From patchwork Thu May 6 01:10:14 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Packham X-Patchwork-Id: 1474725 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=alliedtelesis.co.nz header.i=@alliedtelesis.co.nz header.a=rsa-sha256 header.s=mail181024 header.b=CJO2vyhY; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4FbG4q3ClFz9sRf for ; Thu, 6 May 2021 11:21:31 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4FbG4q2YHDz3brp for ; Thu, 6 May 2021 11:21:31 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=alliedtelesis.co.nz header.i=@alliedtelesis.co.nz header.a=rsa-sha256 header.s=mail181024 header.b=CJO2vyhY; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=alliedtelesis.co.nz (client-ip=202.36.163.20; helo=gate2.alliedtelesis.co.nz; envelope-from=chrisp@alliedtelesis.co.nz; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=alliedtelesis.co.nz header.i=@alliedtelesis.co.nz header.a=rsa-sha256 header.s=mail181024 header.b=CJO2vyhY; dkim-atps=neutral X-Greylist: delayed 589 seconds by postgrey-1.36 at boromir; Thu, 06 May 2021 11:20:12 AEST Received: from gate2.alliedtelesis.co.nz (gate2.alliedtelesis.co.nz [202.36.163.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4FbG3J6krDz2yxl for ; Thu, 6 May 2021 11:20:12 +1000 (AEST) Received: from svr-chch-seg1.atlnz.lc (mmarshal3.atlnz.lc [10.32.18.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by gate2.alliedtelesis.co.nz (Postfix) with ESMTPS id 69F1D891B0; Thu, 6 May 2021 13:10:21 +1200 (NZST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alliedtelesis.co.nz; s=mail181024; t=1620263421; bh=gBEcofK4p1A630R6Q3AHSfqkVuQENtsMTmONpfzCBKk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CJO2vyhY5WhFQWa9eulWExgthvqn/SFzPyx5lj3yZZS+vH0W9rwZVD+0MWQ3tt/a+ 2H/qPPw+Bt7ITXNTU2p7DzjAVhJn+KCH9Y1IY+tuCVtOnXy5wRiiEBPDDPVmbTuzbE YcFjo97n4Eovkyv6OiMdXoFjc/qn/ruCRUzf9e+XHu89rzuikPfb6qeNhTneKAl+HU jppaQYsJ2V7IM+mqlkZFGcoY54EA1nlGofza8wRgDtu6nRN5qi4jHru5RhwVM2H5SS IZ/BnSG8Ub5x17Jq/KwuXbGkT//KOPzkdO1Qkd2hQB7aD70DZQxkPG0grz8ysNBCCS 4AWpVgqB7d2hw== Received: from pat.atlnz.lc (Not Verified[10.32.16.33]) by svr-chch-seg1.atlnz.lc with Trustwave SEG (v8, 2, 6, 11305) id ; Thu, 06 May 2021 13:10:21 +1200 Received: from chrisp-dl.ws.atlnz.lc (chrisp-dl.ws.atlnz.lc [10.33.22.20]) by pat.atlnz.lc (Postfix) with ESMTP id 0986413ECA6; Thu, 6 May 2021 13:10:21 +1200 (NZST) Received: by chrisp-dl.ws.atlnz.lc (Postfix, from userid 1030) id 051E3283A60; Thu, 6 May 2021 13:10:21 +1200 (NZST) From: Chris Packham To: wsa@kernel.org, andriy.shevchenko@linux.intel.com, andy.shevchenko@gmail.com, robh+dt@kernel.org, mpe@ellerman.id.au Subject: [PATCH 3/3] i2c: mpc: implement erratum A-004447 workaround Date: Thu, 6 May 2021 13:10:14 +1200 Message-Id: <20210506011015.17347-4-chris.packham@alliedtelesis.co.nz> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210506011015.17347-1-chris.packham@alliedtelesis.co.nz> References: <20210506011015.17347-1-chris.packham@alliedtelesis.co.nz> MIME-Version: 1.0 X-SEG-SpamProfiler-Analysis: v=2.3 cv=B+jHL9lM c=1 sm=1 tr=0 a=KLBiSEs5mFS1a/PbTCJxuA==:117 a=5FLXtPjwQuUA:10 a=w4j1xu5M8ypyE8uBZIYA:9 X-SEG-SpamProfiler-Score: 0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Chris Packham , linuxppc-dev@lists.ozlabs.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" The P2040/P2041 has an erratum where the normal i2c recovery mechanism does not work. Implement the alternative recovery mechanism documented in the P2040 Chip Errata Rev Q. Signed-off-by: Chris Packham Signed-off-by: Chris Packham > --- drivers/i2c/busses/i2c-mpc.c | 88 +++++++++++++++++++++++++++++++++++- 1 file changed, 86 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c index 30d9e89a3db2..052e37718771 100644 --- a/drivers/i2c/busses/i2c-mpc.c +++ b/drivers/i2c/busses/i2c-mpc.c @@ -45,6 +45,7 @@ #define CCR_MTX 0x10 #define CCR_TXAK 0x08 #define CCR_RSTA 0x04 +#define CCR_RSVD 0x02 #define CSR_MCF 0x80 #define CSR_MAAS 0x40 @@ -97,7 +98,7 @@ struct mpc_i2c { u32 block; int rc; int expect_rxack; - + bool has_errata_A004447; }; struct mpc_i2c_divider { @@ -136,6 +137,83 @@ static void mpc_i2c_fixup(struct mpc_i2c *i2c) } } +static int i2c_mpc_wait_sr(struct mpc_i2c *i2c, int mask) +{ + unsigned long timeout = jiffies + usecs_to_jiffies(100); + int ret = 0; + + while ((readb(i2c->base + MPC_I2C_SR) & mask) == 0) { + if (time_after(jiffies, timeout)) { + ret = -ETIMEDOUT; + break; + } + cond_resched(); + } + + return ret; +} + +/* + * Workaround for Erratum A004447. From the P2040CE Rev Q + * + * 1. Set up the frequency divider and sampling rate. + * 2. I2CCR - a0h + * 3. Poll for I2CSR[MBB] to get set. + * 4. If I2CSR[MAL] is set (an indication that SDA is stuck low), then go to + * step 5. If MAL is not set, then go to step 13. + * 5. I2CCR - 00h + * 6. I2CCR - 22h + * 7. I2CCR - a2h + * 8. Poll for I2CSR[MBB] to get set. + * 9. Issue read to I2CDR. + * 10. Poll for I2CSR[MIF] to be set. + * 11. I2CCR - 82h + * 12. Workaround complete. Skip the next steps. + * 13. Issue read to I2CDR. + * 14. Poll for I2CSR[MIF] to be set. + * 15. I2CCR - 80h + */ +static void mpc_i2c_fixup_A004447(struct mpc_i2c *i2c) +{ + int ret; + u32 val; + + writeccr(i2c, CCR_MEN | CCR_MSTA); + ret = i2c_mpc_wait_sr(i2c, CSR_MBB); + if (ret) { + dev_err(i2c->dev, "timeout waiting for CSR_MBB\n"); + return; + } + + val = readb(i2c->base + MPC_I2C_SR); + + if (val & CSR_MAL) { + writeccr(i2c, 0x00); + writeccr(i2c, CCR_MSTA | CCR_RSVD); + writeccr(i2c, CCR_MEN | CCR_MSTA | CCR_RSVD); + ret = i2c_mpc_wait_sr(i2c, CSR_MBB); + if (ret) { + dev_err(i2c->dev, "timeout waiting for CSR_MBB\n"); + return; + } + val = readb(i2c->base + MPC_I2C_DR); + ret = i2c_mpc_wait_sr(i2c, CSR_MIF); + if (ret) { + dev_err(i2c->dev, "timeout waiting for CSR_MIF\n"); + return; + } + writeccr(i2c, CCR_MEN | CCR_RSVD); + } else { + val = readb(i2c->base + MPC_I2C_DR); + ret = i2c_mpc_wait_sr(i2c, CSR_MIF); + if (ret) { + dev_err(i2c->dev, "timeout waiting for CSR_MIF\n"); + return; + } + writeccr(i2c, CCR_MEN); + } +} + #if defined(CONFIG_PPC_MPC52xx) || defined(CONFIG_PPC_MPC512x) static const struct mpc_i2c_divider mpc_i2c_dividers_52xx[] = { {20, 0x20}, {22, 0x21}, {24, 0x22}, {26, 0x23}, @@ -670,7 +748,10 @@ static int fsl_i2c_bus_recovery(struct i2c_adapter *adap) { struct mpc_i2c *i2c = i2c_get_adapdata(adap); - mpc_i2c_fixup(i2c); + if (i2c->has_errata_A004447) + mpc_i2c_fixup_A004447(i2c); + else + mpc_i2c_fixup(i2c); return 0; } @@ -767,6 +848,9 @@ static int fsl_i2c_probe(struct platform_device *op) } dev_info(i2c->dev, "timeout %u us\n", mpc_ops.timeout * 1000000 / HZ); + if (of_property_read_bool(op->dev.of_node, "fsl,i2c-erratum-a004447")) + i2c->has_errata_A004447 = true; + i2c->adap = mpc_ops; scnprintf(i2c->adap.name, sizeof(i2c->adap.name), "MPC adapter (%s)", of_node_full_name(op->dev.of_node));