From patchwork Thu Oct 24 20:12:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamel BOUHARA X-Patchwork-Id: 11210675 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 7EB63112C for ; Thu, 24 Oct 2019 20:15:15 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 5C33A20684 for ; Thu, 24 Oct 2019 20:15:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="UMYmBrv7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5C33A20684 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=CKIQwvMZm0Lh6GFlfdfeYZknXDI61lTkeNgoiqdjVjk=; b=UMYmBrv7DNfUr1 jgz5WF4uxqyMb17JDcKJ26rLwC7pnoVcFqr8Tq5NRXbkR0g0NOHDSl6Ae6UzS7lEM/+x+4PDQ6iKz 6fPVL1+PvN3ml20hwHnlMAUDS+3G3xkAQNGNgfWR6Edx3QEyfcmn6GzmqMqwGIOvMWrMB8mvwhksX JCq2bBPLZo3Oxvik2JnKO2C9716PzU0FdrduIc4EfqaYQhZVYLfg6I5BL/26oXwoUF0zHDBi9MHv0 4TslArlgMRgBGVtjZx2FDwgl+xcsYupsDa2D5gfrsrHzXwNdNk84jIbqYXpNqKGr1ID1E89zy34ht FyIOtaMV9jl6G+wwMhjw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iNjVp-000119-Jw; Thu, 24 Oct 2019 20:15:13 +0000 Received: from relay10.mail.gandi.net ([217.70.178.230]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iNjUF-0007LZ-G9 for linux-arm-kernel@lists.infradead.org; Thu, 24 Oct 2019 20:13:37 +0000 Received: from localhost (unknown [78.193.40.249]) (Authenticated sender: kamel.bouhara@bootlin.com) by relay10.mail.gandi.net (Postfix) with ESMTPSA id 7EF92240004; Thu, 24 Oct 2019 20:13:26 +0000 (UTC) From: Kamel Bouhara To: Wolfram Sang , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/5] i2c: at91: Send bus clear command if SCL or SDA is down Date: Thu, 24 Oct 2019 22:12:58 +0200 Message-Id: <20191024201302.23376-2-kamel.bouhara@bootlin.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191024201302.23376-1-kamel.bouhara@bootlin.com> References: <20191024201302.23376-1-kamel.bouhara@bootlin.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191024_131335_809671_3DB2FE23 X-CRM114-Status: GOOD ( 14.44 ) X-Spam-Score: -0.7 (/) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-0.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at https://www.dnswl.org/, low trust [217.70.178.230 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Alexandre Belloni , Ludovic Desroches , Rob Herring , Thomas Petazzoni , Codrin Ciubotariu , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org From: Codrin Ciubotariu After a transfer timeout, some faulty I2C slave devices might hold down the SCL or the SDA pins. We can generate a bus clear command, hoping that the slave might release the pins. Signed-off-by: Codrin Ciubotariu Acked-by: Ludovic Desroches --- drivers/i2c/busses/i2c-at91-core.c | 8 ++++++++ drivers/i2c/busses/i2c-at91-master.c | 22 ++++++++++++++++++++++ drivers/i2c/busses/i2c-at91.h | 7 ++++++- 3 files changed, 36 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c index 435c7d7377a3..cb07489e698f 100644 --- a/drivers/i2c/busses/i2c-at91-core.c +++ b/drivers/i2c/busses/i2c-at91-core.c @@ -68,6 +68,7 @@ static struct at91_twi_pdata at91rm9200_config = { .has_unre_flag = true, .has_alt_cmd = false, .has_hold_field = false, + .has_clear_cmd = false, }; static struct at91_twi_pdata at91sam9261_config = { @@ -76,6 +77,7 @@ static struct at91_twi_pdata at91sam9261_config = { .has_unre_flag = false, .has_alt_cmd = false, .has_hold_field = false, + .has_clear_cmd = false, }; static struct at91_twi_pdata at91sam9260_config = { @@ -84,6 +86,7 @@ static struct at91_twi_pdata at91sam9260_config = { .has_unre_flag = false, .has_alt_cmd = false, .has_hold_field = false, + .has_clear_cmd = false, }; static struct at91_twi_pdata at91sam9g20_config = { @@ -92,6 +95,7 @@ static struct at91_twi_pdata at91sam9g20_config = { .has_unre_flag = false, .has_alt_cmd = false, .has_hold_field = false, + .has_clear_cmd = false, }; static struct at91_twi_pdata at91sam9g10_config = { @@ -100,6 +104,7 @@ static struct at91_twi_pdata at91sam9g10_config = { .has_unre_flag = false, .has_alt_cmd = false, .has_hold_field = false, + .has_clear_cmd = false, }; static const struct platform_device_id at91_twi_devtypes[] = { @@ -130,6 +135,7 @@ static struct at91_twi_pdata at91sam9x5_config = { .has_unre_flag = false, .has_alt_cmd = false, .has_hold_field = false, + .has_clear_cmd = false, }; static struct at91_twi_pdata sama5d4_config = { @@ -138,6 +144,7 @@ static struct at91_twi_pdata sama5d4_config = { .has_unre_flag = false, .has_alt_cmd = false, .has_hold_field = true, + .has_clear_cmd = false, }; static struct at91_twi_pdata sama5d2_config = { @@ -146,6 +153,7 @@ static struct at91_twi_pdata sama5d2_config = { .has_unre_flag = true, .has_alt_cmd = true, .has_hold_field = true, + .has_clear_cmd = true, }; static const struct of_device_id atmel_twi_dt_ids[] = { diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c index a3fcc35ffd3b..12d4fa946a82 100644 --- a/drivers/i2c/busses/i2c-at91-master.c +++ b/drivers/i2c/busses/i2c-at91-master.c @@ -440,6 +440,7 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) unsigned long time_left; bool has_unre_flag = dev->pdata->has_unre_flag; bool has_alt_cmd = dev->pdata->has_alt_cmd; + bool has_clear_cmd = dev->pdata->has_clear_cmd; /* * WARNING: the TXCOMP bit in the Status Register is NOT a clear on @@ -599,6 +600,27 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_THRCLR | AT91_TWI_LOCKCLR); } + + /* + * After timeout, some faulty I2C slave devices might hold SCL/SDA down; + * we can send a bus clear command, hoping that the pins will be + * released + */ + if (has_clear_cmd && + (!(dev->transfer_status & AT91_TWI_SDA) || + !(dev->transfer_status & AT91_TWI_SCL))) { + dev_dbg(dev->dev, + "SDA/SCL are down; sending bus clear command\n"); + if (dev->use_alt_cmd) { + unsigned int acr; + + acr = at91_twi_read(dev, AT91_TWI_ACR); + acr &= ~AT91_TWI_ACR_DATAL_MASK; + at91_twi_write(dev, AT91_TWI_ACR, acr); + } + at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_CLEAR); + } + return ret; } diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h index 499b506f6128..0827c28a84db 100644 --- a/drivers/i2c/busses/i2c-at91.h +++ b/drivers/i2c/busses/i2c-at91.h @@ -36,6 +36,7 @@ #define AT91_TWI_SVDIS BIT(5) /* Slave Transfer Disable */ #define AT91_TWI_QUICK BIT(6) /* SMBus quick command */ #define AT91_TWI_SWRST BIT(7) /* Software Reset */ +#define AT91_TWI_CLEAR BIT(15) /* Bus clear command */ #define AT91_TWI_ACMEN BIT(16) /* Alternative Command Mode Enable */ #define AT91_TWI_ACMDIS BIT(17) /* Alternative Command Mode Disable */ #define AT91_TWI_THRCLR BIT(24) /* Transmit Holding Register Clear */ @@ -69,6 +70,8 @@ #define AT91_TWI_NACK BIT(8) /* Not Acknowledged */ #define AT91_TWI_EOSACC BIT(11) /* End Of Slave Access */ #define AT91_TWI_LOCK BIT(23) /* TWI Lock due to Frame Errors */ +#define AT91_TWI_SCL BIT(24) /* TWI SCL status */ +#define AT91_TWI_SDA BIT(25) /* TWI SDA status */ #define AT91_TWI_INT_MASK \ (AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY | AT91_TWI_NACK \ @@ -81,7 +84,8 @@ #define AT91_TWI_THR 0x0034 /* Transmit Holding Register */ #define AT91_TWI_ACR 0x0040 /* Alternative Command Register */ -#define AT91_TWI_ACR_DATAL(len) ((len) & 0xff) +#define AT91_TWI_ACR_DATAL_MASK GENMASK(15, 0) +#define AT91_TWI_ACR_DATAL(len) ((len) & AT91_TWI_ACR_DATAL_MASK) #define AT91_TWI_ACR_DIR BIT(8) #define AT91_TWI_FMR 0x0050 /* FIFO Mode Register */ @@ -108,6 +112,7 @@ struct at91_twi_pdata { bool has_unre_flag; bool has_alt_cmd; bool has_hold_field; + bool has_clear_cmd; struct at_dma_slave dma_slave; };