On 23/02/12 19:14, Thierry Reding wrote: > * 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@xxxxxxxxxxxxxxxxx> >>> --- >> >> <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? Just returning -EINVAL should be okay. I don't think you need a WARN_ON, since failing to register the hardware should be enough of a reason for a user to report a problem. ~Ryan -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
