Messages in this thread | | | From | Grant Likely <> | Date | Thu, 3 Mar 2011 09:43:59 -0700 | Subject | Re: problems with GPIO |
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"Murali K. Vemuri" <vemuri.muralikrishna@gmail.com> wrote:
>hi, >I am doing a gpio_set_value() to ensure it is an input pin to OMAP. >I tried my device with and without that, and no difference though. >any pointers?
Please don't top post on lkml replies. Put your reply below the text you're replying to. Also, don't forget to "reply-all". You replied to me personally instead of on-list.
gpio_set_value() is for setting gpio output value, not input. It won't have any usefulness for a pin configured for input.
I don't know anything about the specific gpio controller driver that you're using. You'll need to read up in the reference manual to figure out if there is any other SoC configuration that you need to do.
g.
> >On Thu, Mar 3, 2011 at 3:24 PM, Grant Likely ><grant.likely@secretlab.ca> wrote: >> On Thu, Feb 17, 2011 at 9:21 PM, Murali K. Vemuri >> <vemuri.muralikrishna@gmail.com> wrote: >>> Hi There, >>> >>> I am rather a novice with linux kernel and I have this problem. >>> My board is OMAP 3530 based and I use GPIO 21 to detect an external >>> device plug-in. >>> Now, when the board is just booted (after a complete power >disconnect >>> ), the GPIO is high, and when I plug in my external device, the GPIO >>> goes low, and I am able to detect it. >>> However, I see the voltage level still low after I remove the >external >>> plug-in, and any further plug-ins, remain un-detected. >>> My H/W engineers say it is some config I am missing in Kernel. >>> can someone point me? >>> >>> my code snippet is like: >>> >>> omap_mux_init_gpio(MY_GPIO, OMAP_PIN_INPUT_PULLDOWN ); >>> gpio_request(MY_GPIO,"CABLE IN"); >>> gpio_direction_input(MY_GPIO); >>> gpio_set_value(MY_GPIO,1); >> >> It depends on the gpio controller driver, but gpio_set_value() is >very >> likely switching the GPIO pin from input to output. Why are you >> calling gpio_set_value()? >> >> g. >> -- 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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