On Mon, Feb 08, 2010 at 09:03:50PM +0000, Andrew Clayton wrote:
> While trying to get a rotary encoder working under a beagle board using
> the drivers/input/misc/rotary-encoder.c driver, we found that even with
> the right pin mux settings configured through /sys/kernel/debug/omap_mux/*,
> i.e INPUT_PULLUP and MODE4, the gpio_get_value() functions only ever
> returned 1.
>
> By explicitly calling gpio_direction_input() after each requested gpio,
> the driver started working and started returning correct input events.
>
> The following is the patch that works for us. What do you think?
Adding my Signed-off-by tag:
Signed-off-by: Mark Somerville <mark@xxxxxxxxxxxxxxxxxx>
> Cheers,
> Andrew
>
>
> Set the gpio direction to input for each requested gpio.
>
> Even with the correct pin mux settings, you still need to explicitly
> set the gpio direction. Call gpio_direction_input() after each
> requested gpio.
>
> Signed-off-by: Andrew Clayton <andrew@xxxxxxxxxxxxxxxxxx>
> ---
> diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c
> index 3b9f588..4ae0793 100644
> --- a/drivers/input/misc/rotary_encoder.c
> +++ b/drivers/input/misc/rotary_encoder.c
> @@ -152,6 +152,13 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
> goto exit_unregister_input;
> }
>
> + err = gpio_direction_input(pdata->gpio_a);
> + if (err) {
> + dev_err(&pdev->dev, "unable to set GPIO %d for input\n",
> + pdata->gpio_a);
> + goto exit_unregister_input;
> + }
> +
> err = gpio_request(pdata->gpio_b, DRV_NAME);
> if (err) {
> dev_err(&pdev->dev, "unable to request GPIO %d\n",
> @@ -159,6 +166,13 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
> goto exit_free_gpio_a;
> }
>
> + err = gpio_direction_input(pdata->gpio_b);
> + if (err) {
> + dev_err(&pdev->dev, "unable to set GPIO %d for input\n",
> + pdata->gpio_b);
> + goto exit_free_gpio_a;
> + }
> +
> /* request the IRQs */
> err = request_irq(encoder->irq_a, &rotary_encoder_irq,
> IORESOURCE_IRQ_HIGHEDGE | IORESOURCE_IRQ_LOWEDGE,
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