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SubjectRe: [PATCH 02/18] staging: typec: tcpm: Add extcon helper functions for USB2 current limit detect
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On 08/06/2017 05:35 AM, Hans de Goede wrote:
> Some type-c port-controllers, such as the fusb302 port-controller, rely
> on an external device doing USB2 charger-type detection.
>
> Existing PMIC (and charger) drivers already use extcon to communicate the
> detected charger-type from the PMIC (extcon) driver to the charger driver.
>
> Rather then inventing a new API for USB2 charger-type detection
> specifically for use with the tcpm code, lets simply re-use the existing
> support. This will also allow re-using existing PMIC extcon drivers such
> as the axp288 and Intel Whiskey Cove drivers as is on devices where these
> are combined with a fusb302 (or in the future another port-controller
> which relies on external USB2 charger-type detection).
>
> This commit adds a helper function which tcpc drivers can use to easily
> hook into existing PMIC extcon drivers for USB2 charger-type detection:
>
> int tcpm_get_usb2_current_limit_extcon(struct tcpc_dev *tcpc);
>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
> drivers/staging/typec/tcpm.c | 40 ++++++++++++++++++++++++++++++++++++++++
> drivers/staging/typec/tcpm.h | 6 ++++++
> 2 files changed, 46 insertions(+)
>
> diff --git a/drivers/staging/typec/tcpm.c b/drivers/staging/typec/tcpm.c
> index 9f5adace4309..06bb0e640bcf 100644
> --- a/drivers/staging/typec/tcpm.c
> +++ b/drivers/staging/typec/tcpm.c
> @@ -16,6 +16,7 @@
>
> #include <linux/completion.h>
> #include <linux/debugfs.h>
> +#include <linux/delay.h>
> #include <linux/device.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> @@ -3532,6 +3533,45 @@ void tcpm_unregister_port(struct tcpm_port *port)
> }
> EXPORT_SYMBOL_GPL(tcpm_unregister_port);
>
> +/* Generic (helper) implementations for some tcpc_dev callbacks */
> +int tcpm_get_usb2_current_limit_extcon(struct tcpc_dev *tcpc)
> +{
> + struct extcon_dev *extcon = tcpc->usb2_extcon;
> + int current_limit = 0;
> + unsigned long timeout;
> +
> + if (!extcon)
> + return 0;
> +
> + /*
> + * USB2 Charger detection may still be in progress when we get here,
> + * this can take upto 600ms, wait 800ms max.
> + */
> + timeout = jiffies + msecs_to_jiffies(800);
> + do {
> + if (extcon_get_state(extcon, EXTCON_CHG_USB_SDP) == 1) {
> + current_limit = 500;
> + break;
> + }
> +
> + if (extcon_get_state(extcon, EXTCON_CHG_USB_CDP) == 1 ||
> + extcon_get_state(extcon, EXTCON_CHG_USB_ACA) == 1) {
> + current_limit = 1500;
> + break;
> + }
> +
> + if (extcon_get_state(extcon, EXTCON_CHG_USB_DCP) == 1) {
> + current_limit = 2000;
> + break;
> + }
> +
> + msleep(50);
> + } while (time_before(jiffies, timeout));
> +
> + return current_limit;
> +}
> +EXPORT_SYMBOL_GPL(tcpm_get_usb2_current_limit_extcon);
> +

Not really sure about this one. Should it be part of low level drivers ?

Guenter

> MODULE_AUTHOR("Guenter Roeck <groeck@chromium.org>");
> MODULE_DESCRIPTION("USB Type-C Port Manager");
> MODULE_LICENSE("GPL");
> diff --git a/drivers/staging/typec/tcpm.h b/drivers/staging/typec/tcpm.h
> index 01b7d89379a3..35e8c1e7dba0 100644
> --- a/drivers/staging/typec/tcpm.h
> +++ b/drivers/staging/typec/tcpm.h
> @@ -16,6 +16,7 @@
> #define __LINUX_USB_TCPM_H
>
> #include <linux/bitops.h>
> +#include <linux/extcon.h>
> #include <linux/usb/typec.h>
> #include "pd.h"
>
> @@ -126,6 +127,8 @@ struct tcpc_dev {
> int (*pd_transmit)(struct tcpc_dev *dev, enum tcpm_transmit_type type,
> const struct pd_message *msg);
> struct tcpc_mux_dev *mux;
> + /* Used by tcpm_get_usb2_current_limit_extcon helpers */
> + struct extcon_dev *usb2_extcon;
> };
>
> struct tcpm_port;
> @@ -151,4 +154,7 @@ 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);
>
> +/* Generic (helper) implementations for some tcpc_dev callbacks */
> +int tcpm_get_usb2_current_limit_extcon(struct tcpc_dev *tcpc);
> +
> #endif /* __LINUX_USB_TCPM_H */
>

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