From patchwork Wed Dec 18 00:16:18 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Prabhakar X-Patchwork-Id: 13912749 X-Patchwork-Delegate: geert@linux-m68k.org Received: from mail-wr1-f51.google.com (mail-wr1-f51.google.com [209.85.221.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C8AD81BDC3; Wed, 18 Dec 2024 00:16:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734481004; cv=none; b=ZCWFM2aQFR5Yxu6aFE/9Vyj/mbeuIjrNRRRl3S8ANbLzYQw3U+q4APG5jkeR1FTVoFffbQlgUjV3Khl9dWhoEqN/o8m8aATbvAjC70glp9XA4K9PxWiE/q1D41mqvXicip9McZ+9uHmPzZFib1lC0jXCl57XpOmQyRl6hbE6cso= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734481004; c=relaxed/simple; bh=DgiiOozTR2Ns2as9XxnYghQ5OWP1bjSFARR0iQ4+cOE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lJJCrcwG342Ln+rjvlPKvtg4DE181zvfaoG9ppfwMDYSlmT+iRFK3D0gbsLqSRoiHUK1xAmV+ZQDJikxBun3R+PrvDys4lwhyu6bxxG/EkL0fm+cyoxh54HEaOl3RNRKxFx/f7sECogOzdIuTRFkYQCt1Zc/KFfv5hoErees0Qs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=Rnlayz0T; arc=none smtp.client-ip=209.85.221.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Rnlayz0T" Received: by mail-wr1-f51.google.com with SMTP id ffacd0b85a97d-382610c7116so3041419f8f.0; Tue, 17 Dec 2024 16:16:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1734481001; x=1735085801; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=q5HWS+/1/yNx246kpN3OwCxUSSCvlzQsqFE+TbYgREo=; b=Rnlayz0T7JFnrQ2/lvw/uq4eR+Bn7FwqVn0/cp157Qj+cEwxi0T6GgaXQiTDOkGguK hVvsAZlXZGS2mMp0Y4j6GHf+JlJpnWqy4A5JD9lHV56tTmVMhhmwS3q39FtRWbayV+h9 UF+sxhPy/m+UQdcBehXcetYIowRNLyXGPxZE63TP0l86rMpamWDKpGAjY+5paAWRCH5C wT2dqBUo/OkAiVqoWcQe5o5Ih+iMEhga4TQsTvbUljAG71mrrWb+8CgE0ARC9DMRj3ci 4lKl03IjpdGaYTO+mLRj7HGEqeOc5+vW4JXiDO8Vzyi3xSkUQ46YsDl46Lqfg3OCyXvj E1Ug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1734481001; x=1735085801; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=q5HWS+/1/yNx246kpN3OwCxUSSCvlzQsqFE+TbYgREo=; b=NucE3kpGAFYovEc6dr09IapxHTv+VCpyRgvrbzTBPl9dzGvTUAIJaNzLp/8rjk3C4N /kN3h3gWgSRH8GvypfHnakiUjt/v7pFUOQXGyZTlbcMPAmzgUflXifbTGxeGQytgC0WN COYK1SqRGsuZ6CorsxQI67zA4IoN5CP6NeXDpP1MT2BjKLUdR3XZe6n+ZILYTHGbHiAz ogo93YA0goI+xMyBrwrWSj+PwZbv6l+NSQOMNr9D6AWeajzq5T9DzLo684c1fGkAO/up WHLYpZMNJ0Ttwo3OmhdT4IdscKIyGhQcHdejDoIimat87oWHCXNhF25zdT9ROsyFgw6V PWkw== X-Forwarded-Encrypted: i=1; AJvYcCU/rOmEPpvHurJzUkrrNo/5CNffFqs1naGwMHmeJaNRFV1fIlDqMrX+qVhzkB55q2FgPkmHxkaonS0=@vger.kernel.org, AJvYcCUoSqMf0INei+Arp7e2tGeZVp2+jwhEw+YkkwJrOEsgtc8UzP2xfaltayHT+ZvznDidNY36P9f93MPJR5E0@vger.kernel.org X-Gm-Message-State: AOJu0Yw0OEJ8H1i0l/w4fmpGFDasHsejzB+FD2lGYxNsZDcdLWZT0gCY IIfd5/zU9fnA6mJ+fj6TTiGtEGS33oFeDDcqNb3XcwNc1pwjYh+w4jlCGQ== X-Gm-Gg: ASbGncueo4ZwPSn81O0IOJ9UBKKo0GND4qedTEskuHl9FIbAQS1QjpYsMVgeAvTe4ua 16XXO20SQVO3DVU1Q8UNBlaccPR7OiwbczbqNWlZmFwk1dUiiFlez+jUkkX0W4WS9/mmUzFcs4g TStBF+TmPXTfBPTz+hTV5oQGK4Z+deqBJueRJOwkaPqTXq4GjqLJTe+jd80ZrN1hywwm0x6tsxG RNlDAnBFh9ODrelDPrsPNq6rBY/AxsaS6BVaOAxfjtdKAZj6HtfKq4PGHLkhxEMhv6YKS/g71o+ RvXXFsjBdA== X-Google-Smtp-Source: AGHT+IFXdoejpCqwZZa6wAHPN1wrhEv9r8FHGpbElFBnqM3y+UrdqwfDDeh57fW2hHAT+zLbFnnsUg== X-Received: by 2002:a05:6000:4a1a:b0:385:df2c:91aa with SMTP id ffacd0b85a97d-388e4d2dd31mr694592f8f.7.1734481000860; Tue, 17 Dec 2024 16:16:40 -0800 (PST) Received: from prasmi.Home ([2a06:5906:61b:2d00:ca61:1d3a:8af0:1c5a]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43656b1f638sm2135495e9.37.2024.12.17.16.16.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Dec 2024 16:16:40 -0800 (PST) From: Prabhakar X-Google-Original-From: Prabhakar To: Chris Brandt , Andi Shyti , Philipp Zabel , Wolfram Sang , Geert Uytterhoeven Cc: linux-renesas-soc@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, Prabhakar , Biju Das , Fabrizio Castro , Lad Prabhakar Subject: [PATCH v2 9/9] i2c: riic: Implement bus recovery Date: Wed, 18 Dec 2024 00:16:18 +0000 Message-ID: <20241218001618.488946-10-prabhakar.mahadev-lad.rj@bp.renesas.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241218001618.488946-1-prabhakar.mahadev-lad.rj@bp.renesas.com> References: <20241218001618.488946-1-prabhakar.mahadev-lad.rj@bp.renesas.com> Precedence: bulk X-Mailing-List: linux-renesas-soc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Lad Prabhakar Implement bus recovery by reinitializing the hardware to reset the bus state and generating 9 clock cycles (and a stop condition) to release the SDA line. Signed-off-by: Lad Prabhakar --- v1->v2 - Used single register read to check SDA/SCL lines --- drivers/i2c/busses/i2c-riic.c | 100 ++++++++++++++++++++++++++++++---- 1 file changed, 90 insertions(+), 10 deletions(-) diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c index 586092454bb2..d93c371a22de 100644 --- a/drivers/i2c/busses/i2c-riic.c +++ b/drivers/i2c/busses/i2c-riic.c @@ -50,6 +50,7 @@ #define ICCR1_ICE BIT(7) #define ICCR1_IICRST BIT(6) +#define ICCR1_CLO BIT(5) #define ICCR1_SOWP BIT(4) #define ICCR1_SCLI BIT(1) #define ICCR1_SDAI BIT(0) @@ -68,6 +69,7 @@ #define ICMR3_ACKBT BIT(3) #define ICFER_FMPE BIT(7) +#define ICFER_MALE BIT(1) #define ICIER_TIE BIT(7) #define ICIER_TEIE BIT(6) @@ -81,6 +83,8 @@ #define RIIC_INIT_MSG -1 +#define RIIC_RECOVERY_CLK_CNT 9 + enum riic_reg_list { RIIC_ICCR1 = 0, RIIC_ICCR2, @@ -150,13 +154,16 @@ static int riic_bus_barrier(struct riic_dev *riic) ret = readb_poll_timeout(riic->base + riic->info->regs[RIIC_ICCR2], val, !(val & ICCR2_BBSY), 10, riic->adapter.timeout); if (ret) - return -EBUSY; + goto i2c_recover; if ((riic_readb(riic, RIIC_ICCR1) & (ICCR1_SDAI | ICCR1_SCLI)) != (ICCR1_SDAI | ICCR1_SCLI)) - return -EBUSY; + goto i2c_recover; return 0; + +i2c_recover: + return i2c_recover_bus(&riic->adapter); } static int riic_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) @@ -332,7 +339,7 @@ static const struct i2c_algorithm riic_algo = { .functionality = riic_func, }; -static int riic_init_hw(struct riic_dev *riic) +static int riic_init_hw(struct riic_dev *riic, bool recover) { int ret; unsigned long rate; @@ -414,9 +421,11 @@ static int riic_init_hw(struct riic_dev *riic) rate / total_ticks, ((brl + 3) * 100) / (brl + brh + 6), t->scl_fall_ns / ns_per_tick, t->scl_rise_ns / ns_per_tick, cks, brl, brh); - ret = pm_runtime_resume_and_get(dev); - if (ret) - return ret; + if (!recover) { + ret = pm_runtime_resume_and_get(dev); + if (ret) + return ret; + } /* Changing the order of accessing IICRST and ICE may break things! */ riic_writeb(riic, ICCR1_IICRST | ICCR1_SOWP, RIIC_ICCR1); @@ -434,8 +443,74 @@ static int riic_init_hw(struct riic_dev *riic) riic_clear_set_bit(riic, ICCR1_IICRST, 0, RIIC_ICCR1); - pm_runtime_mark_last_busy(dev); - pm_runtime_put_autosuspend(dev); + if (!recover) { + pm_runtime_mark_last_busy(dev); + pm_runtime_put_autosuspend(dev); + } + return 0; +} + +static int riic_recover_bus(struct i2c_adapter *adap) +{ + struct riic_dev *riic = i2c_get_adapdata(adap); + struct device *dev = riic->adapter.dev.parent; + int ret; + u8 val; + + ret = riic_init_hw(riic, true); + if (ret) + return -EINVAL; + + /* output extra SCL clock cycles with master arbitration-lost detection disabled */ + riic_clear_set_bit(riic, ICFER_MALE, 0, RIIC_ICFER); + + for (unsigned int i = 0; i < RIIC_RECOVERY_CLK_CNT; i++) { + riic_clear_set_bit(riic, 0, ICCR1_CLO, RIIC_ICCR1); + ret = readb_poll_timeout(riic->base + riic->info->regs[RIIC_ICCR1], val, + !(val & ICCR1_CLO), 0, 100); + if (ret) { + dev_err(dev, "SCL clock cycle timeout\n"); + return ret; + } + } + + /* + * The last clock cycle may have driven the SDA line high, so add a + * short delay to allow the line to stabilize before checking the status. + */ + udelay(5); + + /* + * If an incomplete byte write occurs, the SDA line may remain low + * even after 9 clock pulses, indicating the bus is not released. + * To resolve this, send an additional clock pulse to simulate a STOP + * condition and ensure proper bus release. + */ + if ((riic_readb(riic, RIIC_ICCR1) & (ICCR1_SDAI | ICCR1_SCLI)) != + (ICCR1_SDAI | ICCR1_SCLI)) { + riic_clear_set_bit(riic, 0, ICCR1_CLO, RIIC_ICCR1); + ret = readb_poll_timeout(riic->base + riic->info->regs[RIIC_ICCR1], val, + !(val & ICCR1_CLO), 0, 100); + if (ret) { + dev_err(dev, "SCL clock cycle timeout occurred while issuing the STOP condition\n"); + return ret; + } + /* delay to make sure SDA line goes back HIGH again */ + udelay(5); + } + + /* clear any flags set */ + riic_writeb(riic, 0, RIIC_ICSR2); + /* read back register to confirm writes */ + riic_readb(riic, RIIC_ICSR2); + + /* restore back ICFER_MALE */ + riic_clear_set_bit(riic, 0, ICFER_MALE, RIIC_ICFER); + + if ((riic_readb(riic, RIIC_ICCR1) & (ICCR1_SDAI | ICCR1_SCLI)) != + (ICCR1_SDAI | ICCR1_SCLI)) + return -EINVAL; + return 0; } @@ -447,6 +522,10 @@ static const struct riic_irq_desc riic_irqs[] = { { .res_num = 5, .isr = riic_tend_isr, .name = "riic-nack" }, }; +static struct i2c_bus_recovery_info riic_bri = { + .recover_bus = riic_recover_bus, +}; + static int riic_i2c_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; @@ -491,6 +570,7 @@ static int riic_i2c_probe(struct platform_device *pdev) strscpy(adap->name, "Renesas RIIC adapter", sizeof(adap->name)); adap->owner = THIS_MODULE; adap->algo = &riic_algo; + adap->bus_recovery_info = &riic_bri; adap->dev.parent = dev; adap->dev.of_node = dev->of_node; @@ -503,7 +583,7 @@ static int riic_i2c_probe(struct platform_device *pdev) pm_runtime_use_autosuspend(dev); pm_runtime_enable(dev); - ret = riic_init_hw(riic); + ret = riic_init_hw(riic, false); if (ret) goto out; @@ -611,7 +691,7 @@ static int riic_i2c_resume(struct device *dev) if (ret) return ret; - ret = riic_init_hw(riic); + ret = riic_init_hw(riic, false); if (ret) { /* * In case this happens there is no way to recover from this