From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH v3 6/6] mfd: cros_ec: Instantiate sub-devices from device tree Date: Thu, 18 Sep 2014 17:15:12 -0700 Message-ID: <20140919001512.GA29852@lee--X1> References: <1410428289-18229-1-git-send-email-javier.martinez@collabora.co.uk> <1410428289-18229-7-git-send-email-javier.martinez@collabora.co.uk> <20140917163114.GL30918@lee--X1> <541A8E88.6050707@collabora.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <541A8E88.6050707-ZGY8ohtN/8pPYcu2f3hruQ@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Javier Martinez Canillas Cc: Wolfram Sang , Dmitry Torokhov , Doug Anderson , Simon Glass , Bill Richardson , Andrew Bresticker , Derek Basehore , Todd Broch , Olof Johansson , Andreas Faerber , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org On Thu, 18 Sep 2014, Javier Martinez Canillas wrote: > Hello Lee, >=20 > On 09/17/2014 06:31 PM, Lee Jones wrote: > >> =20 > >> -static const struct mfd_cell cros_devs[] =3D { > >> - { > >> - .name =3D "cros-ec-keyb", > >> - .id =3D 1, > >> - .of_compatible =3D "google,cros-ec-keyb", > >> - }, > >> - { > >> - .name =3D "cros-ec-i2c-tunnel", > >> - .id =3D 2, > >> - .of_compatible =3D "google,cros-ec-i2c-tunnel", > >> - }, > >> -}; > >> - > >> int cros_ec_register(struct cros_ec_device *ec_dev) > >> { > >> struct device *dev =3D ec_dev->dev; > >> + struct device_node *node =3D dev->of_node; > >> int err =3D 0; > >> =20 > >> if (ec_dev->din_size) { > >> @@ -140,12 +129,12 @@ int cros_ec_register(struct cros_ec_device *= ec_dev) > >> =20 > >> mutex_init(&ec_dev->lock); > >> =20 > >> - err =3D mfd_add_devices(dev, 0, cros_devs, > >> - ARRAY_SIZE(cros_devs), > >> - NULL, ec_dev->irq, NULL); > >> - if (err) { > >> - dev_err(dev, "failed to add mfd devices\n"); > >> - return err; > >=20 > > So these devices will only ever probe with DT now ... > > >=20 > Well, these are preparatory patches to reduce the delta between upstr= eam and > the downstream so the missing functionality could be added. One of th= e missing > drivers is the cros_ec_dev.c [0] which allows user-space to access th= e > ChromeOS Embedded Controller using a virtual character device (/dev/c= ros_ec). >=20 > Since that is a virtual device, it does not fit on the DT which only = describes > hw and also is used on x86 machines so that subdevice is still probed= using > mfd_add_devices() and the mfd_cells array is not empty in the downstr= eam > cros_ec driver [1]. >=20 > That's why I didn't just made the cros_ec MFD to depend on OF, since = I didn't > want to diverge too much from the downstream driver because the idea = of the > series was to reduce the difference in order to add the missing bits = on top. >=20 > >> + if (node) { > >=20 > > So it would be wrong for dev->of_node not to be populated. > >=20 >=20 > As explained above, DT, non-DT and x86 platforms instantiate the cros= -ec-dev > cells but DT platforms can define other child nodes. But I can remove= the > conditional if you want and reintroduce it once cros-ec-dev support i= s added. Yes, that makes sense. I only care about doing what's right for Mainline, so if it doesn't make sense here, then we shouldn't be doing it. > >> + err =3D of_platform_populate(node, NULL, NULL, dev); > >> + if (err) { > >> + dev_err(dev, "Failed to register subordinate devices"); > >> + return err; > >> + } > >> } > >> =20 > >> dev_info(dev, "Chrome EC device registered\n"); > >=20 >=20 > Best regards, > Javier >=20 > [0]: > https://chromium.googlesource.com/chromiumos/third_party/kernel/+/chr= omeos-3.8/drivers/mfd/cros_ec_dev.c > [1]: > https://chromium.googlesource.com/chromiumos/third_party/kernel/+/chr= omeos-3.8/drivers/mfd/cros_ec.c#93 --=20 Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org =E2=94=82 Open source software for ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog