linux-kernel - Re: [PATCH 1/3] usb: typec: ps883x: fix registration race

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Message-ID: <Z77k0MzLV3htrIbd@kuha.fi.intel.com>
Date: Wed, 26 Feb 2025 11:54:24 +0200
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: Johan Hovold <johan+linaro@...nel.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Abel Vesa <abel.vesa@...aro.org>,
	Stephan Gerhold <stephan.gerhold@...aro.org>,
	linux-arm-msm@...r.kernel.org, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] usb: typec: ps883x: fix registration race

On Tue, Feb 18, 2025 at 04:29:31PM +0100, Johan Hovold wrote:
> Make sure that the retimer is fully setup before registering it to avoid
> having consumers try to access it while it is being reset.
> 
> Fixes: 257a087c8b52 ("usb: typec: Add support for Parade PS8830 Type-C Retimer")
> Cc: Abel Vesa <abel.vesa@...aro.org>
> Signed-off-by: Johan Hovold <johan+linaro@...nel.org>

Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

> ---
>  drivers/usb/typec/mux/ps883x.c | 31 ++++++++++++++++---------------
>  1 file changed, 16 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/usb/typec/mux/ps883x.c b/drivers/usb/typec/mux/ps883x.c
> index ef086989231f..274de7abe585 100644
> --- a/drivers/usb/typec/mux/ps883x.c
> +++ b/drivers/usb/typec/mux/ps883x.c
> @@ -346,6 +346,22 @@ static int ps883x_retimer_probe(struct i2c_client *client)
>  		goto err_vregs_disable;
>  	}
>  
> +	/* skip resetting if already configured */
> +	if (regmap_test_bits(retimer->regmap, REG_USB_PORT_CONN_STATUS_0,
> +			     CONN_STATUS_0_CONNECTION_PRESENT) == 1) {
> +		gpiod_direction_output(retimer->reset_gpio, 0);
> +	} else {
> +		gpiod_direction_output(retimer->reset_gpio, 1);
> +
> +		/* VDD IO supply enable to reset release delay */
> +		usleep_range(4000, 14000);
> +
> +		gpiod_set_value(retimer->reset_gpio, 0);
> +
> +		/* firmware initialization delay */
> +		msleep(60);
> +	}
> +
>  	sw_desc.drvdata = retimer;
>  	sw_desc.fwnode = dev_fwnode(dev);
>  	sw_desc.set = ps883x_sw_set;
> @@ -368,21 +384,6 @@ static int ps883x_retimer_probe(struct i2c_client *client)
>  		goto err_switch_unregister;
>  	}
>  
> -	/* skip resetting if already configured */
> -	if (regmap_test_bits(retimer->regmap, REG_USB_PORT_CONN_STATUS_0,
> -			     CONN_STATUS_0_CONNECTION_PRESENT) == 1)
> -		return gpiod_direction_output(retimer->reset_gpio, 0);
> -
> -	gpiod_direction_output(retimer->reset_gpio, 1);
> -
> -	/* VDD IO supply enable to reset release delay */
> -	usleep_range(4000, 14000);
> -
> -	gpiod_set_value(retimer->reset_gpio, 0);
> -
> -	/* firmware initialization delay */
> -	msleep(60);
> -
>  	return 0;
>  
>  err_switch_unregister:
> -- 
> 2.45.3

-- 
heikki