From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f50.google.com (mail-pj1-f50.google.com [209.85.216.50]) (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 6F2A59463 for ; Mon, 4 May 2026 01:33:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.50 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777858387; cv=none; b=EwSU/9sWJ67KJaeeDgxxH4ONZp4wivB+Esk7fX6sDlUFE9J/UszvitPR78q7rjRe2WI74WK1wXm0XoHfO4kKvSPg7NdFovEeXKYhAUL+JAy8nh6ke+WDnEwY6AgHXk7zJuSH0N581tUnbpeJBx1YAx1itmvQ7bKVELbyCGrG1rA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777858387; c=relaxed/simple; bh=iIZwcSJHTKXE1raLWL9tGJ3+wg5Yrl2KpUp4gDdaCwc=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=j8oFWi6FULhgswnikA0I7g3cZkV58FOiT4q9wjPw4WM3YegEkORTgd9/V8b5ECr5yID5l2RmhWwn2ZyR+nSsZugPBRcMDlKcchtP9pmTB8YgF5UEOgMKU+nzCSVTgU6OoJJ3vdLQRd1+r3ZvL8lWw1AD2kJwsYH0344Zgj48c2U= 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=oBTjxwS4; arc=none smtp.client-ip=209.85.216.50 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="oBTjxwS4" Received: by mail-pj1-f50.google.com with SMTP id 98e67ed59e1d1-365312a27abso709369a91.3 for ; Sun, 03 May 2026 18:33:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1777858386; x=1778463186; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=Vt1MXjRWO808dcrw7GdArARkDsPebzOjnTivrvOFjdE=; b=oBTjxwS4+p0JZZZkqE6JL7IpjACBrlNTMmGPkjpUJeJAGbiAC/erkpxDtF+e/+pqWr zyC1NrR4hX8WTiuKxt5d9qRRwRLegofMsgvR4TzbfPG8sTSVA/KQ8AByxOaNcTaNtyKI 7OdWczgY1DP5vT3M46oRsTeugNg6D8Iak9GMtpA+GMMoQ3TdBwEImI8qUbBYMV0g51Sq hsIPIztILtYhz6mU9fnKTZKOJSt3rvYIkjPnWHlMIUwkafaezwhY5LVHZxYBIAc7slgK cIjmlZOVYDOlE4p2mbihR5f1d1Woiz8IS4tVEpTEWfvSg31EK45iyUnFwfon+Wz/4z3i ghCg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777858386; x=1778463186; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Vt1MXjRWO808dcrw7GdArARkDsPebzOjnTivrvOFjdE=; b=IcQcNfAKqF9JCBDh4Fr5TdfVbJhg+gQXbfKBYjPAHfpTR8zv7DYl4qkuL8r/eVVcuD GLYDFtuEl/OF+Hp5o5lo96ZiTCFy6W+gfI7AdiBOMHILkiDA1tqbJ5XcUd1zza2S2MvQ FJYzGngX1CYWaY37w7EEP6obnCJ9yxBmWEqM2a2CCgBPmpNmEbCW4nxXjlzQ/XIdVLpT bqAt7hbBcCc0rXAn5vKlnm8U07DbHj2rbdFVzQ12vtJD7+tcLpzpL1qLspJC3XyX+Fdc cO0dB5MUnZCg/PjFj44ftmkkUp8LCpAeI9ZCRZ+EAV2VcE869GcqdvLAMFk3miPdLBtJ 9yhw== X-Forwarded-Encrypted: i=1; AFNElJ8+wky5mHb5x2Fm2sEb8aEWb/Bm/sb1lE4SSiM2Tk++yfpZL5yqVDwqdmfNYppALQms+5uqZsvQ/vzjbA8=@vger.kernel.org X-Gm-Message-State: AOJu0Yz7CIi3tUKHB8qA9He1lZPzYOKGH3tP+uFMP8VCgHsPm7GpS9AI GUozoI1XjcIUO0tZvhVwRcrMmYvtfiJkj4m+x+diud2aYS2CLi0ffuE9 X-Gm-Gg: AeBDietCELkV7dZ8HwMU/wlpSrhdZ3EzAxm+kSMSVQNbFw4QdpawrkUNWsfSs9cnBuw NELprMWsWPBkwRfLIacA23v5s5pBP4Ovek83gKAwQ1SacfXH14IkB+iCiICzs83PgTLpFa/orpA 0VaKGs5tdjlGRv2j0qDC9y6Qswi5jduyaL+TTCr26LjDmIPF53P7RTmy49pdDYC/WUIjNBOg1UN skATVc0Sb0z6ojTLZNvNjDnGHJ09tfDMl/jipFf1+2zvwX3ejyQYc58YqWa9AObTRxxdEusfyZP /M6j3utvrnPHuzJxO2YWHkagK3eIIhU3/YBVD/OAZguarFIEJgF7xQmAQpCIyQ6lp9WwLd1P3EL GrFNwxrnkLHmZBz83rOdCjyy9DgsJn2GgkOSOLqYdJSSgSPkz520xyG5TKUBNCA52TttIqfK+WU Izpt86yaWe7Xkh4e0JoxPBOhaxu6g16cP3qNDSeZ3ABuR/xEDmIEI9AIZOUmXlCNZ2 X-Received: by 2002:a17:90b:4ac2:b0:35f:b6a1:8d27 with SMTP id 98e67ed59e1d1-3650ce83a97mr8193407a91.18.1777858385651; Sun, 03 May 2026 18:33:05 -0700 (PDT) Received: from localhost (61-219-108-167.hinet-ip.hinet.net. [61.219.108.167]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-364ec027690sm9306553a91.13.2026.05.03.18.33.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 03 May 2026 18:33:05 -0700 (PDT) From: Jack Wu X-Google-Original-From: Jack Wu To: Hans de Goede , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Cc: platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, Mario Limonciello , Armin Wolf Subject: [PATCH v6 1/2] platform/x86: dell-dw5826e: Add reset driver for DW5826e Date: Mon, 4 May 2026 09:32:43 +0800 Message-Id: <20260504013243.2445940-1-jackbb_wu@compal.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit If the DW5826e is in a frozen state and unable to receive USB commands, this driver provides a method for the user to reset the DW5826e via ACPI. E.g: echo 1 > /sys/bus/platform/devices/PALC0001\:00/wwan_reset Reviewed-by: Mario Limonciello (AMD) Reviewed-by: Armin Wolf Signed-off-by: Jack Wu --- v6: - Use same define for the DSM check v5: - Use BIT() for the DSM method v4: - Fix version of the ABI documentation to 7.2 - Add include linux/types.h v3: - Rename sysfs attribute from "pldr" to "wwan_reset" for clarity - Add ABI documentation for the wwan_reset sysfs interface - Validate _DSM method availability in probe using acpi_check_dsm() v2: - Remove extra empty line - Add missing includes and Remove unnecessary includes, sort includes alphabetically - Remove noisy dev_info() - Handle obj->type != ACPI_TYPE_BUFFER as error with proper return code - Replace miscdevice/file_operations with sysfs attribute (DEVICE_ATTR_WO) to reduce boilerplate - Propagate trigger_palc_pldr() return code to userspace - Convert from acpi_driver to platform_driver --- --- .../testing/sysfs-driver-dell-dw5826e-reset | 9 ++ drivers/platform/x86/dell/Kconfig | 6 ++ drivers/platform/x86/dell/Makefile | 2 + .../platform/x86/dell/dell-dw5826e-reset.c | 93 +++++++++++++++++++ 4 files changed, 110 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-driver-dell-dw5826e-reset create mode 100644 drivers/platform/x86/dell/dell-dw5826e-reset.c diff --git a/Documentation/ABI/testing/sysfs-driver-dell-dw5826e-reset b/Documentation/ABI/testing/sysfs-driver-dell-dw5826e-reset new file mode 100644 index 000000000000..a665e265633f --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-dell-dw5826e-reset @@ -0,0 +1,9 @@ +What: /sys/bus/platform/devices//wwan_reset +Date: April 2026 +KernelVersion: 7.2 +Contact: Jackbb Wu +Description: + Writing to this file triggers a Platform Level Device Reset + (PLDR) of the Dell DW5826e WWAN module via an ACPI _DSM + method. This can be used to recover the modem when it is in + a frozen state and unable to respond to USB commands. diff --git a/drivers/platform/x86/dell/Kconfig b/drivers/platform/x86/dell/Kconfig index 738c108c2163..c4540c837a88 100644 --- a/drivers/platform/x86/dell/Kconfig +++ b/drivers/platform/x86/dell/Kconfig @@ -276,4 +276,10 @@ config DELL_WMI_SYSMAN To compile this driver as a module, choose M here: the module will be called dell-wmi-sysman. +config DELL_DW5826E_RESET + tristate "Dell DW5826e PLDR reset support" + default m + depends on ACPI + help + This adds support for the Dell DW5826e PLDR reset via ACPI endif # X86_PLATFORM_DRIVERS_DELL diff --git a/drivers/platform/x86/dell/Makefile b/drivers/platform/x86/dell/Makefile index c7501c25e627..8150283cfd1d 100644 --- a/drivers/platform/x86/dell/Makefile +++ b/drivers/platform/x86/dell/Makefile @@ -28,3 +28,5 @@ obj-$(CONFIG_DELL_WMI_DESCRIPTOR) += dell-wmi-descriptor.o obj-$(CONFIG_DELL_WMI_DDV) += dell-wmi-ddv.o obj-$(CONFIG_DELL_WMI_LED) += dell-wmi-led.o obj-$(CONFIG_DELL_WMI_SYSMAN) += dell-wmi-sysman/ +obj-$(CONFIG_DELL_DW5826E_RESET) += dell-dw5826e-reset.o + diff --git a/drivers/platform/x86/dell/dell-dw5826e-reset.c b/drivers/platform/x86/dell/dell-dw5826e-reset.c new file mode 100644 index 000000000000..d37c6a66c4c3 --- /dev/null +++ b/drivers/platform/x86/dell/dell-dw5826e-reset.c @@ -0,0 +1,93 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * dell-dw5826e-reset.c - Dell DW5826e reset driver + * + * Copyright (C) 2026 Jackbb Wu + */ + +#include +#include +#include +#include +#include +#include +#include + +#define PALC_DSM_FN_TRIGGER_PLDR 1 + +static guid_t palc_dsm_guid = + GUID_INIT(0x5a1a4bba, 0x8006, 0x487e, 0xbe, 0x0a, 0xac, 0xf5, 0xd8, 0xfd, 0xfe, 0x59); + +static int trigger_palc_pldr(struct device *dev, acpi_handle handle) +{ + union acpi_object *obj; + int ret = 0; + + obj = acpi_evaluate_dsm(handle, &palc_dsm_guid, 1, BIT(PALC_DSM_FN_TRIGGER_PLDR), NULL); + if (!obj) { + dev_err(dev, "Failed to evaluate _DSM\n"); + return -EIO; + } + + if (obj->type != ACPI_TYPE_BUFFER) { + dev_err(dev, "Unexpected _DSM return type: %d\n", obj->type); + ret = -EINVAL; + } + + ACPI_FREE(obj); + return ret; +} + +static ssize_t wwan_reset_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + acpi_handle handle = ACPI_HANDLE(dev); + int ret; + + ret = trigger_palc_pldr(dev, handle); + if (ret) + return ret; + + return count; +} +static DEVICE_ATTR_WO(wwan_reset); + +static struct attribute *palc_attrs[] = { + &dev_attr_wwan_reset.attr, + NULL +}; +ATTRIBUTE_GROUPS(palc); + +static int palc_probe(struct platform_device *pdev) +{ + acpi_handle handle; + + handle = ACPI_HANDLE(&pdev->dev); + if (!handle) + return -ENODEV; + + if (!acpi_check_dsm(handle, &palc_dsm_guid, 1, BIT(PALC_DSM_FN_TRIGGER_PLDR))) + return -ENODEV; + + return 0; +} + +static const struct acpi_device_id palc_acpi_ids[] = { + { "PALC0001", 0 }, + { } +}; +MODULE_DEVICE_TABLE(acpi, palc_acpi_ids); + +static struct platform_driver palc_driver = { + .driver = { + .name = "dell-dw5826e-reset", + .acpi_match_table = palc_acpi_ids, + .dev_groups = palc_groups, + }, + .probe = palc_probe, +}; +module_platform_driver(palc_driver); + +MODULE_DESCRIPTION("Dell DW5826e reset driver"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("JackBB Wu"); -- 2.34.1