From patchwork Tue Apr 23 07:36:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Raag Jadav X-Patchwork-Id: 1089110 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-i2c-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="Z0jSuOww"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44pFfl6Rczz9sNf for ; Tue, 23 Apr 2019 17:38:07 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725990AbfDWHiG (ORCPT ); Tue, 23 Apr 2019 03:38:06 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:35955 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725939AbfDWHiG (ORCPT ); Tue, 23 Apr 2019 03:38:06 -0400 Received: by mail-pf1-f193.google.com with SMTP id z5so7034200pfn.3; Tue, 23 Apr 2019 00:38:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=RxFYCJET9zHUcOpjZ9bK7uMOuTUHPRpqiuEPuAi6Gtw=; b=Z0jSuOwwX6CFicJKldwZoTo3ZmYf1Xq5y9XX+JTNi1/r0ynpw2oqhP9K2VKQjxJz+p GbBOSoCne+u1WRAw2ID3l48V26UcB4jIJ1j6qBo4cqSwNExQfI4u3q7wBqay8lCxWm+4 Ui8fxxAMs+GW4OdS7YGM5exYAwczGQzOFo83iSURpe+bqWvtmRN1jhC9y9ZgrJoqQxJy RCm9EGGpSrkz0JVM5+5oCu/BqmrIC25WByjyCo/Vb9HBaE1RI6junCh4M2DpLvPUd/Km VKi6LDJBUfLFOpQhufhVJ843f1vMIHFcZVBZByRRE2cOSXIYr41V/s5DNeAjAJyHx8xl 5JZw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=RxFYCJET9zHUcOpjZ9bK7uMOuTUHPRpqiuEPuAi6Gtw=; b=SRUNUTLHGcjVq6Cw7Sy0VEoIG6n59DuOD8ptKrkCylj/KcRbUhnxQw6Uqn2qdcYDRI NJUYeW349pia8B5vYHhARVb0+gvPgNs9IOH6CWBWJ5L7LuLl4WaPiNX8l/dv6rkhATSK R7/IyXmF7ypzYB3Viin7M1RVcR83V2mlacbxhLAcoJH/3r9AcFtRzD9n0ires4qT4h/V dQxRBukzMR2gskfEyIyqvRL1OrvQWkjWtplv1X1+mVIU98/wuJlf6vOupI17HtKv+Dxz 7o/qZgWsOIdKZx2XvrmmBqbeO2PbZIbA48jifaK6CBcqKTH8hS1eAcVO2IBKXdl90SSz qL1A== X-Gm-Message-State: APjAAAXsH5byiq9NiMk7V3NOWkdUGZvs6f6Hn/8DVeDU9/tYtpLmJsrt En7OAZTR7kBoyIPeRlBpFH949oGALUM= X-Google-Smtp-Source: APXvYqxnz3kkhBSsB7V7qIRsA9Pk5nBHcRVpjVStC9T1ow+buVdCOiyRAH3sROKewjUe6EITFOZfVw== X-Received: by 2002:a62:4d43:: with SMTP id a64mr25026195pfb.174.1556005085025; Tue, 23 Apr 2019 00:38:05 -0700 (PDT) Received: from localhost.localdomain ([219.91.196.67]) by smtp.googlemail.com with ESMTPSA id o81sm26360447pfa.156.2019.04.23.00.38.00 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 23 Apr 2019 00:38:04 -0700 (PDT) From: Raag Jadav To: linux-i2c@vger.kernel.org Cc: ludovic.desroches@microchip.com, nicolas.ferre@microchip.com, alexandre.belloni@bootlin.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Raag Jadav Subject: [PATCH] i2c: at91: handle TXRDY interrupt spam Date: Tue, 23 Apr 2019 13:06:48 +0530 Message-Id: <1556005008-6318-1-git-send-email-raagjadav@gmail.com> X-Mailer: git-send-email 2.7.4 Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Performing i2c write operation while SDA or SCL line is held or grounded by slave device, we go into infinite at91_twi_write_next_byte loop with TXRDY interrupt spam. Signed-off-by: Raag Jadav --- drivers/i2c/busses/i2c-at91.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c index 3f3e8b3..b2f5fdb 100644 --- a/drivers/i2c/busses/i2c-at91.c +++ b/drivers/i2c/busses/i2c-at91.c @@ -72,6 +72,7 @@ #define AT91_TWI_TXCOMP BIT(0) /* Transmission Complete */ #define AT91_TWI_RXRDY BIT(1) /* Receive Holding Register Ready */ #define AT91_TWI_TXRDY BIT(2) /* Transmit Holding Register Ready */ +#define AT91_TWI_SVREAD BIT(3) /* Slave Read */ #define AT91_TWI_OVRE BIT(6) /* Overrun Error */ #define AT91_TWI_UNRE BIT(7) /* Underrun Error */ #define AT91_TWI_NACK BIT(8) /* Not Acknowledged */ @@ -571,7 +572,10 @@ static irqreturn_t atmel_twi_interrupt(int irq, void *dev_id) at91_disable_twi_interrupts(dev); complete(&dev->cmd_complete); } else if (irqstatus & AT91_TWI_TXRDY) { - at91_twi_write_next_byte(dev); + if ((status & AT91_TWI_SVREAD) && (dev->buf_len == 0)) + at91_twi_write(dev, AT91_TWI_IDR, AT91_TWI_TXRDY); + else + at91_twi_write_next_byte(dev); } /* catch error flags */