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Date:   Sat, 17 Apr 2021 21:57:51 +0200
From:   Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>
To:     Clemens Gruber <clemens.gruber@pqgruber.com>
Cc:     linux-pwm@vger.kernel.org,
        Thierry Reding <thierry.reding@gmail.com>,
        Sven Van Asbroeck <TheSven73@gmail.com>,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v9 2/8] pwm: pca9685: Support hardware readout
Message-ID: <20210417195751.fmp23yalcrra5dtw@pengutronix.de>
References: <20210415121455.39536-1-clemens.gruber@pqgruber.com>
 <20210415121455.39536-2-clemens.gruber@pqgruber.com>
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Hello,

On Thu, Apr 15, 2021 at 02:14:49PM +0200, Clemens Gruber wrote:
> Implement .get_state to read-out the current hardware state.
>=20
> The hardware readout may return slightly different values than those
> that were set in apply due to the limited range of possible prescale and
> counter register values.
>=20
> Also note that although the datasheet mentions 200 Hz as default
> frequency when using the internal 25 MHz oscillator, the calculated
> period from the default prescaler register setting of 30 is 5079040ns.
>=20
> Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com>
> ---
> Changes since v8:
> - As we left the math in apply as-is, use DIV_ROUND_DOWN in get_state

I first thought this was wrong, because .apply uses ROUND_CLOSEST for
period and ROUND_UP for duty. But as the calculation for period is exact
this doesn't matter and round-down is indeed correct here.

Reviewed-by: Uwe Kleine-K=F6nig <u.kleine-koenig@pengutronix.de>

Thanks
Uwe

--=20
Pengutronix e.K.                           | Uwe Kleine-K=F6nig            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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