linux-kernel - Re: [PATCH v2 02/14] staging: typec: tcpm: Add get_current_limit tcpc

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Date:   Wed, 16 Aug 2017 08:11:18 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Hans de Goede <hdegoede@...hat.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Sebastian Reichel <sre@...nel.org>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Liam Breck <liam@...workimprov.net>,
        Tony Lindgren <tony@...mide.com>, linux-i2c@...r.kernel.org,
        linux-pm@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        linux-kernel@...r.kernel.org, devel@...verdev.osuosl.org
Subject: Re: [PATCH v2 02/14] staging: typec: tcpm: Add get_current_limit
 tcpc_dev callback

On 08/15/2017 01:04 PM, Hans de Goede wrote:
> A Rp signalling the default current limit indicates that we're possibly
> connected to an USB2 power-source. In some cases the type-c port-controller
> may provide the capability to detect the current-limit in this case,
> through e.g. BC1.2 detection.
> 
> This commit adds an optional get_current_limit tcpc_dev callback which
> allows the port-controller to provide current-limit detection for when
> the CC pin is pulled up with Rp.
> 
> Signed-off-by: Hans de Goede <hdegoede@...hat.com>

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
> Changes in v2:
> -s/get_usb2_current_limit/get_current_limit/
> ---
>   drivers/staging/typec/tcpm.c | 5 ++++-
>   drivers/staging/typec/tcpm.h | 7 +++++++
>   2 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/typec/tcpm.c b/drivers/staging/typec/tcpm.c
> index 20eb4eb..8e823af 100644
> --- a/drivers/staging/typec/tcpm.c
> +++ b/drivers/staging/typec/tcpm.c
> @@ -660,7 +660,10 @@ static u32 tcpm_get_current_limit(struct tcpm_port *port)
>   		break;
>   	case TYPEC_CC_RP_DEF:
>   	default:
> -		limit = 0;
> +		if (port->tcpc->get_current_limit)
> +			limit = port->tcpc->get_current_limit(port->tcpc);
> +		else
> +			limit = 0;
>   		break;
>   	}
>   
> diff --git a/drivers/staging/typec/tcpm.h b/drivers/staging/typec/tcpm.h
> index 19c307d..1465668 100644
> --- a/drivers/staging/typec/tcpm.h
> +++ b/drivers/staging/typec/tcpm.h
> @@ -108,6 +108,13 @@ struct tcpc_dev {
>   
>   	int (*init)(struct tcpc_dev *dev);
>   	int (*get_vbus)(struct tcpc_dev *dev);
> +	/*
> +	 * This optional callback gets called by the tcpm core when configured
> +	 * as a snk and cc=Rp-def. This allows the tcpm to provide a fallback
> +	 * current-limit detection method for the cc=Rp-def case. E.g. some
> +	 * tcpcs may include BC1.2 charger detection and use that in this case.
> +	 */
> +	int (*get_current_limit)(struct tcpc_dev *dev);
>   	int (*set_cc)(struct tcpc_dev *dev, enum typec_cc_status cc);
>   	int (*get_cc)(struct tcpc_dev *dev, enum typec_cc_status *cc1,
>   		      enum typec_cc_status *cc2);
>