From: Stephen Warren <swarren@wwwdotorg.org>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH v2 5/7] tegra: Implement gpio_early_init() on Tamonten
Date: Fri, 25 May 2012 10:27:02 -0600 [thread overview]
Message-ID: <4FBFB2D6.1040602@wwwdotorg.org> (raw)
In-Reply-To: <1337953588-20696-5-git-send-email-thierry.reding@avionic-design.de>
On 05/25/2012 07:46 AM, Thierry Reding wrote:
> The PI4 GPIO is used on Tamonten to reset carrier board peripherals.
> Power sequencing hardware on the carrier pulls the reset low before
> powering up the Tegra, and the CPU is supposed to signal readiness,
> and therefore bring peripherals out of reset by pulling PI4 high.
> +void gpio_early_init(void)
> +{
> + gpio_request(GPIO_PI4, NULL);
> + gpio_direction_output(GPIO_PI4, 1);
> + gpio_free(GPIO_PI4);
> +}
Do you really mean to free the GPIO here?
While gpio_free() does not do this at present, it seems perfectly
reasonable for someone to modify gpio_free() so that instead of leaving
the HW in some random state when free, it actively reprograms the pin to
be an input instead, since that's the most conflict-free setting when
the pin is actively unused.
next prev parent reply other threads:[~2012-05-25 16:27 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-25 13:46 [U-Boot] [PATCH v2 1/7] tegra: Rework Tamonten support Thierry Reding
2012-05-25 13:46 ` [U-Boot] [PATCH v2 2/7] tegra: medcom: Add device tree support Thierry Reding
2012-05-25 13:46 ` [U-Boot] [PATCH v2 3/7] tegra: plutux: " Thierry Reding
2012-05-25 13:46 ` [U-Boot] [PATCH v2 4/7] tegra: Allow boards to perform early GPIO setup Thierry Reding
2012-05-25 16:24 ` Stephen Warren
2012-05-25 17:31 ` Thierry Reding
2012-05-25 17:59 ` Thierry Reding
2012-05-31 20:35 ` Tom Warren
2012-06-04 6:09 ` Thierry Reding
2012-06-04 16:47 ` Tom Warren
2012-05-25 13:46 ` [U-Boot] [PATCH v2 5/7] tegra: Implement gpio_early_init() on Tamonten Thierry Reding
2012-05-25 16:27 ` Stephen Warren [this message]
2012-05-25 17:40 ` Thierry Reding
2012-05-25 18:56 ` Kai Poggensee
2012-05-29 14:57 ` Thierry Reding
2012-05-29 16:06 ` Stephen Warren
2012-05-25 13:46 ` [U-Boot] [PATCH v2 6/7] tegra: Use SD write-protect GPIO " Thierry Reding
2012-05-25 13:46 ` [U-Boot] [PATCH v2 7/7] tegra: Add Tamonten Evaluation Carrier support Thierry Reding
2012-05-25 16:31 ` Stephen Warren
2012-06-08 20:01 ` [U-Boot] [PATCH v2 1/7] tegra: Rework Tamonten support Allen Martin
2012-06-08 21:07 ` Stephen Warren
2012-06-08 21:27 ` Allen Martin
2012-06-09 5:28 ` Stephen Warren
2012-06-09 6:25 ` Allen Martin
2012-06-09 16:18 ` Stephen Warren
2012-06-11 9:29 ` Thierry Reding
2012-06-11 17:59 ` Allen Martin
2012-06-11 18:07 ` Thierry Reding
2012-06-11 18:03 ` Allen Martin
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