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From:   Jean-Baptiste Maneyrol <JManeyrol@invensense.com>
To:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: regmap issue with ranges and noinc read
Thread-Topic: regmap issue with ranges and noinc read
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Date:   Fri, 3 Apr 2020 07:46:13 +0000
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Hello,=0A=
=0A=
I have an issue using regmap noinc read when using ranges.=0A=
=0A=
My device is 8-bits registers and 8-bits values and uses several register b=
anks that you can switch using a bank register available on all banks.=0A=
I am configuring regmap with 1 range with window len of 0x100 and using vir=
tual register addresses like 0x0aRR, where a is the bank number and RR regi=
ster address (0x0032 for register 0x32 in bank 0, and 0x0123 for register 0=
x23 in bank 1). This is working pretty well so far.=0A=
=0A=
The device has in bank 0 a virtual register for reading a data FIFO, which =
is larger than a bank (0x800, 2048). When using the regmap_noinc_read API f=
or reading my FIFO, I am limited in size to not overflow the range window l=
en. regmap is checking that and returns EINVAL in this case (check is done =
inside _regmap_select_page called in _regmap_raw_read). It certainly makes =
sense when using the standard remap_bulk_read API, but for the noinc_read w=
here we are not reading continuous register this doesn't seem to be relevan=
t. And this prevent the read of the entire FIFO data in this case.=0A=
=0A=
Is there any reason to check the range window len bounds for the noinc_read=
 API or is this a bug?=0A=
=0A=
Thanks for your help.=0A=
=0A=
Best regards,=0A=
JB=