From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Subject: Re: [PATCH] i2c-qoriq: modified compatibility for correct prescaler Date: Tue, 28 Oct 2014 18:08:51 -0500 Message-ID: <1414537731.23458.120.camel@snotra.buserror.net> References: <1413538026-15739-1-git-send-email-valentin.longchamp@keymile.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1413538026-15739-1-git-send-email-valentin.longchamp-SkAbAL50j+5BDgjK7y7TUQ@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Valentin Longchamp Cc: Linux PowerPC Kernel , Linux device trees , Linux I2C , Holger Brunck , Rainer Boschung List-Id: devicetree@vger.kernel.org On Fri, 2014-10-17 at 11:27 +0200, Valentin Longchamp wrote: > With "fsl-i2c" compatibility the i2c frequency is not set > correctly, because it sets no prescaler. According to the AN2919 from > Freescale and the QorIQ (P2041) documentation, the source clock is 1/2 > the platform clock. This implies that a prescaler of 2 must be used. > > This changes the compatibility of the qoriq-i2c .dtsi files to pick the > mpc8543, which uses the same driver but sets the correct prescaler. > > Signed-off-by: Rainer Boschung > Signed-off-by: Valentin Longchamp > --- > > arch/powerpc/boot/dts/fsl/qoriq-i2c-0.dtsi | 4 ++-- > arch/powerpc/boot/dts/fsl/qoriq-i2c-1.dtsi | 4 ++-- > 2 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/arch/powerpc/boot/dts/fsl/qoriq-i2c-0.dtsi b/arch/powerpc/boot/dts/fsl/qoriq-i2c-0.dtsi > index 5f9bf7d..aa6c366 100644 > --- a/arch/powerpc/boot/dts/fsl/qoriq-i2c-0.dtsi > +++ b/arch/powerpc/boot/dts/fsl/qoriq-i2c-0.dtsi > @@ -36,7 +36,7 @@ i2c@118000 { > #address-cells = <1>; > #size-cells = <0>; > cell-index = <0>; > - compatible = "fsl-i2c"; > + compatible = "fsl,mpc8543-i2c", "fsl-i2c"; > reg = <0x118000 0x100>; > interrupts = <38 2 0 0>; > dfsrr; > @@ -46,7 +46,7 @@ i2c@118100 { > #address-cells = <1>; > #size-cells = <0>; > cell-index = <1>; > - compatible = "fsl-i2c"; > + compatible = "fsl,mpc8543-i2c", "fsl-i2c"; > reg = <0x118100 0x100>; > interrupts = <38 2 0 0>; > dfsrr; Are all chips that use this dtsi 100% compatible with mpc8543's i2c, or just in ways the Linux driver cares about? What about fsl,mpc8544-i2c, which has additional special handling in the driver, but is only used in socrates.dts (not mpc8544ds.dts)? What about pq3-i2c-*.dtsi? -Scott -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html