Hello, On Sat, Feb 19, 2022 at 11:46:31AM +0500, Nikita Travkin wrote: > Uwe Kleine-König писал(а) 14.02.2022 23:43: > > On Sat, Feb 12, 2022 at 09:23:42PM +0500, Nikita Travkin wrote: > >> + * Limitations: > >> + * - Glitches are possible when new pwm state is applied. > >> + * - Due to the fact that exact behavior depends on the underlying > >> + * clock driver, various limitations are possible. > >> + * - Period depends on the clock and, in general, not guaranteed. > > > > This sentence is broken. > > > > Here what I mean is that the clock driver might e.g. have a lookup table > for some rates and will only set one close to the requested ones. > (Extreme scenario is that only one rate is allowed in the lookup table, > which is a real possibility for some platforms that I think this driver > will be used with, the lookup may need to be changed for those clocks) > > I will reword this like: > > Some clock drivers may only pick the closest available rate > and not the exact requested one. Because of this, exact period > is not guaranteed. That there is no exact match is quite normal also for dedicated PWM HW blocks. So I think the second item in your list is good enough to cover the non-existing guaranteed for period and glitches. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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