From: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> To: Russell King - ARM Linux <linux@arm.linux.org.uk> Cc: Jason Cooper <jason@lakedaemon.net>, Andrew Lunn <andrew@lunn.ch>, Gregory Clement <gregory.clement@free-electrons.com>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/4] ARM: mvebu: add armada drm init to Dove board setup Date: Tue, 01 Jul 2014 15:21:41 +0200 [thread overview] Message-ID: <53B2B5E5.50502@gmail.com> (raw) In-Reply-To: <20140701131026.GO32514@n2100.arm.linux.org.uk> On 07/01/2014 03:10 PM, Russell King - ARM Linux wrote: > On Tue, Jul 01, 2014 at 03:04:31PM +0200, Sebastian Hesselbarth wrote: >> + pdev = platform_device_register_full(&armada_drm_dev_info); >> + /* assign last found lcd node to drm device for clk lookup */ >> + pdev->dev.of_node = clknp; > > NAK. This really isn't a good way to deal with this, even in a > temporary basis. While assigning a DT node to a manually created > platform device does solve that problem, it also introduces the > problem that this platform device will now match any platform driver > which recognises the "marvell,dove-lcd" compatible type, which may > occur _before_ we find the driver to match using the legacy strings. Right, I never said it is a good solution but there is no driver for "marvell,dove-lcd" *and* there is no way to assign clock aliases for clocks not yet registered. > There really isn't an easy solution to this other than doing the thing > properly. Well, you may have noticed that three moving subsystems plus new bindings plus non-DT/DT drivers quickly create some kind of patch deadlock. This is a dirty but tiny step to resolve one of those deadlocks. > The other problem in this series is that while you introduce some > bindings which may work today, they're not going to work tomorrow, and > that's a problem. Don't do DT piecemeal like this and end up having to > break the bindings (which we will have to do to add the endpoints.) Adding new properties/subnodes never has been a problem for us at all. New generic bindings were introduced *often* in the past and added to existing bindings, e.g. clocks, gpio, pinctrl. The proposed binding for dove-lcd simply reflects the tiny part that is mandatory for identifying the lcd controllers. It only contains reg and interrupts which would also be in the corresponding platform_device. > If you want to do this then you need to add the endpoints from the start > even though the driver doesn't yet make use of them - or don't add the > DT bits at all. If you really think that way, I definitely give up on mainline Dove and SolidRun Cubox. You are /really/ proposing to wait for *all* related subsystem bindings to settle before even starting to add DT support? Sebastian
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From: sebastian.hesselbarth@gmail.com (Sebastian Hesselbarth) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 4/4] ARM: mvebu: add armada drm init to Dove board setup Date: Tue, 01 Jul 2014 15:21:41 +0200 [thread overview] Message-ID: <53B2B5E5.50502@gmail.com> (raw) In-Reply-To: <20140701131026.GO32514@n2100.arm.linux.org.uk> On 07/01/2014 03:10 PM, Russell King - ARM Linux wrote: > On Tue, Jul 01, 2014 at 03:04:31PM +0200, Sebastian Hesselbarth wrote: >> + pdev = platform_device_register_full(&armada_drm_dev_info); >> + /* assign last found lcd node to drm device for clk lookup */ >> + pdev->dev.of_node = clknp; > > NAK. This really isn't a good way to deal with this, even in a > temporary basis. While assigning a DT node to a manually created > platform device does solve that problem, it also introduces the > problem that this platform device will now match any platform driver > which recognises the "marvell,dove-lcd" compatible type, which may > occur _before_ we find the driver to match using the legacy strings. Right, I never said it is a good solution but there is no driver for "marvell,dove-lcd" *and* there is no way to assign clock aliases for clocks not yet registered. > There really isn't an easy solution to this other than doing the thing > properly. Well, you may have noticed that three moving subsystems plus new bindings plus non-DT/DT drivers quickly create some kind of patch deadlock. This is a dirty but tiny step to resolve one of those deadlocks. > The other problem in this series is that while you introduce some > bindings which may work today, they're not going to work tomorrow, and > that's a problem. Don't do DT piecemeal like this and end up having to > break the bindings (which we will have to do to add the endpoints.) Adding new properties/subnodes never has been a problem for us at all. New generic bindings were introduced *often* in the past and added to existing bindings, e.g. clocks, gpio, pinctrl. The proposed binding for dove-lcd simply reflects the tiny part that is mandatory for identifying the lcd controllers. It only contains reg and interrupts which would also be in the corresponding platform_device. > If you want to do this then you need to add the endpoints from the start > even though the driver doesn't yet make use of them - or don't add the > DT bits at all. If you really think that way, I definitely give up on mainline Dove and SolidRun Cubox. You are /really/ proposing to wait for *all* related subsystem bindings to settle before even starting to add DT support? Sebastian
next prev parent reply other threads:[~2014-07-01 13:21 UTC|newest] Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-07-01 13:04 [PATCH 0/4] Marvell Dove DRM for DT Sebastian Hesselbarth 2014-07-01 13:04 ` Sebastian Hesselbarth 2014-07-01 13:04 ` [PATCH 1/4] dt-bindings: add Marvell Dove LCD controller documentation Sebastian Hesselbarth 2014-07-01 13:04 ` Sebastian Hesselbarth 2014-07-01 13:04 ` [PATCH 2/4] ARM: dts: dove: add DT LCD controllers Sebastian Hesselbarth 2014-07-01 13:04 ` Sebastian Hesselbarth 2014-07-01 13:04 ` Sebastian Hesselbarth 2014-07-01 13:04 ` [PATCH 3/4] ARM: dts: dove: enable lcd0 on SolidRun CuBox Sebastian Hesselbarth 2014-07-01 13:04 ` Sebastian Hesselbarth 2014-07-01 13:04 ` Sebastian Hesselbarth 2014-07-01 13:18 ` Mark Rutland 2014-07-01 13:18 ` Mark Rutland 2014-07-01 13:18 ` Mark Rutland 2014-07-01 15:40 ` Jean-Francois Moine 2014-07-01 15:40 ` Jean-Francois Moine 2014-07-01 15:40 ` Jean-Francois Moine 2014-07-01 13:04 ` [PATCH 4/4] ARM: mvebu: add armada drm init to Dove board setup Sebastian Hesselbarth 2014-07-01 13:04 ` Sebastian Hesselbarth 2014-07-01 13:10 ` Russell King - ARM Linux 2014-07-01 13:10 ` Russell King - ARM Linux 2014-07-01 13:21 ` Sebastian Hesselbarth [this message] 2014-07-01 13:21 ` Sebastian Hesselbarth 2014-07-01 13:36 ` Russell King - ARM Linux 2014-07-01 13:36 ` Russell King - ARM Linux 2014-07-01 13:40 ` Sebastian Hesselbarth 2014-07-01 13:40 ` Sebastian Hesselbarth 2014-07-01 13:42 ` Russell King - ARM Linux 2014-07-01 13:42 ` Russell King - ARM Linux 2014-07-01 16:04 ` Jean-Francois Moine 2014-07-01 16:04 ` Jean-Francois Moine 2014-07-01 16:45 ` Russell King - ARM Linux 2014-07-01 16:45 ` Russell King - ARM Linux 2014-07-01 17:49 ` Jean-Francois Moine 2014-07-01 17:49 ` Jean-Francois Moine 2014-07-01 22:00 ` Russell King - ARM Linux 2014-07-01 22:00 ` Russell King - ARM Linux 2014-07-01 16:53 ` Jason Cooper 2014-07-01 16:53 ` Jason Cooper 2014-07-01 17:06 ` Russell King - ARM Linux 2014-07-01 17:06 ` Russell King - ARM Linux
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