From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [RESEND PATCH V5 12/12] drm/exynos: Add ps8622 lvds bridge discovery to DP driver Date: Mon, 21 Jul 2014 16:44:28 +0200 Message-ID: <20140721144427.GA28336@ulmo> References: <1405629839-12086-1-git-send-email-ajaykumar.rs@samsung.com> <1405629839-12086-13-git-send-email-ajaykumar.rs@samsung.com> <20140721071028.GB8843@ulmo> <20140721125424.GD15238@ulmo> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============2027931073==" Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Ajay kumar Cc: "linux-samsung-soc@vger.kernel.org" , Sean Paul , Daniel Vetter , sunil joshi , "dri-devel@lists.freedesktop.org" , Javier Martinez Canillas , Prashanth G , Ajay Kumar , Rahul Sharma List-Id: linux-samsung-soc@vger.kernel.org --===============2027931073== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="OgqxwSJOaUobr8KG" Content-Disposition: inline --OgqxwSJOaUobr8KG Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jul 21, 2014 at 08:06:01PM +0530, Ajay kumar wrote: > Hi Thierry, >=20 > On Mon, Jul 21, 2014 at 6:24 PM, Thierry Reding > wrote: > > On Mon, Jul 21, 2014 at 04:58:25PM +0530, Ajay kumar wrote: > >> On Mon, Jul 21, 2014 at 12:40 PM, Thierry Reding > >> wrote: > >> > On Fri, Jul 18, 2014 at 02:13:58AM +0530, Ajay Kumar wrote: > >> >> From: Rahul Sharma > >> >> > >> >> This patch adds ps8622 lvds bridge discovery code to the dp driver. > >> >> > >> >> Signed-off-by: Rahul Sharma > >> >> Signed-off-by: Ajay Kumar > >> >> --- > >> >> drivers/gpu/drm/exynos/exynos_dp_core.c | 5 +++++ > >> >> 1 file changed, 5 insertions(+) > >> >> > >> >> diff --git a/drivers/gpu/drm/exynos/exynos_dp_core.c b/drivers/gpu/= drm/exynos/exynos_dp_core.c > >> >> index 0ca6256..82e2942 100644 > >> >> --- a/drivers/gpu/drm/exynos/exynos_dp_core.c > >> >> +++ b/drivers/gpu/drm/exynos/exynos_dp_core.c > >> >> @@ -31,6 +31,7 @@ > >> >> #include > >> >> #include > >> >> #include > >> >> +#include > >> >> > >> >> #include "exynos_drm_drv.h" > >> >> #include "exynos_dp_core.h" > >> >> @@ -999,6 +1000,10 @@ static int exynos_drm_attach_lcd_bridge(struc= t exynos_dp_device *dp, > >> >> if (find_bridge("nxp,ptn3460", &bridge)) { > >> >> bridge_chain =3D ptn3460_init(dp->drm_dev, encoder, b= ridge.client, > >> >> bridg= e.node); > >> >> + } else if (find_bridge("parade,ps8622", &bridge) || > >> >> + find_bridge("parade,ps8625", &bridge)= ) { > >> >> + bridge_chain =3D ps8622_init(dp->drm_dev, encoder, br= idge.client, > >> >> + bridg= e.node); > >> >> } > >> > > >> > We really ought to be adding some sort of registry at some point. > >> > Otherwise every driver that wants to use bridges needs to come up wi= th a > >> > similar set of helpers to instantiate them. > >> > > >> > Also you're making this driver depend on (now) two bridges, whereas = it > >> > really shouldn't matter which exact types it supports. Bridges shoul= d be > >> > exposed via a generic interface. > >> > >> How about moving out the find_bridge() function into a common header f= ile, > >> and also supporting the list of bridge_init declarations in the same f= ile? > >> > >> We get bridge chip node from phandle, and then pass the same node > >> to find_bridge() which searches the list using of_device_is_compatible= () > >> to call the appropriate bridge_init function? > > > > That could work, but it's still somewhat unusual and shouldn't be > > required. I think we'd be better of with some sort of registry like we > > have for panels. That would mean that a driver that wants to use a > > bridge would do something like this: > > > > struct drm_bridge *bridge; > > struct device_node *np; > > > > np =3D of_parse_phandle(dev->of_node, "bridge", 0); > > if (np) { > > bridge =3D of_drm_find_bridge(np); > > of_node_put(np); > > > > if (!bridge) > > return -EPROBE_DEFER; > > } > > > > An alternative way would be to add a non-OF wrapper around this, like > > this for example: > Let me try the DT version first :) >=20 > > bridge =3D drm_bridge_get(dev, NULL); > > > > Which would be conceptually the same as clk_get() or regulator_get() and > > could be easily extended to support non-DT setups as well. > > > > As for bridge drivers I think we may have to rework things a little, so > > that a driver can call some sequence like this: > > > > struct foo_bridge { > > struct drm_bridge base; > > ... > > }; > > > > static const struct drm_bridge_funcs foo_bridge_funcs =3D { > > ... > > }; > > > > static int foo_probe(...) > > { > > struct foo_bridge *bridge; > > int err; > > > > bridge =3D devm_kzalloc(dev, sizeof(*bridge), GFP_KERNE= L); > > if (!bridge) > > return -ENOMEM; > > > > /* setup bridge (return -EPROBE_DEFER if necessary, ...= ) */ > > > > /* register bridge with DRM */ > > drm_bridge_init(&bridge->base); > > bridge->base.dev =3D dev; > > bridge->base.funcs =3D &foo_bridge_funcs; > > > > err =3D drm_bridge_add(&bridge->base); > > if (err < 0) > > return err; > > > > dev_set_drvdata(dev, bridge); > > ... > > } > > > > drm_bridge_add() would add the bridge to a global list of bridge devices > > which drm_bridge_get()/of_drm_find_bridge() can use to find the one that > > it needs. The above has the big advantage that it'sdev->mode_config.bri= dge_list completely > > independent of the underlying bus that the bridge is on. It could be I2C > > or SPI, platform device or PCI device. > > > > Thierry > Ok. This is all about making the bridge driver confine to the driver mode= l. > But, I would need a drm_device pointer to register the bridge to DRM core. > How do I get it? Once you've obtained a reference to the DRM bridge from your driver you should carry it around until you've set up the DRM device. Then you can hook it up, which possibly requires a new function (since it's what the drm_bridge_init() used to do). Thierry --OgqxwSJOaUobr8KG Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJTzSdLAAoJEN0jrNd/PrOhBpkP/A5L6vIod+WyT67vqSac30cr DU0J4BlZD3bs0YMC7QkjGx0dOVwwA3bdzSrGpCq8DExOwT/1hIeH5eUx5rYgFotD S0JEkMQZsdoScvG/4ZQfYq4tp0RS6fWp7Y1Rf6wjfuzophBkelBTPPZNk69xwZl7 nTsUR3Yx3UxDnfu5XYPaBCOdDe7AbLldz//8vY50dM3pV90APwIx7tnyFBhlJeJN HJGNKUUasuycOeJ2gsRg8ObufVy1GZ8Ja+WkPAyybQvv1ZlZJhVOEALj+kjp7E8K rAFoci/TThJFZz91EPe5F/Vrr/ljeajLSCBEDGmH619+bDz+mspET51CG9XoP5+r AbMBYomzOOfg68x0SlbsSRjo0E6uZa0RtL3SmN22ODoOIqNblZ52ND6nQu77b/as vxGYb9Fhinqlh6jydl2/cIdDFsc9293BcpsT5Tq5s474YKgjJOUQE5ZilIMwooH9 VcGQO/EM5i0n5YHDalLdWcB43XbGnL+0Is0EIJTdhihb4Yv2EQHBmzOs6mXVodJw Glml6Y4qnjcOleYe8hBW1cVQf72w4oeZFDTZONtvz0cJtLusLLjOJEGTXY9hoaCx jJvhh8Vi/WuFEawsXlKPOVlZlDuPIYd7PnhReheNKGCrJ4NWWVketj1eTehk0YOk Hou5k2A4cmZin0MQ1no3 =5W44 -----END PGP SIGNATURE----- --OgqxwSJOaUobr8KG-- --===============2027931073== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel --===============2027931073==--