Re: [PATCH net v3 1/2] ptp: ocp: adjust sysfs entries to expose tty information

[Simon Horman <horms@kernel.org>]

On Thu, Aug 15, 2024 at 05:59:04AM -0700, Vadim Fedorenko wrote:
> Starting v6.8 the serial port subsystem changed the hierarchy of devices
> and symlinks are not working anymore. Previous discussion made it clear
> that the idea of symlinks for tty devices was wrong by design. Implement
> additional attributes to expose the information. Fixes tag points to the
> commit which introduced the change.

Hi Vadim,

Would it be possible to provide a link to the discussion(s)?

> 
> Fixes: b286f4e87e32 ("serial: core: Move tty and serdev to be children of serial core port device")
> Signed-off-by: Vadim Fedorenko <vadfed@meta.com>

...

> diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c

...

> @@ -3346,6 +3352,54 @@ static EXT_ATTR_RO(freq, frequency, 1);
>  static EXT_ATTR_RO(freq, frequency, 2);
>  static EXT_ATTR_RO(freq, frequency, 3);
>  
> +static ssize_t
> +ptp_ocp_tty_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct dev_ext_attribute *ea = to_ext_attr(attr);
> +	struct ptp_ocp *bp = dev_get_drvdata(dev);
> +	struct ptp_ocp_serial_port *port;

nit: Port is unused in this function, it should be removed.

> +
> +	return sysfs_emit(buf, "ttyS%d", bp->port[(uintptr_t)ea->var].line);
> +}

...