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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 6E1F0C47091 for ; Mon, 10 May 2021 11:20:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3AF6C6108B for ; Mon, 10 May 2021 11:20:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237885AbhEJLQY (ORCPT ); Mon, 10 May 2021 07:16:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:45210 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233080AbhEJKvg (ORCPT ); Mon, 10 May 2021 06:51:36 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E3D156196A; Mon, 10 May 2021 10:40:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620643239; bh=hnhUQG8hywRvEAsV0Rzwy6G3+gLrcQvD1aVufN/pTm4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gCBnEv25W7r5hvB0DCFZ9kI60GunGvyMuGyQc+PDMf6XD92HZxcaziDLz+IstHSpb bZQGn1x+O8LRgqSqPeLsYulu1/z2702YfQRdqwVAny3QEEebETQ736gH9lHglLSx2X Wc/OwdnWuQueLiqMTPYhvUOQpA/1hcuNRAJDSLUg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hubert Streidl , Mark Jonas , Wolfram Sang , Lee Jones , Sasha Levin Subject: [PATCH 5.10 200/299] mfd: da9063: Support SMBus and I2C mode Date: Mon, 10 May 2021 12:19:57 +0200 Message-Id: <20210510102011.549828819@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210510102004.821838356@linuxfoundation.org> References: <20210510102004.821838356@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hubert Streidl [ Upstream commit 586478bfc9f7e16504d6f64cf18bcbdf6fd0cbc9 ] By default the PMIC DA9063 2-wire interface is SMBus compliant. This means the PMIC will automatically reset the interface when the clock signal ceases for more than the SMBus timeout of 35 ms. If the I2C driver / device is not capable of creating atomic I2C transactions, a context change can cause a ceasing of the clock signal. This can happen if for example a real-time thread is scheduled. Then the DA9063 in SMBus mode will reset the 2-wire interface. Subsequently a write message could end up in the wrong register. This could cause unpredictable system behavior. The DA9063 PMIC also supports an I2C compliant mode for the 2-wire interface. This mode does not reset the interface when the clock signal ceases. Thus the problem depicted above does not occur. This patch tests for the bus functionality "I2C_FUNC_I2C". It can reasonably be assumed that the bus cannot obey SMBus timings if this functionality is set. SMBus commands most probably are emulated in this case which is prone to the latency issue described above. This patch enables the I2C bus mode if I2C_FUNC_I2C is set or otherwise keeps the default SMBus mode. Signed-off-by: Hubert Streidl Signed-off-by: Mark Jonas Reviewed-by: Wolfram Sang Signed-off-by: Lee Jones Signed-off-by: Sasha Levin --- drivers/mfd/da9063-i2c.c | 10 ++++++++++ include/linux/mfd/da9063/registers.h | 3 +++ 2 files changed, 13 insertions(+) diff --git a/drivers/mfd/da9063-i2c.c b/drivers/mfd/da9063-i2c.c index b8217ad303ce..3419814d016b 100644 --- a/drivers/mfd/da9063-i2c.c +++ b/drivers/mfd/da9063-i2c.c @@ -442,6 +442,16 @@ static int da9063_i2c_probe(struct i2c_client *i2c, return ret; } + /* If SMBus is not available and only I2C is possible, enter I2C mode */ + if (i2c_check_functionality(i2c->adapter, I2C_FUNC_I2C)) { + ret = regmap_clear_bits(da9063->regmap, DA9063_REG_CONFIG_J, + DA9063_TWOWIRE_TO); + if (ret < 0) { + dev_err(da9063->dev, "Failed to set Two-Wire Bus Mode.\n"); + return -EIO; + } + } + return da9063_device_init(da9063, i2c->irq); } diff --git a/include/linux/mfd/da9063/registers.h b/include/linux/mfd/da9063/registers.h index 1dbabf1b3cb8..6e0f66a2e727 100644 --- a/include/linux/mfd/da9063/registers.h +++ b/include/linux/mfd/da9063/registers.h @@ -1037,6 +1037,9 @@ #define DA9063_NONKEY_PIN_AUTODOWN 0x02 #define DA9063_NONKEY_PIN_AUTOFLPRT 0x03 +/* DA9063_REG_CONFIG_J (addr=0x10F) */ +#define DA9063_TWOWIRE_TO 0x40 + /* DA9063_REG_MON_REG_5 (addr=0x116) */ #define DA9063_MON_A8_IDX_MASK 0x07 #define DA9063_MON_A8_IDX_NONE 0x00 -- 2.30.2