From patchwork Thu Sep 3 10:51:03 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 251668 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=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS 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 CECBFC433E9 for ; Thu, 3 Sep 2020 10:52:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 95EF2207EA for ; Thu, 3 Sep 2020 10:52:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gsw9799j" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728354AbgICKwc (ORCPT ); Thu, 3 Sep 2020 06:52:32 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:58851 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728331AbgICKv4 (ORCPT ); Thu, 3 Sep 2020 06:51:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599130304; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=hVk4/afJyWb9pRR5r2+53kQrVqN8NW1p5YVuK1f/Xj0=; b=gsw9799jYx3RRNmwN7fMHLspS91uJ250sSRrjQ0cQ4bbKqp1a8arxoc2TTNSIfZcfstU8f FqF/tviK6Ga5pDwQJW3Q5mDCapImtzUrAK+zOnUdp5tFiz2FwFnNhRNc6R7HS8H0v0nI5q K1SA0bpIRwD+GlKS56irELPONTeQDUI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-488-2Rz00j7dMPaimYbtNsUGlw-1; Thu, 03 Sep 2020 06:51:41 -0400 X-MC-Unique: 2Rz00j7dMPaimYbtNsUGlw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3B9301091062; Thu, 3 Sep 2020 10:51:39 +0000 (UTC) Received: from x1.localdomain.com (ovpn-115-4.ams2.redhat.com [10.36.115.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 858D6784A8; Thu, 3 Sep 2020 10:51:36 +0000 (UTC) From: Hans de Goede To: Thierry Reding , =?utf-8?q?Uwe_Kleine-K?= =?utf-8?b?w7ZuaWc=?= , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , =?utf-8?b?VmlsbGUgU3lyasOkbMOk?= , "Rafael J . Wysocki" , Len Brown Cc: Hans de Goede , linux-pwm@vger.kernel.org, intel-gfx , dri-devel@lists.freedesktop.org, Andy Shevchenko , Mika Westerberg , linux-acpi@vger.kernel.org Subject: [PATCH v9 06/17] pwm: lpss: Make pwm_lpss_apply() not rely on existing hardware state Date: Thu, 3 Sep 2020 12:51:03 +0200 Message-Id: <20200903105114.9969-7-hdegoede@redhat.com> In-Reply-To: <20200903105114.9969-1-hdegoede@redhat.com> References: <20200903105114.9969-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Before this commit pwm_lpss_apply() was making 2 assuming 2 pre-conditions were met by the existing hardware state: 1. That the base-unit and on-time-div read back from the control register are those actually in use, so that it can skip setting the update bit if the read-back value matches the desired values. 2. That the controller is enabled when the cached pwm_state.enabled says that the controller is enabled. As the long history of fixes for subtle (often suspend/resume) lpss-pwm issues shows, this assumptions are not necessary always true. 1. Specifically is not true on some (*) Cherry Trail devices with a nasty GFX0._PS3 method which: a. saves the ctrl reg value. b. sets the base-unit to 0 and writes the update bit to apply/commit c. restores the original ctrl value without setting the update bit, so that the 0 base-unit value is still in use. 2. Assumption 2. currently is true, but only because of the code which saves/restores the state on suspend/resume. By convention restoring the PWM state should be done by the PWM consumer and the presence of this code in the pmw-lpss driver is a bug. Therefor the save/restore code will be dropped in the next patch in this series, after which this assumption also is no longer true. This commit changes the pwm_lpss_apply() to make any assumptions about the state the hardware is in. Instead it makes pwm_lpss_apply() always fully program the PWM controller, making it much less fragile. *) Seen on the Acer One 10 S1003, Lenovo Ideapad Miix 310 and 320 models and various Medion models. Signed-off-by: Hans de Goede --- drivers/pwm/pwm-lpss.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c index 8a136ba2a583..9c5c7217c9b6 100644 --- a/drivers/pwm/pwm-lpss.c +++ b/drivers/pwm/pwm-lpss.c @@ -85,7 +85,7 @@ static void pwm_lpss_prepare(struct pwm_lpss_chip *lpwm, struct pwm_device *pwm, unsigned long long on_time_div; unsigned long c = lpwm->info->clk_rate, base_unit_range; unsigned long long base_unit, freq = NSEC_PER_SEC; - u32 orig_ctrl, ctrl; + u32 ctrl; do_div(freq, period_ns); @@ -104,16 +104,14 @@ static void pwm_lpss_prepare(struct pwm_lpss_chip *lpwm, struct pwm_device *pwm, do_div(on_time_div, period_ns); on_time_div = 255ULL - on_time_div; - orig_ctrl = ctrl = pwm_lpss_read(pwm); + ctrl = pwm_lpss_read(pwm); ctrl &= ~PWM_ON_TIME_DIV_MASK; ctrl &= ~((base_unit_range - 1) << PWM_BASE_UNIT_SHIFT); ctrl |= (u32) base_unit << PWM_BASE_UNIT_SHIFT; ctrl |= on_time_div; - if (orig_ctrl != ctrl) { - pwm_lpss_write(pwm, ctrl); - pwm_lpss_write(pwm, ctrl | PWM_SW_UPDATE); - } + pwm_lpss_write(pwm, ctrl); + pwm_lpss_write(pwm, ctrl | PWM_SW_UPDATE); } static inline void pwm_lpss_cond_enable(struct pwm_device *pwm, bool cond) @@ -124,8 +122,7 @@ static inline void pwm_lpss_cond_enable(struct pwm_device *pwm, bool cond) static int pwm_lpss_prepare_enable(struct pwm_lpss_chip *lpwm, struct pwm_device *pwm, - const struct pwm_state *state, - bool enable) + const struct pwm_state *state) { int ret; @@ -134,12 +131,12 @@ static int pwm_lpss_prepare_enable(struct pwm_lpss_chip *lpwm, return ret; pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period); - pwm_lpss_cond_enable(pwm, enable && lpwm->info->bypass == false); + pwm_lpss_cond_enable(pwm, lpwm->info->bypass == false); ret = pwm_lpss_wait_for_update(pwm); if (ret) return ret; - pwm_lpss_cond_enable(pwm, enable && lpwm->info->bypass == true); + pwm_lpss_cond_enable(pwm, lpwm->info->bypass == true); return 0; } @@ -152,11 +149,11 @@ static int pwm_lpss_apply(struct pwm_chip *chip, struct pwm_device *pwm, if (state->enabled) { if (!pwm_is_enabled(pwm)) { pm_runtime_get_sync(chip->dev); - ret = pwm_lpss_prepare_enable(lpwm, pwm, state, true); + ret = pwm_lpss_prepare_enable(lpwm, pwm, state); if (ret) pm_runtime_put(chip->dev); } else { - ret = pwm_lpss_prepare_enable(lpwm, pwm, state, false); + ret = pwm_lpss_prepare_enable(lpwm, pwm, state); } } else if (pwm_is_enabled(pwm)) { pwm_lpss_write(pwm, pwm_lpss_read(pwm) & ~PWM_ENABLE);