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Date:   Tue, 21 May 2019 10:56:41 +0200
From:   Sascha Hauer <s.hauer@pengutronix.de>
To:     linux-kernel@vger.kernel.org
Cc:     Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        kernel@pengutronix.de, linux-mtd@lists.infradead.org
Subject: nvmem creates multiple devices with the same name
Message-ID: <20190521085641.i6g5aijwa5zbolah@pengutronix.de>
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Hi all,

nvmem derives the device name directly from the partition name of the
underlying device. IMO this is wrong since it's not possible to create
two partitions with the same name on different devices. In my case I
have a NAND device and a SPI NOR device which both happen to have a
partition named 'barebox'. This ends up with:

[   11.222196] sysfs: cannot create duplicate filename '/bus/nvmem/devices/barebox'
[   11.230136] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W         5.2.0-rc1-00014-g793f23e5adb0-dirty #676
[   11.240414] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
[   11.247174] [<c0112928>] (unwind_backtrace) from [<c010d140>] (show_stack+0x10/0x14)
[   11.255171] [<c010d140>] (show_stack) from [<c0bd65cc>] (dump_stack+0xd8/0x110)
[   11.262722] [<c0bd65cc>] (dump_stack) from [<c031682c>] (sysfs_warn_dup+0x50/0x64)
[   11.270527] [<c031682c>] (sysfs_warn_dup) from [<c0316b34>] (sysfs_do_create_link_sd+0xcc/0xd8)
[   11.279487] [<c0316b34>] (sysfs_do_create_link_sd) from [<c06792a0>] (bus_add_device+0x80/0xfc)
[   11.288441] [<c06792a0>] (bus_add_device) from [<c0676208>] (device_add+0x328/0x608)
[   11.296423] [<c0676208>] (device_add) from [<c08bde64>] (nvmem_register.part.1+0x168/0x5e4)
[   11.305030] [<c08bde64>] (nvmem_register.part.1) from [<c06edb34>] (add_mtd_device+0x1e8/0x404)
[   11.313988] [<c06edb34>] (add_mtd_device) from [<c06f1004>] (add_mtd_partitions+0x74/0x15c)
[   11.322589] [<c06f1004>] (add_mtd_partitions) from [<c06f0da8>] (parse_mtd_partitions+0x180/0x368)
[   11.331807] [<c06f0da8>] (parse_mtd_partitions) from [<c06ede68>] (mtd_device_parse_register+0x40/0x164)
[   11.341560] [<c06ede68>] (mtd_device_parse_register) from [<c070654c>] (m25p_probe+0x118/0x200)
[   11.350513] [<c070654c>] (m25p_probe) from [<c073863c>] (spi_drv_probe+0x80/0xa4)

While it's easy to rename the partitions I see no reason why it should
be illegal to have two different (mtd) devices with eqeally named
partitions. Are there any suggestions how to register the nvmem devices
with a different name?

Sascha

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