Date:   Mon, 23 Jan 2023 15:49:29 +0800
From:   Li Chen <me@linux.beauty>
To:     "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>
Cc:     "rafael j. wysocki" <rafael@kernel.org>,
        "li chen" <lchen@ambarella.com>,
        "linux-kernel" <linux-kernel@vger.kernel.org>
Message-ID: <185dd9a850f.103424a4c958820.1375066060155911709@linux.beauty>
In-Reply-To: <Y76UBsukAz+yQ9bW@kroah.com>
References: <20230111072130.3885460-1-me@linux.beauty>
 <Y75odDyZXMzigoaL@kroah.com>
 <1859ff0ddb8.d9ed321d977156.553326609923116766@linux.beauty> <Y76UBsukAz+yQ9bW@kroah.com>
Subject: Re: [PATCH v2] debugfs: allow to use regmap for print regs
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Hi Greg,
 ---- On Wed, 11 Jan 2023 18:48:38 +0800  Greg Kroah-Hartman  wrote --- 
 > On Wed, Jan 11, 2023 at 04:27:20PM +0800, Li Chen wrote:
 > > Hi Greg,
 > >  ---- On Wed, 11 Jan 2023 15:42:44 +0800  Greg Kroah-Hartman  wrote --- 
 > >  > On Wed, Jan 11, 2023 at 03:21:29PM +0800, Li Chen wrote:
 > >  > > From: Li Chen lchen@ambarella.com>
 > >  > > 
 > >  > > Currently, debugfs_regset32 only contains void __iomem *base,
 > >  > > and it is not friendly to regmap user.
 > >  > > 
 > >  > > Let's add regmap to debugfs_regset32, and add debugfs_print_regmap_reg32
 > >  > > to allow debugfs_regset32_show handle regmap.
 > >  > > 
 > >  > > Signed-off-by: Li Chen lchen@ambarella.com>
 > >  > 
 > >  > Do you have an actual in-kernel user for this new function?  We can't
 > >  > accept new apis without users for obvious reasaons.
 > > 
 > > Actually, both the old debugfs_print_regs32 and the new debugfs_regmap_print_regs32
 > > have only one user: debugfs_regset32_show located inside debugfs/file.c.
 > 
 > Yes, but that function is used by lots of drivers in the kernel today,
 > which is fine.
 > 
 > > The difference is currently all users(device drivers) only use debugfs_regset32->base,
 > > and none of them use debugfs_regset32->regmap, which is provided by this patch.
 > > 
 > > I'm not sure whether it violates the kernel's "no user, no new function" ruler or not.
 > 
 > Yes, you would have to have a user for this functionality for us to be
 > able to take the change.
 > 
 > > I use this regmap locally on our SoC driver, but it is still not ready to upstream, really sorry for it,
 > > and it is not a good idea to change existing non-regmap users to regmap haha.
 > >  
 > > If you think it does matter, please tell me and I will upload v3 with our SoC driver in the future.
 > 
 > Please add it to your SoC driver patch series instead and I will be glad
 > to review it at that point in time.  But for now, this shouldn't be
 > needed.
 
This patch is integrated into this series now: http://lists.infradead.org/pipermail/linux-arm-kernel/2023-January/804858.html

and its user is inside the first patch of the series, please help review it, thanks a lot!

Regards,
Li