kirkwood_nand: claim MPP pins on the fly

Claim the MPP pins for the NAND flash controller only when it's actually
being used. This allows the pins to be shared with the SPI interface
which already supports an equivalent on-access MPP reconfiguration.

Reviewed-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
Signed-off-by: Chris Packham <judge.packham@gmail.com>
Acked-by: Scott Wood <oss@buserror.net>
Signed-off-by: Stefan Roese <sr@denx.de>

drivers/mtd/nand/kirkwood_nand.c

@@ -9,6 +9,7 @@
 #include <common.h>
 #include <asm/io.h>
 #include <asm/arch/soc.h>
+#include <asm/arch/mpp.h>
 #include <nand.h>
 
 /* NAND Flash Soc registers */
@@ -22,6 +23,8 @@ struct kwnandf_registers {
 static struct kwnandf_registers *nf_reg =
 	(struct kwnandf_registers *)KW_NANDF_BASE;
 
+static u32 nand_mpp_backup[9] = { 0 };
+
 /*
  * hardware specific access to control-lines/bits
  */
@@ -49,6 +52,22 @@ static void kw_nand_hwcontrol(struct mtd_info *mtd, int cmd,
 void kw_nand_select_chip(struct mtd_info *mtd, int chip)
 {
 	u32 data;
+	static const u32 nand_config[] = {
+		MPP0_NF_IO2,
+		MPP1_NF_IO3,
+		MPP2_NF_IO4,
+		MPP3_NF_IO5,
+		MPP4_NF_IO6,
+		MPP5_NF_IO7,
+		MPP18_NF_IO0,
+		MPP19_NF_IO1,
+		0
+	};
+
+	if (chip >= 0)
+		kirkwood_mpp_conf(nand_config, nand_mpp_backup);
+	else
+		kirkwood_mpp_conf(nand_mpp_backup, NULL);
 
 	data = readl(&nf_reg->ctrl);
 	data |= NAND_ACTCEBOOT_BIT;