From patchwork Sun Jan 7 13:26:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Elad Nachman X-Patchwork-Id: 760949 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 D61D7134A5; Sun, 7 Jan 2024 13:27:11 +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="ZBiCegkz" 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 407BL5rJ025934; Sun, 7 Jan 2024 05:26:55 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=marvell.com; h= from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding:content-type; s= pfpt0220; bh=kTBCfQFVMTFwhZ+RBcu+Y/wUEgP6lDYodciSiwX/zeo=; b=ZBi CegkzIkJv8HB5O+IhdYIrRlKQ7HXO04ESV0AkTVqdbwGFsc5oYH0I13bDdgsDrbV PSalR+/vREPR7pXtR7xSBXM844k6nz2PPNlMvBMWQyB+3UC20hxZaiX8Olyf5zcu aZXrltgqx2n8+Y81SKUwKdjn6TlaJYK5wojLTjIotPnc7LA+IF857zeMAuLM4XL8 eQYqBLsUoHxoX4sB7FcaGcuCfmZ2r94T1tuH/wbFMvVDaxvVIE7e5MDLZvUuVo8B wTH/ywhM6k8+dBLqEnAWWheJNKLATKGYY2YdR9FyAgIgq5QsoXZigAO4waTbRKyj /lznj/MMiiheg9VZRrQ== Received: from dc5-exch01.marvell.com ([199.233.59.181]) by mx0b-0016f401.pphosted.com (PPS) with ESMTPS id 3vf78n23j9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Sun, 07 Jan 2024 05:26:54 -0800 (PST) Received: from DC5-EXCH01.marvell.com (10.69.176.38) by DC5-EXCH01.marvell.com (10.69.176.38) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Sun, 7 Jan 2024 05:26:48 -0800 Received: from maili.marvell.com (10.69.176.80) by DC5-EXCH01.marvell.com (10.69.176.38) with Microsoft SMTP Server id 15.0.1497.48 via Frontend Transport; Sun, 7 Jan 2024 05:26:48 -0800 Received: from dc3lp-swdev041.marvell.com (dc3lp-swdev041.marvell.com [10.6.60.191]) by maili.marvell.com (Postfix) with ESMTP id 4E4FF3F7093; Sun, 7 Jan 2024 05:26:46 -0800 (PST) From: Elad Nachman To: , , , CC: , Subject: [PATCH v4 1/1] i2c: busses: i2c-mv64xxx: fix arb-loss i2c lock Date: Sun, 7 Jan 2024 15:26:41 +0200 Message-ID: <20240107132641.3418208-2-enachman@marvell.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240107132641.3418208-1-enachman@marvell.com> References: <20240107132641.3418208-1-enachman@marvell.com> Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-ORIG-GUID: Tyhjr7KF__O2C0TMiUe3wgoBhl8EJrvu X-Proofpoint-GUID: Tyhjr7KF__O2C0TMiUe3wgoBhl8EJrvu 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. Signed-off-by: Elad Nachman --- drivers/i2c/busses/i2c-mv64xxx.c | 108 +++++++++++++++++++++++++++++++ 1 file changed, 108 insertions(+) diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c index dc160cbc3155..c06eecef66dc 100644 --- a/drivers/i2c/busses/i2c-mv64xxx.c +++ b/drivers/i2c/busses/i2c-mv64xxx.c @@ -26,6 +26,7 @@ #include #include #include +#include #define MV64XXX_I2C_ADDR_ADDR(val) ((val & 0x7f) << 1) #define MV64XXX_I2C_BAUD_DIV_N(val) (val & 0x7) @@ -104,6 +105,7 @@ enum { MV64XXX_I2C_ACTION_RCV_DATA, MV64XXX_I2C_ACTION_RCV_DATA_STOP, MV64XXX_I2C_ACTION_SEND_STOP, + MV64XXX_I2C_ACTION_UNLOCK_BUS }; struct mv64xxx_i2c_regs { @@ -150,6 +152,12 @@ struct mv64xxx_i2c_data { bool clk_n_base_0; struct i2c_bus_recovery_info rinfo; bool atomic; + /* I2C mpp states & gpios needed for arbitration lost recovery */ + int scl_gpio, sda_gpio; + bool soft_reset; + struct pinctrl_state *i2c_mpp_state; + struct pinctrl_state *i2c_gpio_state; + struct pinctrl *pc; }; static struct mv64xxx_i2c_regs mv64xxx_i2c_regs_mv64xxx = { @@ -318,6 +326,11 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status) drv_data->state = MV64XXX_I2C_STATE_IDLE; break; + case MV64XXX_I2C_STATUS_MAST_LOST_ARB: /* 0x38 */ + drv_data->action = MV64XXX_I2C_ACTION_UNLOCK_BUS; + drv_data->state = MV64XXX_I2C_STATE_IDLE; + break; + case MV64XXX_I2C_STATUS_MAST_WR_ADDR_NO_ACK: /* 0x20 */ case MV64XXX_I2C_STATUS_MAST_WR_NO_ACK: /* 30 */ case MV64XXX_I2C_STATUS_MAST_RD_ADDR_NO_ACK: /* 48 */ @@ -356,6 +369,9 @@ static void mv64xxx_i2c_send_start(struct mv64xxx_i2c_data *drv_data) static void mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data) { + struct pinctrl *pc; + int i; + switch(drv_data->action) { case MV64XXX_I2C_ACTION_SEND_RESTART: /* We should only get here if we have further messages */ @@ -409,6 +425,54 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data) drv_data->reg_base + drv_data->reg_offsets.control); break; + case MV64XXX_I2C_ACTION_UNLOCK_BUS: + if (!drv_data->soft_reset) + break; + + pc = drv_data->pc; + if (IS_ERR(pc)) { + dev_err(&drv_data->adapter.dev, + "failed to get pinctrl for bus unlock!\n"); + break; + } + + /* Change i2c MPPs state to act as GPIOs: */ + if (pinctrl_select_state(pc, drv_data->i2c_gpio_state) >= 0) { + /* + * Toggle i2c scl (serial clock) 10 times. + * 10 clocks are enough to transfer a full + * byte plus extra as seen from tests with + * Ubiquity SFP module causing the issue. + * This allows the slave that occupies + * the bus to transmit its remaining data, + * so it can release the i2c bus: + */ + for (i = 0; i < 10; i++) { + gpio_set_value(drv_data->scl_gpio, 1); + usleep_range(100, 1000); + gpio_set_value(drv_data->scl_gpio, 0); + }; + + /* restore i2c pin state to MPPs: */ + pinctrl_select_state(pc, drv_data->i2c_mpp_state); + } + + /* + * Trigger controller soft reset + * This register is write only, with none of the bits defined. + * So any value will do. + * 0x1 just seems more intuitive than 0x0 ... + */ + writel(0x1, drv_data->reg_base + drv_data->reg_offsets.soft_reset); + /* wait for i2c controller to complete reset: */ + usleep_range(100, 1000); + /* + * Need to proceed to the data stop condition generation clause. + * This is needed after clock toggling to put the i2c slave + * in the correct state. + */ + fallthrough; + case MV64XXX_I2C_ACTION_RCV_DATA_STOP: drv_data->msg->buf[drv_data->byte_posn++] = readl(drv_data->reg_base + drv_data->reg_offsets.data); @@ -950,6 +1014,8 @@ static int mv64xxx_i2c_init_recovery_info(struct mv64xxx_i2c_data *drv_data, return -ENODEV; } + rinfo->sda_gpiod = devm_gpiod_get(dev, "sda", GPIOD_OUT_HIGH); + rinfo->scl_gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH); drv_data->adapter.bus_recovery_info = rinfo; return 0; } @@ -985,6 +1051,7 @@ mv64xxx_i2c_probe(struct platform_device *pd) { struct mv64xxx_i2c_data *drv_data; struct mv64xxx_i2c_pdata *pdata = dev_get_platdata(&pd->dev); + struct pinctrl *pc; int rc; if ((!pdata && !pd->dev.of_node)) @@ -1040,6 +1107,47 @@ mv64xxx_i2c_probe(struct platform_device *pd) if (rc == -EPROBE_DEFER) return rc; + /* + * Start with arbitration lost soft reset enabled as to false. + * Try to locate the necessary items in the device tree to + * make this feature work. + * Only after we verify that the device tree contains all of + * the needed information and that it is sound and usable, + * then we enable this flag. + * This information should be defined, but the driver maintains + * backward compatibility with old dts files, so it will not fail + * the probe in case these are missing. + */ + drv_data->soft_reset = false; + pc = devm_pinctrl_get(&pd->dev); + if (!IS_ERR(pc)) { + drv_data->pc = pc; + drv_data->i2c_mpp_state = + pinctrl_lookup_state(pc, "default"); + drv_data->i2c_gpio_state = + pinctrl_lookup_state(pc, "gpio"); + drv_data->scl_gpio = + of_get_named_gpio(pd->dev.of_node, "scl-gpios", 0); + drv_data->sda_gpio = + of_get_named_gpio(pd->dev.of_node, "sda-gpios", 0); + + if (!IS_ERR(drv_data->i2c_gpio_state) && + !IS_ERR(drv_data->i2c_mpp_state) && + gpio_is_valid(drv_data->scl_gpio) && + gpio_is_valid(drv_data->sda_gpio)) { + rc = devm_gpio_request_one(&pd->dev, drv_data->scl_gpio, + GPIOF_DIR_OUT, NULL); + rc |= devm_gpio_request_one(&pd->dev, drv_data->sda_gpio, + GPIOF_DIR_OUT, NULL); + if (!rc) + drv_data->soft_reset = true; + } + } + + if (!drv_data->soft_reset) + dev_info(&pd->dev, + "mv64xxx: missing arbitration-lost recovery definitions in dts file\n"); + drv_data->adapter.dev.parent = &pd->dev; drv_data->adapter.algo = &mv64xxx_i2c_algo; drv_data->adapter.owner = THIS_MODULE;