From: "Erhard F." <erhard_f@mailbox.org>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: Aishwarya R <aishwaryarj100@gmail.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Kate Stewart <kstewart@linuxfoundation.org>,
Richard Fontana <rfontana@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-i2c@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] i2c: powermac: Simplify reading the "reg" and "i2c-address" property
Date: Wed, 22 Apr 2020 23:07:14 +0200 [thread overview]
Message-ID: <20200422230709.19a81ef9@supah> (raw)
In-Reply-To: <20200421093712.GA1241@ninjato>
On Tue, 21 Apr 2020 11:37:13 +0200
Wolfram Sang <wsa@the-dreams.de> wrote:
> On Wed, Apr 15, 2020 at 06:49:14PM +0530, Aishwarya R wrote:
> > >> Use of_property_read_u32 to read the "reg" and "i2c-address" property
> > >> instead of using of_get_property to check the return values.
> > >>
> > >> Signed-off-by: Aishwarya R <aishwaryarj100@gmail.com>
> >
> > > This is quite a fragile driver. Have you tested it on HW?
> >
> > This change is not tested with the Hardware.
> > But of_property_read_u32 is better here than generic of_get_property.
> > This make sure that value read properly independent of system endianess.
>
> This driver is only used on PPC_BE. And it is *very* fragile. The gain
> is not enough for me to accept it without testing. Maybe Erhard (CCed)
> is interested. If not, you may find someone on the ppc lists.
>
I applied the patch on top of kernel 5.6.6 and tested it on a PowerMac G4 3,6 DP and a PowerMac G5 11,2. Both machines run without anything suspicious going on. dmesg | grep i2c looks the same with patch and without patch.
Tested-by: Erhard Furtner <erhard_f@mailbox.org>
WARNING: multiple messages have this Message-ID (diff)
From: "Erhard F." <erhard_f@mailbox.org>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>,
linux-kernel@vger.kernel.org,
Richard Fontana <rfontana@redhat.com>,
Paul Mackerras <paulus@samba.org>,
linux-i2c@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
linuxppc-dev@lists.ozlabs.org,
Aishwarya R <aishwaryarj100@gmail.com>
Subject: Re: [PATCH] i2c: powermac: Simplify reading the "reg" and "i2c-address" property
Date: Wed, 22 Apr 2020 23:07:14 +0200 [thread overview]
Message-ID: <20200422230709.19a81ef9@supah> (raw)
In-Reply-To: <20200421093712.GA1241@ninjato>
On Tue, 21 Apr 2020 11:37:13 +0200
Wolfram Sang <wsa@the-dreams.de> wrote:
> On Wed, Apr 15, 2020 at 06:49:14PM +0530, Aishwarya R wrote:
> > >> Use of_property_read_u32 to read the "reg" and "i2c-address" property
> > >> instead of using of_get_property to check the return values.
> > >>
> > >> Signed-off-by: Aishwarya R <aishwaryarj100@gmail.com>
> >
> > > This is quite a fragile driver. Have you tested it on HW?
> >
> > This change is not tested with the Hardware.
> > But of_property_read_u32 is better here than generic of_get_property.
> > This make sure that value read properly independent of system endianess.
>
> This driver is only used on PPC_BE. And it is *very* fragile. The gain
> is not enough for me to accept it without testing. Maybe Erhard (CCed)
> is interested. If not, you may find someone on the ppc lists.
>
I applied the patch on top of kernel 5.6.6 and tested it on a PowerMac G4 3,6 DP and a PowerMac G5 11,2. Both machines run without anything suspicious going on. dmesg | grep i2c looks the same with patch and without patch.
Tested-by: Erhard Furtner <erhard_f@mailbox.org>
next prev parent reply other threads:[~2020-04-22 21:07 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-08 10:03 [PATCH] i2c: powermac: Simplify reading the "reg" and "i2c-address" property Aishwarya R
2020-04-08 10:03 ` Aishwarya R
2020-04-15 11:12 ` Wolfram Sang
2020-04-15 11:12 ` Wolfram Sang
2020-04-15 13:19 ` Aishwarya R
2020-04-15 13:19 ` Aishwarya R
2020-04-21 9:37 ` Wolfram Sang
2020-04-21 9:37 ` Wolfram Sang
2020-04-22 21:07 ` Erhard F. [this message]
2020-04-22 21:07 ` Erhard F.
2020-04-26 8:32 ` Wolfram Sang
2020-04-26 8:32 ` Wolfram Sang
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