[PATCH v3 06/10] pwm: Add NVIDIA Tegra SoC support

Thierry Reding thierry.reding at avionic-design.de
Thu Feb 23 19:14:59 EST 2012


* Ryan Mallon wrote:
> On 23/02/12 02:17, Thierry Reding wrote:
> 
> > This commit adds a generic PWM framework driver for the PWFM controller
> > found on NVIDIA Tegra SoCs. The driver is based on code from the
> > Chromium kernel tree and was originally written by Gary King (NVIDIA)
> > and later modified by Simon Que (Chromium).
> > 
> > Signed-off-by: Thierry Reding <thierry.reding at avionic-design.de>
> > ---
> 
> <snip>
> 
> > +
> > +	pwm->chip.dev = &pdev->dev;
> > +	pwm->chip.ops = &tegra_pwm_ops;
> > +	pwm->chip.base = -1;
> > +	pwm->chip.npwm = NUM_PWM;
> 
> > +
> > +	ret = pwmchip_add(&pwm->chip);
> 
> 
> If a driver fails to initialise the pwm_chip structure correctly it can
> cause problems in the pwm core. For example, if the dev field doesn't
> get set, then you will get an oops if you try to cat the pwm debugfs file.
> 
> pwmchip_add should probably verify that the initialisation of the
> pwm_chip structure is sane to avoid problems like this.

Absolutely. What would be the best response to an invalid struct pwm_chip? I
suppose at least returning -EINVAL, perhaps complemented with WARN_ON?

Thierry
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