From patchwork Mon Feb 11 22:57:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Lindgren X-Patchwork-Id: 10806931 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3C6C313B4 for ; Mon, 11 Feb 2019 22:57:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2C3992B426 for ; Mon, 11 Feb 2019 22:57:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1E0BC2B42D; Mon, 11 Feb 2019 22:57:32 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5EC402B426 for ; Mon, 11 Feb 2019 22:57:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727006AbfBKW5a (ORCPT ); Mon, 11 Feb 2019 17:57:30 -0500 Received: from muru.com ([72.249.23.125]:38134 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726847AbfBKW5a (ORCPT ); Mon, 11 Feb 2019 17:57:30 -0500 Received: from hillo.muru.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTP id 919A580BF; Mon, 11 Feb 2019 22:57:39 +0000 (UTC) From: Tony Lindgren To: Lee Jones Cc: linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, Florian Vaussard , Peter Ujfalusi Subject: [PATCH] mfd: twl6040: Fix device init errors for ACCCTL register Date: Mon, 11 Feb 2019 14:57:26 -0800 Message-Id: <20190211225726.38355-1-tony@atomide.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP I noticed that we can get a -EREMOTEIO errors on at least omap4 duovero: twl6040 0-004b: Failed to write 2d = 19: -121 And then any following register access will produce errors. There 2d offset above is register ACCCTL that gets written on twl6040 powerup. With error checking added to the related regcache_sync() call, the -EREMOTEIO error is reproducable on twl6040 powerup at least duovero. To fix the error, we need to wait until twl6040 is accessible after the powerup. Based on tests on omap4 duovero, we need to wait over 8ms after powerup before register write will complete without failures. Let's also make sure we warn about possible errors too. Note that we have twl6040_patch[] reg_sequence with the ACCCTL register configuration and regcache_sync() will write the new value to ACCCTL. Cc: Florian Vaussard Cc: Peter Ujfalusi Signed-off-by: Tony Lindgren Acked-by: Peter Ujfalusi --- drivers/mfd/twl6040.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c --- a/drivers/mfd/twl6040.c +++ b/drivers/mfd/twl6040.c @@ -322,8 +322,19 @@ int twl6040_power(struct twl6040 *twl6040, int on) } } + /* + * Register access can produce errors after power-up unless we + * wait at least 8ms based on measurements on duovero. + */ + usleep_range(10000, 12000); + /* Sync with the HW */ - regcache_sync(twl6040->regmap); + ret = regcache_sync(twl6040->regmap); + if (ret) { + dev_err(twl6040->dev, "%s register write failed: %i\n", + __func__, ret); + goto out; + } /* Default PLL configuration after power up */ twl6040->pll = TWL6040_SYSCLK_SEL_LPPLL;