linux-kernel - Re: [PATCH 3/3] pinctrl: qcom: handle input-enable pinconf property

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Message-ID: <20150130162004.GT11960@sonymobile.com>
Date:	Fri, 30 Jan 2015 08:20:05 -0800
From:	Bjorn Andersson <bjorn.andersson@...ymobile.com>
To:	Stanimir Varbanov <svarbanov@...sol.com>,
	Linus Walleij <linus.walleij@...aro.org>
CC:	"linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	Stephen Boyd <sboyd@...eaurora.org>
Subject: Re: [PATCH 3/3] pinctrl: qcom: handle input-enable pinconf property

On Fri 30 Jan 02:27 PST 2015, Stanimir Varbanov wrote:

> This enables support of 'input-enable' pinconf generic property in
> the pinctrl driver.

Patch looks good, but I think the api is broken for boolean properties.

> 
> Signed-off-by: Stanimir Varbanov <svarbanov@...sol.com>
> ---
>  drivers/pinctrl/qcom/pinctrl-msm.c |   11 +++++++++++
>  1 files changed, 11 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
> index b66cd58..55a64ea 100644
> --- a/drivers/pinctrl/qcom/pinctrl-msm.c
> +++ b/drivers/pinctrl/qcom/pinctrl-msm.c
> @@ -193,6 +193,7 @@ static int msm_config_reg(struct msm_pinctrl *pctrl,
>  		*mask = 7;
>  		break;
>  	case PIN_CONFIG_OUTPUT:
> +	case PIN_CONFIG_INPUT_ENABLE:
>  		*bit = g->oe_bit;
>  		*mask = 1;
>  		break;
> @@ -260,6 +261,12 @@ static int msm_config_group_get(struct pinctrl_dev *pctldev,
>  		val = readl(pctrl->regs + g->io_reg);
>  		arg = !!(val & BIT(g->in_bit));
>  		break;
> +	case PIN_CONFIG_INPUT_ENABLE:
> +		/* Pin is output */
> +		if (arg)
> +			return -EINVAL;
> +		arg = 1;
> +		break;

My idea of this function is to query if we have the specific option
enabled, so I don't like the fact that we're returning an error here, we
should just return 0 with arg 0 (or something like that).

However, that would not give the results we expect and your patch is
"correct".

Linus, conf_items in pinconf_generic_dump_one() seems to represent
boolean properties of the pins. Returning 0 from pin_config_*_get()
should in my view then be treated as it not being active.

Is this in line with your view and should we modify
pinconf_generic_dump_one() to continue for these values if the getter
returns 0?


If not, at least all the bias properties here should return -EINVAL as
well. (which I think is wrong)

>  	default:
>  		return -EINVAL;
>  	}
> @@ -330,6 +337,10 @@ static int msm_config_group_set(struct pinctrl_dev *pctldev,
>  			/* enable output */
>  			arg = 1;
>  			break;
> +		case PIN_CONFIG_INPUT_ENABLE:
> +			/* disable output */
> +			arg = 0;
> +			break;
>  		default:
>  			dev_err(pctrl->dev, "Unsupported config parameter: %x\n",
>  				param);

Regards,
Bjorn
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