From: Pantelis Antoniou <panto@antoniou-consulting.com>
To: Russ Dill <Russ.Dill@ti.com>
Cc: Tony Lindgren <tony@atomide.com>,
Grant Likely <grant.likely@secretlab.ca>,
Rob Herring <robherring2@gmail.com>,
Deepak Saxena <dsaxena@linaro.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Scott Wood <scottwood@freescale.com>, Felipe Balbi <balbi@ti.com>,
Benoit Cousson <b-cousson@ti.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Koen Kooi <koen@dominion.thruhere.net>,
Matt Porter <mporter@ti.com>,
linux-omap@vger.kernel.org, Kevin Hilman <khilman@ti.com>,
Paul Walmsley <paul@pwsan.com>,
devicetree-discuss@lists.ozlabs.org
Subject: Re: [RFC] Device Tree Overlays Proposal (Was Re: capebus moving omap_devices to mach-omap2)
Date: Tue, 6 Nov 2012 20:41:00 +0100 [thread overview]
Message-ID: <56051C08-3ECF-4C0A-9B88-64B4C1DDDF45@antoniou-consulting.com> (raw)
In-Reply-To: <CA+Bv8XZOt7h3dtDsk1SaR71J3tYFOTsPJSjZLSP3RVuLdYdFDg@mail.gmail.com>
Hi Russ,
On Nov 6, 2012, at 8:29 PM, Russ Dill wrote:
> On Tue, Nov 6, 2012 at 10:35 AM, Tony Lindgren <tony@atomide.com> wrote:
>> * Grant Likely <grant.likely@secretlab.ca> [121106 03:16]:
>>> On Tue, Nov 6, 2012 at 10:30 AM, Pantelis Antoniou
>>> <panto@antoniou-consulting.com> wrote:
>>>>
>>>> Another can of worms is the pinctrl nodes.
>>>
>>> Yes... new pinctrl data would need to trigger adding new data to
>>> pinctrl. I don't know if the pinctrl api supports that.
>>
>> The actual pins stay the same, just their configuration
>> changes. AFAIK all that is already supported using the
>> pinctrl framework.
>>
>> For example, considering hotplugging capes on the beaglebone:
>>
>> 1. You need to map all the sensible modes for the pins exposed
>> to the capes in the board specific .dts file. This will
>> add roughly 4 x nr_capbus_pins named modes in the .dts file
>> so not too bad.
>>
>> 2. Claim all the capebus pins during the capbus driver probe
>> and set them to some safe mode.
>>
>> 3. Try to detect the connected cape(s) over i2c.
>>
>> 4. Use pinctr_select_state to set the desired modes for
>> the pins used by the cape(s).
>>
>> 5. Enable capebus regulators and clocks etc.
>>
>> 6. Load the driver modules for whatever omap internal
>> devices the cape supports.
>>
>> You could also claim the pin for the omap internal
>> devices instead of claiming them in the capebus, but then
>> things can get messy with binding and unbinding the
>> drivers. So just claiming all the pins in the capebus
>> probably keeps things simpler.
>
> That assumes that for a particular external bus, certain pins aren't
> already shared with functions already on the board, for instance if an
> I²C bus brought out to the external bus already has a chip connected
> to it.
This is our case on the bone. We don't enable the peripheral until
a cape that references it is enabled.
I don't think that very big changes are going to be needed TBH.
So now we use:
am3358_pinmux: pinmux@44e10800 {
....
bone_dvi_cape_led_pins: pinmux_bone_dvi_cape_led_pins {
pinctrl-single,pins = <
0x48 0x07 /* gpmc_a2.gpio1_18, OUTPUT | MODE7 */
0x4c 0x07 /* gpmc_a3.gpio1_19, OUTPUT | MODE7 */
>;
};
....
};
And in the cape definition:
pinctrl-0 = <&bone_geiger_cape_pins>;
Ideally if we could do this in the cape definition:
cape_pinmux {
parent = <&am3358_pinmux>;
bone_dvi_cape_led_pins: pinmux_bone_dvi_cape_led_pins {
pinctrl-single,pins = <
0x48 0x07 /* gpmc_a2.gpio1_18, OUTPUT | MODE7 */
0x4c 0x07 /* gpmc_a3.gpio1_19, OUTPUT | MODE7 */
>;
};
pinctrl-0 = <&bone_geiger_cape_pins>;
It would be just fine.
Regards
-- Pantelis
next prev parent reply other threads:[~2012-11-06 19:41 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-05 20:40 [RFC] Device Tree Overlays Proposal (Was Re: capebus moving omap_devices to mach-omap2) Grant Likely
2012-11-05 21:40 ` Tabi Timur-B04825
2012-11-05 23:22 ` Tony Lindgren
2012-11-09 12:06 ` Grant Likely
2012-11-06 0:07 ` Grant Likely
2012-11-06 10:31 ` Pantelis Antoniou
2012-11-07 22:35 ` Ryan Mallon
2012-11-08 13:28 ` Koen Kooi
2012-11-08 14:09 ` Timur Tabi
2012-11-08 17:00 ` Mitch Bradley
2012-11-06 10:30 ` Pantelis Antoniou
2012-11-06 11:14 ` Grant Likely
2012-11-06 18:35 ` Tony Lindgren
2012-11-06 19:29 ` Russ Dill
2012-11-06 19:41 ` Pantelis Antoniou [this message]
2012-11-06 22:17 ` Stephen Warren
2012-11-06 19:34 ` Pantelis Antoniou
2012-11-06 20:45 ` Grant Likely
2012-11-06 20:50 ` Grant Likely
2012-11-07 8:06 ` Pantelis Antoniou
2012-11-07 15:33 ` Alan Tull
2012-11-09 17:03 ` Grant Likely
2012-11-07 8:13 ` Pantelis Antoniou
2012-11-07 10:19 ` Benoit Cousson
2012-11-07 11:02 ` Pantelis Antoniou
2012-11-07 11:12 ` Benoit Cousson
2012-11-07 11:23 ` Pantelis Antoniou
2012-11-09 20:33 ` Grant Likely
2012-11-12 11:34 ` Pantelis Antoniou
2012-11-12 13:01 ` Grant Likely
2012-11-07 17:25 ` Stephen Warren
2012-11-07 22:10 ` Pantelis Antoniou
2012-11-08 10:36 ` Cousson, Benoit
2012-11-09 5:32 ` Joel A Fernandes
2012-11-09 14:29 ` David Gibson
2012-11-10 3:15 ` Joel A Fernandes
2012-11-09 21:22 ` Grant Likely
2012-11-12 11:47 ` Pantelis Antoniou
2012-11-13 3:59 ` Joel A Fernandes
2012-11-09 22:59 ` Stephen Warren
[not found] ` <-4237940489086529028@unknownmsgid>
[not found] ` <559B8433-67C3-4A1A-A5D6-859907655176@antoniou-consulting.com>
2012-11-10 3:36 ` Joel A Fernandes
2012-11-12 12:48 ` Pantelis Antoniou
2012-11-13 2:28 ` David Gibson
2012-11-06 22:37 ` Stephen Warren
2012-11-07 0:54 ` Mitch Bradley
2012-11-09 17:02 ` Grant Likely
2012-11-12 11:29 ` Pantelis Antoniou
2012-11-07 8:47 ` Pantelis Antoniou
2012-11-07 17:18 ` Stephen Warren
2012-11-07 22:08 ` Pantelis Antoniou
2012-11-09 16:28 ` Grant Likely
2012-11-09 23:23 ` Stephen Warren
2012-11-09 23:40 ` Grant Likely
2012-11-12 10:53 ` Koen Kooi
2012-11-12 12:10 ` Pantelis Antoniou
2012-11-12 16:52 ` Stephen Warren
2012-11-13 7:25 ` David Gibson
2012-11-13 8:09 ` Pantelis Antoniou
2012-11-13 12:24 ` Grant Likely
2012-11-13 13:38 ` Pantelis Antoniou
2012-11-15 4:57 ` David Gibson
2012-11-13 17:10 ` Stephen Warren
2012-11-13 23:30 ` David Gibson
2012-11-14 0:00 ` Pantelis Antoniou
2012-11-13 16:57 ` Stephen Warren
2012-11-13 18:10 ` Mitch Bradley
2012-11-13 18:29 ` Stephen Warren
2012-11-13 19:09 ` Mitch Bradley
2012-11-13 19:11 ` Pantelis Antoniou
2012-11-17 22:27 ` Jean-Christophe PLAGNIOL-VILLARD
2012-11-20 17:09 ` Grant Likely
2012-11-11 20:47 ` Rob Landley
2012-11-12 12:50 ` Pantelis Antoniou
2012-11-12 16:54 ` Stephen Warren
2012-11-12 11:23 ` Pantelis Antoniou
2012-11-12 16:49 ` Stephen Warren
2012-11-12 17:00 ` Pantelis Antoniou
2012-11-12 17:10 ` Stephen Warren
2012-11-12 17:19 ` Pantelis Antoniou
2012-11-12 17:29 ` Stephen Warren
2012-11-12 17:38 ` Pantelis Antoniou
2012-11-12 20:16 ` Russ Dill
2012-11-12 16:45 ` Stephen Warren
2012-11-09 2:26 ` David Gibson
2012-11-09 15:40 ` Pantelis Antoniou
2012-11-13 0:03 ` David Gibson
2012-11-09 21:08 ` Grant Likely
2012-11-13 0:05 ` David Gibson
2012-11-09 21:42 ` Grant Likely
2012-11-13 1:05 ` David Gibson
2012-11-13 5:22 ` Stephen Warren
2012-11-13 6:54 ` David Gibson
2012-11-09 22:57 ` Stephen Warren
2012-11-09 23:27 ` Grant Likely
2012-11-12 12:05 ` Pantelis Antoniou
2012-11-09 23:14 ` Stephen Warren
2012-11-09 23:06 ` Stephen Warren
2012-11-09 23:32 ` Grant Likely
2012-11-12 11:03 ` Koen Kooi
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