From patchwork Mon Aug 24 12:01:19 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: 11732999 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BED8114F6 for ; Mon, 24 Aug 2020 12:02:12 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9C822207D3 for ; Mon, 24 Aug 2020 12:02:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Cq54sehp" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9C822207D3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 068EB6E25A; Mon, 24 Aug 2020 12:02:12 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from us-smtp-delivery-1.mimecast.com (us-smtp-1.mimecast.com [207.211.31.81]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4C5CF6E25A for ; Mon, 24 Aug 2020 12:02:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598270529; 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=X/u2P3rm/Mt8sbxumEdSG8Sz04qHhuY60Fsw4/vcSuw=; b=Cq54sehpaEj9R7cYpdQ9eU/VH++qOU0nTWTTm15TFGFfFr0HivQtBYukxEQzBPlpDVQ1hD TJuYmpuDzhrswRJzw87TbjK1GCJQyV9jSkrA+hUe8QDulCg+mQLoWP1Xe43EZJg8V8+OaA GFKw9/koN49+rhl9MnNYjSuZ9c7gfTI= 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-239-oI_do7AkPrKD7RLO3zNc-A-1; Mon, 24 Aug 2020 08:02:07 -0400 X-MC-Unique: oI_do7AkPrKD7RLO3zNc-A-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4163A1005E6E; Mon, 24 Aug 2020 12:02:05 +0000 (UTC) Received: from x1.localdomain.com (ovpn-113-147.ams2.redhat.com [10.36.113.147]) by smtp.corp.redhat.com (Postfix) with ESMTP id 423F45D9DD; Mon, 24 Aug 2020 12:02:02 +0000 (UTC) From: Hans de Goede To: Thierry Reding , =?utf-8?q?Uwe_Kleine-K=C3=B6n?= =?utf-8?q?ig?= , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , =?utf-8?b?VmlsbGUgU3lyasOkbMOk?= , "Rafael J . Wysocki" , Len Brown Date: Mon, 24 Aug 2020 14:01:19 +0200 Message-Id: <20200824120126.7116-10-hdegoede@redhat.com> In-Reply-To: <20200824120126.7116-1-hdegoede@redhat.com> References: <20200824120126.7116-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Subject: [Intel-gfx] [PATCH v6 09/16] pwm: crc: Fix period changes not having any effect X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-pwm@vger.kernel.org, linux-acpi@vger.kernel.org, intel-gfx , dri-devel@lists.freedesktop.org, Andy Shevchenko , Mika Westerberg Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" The pwm-crc code is using 2 different enable bits: 1. bit 7 of the PWM0_CLK_DIV (PWM_OUTPUT_ENABLE) 2. bit 0 of the BACKLIGHT_EN register The BACKLIGHT_EN register at address 0x51 really controls a separate output-only GPIO which is earmarked to be used as output connected to the backlight-enable pin for LCD panels, this GPO is part of the PMIC's "Display Panel Control Block." . This pin should probably be moved over to a GPIO provider driver (and consumers modified accordingly), but that is something for an(other) patch. Enabling / disabling the actual PWM output is controlled by the PWM_OUTPUT_ENABLE bit of the PWM0_CLK_DIV register. As the comment in the old code already indicates we must disable the PWM before we can change the clock divider. But the crc_pwm_disable() and crc_pwm_enable() calls the old code make for this only change the BACKLIGHT_EN register; and the value of that register does not matter for changing the period / the divider. What does matter is that the PWM_OUTPUT_ENABLE bit must be cleared before a new value can be written. This commit modifies crc_pwm_config() to clear PWM_OUTPUT_ENABLE instead when changing the period, so that period changes actually work. Note this fix will cause a significant behavior change on some devices using the CRC PWM output to drive their backlight. Before the PWM would always run with the output frequency configured by the BIOS at boot, now the period time specified by the i915 driver will actually be honored. Reviewed-by: Andy Shevchenko Signed-off-by: Hans de Goede --- drivers/pwm/pwm-crc.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/drivers/pwm/pwm-crc.c b/drivers/pwm/pwm-crc.c index 44ec7d5b63e1..81232da0c767 100644 --- a/drivers/pwm/pwm-crc.c +++ b/drivers/pwm/pwm-crc.c @@ -82,14 +82,11 @@ static int crc_pwm_config(struct pwm_chip *c, struct pwm_device *pwm, if (pwm_get_period(pwm) != period_ns) { int clk_div = crc_pwm_calc_clk_div(period_ns); - /* changing the clk divisor, need to disable fisrt */ - crc_pwm_disable(c, pwm); + /* changing the clk divisor, clear PWM_OUTPUT_ENABLE first */ + regmap_write(crc_pwm->regmap, PWM0_CLK_DIV, 0); regmap_write(crc_pwm->regmap, PWM0_CLK_DIV, clk_div | PWM_OUTPUT_ENABLE); - - /* enable back */ - crc_pwm_enable(c, pwm); } /* change the pwm duty cycle */