Re: [PATCH v2] Expose Peak USB device id in sysfs via phys_port_name.

[Andre Naujoks <nautsch2@gmail.com>]

Am 23.07.21 um 09:24 schrieb Stéphane Grosjean:
> Hi,
> 
> We plan to send the patches during the next month.

Thank you for the info! Sounds great. I'm looking forward to it.

Best Regards
   Andre

> 
> Regards,
> 
> — Stéphane
> 
> 
> ------------------------------------------------------------------------
> *De :* Andre Naujoks <nautsch2@gmail.com>
> *Envoyé :* mercredi 21 juillet 2021 15:39
> *À :* Stéphane Grosjean <s.grosjean@peak-system.com>; Wolfgang 
> Grandegger <wg@grandegger.com>; Marc Kleine-Budde <mkl@pengutronix.de>; 
> David S. Miller <davem@davemloft.net>; Jakub Kicinski <kuba@kernel.org>; 
> Vincent Mailhol <mailhol.vincent@wanadoo.fr>; Gustavo A. R. Silva 
> <gustavoars@kernel.org>; Pavel Skripkin <paskripkin@gmail.com>; Colin 
> Ian King <colin.king@canonical.com>; linux-can@vger.kernel.org 
> <linux-can@vger.kernel.org>; netdev@vger.kernel.org 
> <netdev@vger.kernel.org>; linux-kernel@vger.kernel.org 
> <linux-kernel@vger.kernel.org>
> *Objet :* Re: [PATCH v2] Expose Peak USB device id in sysfs via 
> phys_port_name.
> Am 21.07.21 um 15:29 schrieb Stéphane Grosjean:
>> Hi,
>> 
>> The display and the possibility to change this "device_number" is a current modification of the peak_usb driver. This modification will offer this possibility for all CAN - USB interfaces of PEAK-System.
> 
> Hi.
> 
> By "current modification" you mean something not yet public? Do you have
> a time frame for when you are planning to make it public? I'd really
> like to use this :-)
> 
>> 
>> However, it is planned to create new R/W entries for this (under /sys/class/net/canX/...) as is already the case in other USB - CAN interface drivers.
> 
> I'd be fine with that. I just chose something, that was already
> available and looked as if it made the most sense without breaking anything.
> 
> Thanks for the reply!
>     Andre
> 
>> 
>> — Stéphane
>> 
>> 
>> De : Andre Naujoks <nautsch2@gmail.com>
>> Envoyé : mercredi 21 juillet 2021 14:59
>> À : Wolfgang Grandegger <wg@grandegger.com>; Marc Kleine-Budde <mkl@pengutronix.de>; David S. Miller <davem@davemloft.net>; Jakub Kicinski <kuba@kernel.org>; Stéphane Grosjean <s.grosjean@peak-system.com>; Vincent Mailhol <mailhol.vincent@wanadoo.fr>; Gustavo  A. R. Silva <gustavoars@kernel.org>; Pavel Skripkin 
> <paskripkin@gmail.com>; Colin Ian King <colin.king@canonical.com>; Andre 
> Naujoks <nautsch2@gmail.com>; linux-can@vger.kernel.org 
> <linux-can@vger.kernel.org>; netdev@vger.kernel.org 
> <netdev@vger.kernel.org>; linux-kernel@vger.kernel.org 
> <linux-kernel@vger.kernel.org>
>> Objet : [PATCH v2] Expose Peak USB device id in sysfs via phys_port_name.
>> 
>> The Peak USB CAN adapters can be assigned a device id via the Peak
>> provided tools (pcan-settings). This id can currently not be set by the
>> upstream kernel drivers, but some devices expose this id already.
>> 
>> The id can be used for consistent naming of CAN interfaces regardless of
>> order of attachment or recognition on the system. The classical CAN Peak
>> USB adapters expose this id via bcdDevice (combined with another value)
>> on USB-level in the sysfs tree and this value is then available in
>> ID_REVISION from udev. This is not a feasible approach, when a single
>> USB device offers more than one CAN-interface, like e.g. the PCAN-USB
>> Pro FD devices.
>> 
>> This patch exposes those ids via the, up to now unused, netdevice sysfs
>> attribute phys_port_name as a simple decimal ASCII representation of the
>> id. phys_port_id was not used, since the default print functions from
>> net/core/net-sysfs.c output a hex-encoded binary value, which is
>> overkill for a one-byte device id, like this one.
>> 
>> Signed-off-by: Andre Naujoks <nautsch2@gmail.com>
>> ---
>>   drivers/net/can/usb/peak_usb/pcan_usb_core.c | 16 ++++++++++++++++
>>   1 file changed, 16 insertions(+)
>> 
>> diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_core.c b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
>> index e8f43ed90b72..f6cbb01a58cc 100644
>> --- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
>> +++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
>> @@ -408,6 +408,21 @@ static netdev_tx_t peak_usb_ndo_start_xmit(struct sk_buff *skb,
>>           return NETDEV_TX_OK;
>>   }
>> 
>> +static int peak_usb_ndo_get_phys_port_name(struct net_device *netdev,
>> +                                          char *name, size_t len)
>> +{
>> +       const struct peak_usb_device *dev = netdev_priv(netdev);
>> +       int err;
>> +
>> +       err = snprintf(name, len, "%u", dev->device_number);
>> +
>> +       if (err >= len || err <= 0) {
>> +               return -EINVAL;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>>   /*
>>    * start the CAN interface.
>>    * Rx and Tx urbs are allocated here. Rx urbs are submitted here.
>> @@ -769,6 +784,7 @@ static const struct net_device_ops peak_usb_netdev_ops = {
>>           .ndo_stop = peak_usb_ndo_stop,
>>           .ndo_start_xmit = peak_usb_ndo_start_xmit,
>>           .ndo_change_mtu = can_change_mtu,
>> +       .ndo_get_phys_port_name = peak_usb_ndo_get_phys_port_name,
>>   };
>> 
>>   /*
>> --
>> 2.32.0
>> 
>> --
>> PEAK-System Technik GmbH
>> Sitz der Gesellschaft Darmstadt - HRB 9183
>> Geschaeftsfuehrung: Alexander Gach / Uwe Wilhelm
>> Unsere Datenschutzerklaerung mit wichtigen Hinweisen
>> zur Behandlung personenbezogener Daten finden Sie unter
>> www.peak-system.com/Datenschutz.483.0.html 
> <http://www.peak-system.com/Datenschutz.483.0.html>
>> 
> 
> 
> --
> PEAK-System Technik GmbH
> Sitz der Gesellschaft Darmstadt - HRB 9183
> Geschaeftsfuehrung: Alexander Gach / Uwe Wilhelm
> Unsere Datenschutzerklaerung mit wichtigen Hinweisen
> zur Behandlung personenbezogener Daten finden Sie unter
> www.peak-system.com/Datenschutz.483.0.html