.
+    See ../../reset/reset.txt for details.
+  - reset-names: Should be "otp_phy".
 
 See nvmem.txt for more information.
 

drivers/nvmem/rockchip-otp.c

@@ -21,6 +21,7 @@
 #include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/nvmem-provider.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
@@ -67,12 +68,34 @@ struct rockchip_otp {
 	struct clk *clk;
 	struct clk *pclk;
 	struct clk *pclk_phy;
+	struct reset_control *rst;
 };
 
 struct rockchip_data {
 	int size;
 };
 
+static int rockchip_otp_reset(struct rockchip_otp *otp)
+{
+	int ret;
+
+	ret = reset_control_assert(otp->rst);
+	if (ret) {
+		dev_err(otp->dev, "failed to assert otp phy %d\n", ret);
+		return ret;
+	}
+
+	udelay(2);
+
+	ret = reset_control_deassert(otp->rst);
+	if (ret) {
+		dev_err(otp->dev, "failed to deassert otp phy %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
 static int rockchip_otp_wait_status(struct rockchip_otp *otp, u32 flag)
 {
 	u32 status = 0;
@@ -138,6 +161,12 @@ static int rockchip_otp_read(void *context, unsigned int offset,
 		goto opt_pclk;
 	}
 
+	ret = rockchip_otp_reset(otp);
+	if (ret) {
+		dev_err(otp->dev, "failed to reset otp phy\n");
+		goto opt_pclk_phy;
+	}
+
 	ret = rockchip_otp_ecc_enable(otp, false);
 	if (ret < 0) {
 		dev_err(otp->dev, "rockchip_otp_ecc_enable err\n");
@@ -232,6 +261,10 @@ static int __init rockchip_otp_probe(struct platform_device *pdev)
 	if (IS_ERR(otp->pclk_phy))
 		return PTR_ERR(otp->pclk_phy);
 
+	otp->rst = devm_reset_control_get(dev, "otp_phy");
+	if (IS_ERR(otp->rst))
+		return PTR_ERR(otp->rst);
+
 	otp_config.size = data->size;
 	otp_config.priv = otp;
 	otp_config.dev = dev;