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Date:   Fri, 2 Sep 2022 11:56:13 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Jiasheng Jiang <jiasheng@iscas.ac.cn>
Cc:     johan@kernel.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] USB: serial: ftdi_sio: Convert to use dev_groups
Message-ID: <YxHTPb8aWhkqEr8t@kroah.com>
References: <20220902094423.4028673-1-jiasheng@iscas.ac.cn>
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On Fri, Sep 02, 2022 at 05:44:23PM +0800, Jiasheng Jiang wrote:
> The driver core supports the ability to handle the creation and removal
> of device-specific sysfs files in a race-free manner. Moreover, it can
> guarantee the success of creation. Therefore, it should be better to
> convert to use dev_groups.
> 
> Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
> ---
> Changelog:
> 
> v2 -> v3:
> 
> 1. Add is_visible to filter the unneeded files.
> 
> v1 -> v2:
> 
> 1. Change the title.
> 2. Switch to use an attribute group.
> ---
>  drivers/usb/serial/ftdi_sio.c | 101 +++++++++++++++++-----------------
>  1 file changed, 51 insertions(+), 50 deletions(-)
> 
> diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
> index d5a3986dfee7..479c3a5caaf8 100644
> --- a/drivers/usb/serial/ftdi_sio.c
> +++ b/drivers/usb/serial/ftdi_sio.c
> @@ -1107,11 +1107,40 @@ static u32 ftdi_232bm_baud_base_to_divisor(int baud, int base);
>  static u32 ftdi_232bm_baud_to_divisor(int baud);
>  static u32 ftdi_2232h_baud_base_to_divisor(int baud, int base);
>  static u32 ftdi_2232h_baud_to_divisor(int baud);
> +static umode_t ftdi_sio_attr_is_visible(struct kobject *kobj,
> +					 struct attribute *attr, int idx);
> +static ssize_t latency_timer_store(struct device *dev,
> +				   struct device_attribute *attr,
> +				   const char *valbuf, size_t count);
> +static ssize_t event_char_store(struct device *dev,
> +	struct device_attribute *attr, const char *valbuf, size_t count);
> +static ssize_t latency_timer_show(struct device *dev,
> +				  struct device_attribute *attr, char *buf);
> +

Please work with the code so that you do not have to pre-define these
functions.  It should be possible.  Worst case, you pre-define the
structure for the driver, that should be it.

And again, have you tested this change?

thanks,

greg k-h