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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2/5/24 23:33, Krzysztof Kozlowski wrote: > On 05/02/2024 17:15, Guenter Roeck wrote: >> On Mon, Feb 05, 2024 at 04:26:08PM +0100, Krzysztof Kozlowski wrote: >>> On 05/02/2024 16:20, Cosmo Chou wrote: >>>> This driver implements support for temperature monitoring of Astera Labs >>>> PT5161L series PCIe retimer chips. >>>> >>>> This driver implementation originates from the CSDK available at >>>> Link: https://github.com/facebook/openbmc/tree/helium/common/recipes-lib/retimer-v2.14 >>>> The communication protocol utilized is based on the I2C/SMBus standard. >>>> >>>> Signed-off-by: Cosmo Chou >>>> --- >> [ ... ] >> >>>> + >>>> +static int __init pt5161l_init(void) >>>> +{ >>>> + pt5161l_debugfs_dir = debugfs_create_dir("pt5161l", NULL); >>> >>> Drivers don't need initcalls. For sure any debugfs should not be handled >>> here but in probe. >>> >> >> Lots of hwmon drivers have init functions, for basic chip detection of >> Super-I/O chips (example: drivers/hwmon/nct6775-platform.c) and to create >> a parent debugfs subdirectory for the driver. The probe function then adds >> subdirecties per chip instantiation. Example for pmbus, in >> drivers/hwmon/pmbus/pmbus_core.c: > > Core bus components are a bit different... > >> >> static int __init pmbus_core_init(void) >> { >> pmbus_debugfs_dir = debugfs_create_dir("pmbus", NULL); >> if (IS_ERR(pmbus_debugfs_dir)) >> pmbus_debugfs_dir = NULL; >> >> return 0; >> } >> >> static void __exit pmbus_core_exit(void) >> { >> debugfs_remove_recursive(pmbus_debugfs_dir); >> } >> >> Are you saying this is all wrong ? What alternative would you suggest ? > > Just create parent directory in probe and only keep remove in __exit. > But you are right that might not be much better approach. > That would just add more code and increase complexity since it would require a mutex to protect against parallel probes. On the plus side, it would only create the driver root directory if necessary, that is, if there is an actual device. I am not sure if that would be worth the increased complexity. That makes me wonder, though, if an API function such as struct dentry *hwmon_debugfs_get_root(char *name); would make sense. That would move the complexity to the hwmon core and unify its handling. I'll think about that. For the time being, I'll accept the code as-is. Thanks, Guenter