[PATCH 3/9] nvmem: ocotp: add support to query the field-return sticky bit

[Marco Felsch <m.felsch@pengutronix.de>]

The i.MX8M* devices do have an sticky bit which indicates if the
field-return fuse can be written. Add support to query the lock bit.

To make it easy to read align the STICKY bit definitions as well.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
---
 drivers/nvmem/ocotp.c    | 24 ++++++++++++++++++++++++
 include/mach/imx/ocotp.h |  1 +
 2 files changed, 25 insertions(+)

diff --git a/drivers/nvmem/ocotp.c b/drivers/nvmem/ocotp.c
index c0517980fb18..87cc95a636f3 100644
--- a/drivers/nvmem/ocotp.c
+++ b/drivers/nvmem/ocotp.c
@@ -91,6 +91,7 @@
 #define OCOTP_TIMING_WAIT		GENMASK(27, 22)
 
 #define OCOTP_SW_STICKY_SRK_REVOKE_LOCK		BIT(1)
+#define OCOTP_SW_STICKY_FIELD_RETURN_LOCK	BIT(2)
 
 #define OCOTP_READ_CTRL_READ_FUSE	BIT(1)
 
@@ -152,6 +153,7 @@ struct imx_ocotp_data {
 	int (*fuse_blow)(struct ocotp_priv *priv, u32 addr, u32 value);
 	bool (*srk_revoke_locked)(struct ocotp_priv *priv);
 	void (*lock_srk_revoke)(struct ocotp_priv *priv);
+	bool (*field_return_locked)(struct ocotp_priv *priv);
 	u8  mac_offsets[MAX_MAC_OFFSETS];
 	u8  mac_offsets_num;
 	struct imx8m_featctrl_data *feat;
@@ -292,6 +294,11 @@ static void imx8m_lock_srk_revoke(struct ocotp_priv *priv)
 	writel(val, priv->base + OCOTP_SW_STICKY);
 }
 
+static bool imx8m_field_return_locked(struct ocotp_priv *priv)
+{
+	return readl(priv->base + OCOTP_SW_STICKY) & OCOTP_SW_STICKY_FIELD_RETURN_LOCK;
+}
+
 static int imx6_fuse_read_addr(struct ocotp_priv *priv, u32 addr, u32 *pdata)
 {
 	const u32 bm_ctrl_error = priv->data->ctrl->bm_error;
@@ -674,6 +681,20 @@ int imx_ocotp_lock_srk_revoke(void)
 	return -ENOSYS;
 }
 
+int imx_ocotp_field_return_locked(void)
+{
+	int ret;
+
+	ret = imx_ocotp_ensure_probed();
+	if (ret)
+		return ret;
+
+	if (imx_ocotp->data->field_return_locked)
+		return imx_ocotp->data->field_return_locked(imx_ocotp);
+
+	return -ENOSYS;
+}
+
 static void imx_ocotp_format_mac(u8 *dst, const u8 *src,
 				 enum imx_ocotp_format_mac_direction dir)
 {
@@ -1036,6 +1057,7 @@ static struct imx_ocotp_data imx8mp_ocotp_data = {
 	.fuse_read = imx6_fuse_read_addr,
 	.srk_revoke_locked = imx8m_srk_revoke_locked,
 	.lock_srk_revoke = imx8m_lock_srk_revoke,
+	.field_return_locked = imx8m_field_return_locked,
 	.ctrl = &ocotp_ctrl_reg_8mp,
 };
 
@@ -1067,6 +1089,7 @@ static struct imx_ocotp_data imx8mm_ocotp_data = {
 	.fuse_read = imx6_fuse_read_addr,
 	.srk_revoke_locked = imx8m_srk_revoke_locked,
 	.lock_srk_revoke = imx8m_lock_srk_revoke,
+	.field_return_locked = imx8m_field_return_locked,
 	.feat = &imx8mm_featctrl_data,
 	.ctrl = &ocotp_ctrl_reg_default,
 };
@@ -1087,6 +1110,7 @@ static struct imx_ocotp_data imx8mn_ocotp_data = {
 	.fuse_read = imx6_fuse_read_addr,
 	.srk_revoke_locked = imx8m_srk_revoke_locked,
 	.lock_srk_revoke = imx8m_lock_srk_revoke,
+	.field_return_locked = imx8m_field_return_locked,
 	.feat = &imx8mn_featctrl_data,
 	.ctrl = &ocotp_ctrl_reg_default,
 };
diff --git a/include/mach/imx/ocotp.h b/include/mach/imx/ocotp.h
index 7a516ff789b9..e6f62a9da48c 100644
--- a/include/mach/imx/ocotp.h
+++ b/include/mach/imx/ocotp.h
@@ -38,6 +38,7 @@ int imx_ocotp_permanent_write(int enable);
 int imx_ocotp_sense_enable(bool enable);
 int imx_ocotp_srk_revoke_locked(void);
 int imx_ocotp_lock_srk_revoke(void);
+int imx_ocotp_field_return_locked(void);
 
 static inline u64 imx_ocotp_read_uid(void __iomem *ocotp)
 {
-- 
2.39.2