From patchwork Fri Jun 21 12:25:01 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: 806920 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 B5227152166 for ; Fri, 21 Jun 2024 12:26:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718972794; cv=none; b=Wy1MSP4xlsmZyXFHGFiRJs8iYNiBkCG0SwPaPFevmgv1MOySjzf/2R0qGm+ub0xp7RxEqAP179DZkMouUbCAa5/F4AMYQpzSRxgZ7PeC/HpZGx8aEzVgNlTfBpUuZwyL8Sgum+LxCmlB8uPhozlmIsU8nNFSDZaTFcmw2OEXmf8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718972794; c=relaxed/simple; bh=A1l8Jhz+bDuY7N9pVlYA3yIk/SruRDs0ivBIjXPv9Dk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=A8v3YKZ/pR7ScLgU2x8DV/hIu9uYbc0YO42ELo7ZRA/vIAmXHCyjMQ4rLaW96yF2lYano92Y0/mQRdBVNm+IcseBF/TfwszhbgkQqaI0bxIXrxF9DQTBk4OhwUS/6ozKgIOG4RZJgffSAwZurmsOTuxIO0FT9RhwZjhCokPAQ2I= 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=bDkbD4uy; arc=none smtp.client-ip=170.10.129.124 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="bDkbD4uy" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1718972790; 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=/CYA+8vSRT7esfgbbxqXlZIh5TtFOMmDACTrtwInIDY=; b=bDkbD4uyChzmZySW5v/TAF7BcMslRm5aahn6d6avnHGWesticOCFerCBYWq4ZYyZZ9AgW0 5W2aySHEpGmhWnKbgrcOgsJJJ7fSzWA3k6B4OdW5+vccQNG+LCiIcW9Ap6OmIBtKNm1CUM 718jwpkwGSjkFsSQOa0NlNtmtq0g79c= Received: from mx-prod-mc-03.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-549-HjhuZd9HMjC6EIy_xiCuNw-1; Fri, 21 Jun 2024 08:26:25 -0400 X-MC-Unique: HjhuZd9HMjC6EIy_xiCuNw-1 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7370F19373F3; Fri, 21 Jun 2024 12:26:21 +0000 (UTC) Received: from shalem.redhat.com (unknown [10.39.194.69]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id BB08D301B8DE; Fri, 21 Jun 2024 12:26:05 +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 v3 6/6] platform/x86: dell-smo8800: Add support for probing for the accelerometer i2c address Date: Fri, 21 Jun 2024 14:25:01 +0200 Message-ID: <20240621122503.10034-7-hdegoede@redhat.com> In-Reply-To: <20240621122503.10034-1-hdegoede@redhat.com> References: <20240621122503.10034-1-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 3.4.1 on 10.30.177.4 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. Signed-off-by: Hans de Goede --- drivers/platform/x86/dell/dell-smo8800.c | 152 ++++++++++++++++++++++- 1 file changed, 147 insertions(+), 5 deletions(-) diff --git a/drivers/platform/x86/dell/dell-smo8800.c b/drivers/platform/x86/dell/dell-smo8800.c index 4c79b2599d96..d64d200e927a 100644 --- a/drivers/platform/x86/dell/dell-smo8800.c +++ b/drivers/platform/x86/dell/dell-smo8800.c @@ -10,6 +10,7 @@ */ #define DRIVER_NAME "smo8800" +#define LIS3_WHO_AM_I 0x0f #include #include @@ -25,6 +26,10 @@ #include #include +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"); + struct smo8800_device { u32 irq; /* acpi device irq */ atomic_t counter; /* count after last read */ @@ -225,6 +230,130 @@ static const struct dmi_system_id smo8800_lis3lv02d_devices[] = { { } }; +/* + * 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 device *dev, 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); + dev_warn(dev, "I2C safety check for address 0x%02x failed, skipping\n", addr); + return -ENODEV; +} + +static int smo8800_detect_accel(struct smo8800_device *smo8800, + struct i2c_adapter *adap, u8 addr, + struct i2c_board_info *info, bool probe) +{ + union i2c_smbus_data smbus_data; + const char *type; + int err; + + if (probe) { + dev_info(smo8800->dev, "Probing for accelerometer on address 0x%02x\n", addr); + err = i2c_safety_check(smo8800->dev, 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) { + dev_warn(smo8800->dev, "Failed to read who-am-i register: %d\n", err); + return err; + } + + /* who-am-i register mappings from drivers/misc/lis3lv02d/lis3lv02d.c */ + switch (smbus_data.byte) { + case 0x32: + type = "lis331dlh"; + break; + case 0x33: + type = "lis2de12"; /* LIS3DC / HP3DC in drivers/misc/lis3lv02d/lis3lv02d.c */ + break; + case 0x3a: + type = "lis3lv02dl_accel"; + break; + case 0x3b: + type = "lis302dl"; + break; + default: + dev_warn(smo8800->dev, "Unknown who-am-i register value 0x%02x\n", + smbus_data.byte); + return -ENODEV; + } + + dev_dbg(smo8800->dev, "Detected %s accelerometer on address 0x%02x\n", type, addr); + strscpy(info->type, "lis3lv02d", I2C_NAME_SIZE); + info->addr = addr; + return 0; +} + static int smo8800_find_i801(struct device *dev, void *data) { struct i2c_adapter *adap, **adap_ret = data; @@ -247,6 +376,7 @@ static void smo8800_instantiate_i2c_client(struct work_struct *work) const struct dmi_system_id *lis3lv02d_dmi_id; struct i2c_board_info info = { }; struct i2c_adapter *adap = NULL; + int err; if (smo8800->i2c_dev) return; @@ -256,11 +386,22 @@ static void smo8800_instantiate_i2c_client(struct work_struct *work) return; lis3lv02d_dmi_id = dmi_first_match(smo8800_lis3lv02d_devices); - if (!lis3lv02d_dmi_id) + if (lis3lv02d_dmi_id) { + info.addr = (long)lis3lv02d_dmi_id->driver_data; + /* Always detect the accel-type, this also checks the accel is actually there */ + err = smo8800_detect_accel(smo8800, adap, info.addr, &info, false); + if (err) + goto out_put_adapter; + } else if (probe_i2c_addr) { + /* First try address 0x29 (most used) and then try 0x1d */ + if (smo8800_detect_accel(smo8800, adap, 0x29, &info, true) != 0 && + smo8800_detect_accel(smo8800, adap, 0x1d, &info, true) != 0) { + dev_warn(smo8800->dev, "failed to probe for lis3lv02d I2C address\n"); + goto out_put_adapter; + } + } else { goto out_put_adapter; - - info.addr = (long)lis3lv02d_dmi_id->driver_data; - strscpy(info.type, "lis3lv02d", I2C_NAME_SIZE); + } smo8800->i2c_dev = i2c_new_client_device(adap, &info); if (IS_ERR(smo8800->i2c_dev)) { @@ -357,7 +498,7 @@ static int smo8800_probe(struct platform_device *device) smo8800->irq); } - if (dmi_check_system(smo8800_lis3lv02d_devices)) { + if (dmi_check_system(smo8800_lis3lv02d_devices) || probe_i2c_addr) { /* * Register i2c-bus notifier + queue initial scan for lis3lv02d * i2c_client instantiation. @@ -370,6 +511,7 @@ static int smo8800_probe(struct platform_device *device) } else { dev_warn(&device->dev, "lis3lv02d accelerometer is present on SMBus but its address is unknown, skipping registration\n"); + dev_info(&device->dev, "Pass dell_smo8800.probe_i2c_addr=1 on the kernel commandline to probe, this may be dangerous!\n"); if (!smo8800->irq) return -ENODEV; }