Current rsnd driver will fallback to PIO mode if it can't get DMA
handler. But, DMA might return -EPROBE_DEFER when probe timing.
This driver always fallback to PIO mode especially from
commit ac6bbf0c ("iommu: Remove IOMMU_OF_DECLARE") because
of this reason.

The DMA driver will be probed later, but sound driver might be
probed as PIO mode in such case. This patch fixup this issue.
Then, -EPROBE_DEFER is not error. Thus, let's don't indicate error
message in such case.
And it needs to call rsnd_adg_remove() individually if probe failed,
because it registers clk which should be unregister.

Maybe PIO fallback feature itself is not needed,
but let's keep it so far.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Tidyup incoherence between MODULE_LICENSE and header license, too
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

commit 4821d914 ("ASoC: rsnd: use dma_sync_single_for_xxx() for
IOMMU") (= v1) which have been already reverted had supported IPMMU
support on rsnd driver.
Because memory allocating timing and DMAEngine access timing were
different, it used continuous memory and called dma map function by
itself.

OTOH, it is using DMA descriptor mode (= DMA cyclic mode), thus, there
was timing conflict between DMA sync/unsync and DMA transfer starting,
and it maked sound noise.

This patch supports IPMMU with coherent memory, and, it uses Audio DMAC
dev for allocating memory by snd_pcm_lib_preallocate_pages_for_all() to
indicate memory area to IPMMU.
One note is that Playback/Capture need each paired Audio DMAC dev.
Because of this, we need to keep each paired Audio DMAC dev when probing,
and use it when allocating each memory for IPMMU.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: NHiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

rsnd driver is supporting Gen3. The difference between Gen1 and Gen2
were very big, but, between Gen2 and Gen3 are not so much.
Thus, it is assuming Gen2 and Gen3 have compatible, therefore,
there is no RSND_GEN3 and rsnd_is_gen3() macro.
But in the future, it will need Gen2 and Gen3 different operation,
and for Gen4.
This patch adds missing RSND_GEN3 and rsnd_is_gen3() macro.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: NNguyen Viet Dung <dung.nguyen.aj@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

DMA handler had needed to calculate pointer before, but it doesn't
need now. Thus, we can remove unnecessary spin lock from DMAC handler.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

commit 4821d914 ("ASoC: rsnd: use dma_sync_single_for_xxx() for
IOMMU") had supported IOMMU, but it breaks normal sound "recorde"
and both PulseAudio's "playback/recorde". The sound will be noisy.

That commit was using dma_sync_single_for_xxx(), and driver should
make sure memory is protected during CPU or Device are using it.
But if driver returns current "residue" data size correctly on pointer
function, player/recorder will access to protected memory.

IOMMU feature should be supported, but I don't know how to handle it
without memory cache problem at this point.
Thus, this patch simply revert it to avoid current noisy sound.
Tested-by: NHiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Tested-by: NRyo Kodama <ryo.kodama.vz@renesas.com>
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

PTR_ERR(NULL) is success. Normally when a function returns both NULL
and error pointers, it means that NULL is not a error.
But, rsnd_dmaen_request_channel() returns NULL if requested resource
was failed.
Let's return -EIO if rsnd_dmaen_request_channel() was failed on
rsnd_dmaen_nolock_start().
This patch fixes commit edce5c49 ("ASoC: rsnd: Request/Release DMA
channel eachtime")
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Current rsnd driver has rsnd_mod_id() which returns mod ID,
and it returns -1 if mod was NULL.
In the same time, this driver has rsnd_mod_name() which returns mod
name, and it returns "unknown" if mod or mod->ops was NULL.

Basically these "mod" never be NULL, but the reason why rsnd driver
has such behavior is that DMA path finder is assuming memory as
"mod == NULL".
Thus, current DMA path debug code prints like below.
Here "unknown[-1]" means it was memory.

	...
	rcar_sound ec500000.sound:   unknown[-1] from
	rcar_sound ec500000.sound:   src[0] to
	rcar_sound ec500000.sound:   ctu[2]
	rcar_sound ec500000.sound:   mix[0]
	rcar_sound ec500000.sound:   dvc[0]
	rcar_sound ec500000.sound:   ssi[0]
	rcar_sound ec500000.sound: audmac[0] unknown[-1] -> src[0]
	...

1st issue is that it is confusable for user.
2nd issue is rsnd driver has something like below code.

	mask |= 1 << rsnd_mod_id(mod);

Because of this kind of code, some statically code checker will
reports "Shifting by a negative value is undefined behaviour".

But this "mod" never be NULL, thus negative shift never happen.
To avoid these issues, this patch adds new dummy "mem" to
indicate memory, and use it to indicate debug information,
and, remove unneeded "NULL mod" behavior from rsnd_mod_id() and
rsnd_mod_name().

The debug information will be like below by this patch
	...
	rcar_sound ec500000.sound:   mem[0] from
	rcar_sound ec500000.sound:   src[0] to
	rcar_sound ec500000.sound:   ctu[2]
	rcar_sound ec500000.sound:   mix[0]
	rcar_sound ec500000.sound:   dvc[0]
	rcar_sound ec500000.sound:   ssi[0]
	rcar_sound ec500000.sound: audmac[0] mem[0] -> src[0]
	...
Reported-by: NHiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

R-Car sound DMA will be used from SSI/SRC.
dma.c doesn't alloc DMA handler in .probe timing, because we don't
know what kind of DMA transfer will be used then.
Thus, SSI/SRC have *rsnd_mod for DMA. rsnd_dma_attach() will allocate
it and attach it to system.
It will be PIO mode if it can't alloc DMA handler.

In case of MIX is used, rsnd_dma_attach() will be called twice from SSI.
To avoid duplicate allocation, current rsnd_dma_attach() is checking
allocated DMA handler. This DMA related operation is a little bit
difficult to understand.
This patch adds new rsnd_dma_alloc() and separates allocation and attach
for readable code.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Current rsnd driver is sharing pointer related code between
PIO / DMA. But, it is used only PIO mode now, no longer needed.
This patch cleanup these.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Current rsnd driver updates pointer when DMA transfer was finished
in DMA transfer mode. But PulseAudio requests more accurate
pointer update when timer mode.
This patch consider about DMA transfer residue and update more
accurate pointer.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

commit 2a3af642eb20("ASoC: rcar: clear DE bit only in PDMACHCR...")
added rsnd_dmapp_bset(), but it used copy-paste. Thus, it had
unnecessary "volatile", and had below warning on x86.
This patch fix it.

   sound/soc/sh/rcar/dma.c: In function 'rsnd_dmapp_bset':
>> sound/soc/sh/rcar/dma.c:463:21: warning: passing argument 1 of \
   'ioread32' discards 'volatile' qualifier from pointer target \
   type [-Wdiscarded-qualifiers]
     u32 val = ioread32(addr);
                        ^~~~
   In file included from arch/x86/include/asm/io.h:203:0,
                    from arch/x86/include/asm/realmode.h:5,
                    from arch/x86/include/asm/acpi.h:33,
                    from arch/x86/include/asm/fixmap.h:19,
                    from arch/x86/include/asm/apic.h:10,
                    from arch/x86/include/asm/smp.h:12,
                    from include/linux/smp.h:59,
                    from include/linux/topology.h:33,
                    from include/linux/gfp.h:8,
                    from include/linux/idr.h:16,
                    from include/linux/kernfs.h:14,
                    from include/linux/sysfs.h:15,
                    from include/linux/kobject.h:21,
                    from include/linux/of.h:21,
                    from include/linux/of_dma.h:16,
                    from sound/soc/sh/rcar/dma.c:12:
   include/asm-generic/iomap.h:31:21: note: expected 'void *' \
   but argument is of type 'volatile void *'
    extern unsigned int ioread32(void __iomem *);
                        ^~~~~~~~
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

R-Car datasheet indicates "Clear DE in PDMACHCR" for transfer stop,
but current code clears all bits in PDMACHCR.
Because of this, DE bit might never been cleared,
and it causes CMD overflow. This patch fixes this issue.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: NHiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

IOMMU needs DMA mapping function to use it. One solution is that
we can use DMA mapped dev on snd_pcm_lib_preallocate_pages_for_all()
for SNDRV_DMA_TYPE_DEV. But pcm_new and dma map timing are mismatched.
Thus, this patch uses SNDRV_DMA_TYPE_CONTINUOUS for pcm_new,
and use dma_sync_single_for_xxx() for each transfer.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Current Renesas Sound driver requests DMA channel when .probe timing,
and release it when .remove timing. And use DMA on .start/.stop
But, Audio DMAC power ON was handled when request timing (= .probe),
and power OFF was when release timing (= .remove).
This means Audio DMAC power is always ON during driver was enabled.
The best choice to solve this issue is that DMAEngine side handle
this. But current DMAEngine API design can't solve atmic/non-atmic
context issue for power ON/OFF. So next better choice is sound
driver request/release DMA channel each time. This patch do it
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Current rsnd_dmaen_start() is calling of_node_put() for np,
but it is not needed if it goes through this loop.
This patch tidyup it
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

DMA mod is now connected to stream via rsnd_dai_connect().
This means DMA mod can use .remove for its clearance.
rsnd_dma_detach() is no longer needed.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Current Renesas Sound driver is based on DeviceTree, and no one is
using this driver from non DT. Non-DT support is no longer needed.
Let's remove it.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

commit 1a5658c2 ("ASoC: rsnd: count .probe/.remove for
rsnd_mod_call()") solved multi-resource-free issue, by putting
.probe/.remove under count control. But,it breaks sound mixing case
(if it was used under DPCM). In such case, it uses MIXn/DVCn/SSIn,
and these should be always probed.
This patch reverted above patch, and solved the same issue by
modifing _rsnd_kctrl_remove() function.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Current rsnd_dmapp_get_id() returns 0xFF as error code if system used
strange connection. It will be used as PDMACHCRn.SRS, but 0xFF is
prohibited number.
In order not to use prohibited number, this patch indicates error message
and returns 0x00 (same as SSI00) in error case.
Special thanks to Dung-san.
Reported-by: NNguyen Viet Dung <nv-dung@jinso.co.jp>
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

SSI/SRC will try to attach DMAC as Audio-DMAC or Audio-DMAC-periperi.
It is fixed IP, but will be attached to each streams as different module
in case of MUX (= multi sound path will be merged).
This patch solves this issue.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

SSI will be used as normal SSI or as clock parent SSI. Therefor,
rsnd driver wants to control SSI and parent SSI separately. Otherwise it
can't use Playback/Capture in the same time.
And it has been done by c2dc47d5("ASoC: rsnd: rsnd_dai_stream has each
mod's status insted of rsnd_mod") before.

OTOH, rsnd driver doesn't want to control CTU/MUX/DVC/SSIU/SSI in
separately. Otherwise, these will be re-initialized during playing if
MUX merges 2 sounds.
Because of these picky reasons, this patch re-defines status on each mod,
and add new parent_ssi_status on rsnd_dai_stream.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

It can't output corrent dma name *before* rsnd_mod_init().
It goes to *after* rsnd_mod_init() by this patch
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Current Renesas sound driver requests struct platform_device on
probe/remove for each modules. But driver can get it by
rsnd_priv_to_pdev(). This patch removes unnecessary parameter
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

No board is using Renesas sound driver via platform boot now.
This means all user is using DT boot. Platform boot support is
no longer needed. But, it strongly depends on platform boot style.
Now, platform boot style was removed from driver.
This is cleanup patch, and remove pointless struct rsnd_of_data
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

45a4394d03("ASoC: rsnd: use mod base common method on DMA phase3")
Exchanged "void rsnd_dmapp_stop()" to "int rsnd_dmapp_stop()",
but it returns inverted value. This patch fixup it.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Renesas sound needs many devices
(SSI/SSIU/SRC/CTU/MIX/DVC/CMD/AudioDMAC/AudioDMACpp).
SSI/SRC/CTU/MIX/DVC are implemented as module.
SSI parent, SSIU are implemented as part of SSI
CMD is implemented as part of CTU/MIX/DVC
AudioDMAC/AudioDMACpp are implemented as part of SSI/SRC
It is nice sense that these all devices are implemented as mod.

This patch makes DMA mod bse common method
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Renesas sound needs many devices
(SSI/SSIU/SRC/CTU/MIX/DVC/CMD/AudioDMAC/AudioDMACpp).
SSI/SRC/CTU/MIX/DVC are implemented as module.
SSI parent, SSIU are implemented as part of SSI
CMD is implemented as part of CTU/MIX/DVC
AudioDMAC/AudioDMACpp are implemented as part of SSI/SRC
It is nice sense that these all devices are implemented as mod.

DMA will be implemented as module. Then rsnd_dma_ops will be rebased
to rsnd_mod_ops, but these are similar, but different function.
This patch modify rsnd_dma_ops same style as rsnd_mod_ops.
This is prepare for final merge
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Renesas sound needs many devices
(SSI/SSIU/SRC/CTU/MIX/DVC/CMD/AudioDMAC/AudioDMACpp).
SSI/SRC/CTU/MIX/DVC are implemented as module.
SSI parent, SSIU are implemented as part of SSI
CMD is implemented as part of CTU/MIX/DVC
AudioDMAC/AudioDMACpp are implemented as part of SSI/SRC
It is nice sense that these all devices are implemented as mod.

DMA will be implemented as module. Then rsnd_dma will be mod base.
This patch makes rsnd_dma mod base, but still not yet completely
finished. This mod is not yet installed to system at this point.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Renesas sound needs many devices
(SSI/SSIU/SRC/CTU/MIX/DVC/CMD/AudioDMAC/AudioDMACpp).
SSI/SRC/CTU/MIX/DVC are implemented as module.
SSI parent, SSIU are implemented as part of SSI
CMD is implemented as part of CTU/MIX/DVC
AudioDMAC/AudioDMACpp are implemented as part of SSI/SRC
It is nice sense that these all devices are implemented as mod.

Current rsnd_dma_of_path is assuming that all mods are related to DMA.
But it will be wrong. This patch tidyup this wrong assumption
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Renesas sound needs many devices
(SSI/SSIU/SRC/CTU/MIX/DVC/CMD/AudioDMAC/AudioDMACpp).
SSI/SRC/CTU/MIX/DVC are implemented as module.
SSI parent, SSIU are implemented as part of SSI
CMD is implemented as part of CTU/MIX/DVC
AudioDMAC/AudioDMACpp are implemented as part of SSI/SRC
It is nice sense that these all devices are implemented as mod.

DMA will be implemented as module. Then each rsnd_dma_ops will be
rsnd_mod_ops. But current rsnd_dma_ops::init means "DMA attach".
This patch removes .init from rsnd_dma_ops, and renames
rsnd_dma_init() to rsnd_dma_attach()
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Renesas sound needs many devices
(SSI/SSIU/SRC/CTU/MIX/DVC/CMD/AudioDMAC/AudioDMACpp).
SSI/SRC/CTU/MIX/DVC are implemented as module.
SSI parent, SSIU are implemented as part of SSI
CMD is implemented as part of CTU/MIX/DVC
AudioDMAC/AudioDMACpp are implemented as part of SSI/SRC
It is nice sense that these all devices are implemented as mod.

DMA will be implemented as module. Current DMA definition is no longer
needed on rsnd.h. Let's move it to dma.c
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Renesas sound needs many devices
(SSI/SSIU/SRC/CTU/MIX/DVC/CMD/AudioDMAC/AudioDMACpp).
SSI/SRC/CTU/MIX/DVC are implemented as module.
SSI parent, SSIU are implemented as part of SSI
CMD is implemented as part of CTU/MIX/DVC
AudioDMAC/AudioDMACpp are implemented as part of SSI/SRC
It is nice sense that these all devices are implemented as mod.

Current rsnd_mod is member of rsnd_mod. But the DMA user is only
SSI/SRC. This DMA will be implemented as module. As 1st step, DMA
become SSI/SRC member by this patch.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

rsnd_ssi_use_busif() and rsnd_ssi_is_pin_sharing() are the function
which returns current SSI status. But these requests duplicated parameter.
This patch removes duplicated parameter.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

On arm64:

    sound/soc/sh/rcar/dma.c: In function 'rsnd_dmaen_init':
    sound/soc/sh/rcar/dma.c:180:9: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
	     (void *)id);
	     ^
    include/linux/dmaengine.h:1185:75: note: in definition of macro 'dma_request_channel'
     #define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y)
									       ^

Add an intermediate cast to "uintptr_t" to kill the compile warning.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NMark Brown <broonie@kernel.org>

This patch adds MIX (Mixer) initial support for rsnd driver.
It is assuming that this MIX is used via DPCM.

This is sample code for playback.

	CPU0  : [MEM] -> [SRC1] -> [CTU02] -+
					    |
					    +-> [MIX0] -> [DVC0] -> [SSI0]
	                                    |
	CPU1  : [MEM] -> [SRC2] -> [CTU03] -+

	sound {
		compatible = "renesas,rsrc-card";

		...

		cpu@0 {
			sound-dai = <&rcar_sound 0>;
		};

		cpu@1 {
			sound-dai = <&rcar_sound 1>;
		};

		codec {
			...
		};
	};

	rcar_sound {

		...

		rcar_sound,dai {
			dai0 {
				playback = <&src1 &ctu02 &mix0 &dvc0 &ssi0>;
			};
			dai1 {
				playback = <&src2 &ctu03 &mix0 &dvc0 &ssi0>;
			};
		};
	};
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: NKeita Kobayashi <keita.kobayashi.ym@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

This patch adds CTU (Channel Transfer Unit) support for rsnd driver.
But, it does nothing to data at this point, but is required for MIX
support.

CTU design is a little different from other IPs (CTU0 is including
CTU00 - CTU03, and CTU1 is including CTU10 - CTU13, these have different
register mapping) We need to care about it on this driver.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: NKeita Kobayashi <keita.kobayashi.ym@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Current rsnd driver is assuming Audio DMAC / Audio DMAC peri peri
are used from SSI/SSIU/SRC/DVC. But we will add CTU/MIX to this driver.
Then, current DMA path searching method is not understandable, and good
enough for this purpose. This patch update DMA path search method, more
simply.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: NKeita Kobayashi <keita.kobayashi.ym@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Current rsnd driver is using Audio DMAC (via DMAEngine) and
Audio DMAC peri peri (via original method), and usage of these DMAC
are different. Indicates its naming is useful for debugging.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: NKeita Kobayashi <keita.kobayashi.ym@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>