[PATCH v3 101/108] drm/bridge: ti-sn65dsi86: Make use of devm_pwmchip_alloc() function

[Uwe Kleine-König]

Hello Laurent,

On Thu, Nov 23, 2023 at 11:46:52AM +0200, Laurent Pinchart wrote:
> (CC'ing Bartosz)

I'm already in discussion with Bart :-)

> On Tue, Nov 21, 2023 at 02:50:43PM +0100, Uwe Kleine-König wrote:
> > This prepares the pwm driver of the ti-sn65dsi86 to further changes of
> > the pwm core outlined in the commit introducing devm_pwmchip_alloc().
> > There is no intended semantical change and the driver should behave as
> > before.
> > 
> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
> > ---
> >  drivers/gpu/drm/bridge/ti-sn65dsi86.c | 25 ++++++++++++++++---------
> >  1 file changed, 16 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> > index c45c07840f64..cd40530ffd71 100644
> > --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> > @@ -197,7 +197,7 @@ struct ti_sn65dsi86 {
> >  	DECLARE_BITMAP(gchip_output, SN_NUM_GPIOS);
> >  #endif
> >  #if defined(CONFIG_PWM)
> > -	struct pwm_chip			pchip;
> > +	struct pwm_chip			*pchip;
> 
> Dynamic allocation with devm_*() isn't the right solution for lifetime
> issues related to cdev. See my talk at LPC 2022
> (https://www.youtube.com/watch?v=kW8LHWlJPTU, slides at
> https://lpc.events/event/16/contributions/1227/attachments/1103/2115/20220914-lpc-devm_kzalloc.pdf),
> and Bartosz's talk at LPC 2023
> (https://lpc.events/event/17/contributions/1627/attachments/1258/2725/Linux%20Plumbers%20Conference%202023.pdf).

Once the series is completely applied, the pwm_chip isn't allocated
using devm_kzalloc any more. You're only looking at an intermediate
state where I push the broken lifetime tracking from all drivers into a
single function in the core that is then fixed after all drivers are
converted to it.

If you find issues with the complete series applied, please tell me.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |
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