Re: GPIO request failure with PCF pinmux

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Paul,

On Tuesday 18 September 2012 16:12:08 Paul Mundt wrote:
> On Fri, Sep 14, 2012 at 10:11:00PM +0200, Laurent Pinchart wrote:
> > Hi Paul,
> > 
> > I ran into an issue with GPIO and pinmuxing in the TPU PWM driver.
> > 
> > The driver needs to switch the PWM pin between GPIO and function at
> > runtime. To do so, I use the PWM pin GPIO (GPIO_PORT202) and the
> > associated function GPIO (GPIO_FN_TPU0TO2_PORT202).
> > 
> > The driver configures the pin as a GPIO output when loaded with
> > 
> > 	gpio_request_one(GPIO_PORT202, GPIOF_INIT_LOW);
> > 
> > This results in a call to sh_pfc_gpio_request_enable() followed by a call
> > to sh_pfc_reconfig_pin() for GPIO 202. The later changes the pinmux type
> > from PINMUX_TYPE_GPIO (2) to PINMUX_TYPE_OUTPUT (3).
> > 
> > I then call gpio_free(GPIO_PORT202) and
> > gpio_request(GPIO_FN_TPU0TO2_PORT202) to switch from GPIO to function.
> > The former calls sh_pfc_gpio_disable_free:() on GPIO 202.
> > 
> > When I later call gpio_free(GPIO_FN_TPU0TO2_PORT202) and
> > gpio_request_one(GPIO_PORT202, GPIOF_INIT_LOW), the call to
> > sh_pfc_gpio_request_enable() fails with
> > 
> > pinctrl-sh_pfc pinctrl: Unsupported mux type (3), bailing...
> > pinctrl-sh_pfc pinctrl-sh_pfc: request() failed for pin 202
> > pinctrl-sh_pfc pinctrl-sh_pfc: pin-202 (pinctrl-sh_pfc) status -524
> > 
> > You're more familiar with pinmux than I am. Am I doing something wrong, or
> > is there a bug in the PFC pinmux implementation ?
> 
> That's a bug, the pin has been reconfigured to a different mux type which
> we should handle. At first glance, simply handling the input/output types
> ought to work ok, but we may need more work than that. How does it go
> with this?

That seems to work, thank you. Will you push a patch ?

> ---
> 
> diff --git a/drivers/sh/pfc/pinctrl.c b/drivers/sh/pfc/pinctrl.c
> index 2804eaa..c0857d5 100644
> --- a/drivers/sh/pfc/pinctrl.c
> +++ b/drivers/sh/pfc/pinctrl.c
> @@ -208,6 +208,8 @@ static int sh_pfc_gpio_request_enable(struct pinctrl_dev
> *pctldev,
> 
>  		break;
>  	case PINMUX_TYPE_GPIO:
> +	case PINMUX_TYPE_INPUT:
> +	case PINMUX_TYPE_OUTPUT:
>  		break;
>  	default:
>  		pr_err("Unsupported mux type (%d), bailing...\n", pinmux_type);

-- 
Regards,

Laurent Pinchart