linux-kernel - Re: [PATCH 1/3] platform/chrome: typec: Use notifier for updates

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Date:   Thu, 9 Apr 2020 23:01:42 +0200
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Prashant Malani <pmalani@...omium.org>,
        linux-kernel@...r.kernel.org
Cc:     heikki.krogerus@...ux.intel.com,
        Benson Leung <bleung@...omium.org>,
        Guenter Roeck <groeck@...omium.org>
Subject: Re: [PATCH 1/3] platform/chrome: typec: Use notifier for updates

Hi Prashant,

Thank you for the patch.

On 7/4/20 3:09, Prashant Malani wrote:
> Register a listener for the cros-usbpd-notifier, and update port state
> when a notification comes in.
> 
> Signed-off-by: Prashant Malani <pmalani@...omium.org>
> ---
>  drivers/platform/chrome/cros_ec_typec.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> index 874269c070739..cf7c2652a1d6d 100644
> --- a/drivers/platform/chrome/cros_ec_typec.c
> +++ b/drivers/platform/chrome/cros_ec_typec.c
> @@ -11,6 +11,7 @@
>  #include <linux/of.h>
>  #include <linux/platform_data/cros_ec_commands.h>
>  #include <linux/platform_data/cros_ec_proto.h>
> +#include <linux/platform_data/cros_usbpd_notify.h>

I think you need to add a kconfig dependency/selection in order to don't have
build problems.

>  #include <linux/platform_device.h>
>  #include <linux/usb/typec.h>
>  
> @@ -26,6 +27,7 @@ struct cros_typec_data {
>  	struct typec_port *ports[EC_USB_PD_MAX_PORTS];
>  	/* Initial capabilities for each port. */
>  	struct typec_capability *caps[EC_USB_PD_MAX_PORTS];
> +	struct notifier_block nb;
>  };
>  
>  static int cros_typec_parse_port_props(struct typec_capability *cap,
> @@ -272,6 +274,22 @@ static int cros_typec_get_cmd_version(struct cros_typec_data *typec)
>  	return 0;
>  }
>  
> +static int cros_ec_typec_event(struct notifier_block *nb,
> +			       unsigned long host_event, void *_notify)
> +{
> +	struct cros_typec_data *typec = container_of(nb, struct cros_typec_data,
> +						     nb);
> +	int ret, i;
> +
> +	for (i = 0; i < typec->num_ports; i++) {
> +		ret = cros_typec_port_update(typec, i);
> +		if (ret < 0)
> +			dev_warn(typec->dev, "Update failed for port:%d\n", i);

nit: space between : and %d

> +	}
> +
> +	return NOTIFY_OK;
> +}
> +
>  #ifdef CONFIG_ACPI
>  static const struct acpi_device_id cros_typec_acpi_id[] = {
>  	{ "GOOG0014", 0 },
> @@ -332,6 +350,13 @@ static int cros_typec_probe(struct platform_device *pdev)
>  			goto unregister_ports;
>  	}
>  
> +	typec->nb.notifier_call = cros_ec_typec_event;
> +	ret = cros_usbpd_register_notify(&typec->nb);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to register notifier\n");

Currently cros_usbpd_register_notfity calls blocking_notifier_chain_register
that always return zero. Is fine to check the error but the print is unneded. If
probe fails will report the error.

> +		goto unregister_ports;
> +	}
> +
>  	return 0;
>  
>  unregister_ports:
>