[RFC PATCH 2/3] of: mtd: add NAND randomizer mode retrieval

[Boris BREZILLON <b.brezillon.dev@gmail.com>]

Signed-off-by: Boris BREZILLON <b.brezillon.dev@gmail.com>
---
 drivers/of/of_mtd.c    | 35 +++++++++++++++++++++++++++++++++++
 include/linux/of_mtd.h |  6 ++++++
 2 files changed, 41 insertions(+)

diff --git a/drivers/of/of_mtd.c b/drivers/of/of_mtd.c
index a862c08..f941a5e 100644
--- a/drivers/of/of_mtd.c
+++ b/drivers/of/of_mtd.c
@@ -84,6 +84,41 @@ int of_get_nand_ecc_strength(struct device_node *np)
 EXPORT_SYMBOL_GPL(of_get_nand_ecc_strength);
 
 /**
+ * It maps 'enum nand_rnd_modes_t' found in include/linux/mtd/nand.h
+ * into the device tree binding of 'nand-rnd', so that MTD
+ * device driver can get nand rnd from device tree.
+ */
+static const char * const nand_rnd_modes[] = {
+	[NAND_RND_NONE]		= "none",
+	[NAND_RND_SOFT]		= "soft",
+	[NAND_RND_HW]		= "hw",
+};
+
+/**
+ * of_get_nand_rnd_mode - Get nand randomizer mode for given device_node
+ * @np:	Pointer to the given device_node
+ *
+ * The function gets randomizer mode string from property 'nand-rnd-mode',
+ * and return its index in nand_rnd_modes table, or errno in error case.
+ */
+int of_get_nand_rnd_mode(struct device_node *np)
+{
+	const char *pm;
+	int err, i;
+
+	err = of_property_read_string(np, "nand-rnd-mode", &pm);
+	if (err < 0)
+		return err;
+
+	for (i = 0; i < ARRAY_SIZE(nand_rnd_modes); i++)
+		if (!strcasecmp(pm, nand_rnd_modes[i]))
+			return i;
+
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(of_get_nand_rnd_mode);
+
+/**
  * of_get_nand_bus_width - Get nand bus witdh for given device_node
  * @np:	Pointer to the given device_node
  *
diff --git a/include/linux/of_mtd.h b/include/linux/of_mtd.h
index d0145fb..2f43362 100644
--- a/include/linux/of_mtd.h
+++ b/include/linux/of_mtd.h
@@ -15,6 +15,7 @@
 int of_get_nand_ecc_mode(struct device_node *np);
 int of_get_nand_ecc_step_size(struct device_node *np);
 int of_get_nand_ecc_strength(struct device_node *np);
+int of_get_nand_rnd_mode(struct device_node *np);
 int of_get_nand_bus_width(struct device_node *np);
 bool of_get_nand_on_flash_bbt(struct device_node *np);
 int of_get_nand_onfi_timing_mode(struct device_node *np);
@@ -36,6 +37,11 @@ static inline int of_get_nand_ecc_strength(struct device_node *np)
 	return -ENOSYS;
 }
 
+static inline int of_get_nand_rnd_mode(struct device_node *np)
+{
+	return -ENOSYS;
+}
+
 static inline int of_get_nand_bus_width(struct device_node *np)
 {
 	return -ENOSYS;
-- 
1.8.3.2