[PATCH V2] drivers/mtd: Fix device registration error

["Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx>]

This change helps me to get multiple mtd device registered. Without this
I get

sysfs: cannot create duplicate filename '/bus/nvmem/devices/flash0'
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc2-00557-g1ef20ef21f22 #13
Call Trace:
[c0000000b38e3220] [c000000000b58fe4] dump_stack+0xe8/0x164 (unreliable)
[c0000000b38e3270] [c0000000004cf074] sysfs_warn_dup+0x84/0xb0
[c0000000b38e32f0] [c0000000004cf6c4] sysfs_do_create_link_sd.isra.0+0x114/0x150
[c0000000b38e3340] [c000000000726a84] bus_add_device+0x94/0x1e0
[c0000000b38e33c0] [c0000000007218f0] device_add+0x4d0/0x830
[c0000000b38e3480] [c0000000009d54a8] nvmem_register.part.2+0x1c8/0xb30
[c0000000b38e3560] [c000000000834530] mtd_nvmem_add+0x90/0x120
[c0000000b38e3650] [c000000000835bc8] add_mtd_device+0x198/0x4e0
[c0000000b38e36f0] [c00000000083619c] mtd_device_parse_register+0x11c/0x280
[c0000000b38e3780] [c000000000840830] powernv_flash_probe+0x180/0x250
[c0000000b38e3820] [c00000000072c120] platform_drv_probe+0x60/0xf0
[c0000000b38e38a0] [c0000000007283c8] really_probe+0x138/0x4d0
[c0000000b38e3930] [c000000000728acc] driver_probe_device+0x13c/0x1b0
[c0000000b38e39b0] [c000000000728c7c] __driver_attach+0x13c/0x1c0
[c0000000b38e3a30] [c000000000725130] bus_for_each_dev+0xa0/0x120
[c0000000b38e3a90] [c000000000727b2c] driver_attach+0x2c/0x40
[c0000000b38e3ab0] [c0000000007270f8] bus_add_driver+0x228/0x360
[c0000000b38e3b40] [c00000000072a2e0] driver_register+0x90/0x1a0
[c0000000b38e3bb0] [c00000000072c020] __platform_driver_register+0x50/0x70
[c0000000b38e3bd0] [c00000000105c984] powernv_flash_driver_init+0x24/0x38
[c0000000b38e3bf0] [c000000000010904] do_one_initcall+0x84/0x464
[c0000000b38e3cd0] [c000000001004548] kernel_init_freeable+0x530/0x634
[c0000000b38e3db0] [c000000000011154] kernel_init+0x1c/0x168
[c0000000b38e3e20] [c00000000000bed4] ret_from_kernel_thread+0x5c/0x68
mtd mtd1: Failed to register NVMEM device

With the change we now have

root@(none):/sys/bus/nvmem/devices# ls -al
total 0
drwxr-xr-x 2 root root 0 Feb  6 20:49 .
drwxr-xr-x 4 root root 0 Feb  6 20:49 ..
lrwxrwxrwx 1 root root 0 Feb  6 20:49 flash@0 -> ../../../devices/platform/ibm,opal:flash@0/mtd/mtd0/flash@0
lrwxrwxrwx 1 root root 0 Feb  6 20:49 flash@1 -> ../../../devices/platform/ibm,opal:flash@1/mtd/mtd1/flash@1

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
---
Changes from V1:
* update mtd->name to be unique and use that when registering nvmem

 drivers/mtd/devices/powernv_flash.c | 2 +-
 drivers/mtd/mtdcore.c               | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/devices/powernv_flash.c b/drivers/mtd/devices/powernv_flash.c
index 22f753e555ac..83f88b8b5d9f 100644
--- a/drivers/mtd/devices/powernv_flash.c
+++ b/drivers/mtd/devices/powernv_flash.c
@@ -212,7 +212,7 @@ static int powernv_flash_set_driver_info(struct device *dev,
 	 * Going to have to check what details I need to set and how to
 	 * get them
 	 */
-	mtd->name = devm_kasprintf(dev, GFP_KERNEL, "%pOFn", dev->of_node);
+	mtd->name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node);
 	mtd->type = MTD_NORFLASH;
 	mtd->flags = MTD_WRITEABLE;
 	mtd->size = size;
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 999b705769a8..3ef01baef9b6 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -507,6 +507,7 @@ static int mtd_nvmem_add(struct mtd_info *mtd)
 {
 	struct nvmem_config config = {};
 
+	config.id = -1;
 	config.dev = &mtd->dev;
 	config.name = mtd->name;
 	config.owner = THIS_MODULE;
-- 
2.20.1


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