From patchwork Sun Jan 7 13:26:40 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Elad Nachman X-Patchwork-Id: 760730 Received: from mx0b-0016f401.pphosted.com (mx0b-0016f401.pphosted.com [67.231.156.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C4FA3134A6; Sun, 7 Jan 2024 13:27:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=marvell.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.helo=mx0b-0016f401.pphosted.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=marvell.com header.i=@marvell.com header.b="aUhDk0R2" Received: from pps.filterd (m0045851.ppops.net [127.0.0.1]) by mx0b-0016f401.pphosted.com (8.17.1.24/8.17.1.24) with ESMTP id 407BilGH030201; Sun, 7 Jan 2024 05:26:54 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=marvell.com; h= from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding:content-type; s=pfpt0220; bh=iCK08Zkj oWf7LECKvJp5SwPU+2zBuCa9ZFYZl3njIGw=; b=aUhDk0R2FLZYyggQ56m+oF5B 7KK2NyqvKyKqCUWvK0DQLP0c4siGAHcLgbpdJ22i1R1Eq6sIfukyFc4wZ9P0+cTt +wyGpzxdCsvWRgdURpPn8OUrdLTt53JRT7qV5Lh+WbNQaFw5/LDCVNXlbeKGCPOy oHz83xXFN4OsaQWR2LvNDFvd4OrkpRRUSSLlalDr1oVo1u36LJKAF3x7TG2jL6JN kklIkf5kTkjoHrLndtPs6/hjXVljGZRNe9X6vqQA5ytxVjPC8dOh2C0sKsFwmTGG 98jt+G4zfQPWhXN6Mlb9fbACUg+1qA1vIWdH3mmUzG6+vXVslzPWjEk4+mm5Cg== Received: from dc5-exch02.marvell.com ([199.233.59.182]) by mx0b-0016f401.pphosted.com (PPS) with ESMTPS id 3vf78n23j6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Sun, 07 Jan 2024 05:26:54 -0800 (PST) Received: from DC5-EXCH02.marvell.com (10.69.176.39) by DC5-EXCH02.marvell.com (10.69.176.39) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Sun, 7 Jan 2024 05:26:45 -0800 Received: from maili.marvell.com (10.69.176.80) by DC5-EXCH02.marvell.com (10.69.176.39) with Microsoft SMTP Server id 15.0.1497.48 via Frontend Transport; Sun, 7 Jan 2024 05:26:45 -0800 Received: from dc3lp-swdev041.marvell.com (dc3lp-swdev041.marvell.com [10.6.60.191]) by maili.marvell.com (Postfix) with ESMTP id 291D13F709E; Sun, 7 Jan 2024 05:26:43 -0800 (PST) From: Elad Nachman To: , , , CC: , Subject: [PATCH v4 0/1] i2c: busses: i2c-mv64xxx: fix arb-loss i2c lock Date: Sun, 7 Jan 2024 15:26:40 +0200 Message-ID: <20240107132641.3418208-1-enachman@marvell.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-ORIG-GUID: WIN1z8JxW23Clht_kWxm5sSOrj-7DaUm X-Proofpoint-GUID: WIN1z8JxW23Clht_kWxm5sSOrj-7DaUm X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.997,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-12-09_02,2023-12-07_01,2023-05-22_02 From: Elad Nachman Some i2c slaves, mainly SFPs, might cause the bus to lose arbitration while slave is in the middle of responding. This means that the i2c slave has not finished the transmission, but the master has already finished toggling the clock, probably due to the slave missing some of the master's clocks. This was seen with Ubiquity SFP module. This is typically caused by slaves which do not adhere completely to the i2c standard. The solution is to change the I2C mode from mpps to gpios, and toggle the i2c_scl gpio to emulate bus clock toggling, so slave will finish its transmission, driven by the manual clock toggling, and will release the i2c bus. v4: 1) Move to dvm_pinctrl_get() and remove explicit put 2) Add devm_gpiod_get() in recovery info initialization v3: 1) Remove unused / un-initialized variable 2) Replace devm_pinctrl_get() with pinctrl_get() and pinctrl_put() pair in probe and device removal. 3) Replace atomic sleeps with usleep_range() 4) Rework comment to start with a capital letter v2: 1) Explain more about cause of issue in commit message 2) Change variable name to something clearer 3) Leave space between comments 4) Remove redundant blank line 5) Add error message if pinctrl get failed 6) Move gpio request to probe function 7) Fix commenting style 8) Explain in comments why 10 togglings are required 9) Move from mdelay to udelay, reducing delay time 10) Explain in comments what is the value written to the reset register. 11) Explain why fallthrough is required (generate stop condition) 12) Explain why in case of missing i2c arbitration loss details, driver probe will not fail, in order to be backward compatible with older dts files Elad Nachman (1): i2c: busses: i2c-mv64xxx: fix arb-loss i2c lock drivers/i2c/busses/i2c-mv64xxx.c | 108 +++++++++++++++++++++++++++++++ 1 file changed, 108 insertions(+)