lkml.org 
[lkml]   [2020]   [Sep]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] pwm: sysfs: Set class on pwm devices
Hello Lars,

On Tue, Sep 29, 2020 at 02:19:53PM +0200, poeschel@lemonage.de wrote:
> From: Lars Poeschel <poeschel@lemonage.de>
>
> This adds a class to exported pwm devices.
> Exporting a pwm through sysfs did not yield udev events. The

I wonder what is your use-case here. This for sure also has a place to
be mentioned in the commit log. I suspect there is a better way to
accomplish you way.

> dev_uevent_filter function does filter-out devices without a bus or
> class.
> This was already addressed in commit
> commit 7e5d1fd75c3d ("pwm: Set class for exported channels in sysfs")
> but this did cause problems and the commit got reverted with
> commit c289d6625237 ("Revert "pwm: Set class for exported channels in
> sysfs"")
>
> pwm's have to be local to its pwmchip, so we create an individual class
> for each pwmchip

This sounds conceptually wrong.

> and assign this class to the pwm belonging to the
> pwmchip. This does better map to structure that is also visible in
> sysfs.
>
> Signed-off-by: Lars Poeschel <poeschel@lemonage.de>
> ---
> drivers/pwm/sysfs.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
> index 449dbc0f49ed..e2dfbc335366 100644
> --- a/drivers/pwm/sysfs.c
> +++ b/drivers/pwm/sysfs.c
> @@ -259,7 +259,7 @@ static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
> export->child.release = pwm_export_release;
> export->child.parent = parent;
> export->child.devt = MKDEV(0, 0);
> - export->child.groups = pwm_groups;
> + export->child.class = parent->class;
> dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
>
> ret = device_register(&export->child);
> @@ -499,6 +499,9 @@ void pwmchip_sysfs_export(struct pwm_chip *chip)
> dev_warn(chip->dev,
> "device_create failed for pwm_chip sysfs export\n");
> }
> +
> + parent->class = class_create(THIS_MODULE, parent->kobj.name);

This needs error handling.

> + parent->class->dev_groups = pwm_groups;
> }
>
> void pwmchip_sysfs_unexport(struct pwm_chip *chip)
> @@ -518,6 +521,7 @@ void pwmchip_sysfs_unexport(struct pwm_chip *chip)
> pwm_unexport_child(parent, pwm);
> }
>
> + class_destroy(parent->class);
> put_device(parent);
> device_unregister(parent);
> }

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2020-09-30 08:58    [W:0.064 / U:1.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site