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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=ham 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 462BCC43381 for ; Tue, 12 Jan 2021 09:19:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C2B122D58 for ; Tue, 12 Jan 2021 09:19:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392565AbhALJTb (ORCPT ); Tue, 12 Jan 2021 04:19:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731326AbhALJT3 (ORCPT ); Tue, 12 Jan 2021 04:19:29 -0500 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 4414FC061786 for ; Tue, 12 Jan 2021 01:18:49 -0800 (PST) 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 1kzFp7-0000pF-8e; Tue, 12 Jan 2021 10:18:45 +0100 Received: from ukl by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1kzFp4-0006Im-L6; Tue, 12 Jan 2021 10:18:42 +0100 Date: Tue, 12 Jan 2021 10:18:42 +0100 From: Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= To: Nicolas Saenz Julienne Cc: linux-kernel@vger.kernel.org, Thierry Reding , Lee Jones , f.fainelli@gmail.com, linux-pwm@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, wahrenst@gmx.net, linux-input@vger.kernel.org, dmitry.torokhov@gmail.com, gregkh@linuxfoundation.org, devel@driverdev.osuosl.org, p.zabel@pengutronix.de, linux-gpio@vger.kernel.org, linus.walleij@linaro.org, linux-clk@vger.kernel.org, sboyd@kernel.org, linux-rpi-kernel@lists.infradead.org, bgolaszewski@baylibre.com, andy.shevchenko@gmail.com Subject: Re: [PATCH v6 11/11] pwm: Add Raspberry Pi Firmware based PWM bus Message-ID: <20210112091842.3th64ardbqjafvuq@pengutronix.de> References: <20201211164801.7838-1-nsaenzjulienne@suse.de> <20201211164801.7838-12-nsaenzjulienne@suse.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="r23z722cpflr6wgz" Content-Disposition: inline In-Reply-To: <20201211164801.7838-12-nsaenzjulienne@suse.de> 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 --r23z722cpflr6wgz Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello Nicolas, On Fri, Dec 11, 2020 at 05:48:00PM +0100, Nicolas Saenz Julienne wrote: > diff --git a/drivers/pwm/pwm-raspberrypi-poe.c b/drivers/pwm/pwm-raspberr= ypi-poe.c > new file mode 100644 > index 000000000000..24b498839fcc > --- /dev/null > +++ b/drivers/pwm/pwm-raspberrypi-poe.c > @@ -0,0 +1,216 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright 2020 Nicolas Saenz Julienne > + * For more information on Raspberry Pi's PoE hat see: > + * https://www.raspberrypi.org/products/poe-hat/ > + * > + * Limitations: > + * - No disable bit, so a disabled PWM is simulated by duty_cycle 0 > + * - Only normal polarity > + * - Fixed 12.5 kHz period > + * > + * The current period is completed when HW is reconfigured. > + */ > + > +#include > +#include > +#include > +#include > + > +#include > +#include > + > +#define RPI_PWM_MAX_DUTY 255 > +#define RPI_PWM_PERIOD_NS 80000 /* 12.5 kHz */ > + > +#define RPI_PWM_CUR_DUTY_REG 0x0 > +#define RPI_PWM_DEF_DUTY_REG 0x1 > + > +struct raspberrypi_pwm { > + struct rpi_firmware *firmware; > + struct pwm_chip chip; > + unsigned int duty_cycle; > +}; > + > +struct raspberrypi_pwm_prop { > + __le32 reg; > + __le32 val; > + __le32 ret; > +} __packed; > + > +static inline struct raspberrypi_pwm *to_raspberrypi_pwm(struct pwm_chip= *chip) I'd like to see this function use the same prefix as the other functions. I suggest "raspberrypi_pwm_from_chip". > +{ > + return container_of(chip, struct raspberrypi_pwm, chip); > +} > + > +static int raspberrypi_pwm_set_property(struct rpi_firmware *firmware, > + u32 reg, u32 val) > +{ > + struct raspberrypi_pwm_prop msg =3D { > + .reg =3D cpu_to_le32(reg), > + .val =3D cpu_to_le32(val), > + }; > + int ret; > + > + ret =3D rpi_firmware_property(firmware, RPI_FIRMWARE_SET_POE_HAT_VAL, > + &msg, sizeof(msg)); > + if (ret) > + return ret; > + if (msg.ret) > + return -EIO; > + > + return 0; > +} > + > +static int raspberrypi_pwm_get_property(struct rpi_firmware *firmware, > + u32 reg, u32 *val) > +{ > + struct raspberrypi_pwm_prop msg =3D { > + .reg =3D reg > + }; > + int ret; > + > + ret =3D rpi_firmware_property(firmware, RPI_FIRMWARE_GET_POE_HAT_VAL, > + &msg, sizeof(msg)); > + if (ret) > + return ret; > + if (msg.ret) > + return -EIO; > + > + *val =3D le32_to_cpu(msg.val); > + > + return 0; > +} > + > +static void raspberrypi_pwm_get_state(struct pwm_chip *chip, > + struct pwm_device *pwm, > + struct pwm_state *state) > +{ > + struct raspberrypi_pwm *rpipwm =3D to_raspberrypi_pwm(chip); > + > + state->period =3D RPI_PWM_PERIOD_NS; > + state->duty_cycle =3D DIV_ROUND_CLOSEST(rpipwm->duty_cycle * RPI_PWM_PE= RIOD_NS, > + RPI_PWM_MAX_DUTY); Please round up here ... > + state->enabled =3D !!(rpipwm->duty_cycle); > + state->polarity =3D PWM_POLARITY_NORMAL; > +} > + > +static int raspberrypi_pwm_apply(struct pwm_chip *chip, struct pwm_devic= e *pwm, > + const struct pwm_state *state) > +{ > + struct raspberrypi_pwm *rpipwm =3D to_raspberrypi_pwm(chip); > + unsigned int duty_cycle; > + int ret; > + > + if (state->period < RPI_PWM_PERIOD_NS || > + state->polarity !=3D PWM_POLARITY_NORMAL) > + return -EINVAL; > + > + if (!state->enabled) > + duty_cycle =3D 0; > + else if (state->duty_cycle < RPI_PWM_PERIOD_NS) > + duty_cycle =3D DIV_ROUND_CLOSEST_ULL(state->duty_cycle *= RPI_PWM_MAX_DUTY, > + RPI_PWM_PERIOD_NS); =2E.. and round down here. Just to be sure: writing RPI_PWM_MAX_DUTY (i.e. 255) yields 100% duty cycle, right? > + else > + duty_cycle =3D RPI_PWM_MAX_DUTY; > + > + if (duty_cycle =3D=3D rpipwm->duty_cycle) > + return 0; > + > + ret =3D raspberrypi_pwm_set_property(rpipwm->firmware, RPI_PWM_CUR_DUTY= _REG, > + duty_cycle); > + if (ret) { > + dev_err(chip->dev, "Failed to set duty cycle: %d\n", ret); > + return ret; > + } > + > + /* > + * This sets the default duty cycle after resetting the board, we > + * updated it every time to mimic Raspberry Pi's downstream's driver > + * behaviour. > + */ > + ret =3D raspberrypi_pwm_set_property(rpipwm->firmware, RPI_PWM_DEF_DUTY= _REG, > + duty_cycle); > + if (ret) { > + dev_err(chip->dev, "Failed to set default duty cycle: %d\n", ret); > + return ret; > + } > + > + rpipwm->duty_cycle =3D duty_cycle; Please use tabs for indention. (The general hint is to use checkpatch which (I hope) tells you about problems like this.) > + > + return 0; > +} > + > +static const struct pwm_ops raspberrypi_pwm_ops =3D { > + .get_state =3D raspberrypi_pwm_get_state, > + .apply =3D raspberrypi_pwm_apply, > + .owner =3D THIS_MODULE, > +}; > + > +static int raspberrypi_pwm_probe(struct platform_device *pdev) > +{ > + struct device_node *firmware_node; > + struct device *dev =3D &pdev->dev; > + struct rpi_firmware *firmware; > + struct raspberrypi_pwm *rpipwm; > + int ret; > + > + firmware_node =3D of_get_parent(dev->of_node); > + if (!firmware_node) { > + dev_err(dev, "Missing firmware node\n"); > + return -ENOENT; > + } > + > + firmware =3D devm_rpi_firmware_get(&pdev->dev, firmware_node); > + of_node_put(firmware_node); > + if (!firmware) > + return -EPROBE_DEFER; Please use dev_err_probe to benefit from recording an error message in this case. > + rpipwm =3D devm_kzalloc(&pdev->dev, sizeof(*rpipwm), GFP_KERNEL); > + if (!rpipwm) > + return -ENOMEM; > + > + rpipwm->firmware =3D firmware; > + rpipwm->chip.dev =3D dev; > + rpipwm->chip.ops =3D &raspberrypi_pwm_ops; > + rpipwm->chip.base =3D -1; > + rpipwm->chip.npwm =3D RASPBERRYPI_FIRMWARE_PWM_NUM; > + > + platform_set_drvdata(pdev, rpipwm); > + > + ret =3D raspberrypi_pwm_get_property(rpipwm->firmware, RPI_PWM_CUR_DUTY= _REG, > + &rpipwm->duty_cycle); > + if (ret) { > + dev_err(dev, "Failed to get duty cycle: %d\n", ret); Please use %pe for the error codes (directly or still better by using dev_err_probe here, too). > + return ret; > + } > + > + return pwmchip_add(&rpipwm->chip); > +} > [...] Best regards Uwe --=20 Pengutronix e.K. | Uwe Kleine-K=F6nig | Industrial Linux Solutions | https://www.pengutronix.de/ | --r23z722cpflr6wgz Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEfnIqFpAYrP8+dKQLwfwUeK3K7AkFAl/9aW8ACgkQwfwUeK3K 7AkKmAf/X43HuzDS2E9bHa7KzzW9+7rOPBmL3wmZt/Ab01mgp1yRp2gC+qtv7BPT 0n138wPi5O+rOAxm/iC9Uc4Y1s0bpvndj05noMRAK2X+XLXxwWhLARqf63uCvxIr sa6Dl6PDQsOj9ucrNUJPWFNYkjm4YGLmKJQrqjr8lEyydl7j8S4e2IGryiMs+sSV nL9CkhaIA0cFiritdv3THxRfhxnzMLkcG2E3ePHA2eq91FuV1DHqfZpgYwSd0eDf w1egR/8M6Lup6AxF7B5IzSzaBf+XFZi5k5Wj0LuRXNSpUBcL7nv81l0e+A8+fCF5 ZmpW6QOoovobVNxANzKLcZ4hfKwybw== =J/5G -----END PGP SIGNATURE----- --r23z722cpflr6wgz--