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Date:   Fri, 11 Jun 2021 12:17:31 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Marion & Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc:     Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        linux-kernel@vger.kernel.org, Chunyan Zhang <zhang.lyra@gmail.com>
Subject: Re: [PATCH 4/9] nvmem: sprd: Fix an error message
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On Fri, Jun 11, 2021 at 12:10:58PM +0200, Marion & Christophe JAILLET wrote:
> 
> Le 11/06/2021 ? 11:45, Greg KH a ?crit?:
> > On Fri, Jun 11, 2021 at 11:17:50AM +0200, Greg KH wrote:
> > > On Fri, Jun 11, 2021 at 10:05:40AM +0100, Srinivas Kandagatla wrote:
> > > > 
> > > > On 11/06/2021 09:56, Greg KH wrote:
> > > > > On Fri, Jun 11, 2021 at 09:33:43AM +0100, Srinivas Kandagatla wrote:
> > > > > > From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> > > > > > 
> > > > > > 'ret' is known to be 0 here.
> > > > > > The expected error status is stored in 'status', so use it instead.
> > > > > > 
> > > > > > Also change %d in %u, because status is an u32, not a int.
> > > > > > 
> > > > > > Fixes: 096030e7f449 ("nvmem: sprd: Add Spreadtrum SoCs eFuse support")
> > > > > > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> > > > > > Acked-by: Chunyan Zhang <zhang.lyra@gmail.com>
> > > > > > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> > > > > > ---
> > > > > >    drivers/nvmem/sprd-efuse.c | 2 +-
> > > > > >    1 file changed, 1 insertion(+), 1 deletion(-)
> > > > > > 
> > > > > > diff --git a/drivers/nvmem/sprd-efuse.c b/drivers/nvmem/sprd-efuse.c
> > > > > > index 5d394559edf2..e3e721d4c205 100644
> > > > > > --- a/drivers/nvmem/sprd-efuse.c
> > > > > > +++ b/drivers/nvmem/sprd-efuse.c
> > > > > > @@ -234,7 +234,7 @@ static int sprd_efuse_raw_prog(struct sprd_efuse *efuse, u32 blk, bool doub,
> > > > > >    	status = readl(efuse->base + SPRD_EFUSE_ERR_FLAG);
> > > > > >    	if (status) {
> > > > > >    		dev_err(efuse->dev,
> > > > > > -			"write error status %d of block %d\n", ret, blk);
> > > > > > +			"write error status %u of block %d\n", status, blk);
> > > > > Shouldn't this be %pe and not %u?
> > > > This is not error pointer its status value read back from a register.
> > > > 
> > > > I think %u should be good here.
> > > Argh, you are right, my fault.  For some reason I thought this worked
> > > for integers as well.  Don't we have such a printk modifier somewhere to
> > > turn error values into strings?  Let me dig...
> > Ah, errname() will do it.
> > 
> > Looks like no one uses it, so nevermind, sorry for the noise.  I'll go
> > apply this one now.
> > 
> > thanks,
> > 
> > greg k-h
> 
> Hi,
> 
> errname() depends on CONFIG_SYMBOLIC_ERRNAME.
> Is this widely used?

It is set by default if you enable CONFIG_PRINTK

> If not, using errname() directly would loose the error code.
> (note that %pe already deals with it)
> 
> Dan Capenter already spoke about a potential %e extension, but I don't think
> anyone did anything yet.

That would be a fun and simple beginner task for someone to do.  Maybe
I'll mention it to this new round of interns that have just started...

thanks,

greg k-h