linux-kernel - Re: [PATCH v2 6/7] platform/chrome: cros_ec

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Message-ID: <a5emtussqri2jxhchhh4rz5i54lpjij5jxcuuilnkdu2n7tdpo@g2l4xiqrxxzs>
Date: Thu, 31 Oct 2024 20:51:00 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
Cc: heikki.krogerus@...ux.intel.com, tzungbi@...nel.org, 
	linux-usb@...r.kernel.org, chrome-platform@...ts.linux.dev, jthies@...gle.com, 
	akuchynski@...gle.com, pmalani@...omium.org, Benson Leung <bleung@...omium.org>, 
	Guenter Roeck <groeck@...omium.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 6/7] platform/chrome: cros_ec_typec: Thunderbolt
 support

On Wed, Oct 30, 2024 at 02:28:37PM -0700, Abhishek Pandit-Subedi wrote:
> Add support for entering and exiting Thunderbolt alt-mode using AP
> driven alt-mode.
> 
> Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
> ---
> 
> Changes in v2:
> - Refactored thunderbolt support into cros_typec_altmode.c
> 
>  drivers/platform/chrome/cros_ec_typec.c      | 29 ++++---
>  drivers/platform/chrome/cros_typec_altmode.c | 85 ++++++++++++++++++++
>  drivers/platform/chrome/cros_typec_altmode.h | 14 ++++
>  3 files changed, 116 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> index 7997e7136c4c..3e043b1c1cc8 100644
> --- a/drivers/platform/chrome/cros_ec_typec.c
> +++ b/drivers/platform/chrome/cros_ec_typec.c
> @@ -304,21 +304,26 @@ static int cros_typec_register_port_altmodes(struct cros_typec_data *typec,
>  	typec_altmode_set_drvdata(amode, port);
>  	amode->ops = &port_amode_ops;
>  #endif
> -
>  	/*
>  	 * Register TBT compatibility alt mode. The EC will not enter the mode
> -	 * if it doesn't support it, so it's safe to register it unconditionally
> -	 * here for now.
> +	 * if it doesn't support it and it will not enter automatically by
> +	 * design so we can use the |ap_driven_altmode| feature to check if we
> +	 * should register it.
>  	 */
> -	memset(&desc, 0, sizeof(desc));
> -	desc.svid = USB_TYPEC_TBT_SID;
> -	desc.mode = TYPEC_ANY_MODE;
> -	amode = typec_port_register_altmode(port->port, &desc);
> -	if (IS_ERR(amode))
> -		return PTR_ERR(amode);
> -	port->port_altmode[CROS_EC_ALTMODE_TBT] = amode;
> -	typec_altmode_set_drvdata(amode, port);
> -	amode->ops = &port_amode_ops;
> +	if (typec->ap_driven_altmode) {
> +		memset(&desc, 0, sizeof(desc));
> +		desc.svid = USB_TYPEC_TBT_SID;
> +		desc.mode = TYPEC_ANY_MODE;
> +		amode = cros_typec_register_thunderbolt(port, &desc);
> +		if (IS_ERR(amode))
> +			return PTR_ERR(amode);
> +		port->port_altmode[CROS_EC_ALTMODE_TBT] = amode;
> +
> +#if !IS_ENABLED(CONFIG_TYPEC_TBT_ALTMODE)
> +		typec_altmode_set_drvdata(amode, port);
> +		amode->ops = &port_amode_ops;
> +#endif

Why? Usually having the code block under an #if is a frowned upon
practice.

> +	}
>  
>  	port->state.alt = NULL;
>  	port->state.mode = TYPEC_STATE_USB;

[...]

> diff --git a/drivers/platform/chrome/cros_typec_altmode.h b/drivers/platform/chrome/cros_typec_altmode.h
> index c6f8fb02c99c..c71568314e3f 100644
> --- a/drivers/platform/chrome/cros_typec_altmode.h
> +++ b/drivers/platform/chrome/cros_typec_altmode.h
> @@ -31,4 +31,18 @@ static inline int cros_typec_displayport_status_update(struct typec_altmode *alt
>  	return 0;
>  }
>  #endif
> +
> +#if IS_ENABLED(CONFIG_TYPEC_TBT_ALTMODE)
> +struct typec_altmode *
> +cros_typec_register_thunderbolt(struct cros_typec_port *port,
> +				struct typec_altmode_desc *desc);
> +#else
> +struct typec_altmode *

static inline struct ...
LGTM otherwise

> +cros_typec_register_thunderbolt(struct cros_typec_port *port,
> +				struct typec_altmode_desc *desc)
> +{
> +	return typec_port_register_altmode(port->port, desc);
> +}
> +#endif
> +
>  #endif /* __CROS_TYPEC_ALTMODE_H__ */
> -- 
> 2.47.0.163.g1226f6d8fa-goog
> 

-- 
With best wishes
Dmitry