Messages in this thread | | | Date | Tue, 9 Aug 2011 12:04:06 +0200 | Subject | Re: [PATCH] GPIOLIB: add generic gpio_set_pull API | From | Linus Walleij <> |
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On Mon, Aug 8, 2011 at 8:24 PM, Grant Likely <grant.likely@secretlab.ca> wrote: > On Mon, Aug 8, 2011 at 2:15 AM, Paul Mundt <lethal@linux-sh.org> wrote: >> On Sun, Aug 07, 2011 at 10:19:33PM -0700, Barry Song wrote: >>> Now there are many different implementations for GPIO pull configuration, for >>> example: >>> s3c_gpio_setpull() >>> tegra_pinmux_set_pullupdown() >>> chipcHw_setPinPullup() >>> gpio_pullup() >>> s3c2410_gpio_pullup() >>> >>> This patch adds a new generic gpio_set_pull API so that all SoCs can have unified >>> codes. >>> >>> Signed-off-by: Barry Song <Baohua.Song@csr.com> >> >> For arch/arm/mach-shmobile we also have gpio_pull_up() for board-g4evm.c >> and gpio_pull_down() for board-mackerel.c. Both of these would benefit >> from this sort of an API addition. > > I think I'm okay with this API change. Linus, what say you? How does > this interact with your plans for pinctrl?
I have already proposed a similar mechanism in the past, so let's recap:
1.First I proposed to expose gpio_to_chip() so each driver could provide any custom functions using foo_gpio_set_foo() or so by dereferencing the struct gpio_chip. NIXED: due to bad experience with doing exactly this for IRQ chips (Grant)
2. Second I added a sort-of generic control function; gpio_config() which would sit in gpiolib and take an enum for each operation, if one of these would be GPIO_SET_PULL, and a second argument would be whether to pull it up or down or open collector or open drain or schmitt-trigger or whatever. As you see the problem is not limited to up/down. This is equal to the proposed patch but with two arguments and broader scope, can also be used for drive strength etc.
3. Alan Cox suggested that we use a more generic control function instead so I wrapped it to an ioctl()- like operation with an opaque argument instead. This is especially good when you need to pass data *out* of the function, not just *in*.
4. After talks with Grant I submitted (1) again.
I'm basically happy with anything as long as there is some progress, right now we're only bikeshedding, so I'm, resting my case.
Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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