From: jon-hunter@ti•com (Jon Hunter)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 3/5] gpio/omap: Add DT support to GPIO driver
Date: Tue, 26 Feb 2013 17:45:15 -0600 [thread overview]
Message-ID: <512D490B.70900@ti.com> (raw)
In-Reply-To: <512D3FE6.1010300@wwwdotorg.org>
On 02/26/2013 05:06 PM, Stephen Warren wrote:
> On 02/26/2013 04:01 PM, Jon Hunter wrote:
>>
>> On 02/26/2013 04:44 PM, Stephen Warren wrote:
>>> On 02/26/2013 03:40 PM, Jon Hunter wrote:
>>>>
>>>> On 02/26/2013 04:01 AM, Javier Martinez Canillas wrote:
>>>>
>>>> [snip]
>>>>
>>>>> I was wondering if the level/edge settings for gpios is working on OMAP.
>>>>>
>>>>> I'm adding DT support for an SMSC911x ethernet chip connected to the
>>>>> GPMC for an OMAP3 SoC based board.
>>>>>
>>>>> In the smsc911x driver probe function (smsc911x_drv_probe() in
>>>>> drivers/net/ethernet/smsc/smsc911x.c), a call to request_irq() with
>>>>> the flag IRQF_TRIGGER_LOW is needed because of the wiring on my board.
>>>>>
>>>>> Reading the gpio-omap.txt documentation it says that #interrupt-cells
>>>>> should be <2> and that a value of 8 is "active low level-sensitive".
>>>>>
>>>>> So I tried this:
>>>>>
>>>>> &gpmc {
>>>>> ethernet at 5,0 {
>>>>> pinctrl-names = "default";
>>>>> pinctrl-0 = <&smsc911x_pins>;
>>>>> compatible = "smsc,lan9221", "smsc,lan9115";
>>>>> reg = <5 0 0xff>; /* CS5 */
>>>>> interrupt-parent = <&gpio6>;
>>>>> interrupts = <16 8>; /* gpio line 176 */
>>>>> interrupt-names = "smsc911x irq";
>>>>> vmmc-supply = <&vddvario>;
>>>>> vmmc_aux-supply = <&vdd33a>;
>>>>> reg-io-width = <4>;
>>>>>
>>>>> smsc,save-mac-address;
>>>>> };
>>>>> };
>>>>
>>>> Are you requesting the gpio anywhere? If not then this is not going to
>>>> work as-is. This was discussed fairly recently [1] and the conclusion
>>>> was that the gpio needs to be requested before we can use as an interrupt.
>>>
>>> That seems wrong; the GPIO/IRQ driver should handle this internally. The
>>> Ethernet driver shouldn't know/care whether the interrupt it's given is
>>> some form of dedicated interrupt or a GPIO-based interrupt, and even if
>>> it somehow did, there's no irq_to_gpio() any more, so the driver can't
>>> tell which GPIO ID it should request, unless it's given yet another
>>> property to represent this.
>>
>> I agree that ideally this should be handled internally. Did you read the
>> discussion on the thread that I referenced [1]? If you have any thoughts
>> we are open to ideas :-)
>>
>> Cheers
>> Jon
>>
>> [1] http://comments.gmane.org/gmane.linux.ports.arm.omap/92192
>
> Oh, when I clicked that link the first time, all I saw was the patch,
> not any discussion. I guess it must have timed out finding the other
> emails or something.
Actually, I sent a slightly different link the 2nd time to ensure you
saw the thread. So my fault ;-)
> I disagree that the GPIO needs to be requested, and that a custom DT
> property and associated code are needed for that; simply requesting the
> IRQ should be enough to make everything work.
>
> In the Tegra GPIO IRQ driver for example, the irq_set_type irq_chip op
> goes and configures the base GPIO HW to enable the pin as a GPIO, just
> like gpio_request() would. I imagine the OMAP driver can do whatever
> similar action it needs.
Yes that is similar to what the patch in the thread was attempting to
do, but this got shot down.
One issue I see is that by not calling gpio_request, then potentially
you could have someone request a gpio via gpio_request() and someone
trying to use it as an interrupt source via request_irq(). Now obviously
that represents a bug because there is only one physical gpio, but I
gather it is something we need to protect against.
Cheers
Jon
next prev parent reply other threads:[~2013-02-26 23:45 UTC|newest]
Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-15 16:04 [PATCH 0/5] gpio/omap: Cleanup and adaptation to Device Tree Benoit Cousson
2012-02-15 16:04 ` [PATCH 1/5] gpio/omap: Remove bank->id information and misc cleanup Benoit Cousson
2012-02-16 5:53 ` DebBarma, Tarun Kanti
2012-02-16 9:33 ` Cousson, Benoit
2012-02-15 16:04 ` [PATCH 2/5] gpio/omap: Use devm_ API and add request_mem_region Benoit Cousson
2012-02-16 5:41 ` DebBarma, Tarun Kanti
2012-02-16 6:35 ` Grant Likely
2012-02-16 7:11 ` DebBarma, Tarun Kanti
2012-02-16 6:37 ` Shubhrajyoti
2012-02-16 8:56 ` Cousson, Benoit
2012-02-15 16:04 ` [PATCH 3/5] gpio/omap: Add DT support to GPIO driver Benoit Cousson
2012-02-22 14:23 ` Rob Herring
2012-02-22 14:31 ` Cousson, Benoit
2012-02-22 17:23 ` Rob Herring
2012-02-22 18:29 ` Stephen Warren
2012-02-24 15:30 ` Cousson, Benoit
2013-02-26 10:01 ` Javier Martinez Canillas
2013-02-26 16:33 ` Stephen Warren
2013-02-26 22:40 ` Jon Hunter
2013-02-26 22:44 ` Stephen Warren
2013-02-26 23:01 ` Jon Hunter
2013-02-26 23:06 ` Stephen Warren
2013-02-26 23:45 ` Jon Hunter [this message]
2013-02-27 0:13 ` Stephen Warren
2013-02-27 1:07 ` Jon Hunter
2013-02-27 3:57 ` Javier Martinez Canillas
2013-02-27 17:50 ` Stephen Warren
2013-02-27 20:05 ` Javier Martinez Canillas
2013-02-27 23:16 ` Jon Hunter
2013-02-28 12:17 ` Javier Martinez Canillas
2013-02-28 20:49 ` Jon Hunter
2013-03-02 20:05 ` Grant Likely
2013-03-07 23:14 ` Jon Hunter
2013-03-15 11:21 ` Javier Martinez Canillas
2013-03-22 8:10 ` Linus Walleij
2013-03-22 15:33 ` Stephen Warren
2013-03-22 22:52 ` Jon Hunter
2013-03-27 13:52 ` Linus Walleij
2013-03-27 16:09 ` Stephen Warren
2013-03-27 20:55 ` Linus Walleij
2013-03-29 17:01 ` Stephen Warren
2013-04-10 18:12 ` Linus Walleij
2013-04-10 20:29 ` Stephen Warren
2013-04-10 21:28 ` Linus Walleij
2013-04-11 20:30 ` Stephen Warren
2013-04-11 22:16 ` Linus Walleij
2013-04-11 22:47 ` Stephen Warren
2013-04-14 1:35 ` Javier Martinez Canillas
2013-04-14 20:53 ` Linus Walleij
2013-04-15 11:25 ` Javier Martinez Canillas
2013-04-15 16:58 ` Stephen Warren
2013-04-15 21:40 ` Jon Hunter
2013-04-15 21:44 ` Jon Hunter
2013-04-15 22:16 ` Stephen Warren
2013-04-15 23:04 ` Jon Hunter
2013-04-16 18:40 ` Stephen Warren
2013-04-16 19:27 ` Jon Hunter
2013-04-16 21:57 ` Jon Hunter
2013-04-16 22:11 ` Stephen Warren
2013-04-16 23:14 ` Jon Hunter
2013-04-17 0:41 ` Javier Martinez Canillas
2013-04-17 2:00 ` Jon Hunter
2013-04-17 7:55 ` Javier Martinez Canillas
2013-04-17 13:25 ` Jon Hunter
2013-04-17 13:42 ` Javier Martinez Canillas
2013-04-17 13:52 ` Jon Hunter
2013-04-17 14:21 ` Javier Martinez Canillas
2013-04-17 16:18 ` Javier Martinez Canillas
2013-04-26 7:31 ` Linus Walleij
2013-04-26 21:31 ` Jon Hunter
2013-06-11 21:25 ` Grant Likely
2013-06-12 9:43 ` Linus Walleij
2013-04-17 15:41 ` Stephen Warren
2013-04-26 7:27 ` Linus Walleij
2013-04-26 21:25 ` Jon Hunter
2013-05-03 14:35 ` Linus Walleij
2013-04-26 7:11 ` Linus Walleij
2013-04-26 6:59 ` Linus Walleij
2013-04-15 16:53 ` Stephen Warren
2013-04-15 20:00 ` Jon Hunter
2013-04-11 22:49 ` Javier Martinez Canillas
2013-04-11 22:51 ` Stephen Warren
2013-04-10 21:44 ` Arnd Bergmann
2013-02-27 3:33 ` Javier Martinez Canillas
2013-02-27 17:47 ` Stephen Warren
2013-02-27 20:00 ` Javier Martinez Canillas
2013-02-26 23:08 ` Jon Hunter
2013-02-27 3:47 ` Javier Martinez Canillas
2013-02-27 20:13 ` Jon Hunter
2013-02-27 23:41 ` Linus Walleij
2013-02-28 13:04 ` Benoit Cousson
2013-03-01 0:09 ` Linus Walleij
2013-03-01 0:42 ` Jon Hunter
2012-02-15 16:04 ` [PATCH 4/5] arm/dts: OMAP4: Add gpio nodes Benoit Cousson
2012-02-15 16:04 ` [PATCH 5/5] arm/dts: OMAP3: " Benoit Cousson
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