From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B393C433ED for ; Tue, 13 Apr 2021 10:34:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0EA2E613B8 for ; Tue, 13 Apr 2021 10:34:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245611AbhDMKei (ORCPT ); Tue, 13 Apr 2021 06:34:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245197AbhDMKeh (ORCPT ); Tue, 13 Apr 2021 06:34:37 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 476ECC061574 for ; Tue, 13 Apr 2021 03:34:18 -0700 (PDT) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lWGN2-0008Cb-Vn; Tue, 13 Apr 2021 12:34:12 +0200 Received: from ukl by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1lWGN2-0002a2-FD; Tue, 13 Apr 2021 12:34:12 +0200 Date: Tue, 13 Apr 2021 12:34:12 +0200 From: Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= To: Clemens Gruber Cc: linux-pwm@vger.kernel.org, Thierry Reding , Sven Van Asbroeck , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v8 6/8] pwm: pca9685: Support new PWM_USAGE_POWER flag Message-ID: <20210413103412.ngvtk5cw2ftyjvob@pengutronix.de> References: <20210412132745.76609-1-clemens.gruber@pqgruber.com> <20210412132745.76609-6-clemens.gruber@pqgruber.com> <20210412163045.apgnac7atgpboths@pengutronix.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="5yi73bsuwgixsqmt" Content-Disposition: inline In-Reply-To: X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --5yi73bsuwgixsqmt Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Clemens, On Mon, Apr 12, 2021 at 07:11:58PM +0200, Clemens Gruber wrote: > On Mon, Apr 12, 2021 at 06:30:45PM +0200, Uwe Kleine-K=F6nig wrote: > > On Mon, Apr 12, 2021 at 03:27:43PM +0200, Clemens Gruber wrote: > > > static unsigned int pca9685_pwm_get_duty(struct pca9685 *pca, int ch= annel) > > > { > > > - unsigned int off_h =3D 0, val =3D 0; > > > + struct pwm_device *pwm =3D &pca->chip.pwms[channel]; > > > + unsigned int off =3D 0, on =3D 0, val =3D 0; > > > =20 > > > if (WARN_ON(channel >=3D PCA9685_MAXCHAN)) { > > > /* HW does not support reading state of "all LEDs" channel */ > > > return 0; > > > } > > > =20 > > > - regmap_read(pca->regmap, LED_N_OFF_H(channel), &off_h); > > > - if (off_h & LED_FULL) { > > > + regmap_read(pca->regmap, LED_N_OFF_H(channel), &off); > > > + if (off & LED_FULL) { > > > /* Full OFF bit is set */ > > > return 0; > > > } > > > =20 > > > - regmap_read(pca->regmap, LED_N_ON_H(channel), &val); > > > - if (val & LED_FULL) { > > > + regmap_read(pca->regmap, LED_N_ON_H(channel), &on); > > > + if (on & LED_FULL) { > > > /* Full ON bit is set */ > > > return PCA9685_COUNTER_RANGE; > > > } > > > =20 > > > - val =3D 0; > > > regmap_read(pca->regmap, LED_N_OFF_L(channel), &val); > > > - return ((off_h & 0xf) << 8) | (val & 0xff); > > > + off =3D ((off & 0xf) << 8) | (val & 0xff); > > > + if (!pwm->args.usage_power) > > > + return off; > > > + > > > + /* Read ON register to calculate duty cycle of staggered output */ > > > + val =3D 0; > > > + regmap_read(pca->regmap, LED_N_ON_L(channel), &val); > > > + on =3D ((on & 0xf) << 8) | (val & 0xff); > > > + return (off - on) & (PCA9685_COUNTER_RANGE - 1); > >=20 > > If LED_N_ON is !=3D 0 but usage_power is false, the returned state is > > bogus. >=20 > If usage_power is false, LED_N_ON is guaranteed to be 0. It is reset to > 0 in probe and never changed. Or did I miss something? Ah right, so my concern is only a challenge once the reset in probe goes away. > > > } > > > =20 > > > #if IS_ENABLED(CONFIG_GPIOLIB) > > > @@ -439,9 +469,11 @@ static int pca9685_pwm_probe(struct i2c_client *= client, > > > reg &=3D ~(MODE1_ALLCALL | MODE1_SUB1 | MODE1_SUB2 | MODE1_SUB3); > > > regmap_write(pca->regmap, PCA9685_MODE1, reg); > > > =20 > > > - /* Reset OFF registers to POR default */ > > > + /* Reset OFF/ON registers to POR default */ > > > regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, LED_FULL); > > > regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, LED_FULL); > > > + regmap_write(pca->regmap, PCA9685_ALL_LED_ON_L, 0); > > > + regmap_write(pca->regmap, PCA9685_ALL_LED_ON_H, 0); > > > =20 > > > pca->chip.ops =3D &pca9685_pwm_ops; > > > /* Add an extra channel for ALL_LED */ > > > @@ -450,6 +482,9 @@ static int pca9685_pwm_probe(struct i2c_client *c= lient, > > > pca->chip.dev =3D &client->dev; > > > pca->chip.base =3D -1; > > > =20 > > > + pca->chip.of_xlate =3D of_pwm_xlate_with_flags; > > > + pca->chip.of_pwm_n_cells =3D 3; > > > + > >=20 > > Huh, you're incompatibly changing the device tree binding here. >=20 > No, I don't think so: >=20 > The third cell is optional with of_pwm_xlate_with_flags. > So previous DTs with pwm-cells =3D <2> will still work. I thought that .of_pwm_n_cells was enforced, let me check the code ... I had in mind that of_pwm_get() enforced that, but I cannot find it, so I guess you're right and my concern is unjustified. Best regards Uwe --=20 Pengutronix e.K. | Uwe Kleine-K=F6nig | Industrial Linux Solutions | https://www.pengutronix.de/ | --5yi73bsuwgixsqmt Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEfnIqFpAYrP8+dKQLwfwUeK3K7AkFAmB1c6AACgkQwfwUeK3K 7AklQQgAmLXZlUmBHqlmxp/futrTOuHVljzfFpomRmDqlZuObEjkJP81nV8mExNu DBAxVX1Th6DSWddMWZzkEUzVrqGo3xe9EDM1GhSRufq3Eh+PpIQfBEi4j1EiRjW0 uq6Gz0e58FtVAGbcwQl/xEPTBDNdYtPQ3cPcNQ0btvlFGPnyALVaD1TzIajpxoOQ 6sa4XqoXweKu+HNdD3l/VmnT9S7odmJw7BMgnJ8EMtGJVW4T/w9UvKFh6ZcJzskQ cAgv6qMUmEEjKd1bKZeIPui3OPAxVn7lwf9AVpem/U9iTikpuCpmPI7fbHp3jWw9 5TUqU7sLjtkRr9qJr/VkCHNG2Wodeg== =KDCe -----END PGP SIGNATURE----- --5yi73bsuwgixsqmt--