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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26560C4332F for ; Wed, 19 Oct 2022 09:31:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232141AbiJSJbu (ORCPT ); Wed, 19 Oct 2022 05:31:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233853AbiJSJ3j (ORCPT ); Wed, 19 Oct 2022 05:29:39 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F291DC58B2; Wed, 19 Oct 2022 02:13:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 18F2C61828; Wed, 19 Oct 2022 09:04:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 286F3C433D7; Wed, 19 Oct 2022 09:04:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666170272; bh=j+D3BSRw6K3WPL1upC13NhG7/06VKOHGGwiFpM2s2cY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iI4d7Z0psptg7GsWobXlDuAr0eIxIPW3VBCIfnLmiJIU7zyUZxjEKTCcebzq/y8/e alIKvO4+O91BXJo8Vn+93ZOZZ2xQgFYnfGXIiSQb3HQepbIsniS7+k0fMBIFL2abOt yfImzWYRZnBmApjQsb1gZOsZ+6Wy3VxSs3/hKMJk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Serge Semin , Luca Ceresoli , Stephen Boyd , Sasha Levin Subject: [PATCH 6.0 591/862] clk: vc5: Fix 5P49V6901 outputs disabling when enabling FOD Date: Wed, 19 Oct 2022 10:31:18 +0200 Message-Id: <20221019083316.087044841@linuxfoundation.org> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221019083249.951566199@linuxfoundation.org> References: <20221019083249.951566199@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Serge Semin [ Upstream commit c388cc804016cf0f65afdc2362b120aa594ff3e6 ] We have discovered random glitches during the system boot up procedure. The problem investigation led us to the weird outcomes: when none of the Renesas 5P49V6901 ports are explicitly enabled by the kernel driver, the glitches disappeared. It was a mystery since the SoC external clock domains were fed with different 5P49V6901 outputs. The driver code didn't seem like bogus either. We almost despaired to find out a root cause when the solution has been found for a more modern revision of the chip. It turned out the 5P49V6901 clock generator stopped its output for a short period of time during the VC5_OUT_DIV_CONTROL register writing. The same problem was found for the 5P49V6965 revision of the chip and was successfully fixed in commit fc336ae622df ("clk: vc5: fix output disabling when enabling a FOD") by enabling the "bypass_sync" flag hidden inside "Unused Factory Reserved Register". Even though the 5P49V6901 registers description and programming guide doesn't provide any intel regarding that flag, setting it up anyway in the officially unused register completely eliminated the denoted glitches. Thus let's activate the functionality submitted in commit fc336ae622df ("clk: vc5: fix output disabling when enabling a FOD") for the Renesas 5P49V6901 chip too in order to remove the ports implicit inter-dependency. Fixes: dbf6b16f5683 ("clk: vc5: Add support for IDT VersaClock 5P49V6901") Signed-off-by: Serge Semin Reviewed-by: Luca Ceresoli Link: https://lore.kernel.org/r/20220929225402.9696-2-Sergey.Semin@baikalelectronics.ru Signed-off-by: Stephen Boyd Signed-off-by: Sasha Levin --- drivers/clk/clk-versaclock5.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c index e7be3e54b9be..03cfef494b49 100644 --- a/drivers/clk/clk-versaclock5.c +++ b/drivers/clk/clk-versaclock5.c @@ -1204,7 +1204,7 @@ static const struct vc5_chip_info idt_5p49v6901_info = { .model = IDT_VC6_5P49V6901, .clk_fod_cnt = 4, .clk_out_cnt = 5, - .flags = VC5_HAS_PFD_FREQ_DBL, + .flags = VC5_HAS_PFD_FREQ_DBL | VC5_HAS_BYPASS_SYNC_BIT, }; static const struct vc5_chip_info idt_5p49v6965_info = { -- 2.35.1