Messages in this thread | | | Date | Wed, 4 Oct 2023 11:35:58 +0200 | From | Uwe Kleine-König <> | Subject | Re: [PATCH 2/2] media: pwm-ir-tx: trigger edges from hrtimer interrupt context |
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Hello,
On Wed, Oct 04, 2023 at 08:43:53AM +0100, Sean Young wrote: > On Mon, Oct 02, 2023 at 12:52:00PM +0300, Ivaylo Dimitrov wrote: > > On 2.10.23 г. 11:20 ч., Sean Young wrote: > > > Requires a copy of pwm_state in pwm_ir, not a huge difference (copy of 28 > > > bytes vs keeping it around). > > > > see my previous comment re struct var. Also, look at the overhead: > > https://elixir.bootlin.com/linux/v6.6-rc3/source/include/linux/pwm.h#L349 - > > you call pwm_get_state() for every edge. > > That's the 28 bytes copy I was talking about.
Note that pwm_get_state() also has (IMHO) confusing semantics. It gives you (most of the time) the state that was last pwm_state_apply()d and not the state the hardware is currently in. In my book keeping the pwm_state around is the nicer approach that often is also simpler ...
> However keeping a pointer in struct pwm_ir is a good compromise and makes > the rest of the code cleaner.
... which seems to apply here, too.
Best regards Uwe
-- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ | [unhandled content-type:application/pgp-signature] | |