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Message-ID: <49b98ec2-2282-2443-56d1-01d71b66d741@roeck-us.net>
Date: Sun, 6 Aug 2017 07:13:57 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Hans de Goede <hdegoede@...hat.com>,
Darren Hart <dvhart@...radead.org>,
Andy Shevchenko <andy@...radead.org>,
Wolfram Sang <wsa@...-dreams.de>,
Sebastian Reichel <sre@...nel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Cc: platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-i2c@...r.kernel.org, Liam Breck <liam@...workimprov.net>,
Tony Lindgren <tony@...mide.com>, linux-pm@...r.kernel.org,
devel@...verdev.osuosl.org
Subject: Re: [PATCH 04/18] staging: typec: tcpm: Add helpers for exporting
current-limit through a psy
On 08/06/2017 05:35 AM, Hans de Goede wrote:
> Not all type-c port-controller can control the current-limit directly,
> in cases where the current limit can not be controlled directly it needs
> to be exported so that another driver (e.g. the charger driver) can pick
> the limit up and configure the system accordingly.
>
> The power-supply subsys already provides infrastructure for this,
> power-supply devices have the notion of being supplied by another
> power-supply and have properties through which we can export the
> current-limit.
>
> This commits adds 2 helper functions for use by port-controller drivers
> which want to export the current-limit info in this way:
>
> int tcpm_register_psy(struct device *dev, struct tcpc_dev *tcpc,
> const char *name);
> int tcpm_set_current_limit_psy(struct tcpc_dev *tcpc, u32 max_ma, u32 mv);
>
> Signed-off-by: Hans de Goede <hdegoede@...hat.com>
> ---
> drivers/staging/typec/tcpm-helpers.c | 66 ++++++++++++++++++++++++++++++++++++
> drivers/staging/typec/tcpm.h | 9 +++++
> 2 files changed, 75 insertions(+)
>
> diff --git a/drivers/staging/typec/tcpm-helpers.c b/drivers/staging/typec/tcpm-helpers.c
> index 0c87ec9936e1..8f7699576878 100644
> --- a/drivers/staging/typec/tcpm-helpers.c
> +++ b/drivers/staging/typec/tcpm-helpers.c
> @@ -20,6 +20,60 @@
>
> #include "tcpm.h"
>
> +static int tcpm_psy_get_property(struct power_supply *psy,
> + enum power_supply_property psp,
> + union power_supply_propval *val)
> +{
> + struct tcpc_dev *tcpc = power_supply_get_drvdata(psy);
> +
> + switch (psp) {
> + case POWER_SUPPLY_PROP_VOLTAGE_NOW:
> + val->intval = tcpc->supply_voltage * 1000; /* mV -> µV */
> + break;
> + case POWER_SUPPLY_PROP_CURRENT_MAX:
> + val->intval = tcpc->current_limit * 1000; /* mA -> µA */
> + break;
> + default:
> + return -ENODATA;
> + }
> +
> + return 0;
> +}
> +
> +static enum power_supply_property tcpm_psy_properties[] = {
> + POWER_SUPPLY_PROP_VOLTAGE_NOW,
> + POWER_SUPPLY_PROP_CURRENT_MAX,
> +};
> +
> +int tcpm_register_psy(struct device *dev, struct tcpc_dev *tcpc,
> + const char *name)
This is misleading since it relies on devm functions, and there is no unregister function.
Overall I am not too happy with tying this all into tcpm. The functions are not really tcpm
related. Not that I have a better idea how to handle this right now, but conceptually it
doesn't seem correct.
> +{
> + struct power_supply_config psy_cfg = {};
> + struct power_supply_desc *desc;
> + int ret = 0;
> +
> + desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL);
> + if (!desc)
> + return -ENOMEM;
> +
> + desc->name = name;
> + desc->type = POWER_SUPPLY_TYPE_USB;
> + desc->properties = tcpm_psy_properties;
> + desc->num_properties = ARRAY_SIZE(tcpm_psy_properties);
> + desc->get_property = tcpm_psy_get_property;
> + psy_cfg.drv_data = tcpc;
> +
> + tcpc->psy = devm_power_supply_register(dev, desc, &psy_cfg);
> + if (IS_ERR(tcpc->psy)) {
> + ret = PTR_ERR(tcpc->psy);
> + tcpc->psy = NULL;
> + dev_err(dev, "Error registering power-supply: %d\n", ret);
> + }
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(tcpm_register_psy);
> +
> /* Generic (helper) implementations for some tcpc_dev callbacks */
> int tcpm_get_usb2_current_limit_extcon(struct tcpc_dev *tcpc)
> {
> @@ -58,3 +112,15 @@ int tcpm_get_usb2_current_limit_extcon(struct tcpc_dev *tcpc)
> return current_limit;
> }
> EXPORT_SYMBOL_GPL(tcpm_get_usb2_current_limit_extcon);
> +
> +int tcpm_set_current_limit_psy(struct tcpc_dev *tcpc, u32 max_ma, u32 mv)
> +{
> + tcpc->supply_voltage = mv;
> + tcpc->current_limit = max_ma;
> +
> + if (tcpc->psy)
> + power_supply_changed(tcpc->psy);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(tcpm_set_current_limit_psy);
> diff --git a/drivers/staging/typec/tcpm.h b/drivers/staging/typec/tcpm.h
> index 35e8c1e7dba0..1b1475b487b5 100644
> --- a/drivers/staging/typec/tcpm.h
> +++ b/drivers/staging/typec/tcpm.h
> @@ -17,6 +17,7 @@
>
> #include <linux/bitops.h>
> #include <linux/extcon.h>
> +#include <linux/power_supply.h>
> #include <linux/usb/typec.h>
> #include "pd.h"
>
> @@ -129,6 +130,10 @@ struct tcpc_dev {
> struct tcpc_mux_dev *mux;
> /* Used by tcpm_get_usb2_current_limit_extcon helpers */
> struct extcon_dev *usb2_extcon;
> + /* Used by tcpm_set_current_limit_psy helpers */
> + struct power_supply *psy;
> + u32 current_limit;
> + u32 supply_voltage;
> };
>
> struct tcpm_port;
> @@ -154,7 +159,11 @@ void tcpm_pd_transmit_complete(struct tcpm_port *port,
> void tcpm_pd_hard_reset(struct tcpm_port *port);
> void tcpm_tcpc_reset(struct tcpm_port *port);
>
> +int tcpm_register_psy(struct device *dev, struct tcpc_dev *tcpc,
> + const char *name);
> +
> /* Generic (helper) implementations for some tcpc_dev callbacks */
> int tcpm_get_usb2_current_limit_extcon(struct tcpc_dev *tcpc);
> +int tcpm_set_current_limit_psy(struct tcpc_dev *tcpc, u32 max_ma, u32 mv);
>
> #endif /* __LINUX_USB_TCPM_H */
>
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