Re: [PATCH] Print some info into ring-buffer during loading

[Conor.Dooley]

On 19/06/2022 09:32, root wrote:
> ---

Hey Jessen Li/Jason-Lee,
(I hope one of those is your name, sorry if it isn't - just feels weird
addressing a username like "root" haha.

Maybe you already know this, but adding pr_info()s is not generally a
useful change. You should check out kernel newbies [0] - I think they
direct people towards starting kernel development in drivers/staging
where there is a lot of low hanging fruit for new developers.

Also, it might be of use to you to check out the guidelines for writing
commit messages before you go any further [1].

Hope that helps & good luck!
Conor.

[0] https://kernelnewbies.org/FirstKernelPatch
[1] https://www.kernel.org/doc/html/latest/process/submitting-patches.html#the-canonical-patch-format
>  drivers/i2c/i2c-core-base.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index d43db2c3876e..8e127ff3e32e 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -469,6 +469,8 @@ static int i2c_device_probe(struct device *dev)
>  	struct i2c_driver	*driver;
>  	int status;
>  
> +	pr_info("I have changed i2c device driver\n");
> +
>  	if (!client)
>  		return 0;
>  
> @@ -1829,6 +1831,7 @@ int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
>  	int res;
>  
>  	mutex_lock(&core_lock);
> +	pr_info("i2c_for_each_dev: before bus_for_each_dev\n");
>  	res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
>  	mutex_unlock(&core_lock);
>  
> @@ -1838,8 +1841,10 @@ EXPORT_SYMBOL_GPL(i2c_for_each_dev);
>  
>  static int __process_new_driver(struct device *dev, void *data)
>  {
> +	pr_info("Enter process_new_driver\n");
>  	if (dev->type != &i2c_adapter_type)
>  		return 0;
> +	pr_info("__process_new_driver, before i2c_do_add_adapter\n");
>  	return i2c_do_add_adapter(data, to_i2c_adapter(dev));
>  }
>  
> @@ -1860,13 +1865,16 @@ int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
>  	driver->driver.owner = owner;
>  	driver->driver.bus = &i2c_bus_type;
>  	INIT_LIST_HEAD(&driver->clients);
> -
> +	pr_info("i2c driver name is [%s] before driver_register\n", driver->driver.name);
>  	/* When registration returns, the driver core
>  	 * will have called probe() for all matching-but-unbound devices.
>  	 */
>  	res = driver_register(&driver->driver);
> -	if (res)
> +	if (res){
> +		pr_info("i2c driver name is [%s], res is [%d]\n", driver->driver.name, res);
>  		return res;
> +	}
> +	pr_info("i2c driver name is [%s], after driver_register\n", driver->driver.name);
>  
>  	pr_debug("driver [%s] registered\n", driver->driver.name);
>  
> @@ -1933,7 +1941,7 @@ EXPORT_SYMBOL(i2c_clients_command);
>  static int __init i2c_init(void)
>  {
>  	int retval;
> -
> +	pr_info("Jason-Lee: Entering i2c_init\n");
>  	retval = of_alias_get_highest_id("i2c");
>  
>  	down_write(&__i2c_board_lock);