From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko Schocher Subject: Re: [RFC PATCH 5/7] ARM: davinci: i2c: add OF support Date: Tue, 31 Jan 2012 08:31:26 +0100 Message-ID: <4F2798CE.1090804@denx.de> References: <1327308967-8092-1-git-send-email-hs@denx.de> <1327308967-8092-6-git-send-email-hs@denx.de> <4F1DC480.4010603@gmail.com> <4F1E5B44.4090200@denx.de> <4F1E7F36.50505@samsung.com> <20120130201307.GV28397@ponder.secretlab.ca> Reply-To: hs-ynQEQJNshbs@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7BIT Return-path: In-reply-to: <20120130201307.GV28397-e0URQFbLeQY2iJbIjFUEsiwD8/FfD2ys@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Grant Likely Cc: Sylwester Nawrocki , davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Ben Dooks , Wolfram Sang , Sekhar Nori , Wolfgang Denk List-Id: devicetree@vger.kernel.org Hello Grant, Grant Likely wrote: > On Tue, Jan 24, 2012 at 10:51:50AM +0100, Sylwester Nawrocki wrote: >> Hello Heiko, >> >> On 01/24/2012 08:18 AM, Heiko Schocher wrote: >>>> On 01/23/2012 09:56 AM, Heiko Schocher wrote: >>>>> add of support for the davinci i2c driver. >>>>> >>>>> Signed-off-by: Heiko Schocher >>>>> Cc: davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org >>>>> Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org >>>>> Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org >>>>> Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >>>>> Cc: Ben Dooks >>>>> Cc: Wolfram Sang >>>>> Cc: Grant Likely >>>>> Cc: Sekhar Nori >>>>> Cc: Wolfgang Denk >>>>> --- >>>>> .../devicetree/bindings/arm/davinci/i2c.txt | 39 ++++++++++++++++++ >>>>> drivers/i2c/busses/i2c-davinci.c | 43 ++++++++++++++++++++ >>>>> 2 files changed, 82 insertions(+), 0 deletions(-) >>>>> create mode 100644 Documentation/devicetree/bindings/arm/davinci/i2c.txt [...] >> Moreover you seem to overwrite platform device name and id, >> >> if (!of_property_read_u32(pdev->dev.of_node, "id", >> + &prop)) { >> + pdev->id = prop; >> + pdev->dev.init_name = kzalloc(20, GFP_KERNEL); >> + sprintf((char *)pdev->dev.init_name, >> + "i2c_davinci.%d", pdev->id); >> >> I'm not sure if it is a good practice. > > No, it is not good practice. At this point the device is already > registered. Changing the value of pdev->id will cause problems in the > core code because the /sysfs files will have already been created. > >> If you want to pre-define platform >> device name (likely for the clock API to work), it might be more appropriate >> to use OF_DEV_AUXDATA in the machine code, until there are clock bindings >> available. > > Yes, use OF_DEV_AUXDATA, but *only* if you need it for hooking up > clocks, regulators, or similar. Don't use it just because you want > the device to have a different name for cosmetic reasons. The need > for AUXDATA should go away once the DT clock binding code is merged. I now use OF_DEV_AUXDATA in board code, "id" nor "cell-index" used: struct of_dev_auxdata enbw_cmc_auxdata_lookup[] __initdata = { OF_DEV_AUXDATA("ti,davinci-i2c", 0x01c22000, "i2c_davinci.1", NULL), OF_DEV_AUXDATA("ti,davinci-i2c", 0x01e28000, "i2c_davinci.2", NULL), {} }; This is needed for hooking up clocks, see: arch/arm/mach-davinci/da850.c static struct clk_lookup da850_clks [...] CLK("i2c_davinci.1", NULL, &i2c0_clk), [...] CLK("i2c_davinci.2", NULL, &i2c1_clk), bye, Heiko -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany