Hello Ivaylo, On Sat, Oct 14, 2023 at 09:51:12AM +0300, Ivaylo Dimitrov wrote: > On 13.10.23 г. 20:51 ч., Uwe Kleine-König wrote: > > Hello, > > > > On Fri, Oct 13, 2023 at 01:13:50PM +0200, Alexander Stein wrote: > > > Am Freitag, 13. Oktober 2023, 13:04:48 CEST schrieb Stefan Wahren: > > > > Am 13.10.23 um 12:46 schrieb Sean Young: > > > > > clk_get_rate() may do a mutex lock. Since the clock rate cannot change on > > > > > an rpi, simply fetch it once. > > > > > > > > does it mean you checked all possible SoCs (BCM2835, BCM2836, BCM2837, > > > > BCM2711, BCM2712) for this change? > > > > > > > > Is it impossible that the real clock can never be influenced by turbo > > > > mode like SPI? > > > > > > Assuming the clock can change, which I would, then a clock notifier seems > > > appropriate. See [1] for an example. > > > > I'm not a fan. If the clock changes, the output also changes. With a > > clock notifier you can soften the issue and reconfigure to something > > similar as the original wave form, but a glitch happens for sure. > > > > Right, but without notifier, everything rate related after the change will > be wrong So we agree clk_rate_exclusive_get() is the way to go?! It's simple, no need for a notifier and no glitches. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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