linux-kernel - Re: [PATCH v2 3/3] usb: typec: tcpm: add get max power support

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Message-ID: <20230320203139.quld3gmoo6esu56i@mercury.elektranox.org>
Date:   Mon, 20 Mar 2023 21:31:39 +0100
From:   Sebastian Reichel <sebastian.reichel@...labora.com>
To:     Frank Wang <frank.wang@...k-chips.com>
Cc:     linux@...ck-us.net, heikki.krogerus@...ux.intel.com,
        gregkh@...uxfoundation.org, heiko@...ech.de,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-rockchip@...ts.infradead.org, huangtao@...k-chips.com,
        william.wu@...k-chips.com, jianwei.zheng@...k-chips.com,
        yubing.zhang@...k-chips.com, wmc@...k-chips.com
Subject: Re: [PATCH v2 3/3] usb: typec: tcpm: add get max power support

Hi,

On Mon, Mar 20, 2023 at 06:07:11PM +0800, Frank Wang wrote:
> Traverse fixed pdos to calculate the maximum power that the charger
> can provide, and it can be get by POWER_SUPPLY_PROP_INPUT_POWER_LIMIT
> property.
> 
> Signed-off-by: Frank Wang <frank.wang@...k-chips.com>
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 13830b5e2d09f..d6ad3cdf9e4af 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -6320,6 +6320,27 @@ static int tcpm_psy_get_current_now(struct tcpm_port *port,
>  	return 0;
>  }
>  
> +static int tcpm_psy_get_input_power_limit(struct tcpm_port *port,
> +					  union power_supply_propval *val)
> +{
> +	unsigned int src_mv, src_ma, max_src_mw = 0;
> +	unsigned int i, tmp;
> +
> +	for (i = 0; i < port->nr_source_caps; i++) {
> +		u32 pdo = port->source_caps[i];
> +
> +		if (pdo_type(pdo) == PDO_TYPE_FIXED) {
> +			src_mv = pdo_fixed_voltage(pdo);
> +			src_ma = pdo_max_current(pdo);
> +			tmp = src_mv * src_ma / 1000;
> +			max_src_mw = tmp > max_src_mw ? tmp : max_src_mw;
> +		}
> +	}
> +
> +	val->intval = max_src_mw;

The power-supply subsystem expects Microwatts and not Milliwatts.

-- Sebastian

> +	return 0;
> +}
> +
>  static int tcpm_psy_get_prop(struct power_supply *psy,
>  			     enum power_supply_property psp,
>  			     union power_supply_propval *val)
> @@ -6349,6 +6370,9 @@ static int tcpm_psy_get_prop(struct power_supply *psy,
>  	case POWER_SUPPLY_PROP_CURRENT_NOW:
>  		ret = tcpm_psy_get_current_now(port, val);
>  		break;
> +	case POWER_SUPPLY_PROP_INPUT_POWER_LIMIT:
> +		tcpm_psy_get_input_power_limit(port, val);
> +		break;
>  	default:
>  		ret = -EINVAL;
>  		break;
> -- 
> 2.17.1
> 

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