From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH/RFC v9 04/19] mfd: max77693: adjust max77693_led_platform_data Date: Tue, 9 Dec 2014 14:41:00 +0000 Message-ID: <20141209144100.GA3951@x1> References: <1417622814-10845-1-git-send-email-j.anaszewski@samsung.com> <1417622814-10845-5-git-send-email-j.anaszewski@samsung.com> <20141209085047.GR3951@x1> <5486BC44.7010602@samsung.com> <20141209100413.GW3951@x1> <5486CE1F.9010102@samsung.com> <20141209135017.GY3951@x1> <548700DE.2050208@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-qa0-f42.google.com ([209.85.216.42]:47315 "EHLO mail-qa0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751940AbaLIOlN (ORCPT ); Tue, 9 Dec 2014 09:41:13 -0500 Received: by mail-qa0-f42.google.com with SMTP id j7so471810qaq.1 for ; Tue, 09 Dec 2014 06:41:12 -0800 (PST) Content-Disposition: inline In-Reply-To: <548700DE.2050208@samsung.com> Sender: linux-leds-owner@vger.kernel.org List-Id: linux-leds@vger.kernel.org To: Jacek Anaszewski Cc: linux-leds@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, kyungmin.park@samsung.com, b.zolnierkie@samsung.com, pavel@ucw.cz, cooloney@gmail.com, rpurdie@rpsys.net, sakari.ailus@iki.fi, s.nawrocki@samsung.com, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, Chanwoo Choi On Tue, 09 Dec 2014, Jacek Anaszewski wrote: > On 12/09/2014 02:50 PM, Lee Jones wrote: > >On Tue, 09 Dec 2014, Jacek Anaszewski wrote: > > > >>On 12/09/2014 11:04 AM, Lee Jones wrote: > >>>On Tue, 09 Dec 2014, Jacek Anaszewski wrote: > >>> > >>>>On 12/09/2014 09:50 AM, Lee Jones wrote: > >>>>>On Wed, 03 Dec 2014, Jacek Anaszewski wrote: > >>>>> > >>>>>>Add "label" array for Device Tree strings with the name of a LE= D device > >>>>>>and make flash_timeout a two element array, for caching the sub= -led > >>>>>>related flash timeout. Added is also an array for caching point= ers to the > >>>>>>sub-nodes representing sub-leds. > >>>>>> > >>>>>>Signed-off-by: Jacek Anaszewski > >>>>>>Acked-by: Kyungmin Park > >>>>>>Cc: Chanwoo Choi > >>>>>>Cc: Lee Jones > >>>>>>--- > >>>>>> include/linux/mfd/max77693.h | 4 +++- > >>>>>> 1 file changed, 3 insertions(+), 1 deletion(-) > >>>>>> > >>>>>>diff --git a/include/linux/mfd/max77693.h b/include/linux/mfd/m= ax77693.h > >>>>>>index f0b6585..c80ee99 100644 > >>>>>>--- a/include/linux/mfd/max77693.h > >>>>>>+++ b/include/linux/mfd/max77693.h > >>>>>>@@ -88,16 +88,18 @@ enum max77693_led_boost_mode { > >>>>>> }; > >>>>>> > >>>>>> struct max77693_led_platform_data { > >>>>>>+ const char *label[2]; > >>>>>> u32 fleds[2]; > >>>>>> u32 iout_torch[2];for_each_available_child_of_node > >>>>>> u32 iout_flash[2]; > >>>>>> u32 trigger[2]; > >>>>>> u32 trigger_type[2]; > >>>>>>+ u32 flash_timeout[2]; > >>>>>> u32 num_leds; > >>>>>> u32 boost_mode; > >>>>>>- u32 flash_timeout; > >>>>>> u32 boost_vout; > >>>>>> u32 low_vsys; > >>>>>>+ struct device_node *sub_nodes[2]; > >>>>> > >>>>>I haven't seen anyone do this before. Why can't you use the pro= vided > >>>>>OF functions to traverse through your tree? > >>>> > >>>>I use for_each_available_child_of_node when parsing DT node, but = I > >>>>need to cache the pointer to sub-node to be able to use it later > >>>>when it needs to be passed to V4L2 sub-device which is then > >>>>asynchronously matched by the phandle to sub-node. > >>>> > >>>>If it is not well seen to cache it in the platform data then > >>>>I will find different way to accomplish this. > >>> > >>>I haven't seen the end-driver for this, but why can't you use that > >>>device's of_node pointer? > >> > >>Maybe it is indeed a good idea. I could pass the of_node pointer > >>and the sub-led identifier to the V4L2 sub-device and there look > >>for the sub-node containing relevant identifier. The downside > >>would be only that for_each_available_child_of_node would > >>have to be called twice - in the led driver and in the V4L2 sub-dev= ice. > >>I think that we can live with it. > > > >Are the LED and V4L2 drivers children of this MFD? If so, you can u= se > >the of_compatible attribute in struct mfd_cell to populate the each > >child's of_node dynamically i.e. the MFD core will do that for you. > > >=20 > V4L2 driver wraps LED driver. This way the LED device can be > controlled with use of two interfaces - LED subsystem sysfs > and V4L2 Flash. This is the aim of the whole patch set. >=20 > I've thought it over again and it seems that I will need to cache > somewhere these sub_nodes pointers. They have to be easily accessible > for the V4L2 sub-device as it can be asynchronously registered > or unregistered within V4L2 media device. Sub-devices are matched > basing on the sub-node phandle. Not quite getting this. Can you explain this in another way please? --=20 Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org =E2=94=82 Open source software for ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog