From patchwork Mon Jun 24 11:15:18 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 807101 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 909FC442C for ; Mon, 24 Jun 2024 11:16:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719227781; cv=none; b=hyENL3oO/1Nb4s3cP+XYvTnOtSqYDEOITnI88Ez2CrkNOSofgHL4bV+Fmw14+Kq5L6vvF+9PF8zTc5GY4Geu24S73BZwaROFdZn+3JzHFo4ElJJoT4imqfXoWoEHrdM+VjfhHZMoamKrRlTZebkKMMBDx6JvfCsdp/zihJEnDdM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719227781; c=relaxed/simple; bh=f8K+KFCu4v2gxFcfZDlFE3CpP4AowUfk2+j7UrI7KIQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eyFKKs1GOnuCZ0x94KT0tvkD9cncXxudTto0Kf1/gByisbM6oJUjkPbqj0pyxBc2Iqjvp162xZ3/EWqEs/xAOFt6Hgq7MNGUh36Ln+5bqphPvr9L/B+5eLP6Y1cjkIEbW9Mrq4nlrs+zzp+u9YkpMoyxCVg3leuj79It1LjSQfs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Xd8KtO/l; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Xd8KtO/l" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1719227778; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=1MKQZAMPum9/XFHweBiLEqq+DxvimF2wmcbjyqmhaeM=; b=Xd8KtO/lakhkYul0XeQOiYKmt+Ckh9I2ZJpZrVa2mEZLT2Ih3VAQ1xOYZZEDS4lhCMAkaI kMNkSRIjEsyItfoJv1hgtjzU/fBkXOZpsNbmHgqat7KQZGIHP51Lrjfa1I5KB4HFgSE8Cz XfTRbPWawi43M6WprYP9HlXoEkpSNmY= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-528-jBoqmSz_Mt2Dq9flgCss5A-1; Mon, 24 Jun 2024 07:16:14 -0400 X-MC-Unique: jBoqmSz_Mt2Dq9flgCss5A-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0035B195608E; Mon, 24 Jun 2024 11:16:12 +0000 (UTC) Received: from x1.localdomain.com (unknown [10.39.193.82]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 6CDB51956087; Mon, 24 Jun 2024 11:16:07 +0000 (UTC) From: Hans de Goede To: =?utf-8?q?Pali_Roh=C3=A1r?= , =?utf-8?q?Ilpo_J=C3=A4rvi?= =?utf-8?q?nen?= , Andy Shevchenko , Paul Menzel , Wolfram Sang Cc: Hans de Goede , eric.piel@tremplin-utc.net, Marius Hoch , Dell.Client.Kernel@dell.com, Kai Heng Feng , platform-driver-x86@vger.kernel.org, Jean Delvare , Andi Shyti , linux-i2c@vger.kernel.org Subject: [PATCH v4 6/6] platform/x86: dell-smo8800: Add support for probing for the accelerometer i2c address Date: Mon, 24 Jun 2024 13:15:18 +0200 Message-ID: <20240624111519.15652-7-hdegoede@redhat.com> In-Reply-To: <20240624111519.15652-1-hdegoede@redhat.com> References: <20240624111519.15652-1-hdegoede@redhat.com> Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Unfortunately the SMOxxxx ACPI device does not contain the i2c-address of the accelerometer. So a DMI product-name to address mapping table is used. At support to have the kernel probe for the i2c-address for modesl which are not on the list. The new probing code sits behind a new probe_i2c_addr module parameter, which is disabled by default because probing might be dangerous. Link: https://lore.kernel.org/linux-i2c/4820e280-9ca4-4d97-9d21-059626161bfc@molgen.mpg.de/ Signed-off-by: Hans de Goede --- drivers/platform/x86/dell/dell-lis3lv02d.c | 133 ++++++++++++++++++++- 1 file changed, 131 insertions(+), 2 deletions(-) diff --git a/drivers/platform/x86/dell/dell-lis3lv02d.c b/drivers/platform/x86/dell/dell-lis3lv02d.c index a7409db0505b..173615fd2646 100644 --- a/drivers/platform/x86/dell/dell-lis3lv02d.c +++ b/drivers/platform/x86/dell/dell-lis3lv02d.c @@ -15,6 +15,8 @@ #include #include "dell-smo8800-ids.h" +#define LIS3_WHO_AM_I 0x0f + #define DELL_LIS3LV02D_DMI_ENTRY(product_name, i2c_addr) \ { \ .matches = { \ @@ -57,6 +59,121 @@ static const struct dmi_system_id *lis3lv02d_dmi_id; static struct i2c_client *i2c_dev; static bool notifier_registered; +static bool probe_i2c_addr; +module_param(probe_i2c_addr, bool, 0444); +MODULE_PARM_DESC(probe_i2c_addr, "Probe the i801 I2C bus for the accelerometer on models where the address is unknown"); + +/* + * This is the kernel version of the single register device sanity checks from + * the i2c_safety_check function from lm_sensors sensor-detect script: + * This is meant to prevent access to 1-register-only devices, + * which are designed to be accessed with SMBus receive byte and SMBus send + * byte transactions (i.e. short reads and short writes) and treat SMBus + * read byte as a real write followed by a read. The device detection + * routines would write random values to the chip with possibly very nasty + * results for the hardware. Note that this function won't catch all such + * chips, as it assumes that reads and writes relate to the same register, + * but that's the best we can do. + */ +static int i2c_safety_check(struct i2c_adapter *adap, u8 addr) +{ + union i2c_smbus_data smbus_data; + int err; + u8 data; + + /* + * First receive a byte from the chip, and remember it. This + * also checks if there is a device at the address at all. + */ + err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, + I2C_SMBUS_BYTE, &smbus_data); + if (err < 0) + return err; + + data = smbus_data.byte; + + /* + * Receive a byte again; very likely to be the same for + * 1-register-only devices. + */ + err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, + I2C_SMBUS_BYTE, &smbus_data); + if (err < 0) + return err; + + if (smbus_data.byte != data) + return 0; /* Not a 1-register-only device. */ + + /* + * Then try a standard byte read, with a register offset equal to + * the read byte; for 1-register-only device this should read + * the same byte value in return. + */ + err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, data, + I2C_SMBUS_BYTE_DATA, &smbus_data); + if (err < 0) + return err; + + if (smbus_data.byte != data) + return 0; /* Not a 1-register-only device. */ + + /* + * Then try a standard byte read, with a slightly different register + * offset; this should again read the register offset in return. + */ + err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, data ^ 0x01, + I2C_SMBUS_BYTE_DATA, &smbus_data); + if (err < 0) + return err; + + if (smbus_data.byte != (data ^ 0x01)) + return 0; /* Not a 1-register-only device. */ + + /* + * Apparently this is a 1-register-only device, restore the original + * register value and leave it alone. + */ + i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, data, + I2C_SMBUS_BYTE, NULL); + pr_warn("I2C safety check for address 0x%02x failed, skipping\n", addr); + return -ENODEV; +} + +static int detect_lis3lv02d(struct i2c_adapter *adap, u8 addr, + struct i2c_board_info *info) +{ + union i2c_smbus_data smbus_data; + int err; + + pr_info("Probing for lis3lv02d on address 0x%02x\n", addr); + err = i2c_safety_check(adap, addr); + if (err < 0) + return err; + + err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, LIS3_WHO_AM_I, + I2C_SMBUS_BYTE_DATA, &smbus_data); + if (err < 0) { + pr_warn("Failed to read who-am-i register: %d\n", err); + return err; + } + + /* valid who-am-i values are from drivers/misc/lis3lv02d/lis3lv02d.c */ + switch (smbus_data.byte) { + case 0x32: + case 0x33: + case 0x3a: + case 0x3b: + break; + default: + pr_warn("Unknown who-am-i register value 0x%02x\n", smbus_data.byte); + return -ENODEV; + } + + pr_debug("Detected lis3lv02d on address 0x%02x\n", addr); + info->addr = addr; + return 0; +} + static bool i2c_adapter_is_main_i801(struct i2c_adapter *adap) { /* @@ -93,7 +210,17 @@ static void instantiate_i2c_client(struct work_struct *work) if (!adap) return; - info.addr = (long)lis3lv02d_dmi_id->driver_data; + if (lis3lv02d_dmi_id) { + info.addr = (long)lis3lv02d_dmi_id->driver_data; + } else { + /* First try address 0x29 (most used) and then try 0x1d */ + if (detect_lis3lv02d(adap, 0x29, &info) != 0 && + detect_lis3lv02d(adap, 0x1d, &info) != 0) { + pr_warn("failed to probe for lis3lv02d I2C address\n"); + goto out_put_adapter; + } + } + strscpy(info.type, "lis3lv02d", I2C_NAME_SIZE); i2c_dev = i2c_new_client_device(adap, &info); @@ -104,6 +231,7 @@ static void instantiate_i2c_client(struct work_struct *work) pr_debug("registered lis3lv02d on address 0x%02x\n", info.addr); } +out_put_adapter: i2c_put_adapter(adap); } static DECLARE_WORK(i2c_work, instantiate_i2c_client); @@ -166,8 +294,9 @@ static int __init dell_lis3lv02d_init(void) put_device(dev); lis3lv02d_dmi_id = dmi_first_match(lis3lv02d_devices); - if (!lis3lv02d_dmi_id) { + if (!lis3lv02d_dmi_id && !probe_i2c_addr) { pr_warn("accelerometer is present on SMBus but its address is unknown, skipping registration\n"); + pr_info("Pass dell_lis3lv02d.probe_i2c_addr=1 on the kernel commandline to probe, this may be dangerous!\n"); return 0; }