Hello, On Mon, Mar 22, 2021 at 02:15:08PM +0200, Andy Shevchenko wrote: > On Mon, Mar 22, 2021 at 1:48 PM Uwe Kleine-König > <u.kleine-koe...@pengutronix.de> wrote: > > On Mon, Mar 22, 2021 at 01:40:57PM +0200, Andy Shevchenko wrote: > > > On Mon, Mar 22, 2021 at 1:22 PM Uwe Kleine-König > > > <u.kleine-koe...@pengutronix.de> wrote: > > > > When the PWM driver is loaded and the PWM configuration is invalid, it > > > > was already invalid for the time between power up (or warm start) and > > > > PWM driver load time. Then it doesn't really hurt to keep the PWM > > > > in this invalid state for a little moment longer until the consumer of > > > > the PWM becomes active. > > > > > > But this won't work in the cases when we have a chip with a shared > > > settings for period and/or duty cycle. You will never have a user come > > > due to -EBUSY. > > > > That's wrong, the first consumer to enable the PWM (in software) is > > supposed to be able to change the settings. > > If it's a critical PWM, how can you be allowed to do that?
You seem to have a tight concept of a critical PWM. I don't, so I have problems following you. What is your picture about what is to be allowed/denied for a critical PWM? > And if so, what is the difference between resetting the device in this > case? The difference is that we have a consumer that knows what to do with the PWM then. > You may consider it as a change to the settings by the first > consumer. .. but without knowing if the first consumer is a backlight driver or a motor control it's hard to know if disabling the PWM is OK. So I like the concept of not doing anything until a process comes along that knows better. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
signature.asc
Description: PGP signature
