Messages in this thread | | | Subject | Re: [PATCH v2 2/3] pwm: bcm2835: allow pwm driver to be used in atomic context | From | Ivaylo Dimitrov <> | Date | Sat, 14 Oct 2023 09:51:12 +0300 |
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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
Ivo
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