[PATCH v1 2/3] mtd: probe: probe dual die entry from devicetree binding

[Bean Huo]

From: beanhuo <beanhuo at micron.com>

The device_stack property now will be initialized when devicetree
has an entry compatible with "dual_die_stack".

Signed-off-by: beanhuo <beanhuo at micron.com>
---
 drivers/mtd/chips/cfi_probe.c | 7 +++++++
 include/linux/mtd/cfi.h       | 8 ++++++++
 2 files changed, 15 insertions(+)

diff --git a/drivers/mtd/chips/cfi_probe.c b/drivers/mtd/chips/cfi_probe.c
index e8d0164..6182406 100644
--- a/drivers/mtd/chips/cfi_probe.c
+++ b/drivers/mtd/chips/cfi_probe.c
@@ -17,6 +17,7 @@
 #include <linux/mtd/map.h>
 #include <linux/mtd/cfi.h>
 #include <linux/mtd/gen_probe.h>
+#include <linux/of_platform.h>
 
 //#define DEBUG_CFI
 
@@ -159,6 +160,7 @@ static int __xipram cfi_chip_setup(struct map_info *map,
 	int num_erase_regions = cfi_read_query(map, base + (0x10 + 28)*ofs_factor);
 	int i;
 	int addr_unlock1 = 0x555, addr_unlock2 = 0x2AA;
+	struct device_node __maybe_unused *np = map->device_node;
 
 	xip_enable(base, map, cfi);
 #ifdef DEBUG_CFI
@@ -177,6 +179,11 @@ static int __xipram cfi_chip_setup(struct map_info *map,
 
 	cfi->sector_erase_cmd = CMD(0x30);
 
+	cfi->device_stack = CFI_DEVICESTACK_1DIE;
+#ifdef CONFIG_OF
+	if (np && of_property_read_bool(np, "dual-die-stack"))
+		cfi->device_stack = CFI_DEVICESTACK_2DIE;
+#endif
 	/* Read the CFI info structure */
 	xip_disable_qry(base, map, cfi);
 	for (i=0; i<(sizeof(struct cfi_ident) + num_erase_regions * 4); i++)
diff --git a/include/linux/mtd/cfi.h b/include/linux/mtd/cfi.h
index 9b57a9b..bda37a4 100644
--- a/include/linux/mtd/cfi.h
+++ b/include/linux/mtd/cfi.h
@@ -277,11 +277,19 @@ struct cfi_bri_query {
 #define CFI_MODE_CFI	1
 #define CFI_MODE_JEDEC	0
 
+/* These values represent the die count of chip stack.
+ * So far, there only exists two type of stack device,
+ * single or dual die.
+ */
+#define CFI_DEVICESTACK_1DIE	1
+#define CFI_DEVICESTACK_2DIE	2
+
 struct cfi_private {
 	uint16_t cmdset;
 	void *cmdset_priv;
 	int interleave;
 	int device_type;
+	int device_stack;	/* Device stack type, single die or dual die. */
 	int cfi_mode;		/* Are we a JEDEC device pretending to be CFI? */
 	int addr_unlock1;
 	int addr_unlock2;
-- 
2.7.4