From patchwork Mon Dec 27 22:42:01 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cosmin Tanislav X-Patchwork-Id: 12700063 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 601FCC433EF for ; Mon, 27 Dec 2021 22:42:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233894AbhL0Wm1 (ORCPT ); Mon, 27 Dec 2021 17:42:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229643AbhL0Wm0 (ORCPT ); Mon, 27 Dec 2021 17:42:26 -0500 Received: from mail-ed1-x52e.google.com (mail-ed1-x52e.google.com [IPv6:2a00:1450:4864:20::52e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A6344C06173E; Mon, 27 Dec 2021 14:42:25 -0800 (PST) Received: by mail-ed1-x52e.google.com with SMTP id w16so66712231edc.11; Mon, 27 Dec 2021 14:42:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=acGGMkplWtNeHQ2mdvAW/XLbQNWacsZS02d5/9vOayk=; b=BPhICOEdy9n0mW+PxvMqYCj9QMC8jQvQWJroFnUdX9quC6Gy/eDslOWgBoEGsaRcPE /8sUriPw1CgaSnT6b8nDUyxyJFowm64ZMApxqtF44ba57gmEWfCTkZExCXtpg748Tp/A ud2yBm/kHhoj4XiNB29qkBRE4wv/zGCan7PvcUSB6kff9aBJeX809qSss/Sb7BLVqqkV GJ3sVfcE616lH/AbPhuTE3qJPXufCi/TF1YoI+Lr1ks03JTJIQ7+BcSW55rpE+VkK1wj IdAQKZOQoWBiDuIzOqR2jlpLiEn/XKmfbg3Ir+4qblZ9xrk50OzvL2DMoN2DanXVuqIq eeeA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=acGGMkplWtNeHQ2mdvAW/XLbQNWacsZS02d5/9vOayk=; b=VuFdMFvqM+4rFrE6Vf2KCwTbPMTCYnbF28w8VOe06maPcEvi9dS+WI7Ir0MK35w7x4 c9XQqFMSeufTYzeSdMO+cPRhYmoMwosA72ce+4FIsIoXgxfFcxVja8AN714mM8RjFJmc yX8A7FGpp5qVpgeRx2PYPIKXOcZetPP+HZRyKaBzRIhcGrLGtM/TF0mqd74RUARjorwA p/7B4vEzebd9GN5kTZLpBwmHeMJsFjpaKPUPeFqztBC7Q+CvjZNA9rIhvTUS3/2BjDXK +ZEwOpP3AxmuLPiAHo3aJwMYPVPQkeltt73AfWu6e2r30VAQEwwIgxFa4Pcmf4c5HA4/ ja7A== X-Gm-Message-State: AOAM5330BMfYlegeH+rAP32EygrMFGd4MncrPBPnzO4fkQvixA8Ne1R4 ydytDE8MxIkR442oybh/dS8= X-Google-Smtp-Source: ABdhPJzod+OsJmxXBEAnbfCvwmtPpIDMnyLqyTjcX6EO1qknX2r3SZxpqVqR5mSKqfX+k0KnXZc+WQ== X-Received: by 2002:a17:906:5501:: with SMTP id r1mr15677804ejp.212.1640644944225; Mon, 27 Dec 2021 14:42:24 -0800 (PST) Received: from demon-pc.localdomain ([79.112.215.103]) by smtp.gmail.com with ESMTPSA id sb13sm5566806ejc.26.2021.12.27.14.42.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Dec 2021 14:42:23 -0800 (PST) From: Cosmin Tanislav To: Guenter Roeck Cc: cosmin.tanislav@analog.com, demonsingur@gmail.com, Jean Delvare , Jonathan Corbet , linux-hwmon@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/1] hwmon: Add debugfs register access Date: Tue, 28 Dec 2021 00:42:01 +0200 Message-Id: <20211227224201.508331-2-demonsingur@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211227224201.508331-1-demonsingur@gmail.com> References: <20211227224201.508331-1-demonsingur@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org From: Cosmin Tanislav Similar to IIO, create a device directory inside debugfs mount point, and create a direct_reg_access file inside that directory, if debugfs_reg_access callback is defined inside hwmon_ops. Signed-off-by: Cosmin Tanislav --- Documentation/hwmon/hwmon-kernel-api.rst | 9 +++ drivers/hwmon/hwmon.c | 97 ++++++++++++++++++++++++ include/linux/hwmon.h | 12 +++ 3 files changed, 118 insertions(+) diff --git a/Documentation/hwmon/hwmon-kernel-api.rst b/Documentation/hwmon/hwmon-kernel-api.rst index c41eb6108103..d568a0bfa5fb 100644 --- a/Documentation/hwmon/hwmon-kernel-api.rst +++ b/Documentation/hwmon/hwmon-kernel-api.rst @@ -136,6 +136,8 @@ The list of hwmon operations is defined as:: u32 attr, int, long *); int (*write)(struct device *, enum hwmon_sensor_types type, u32 attr, int, long); + int (*reg_access)(struct device *dev, unsigned int reg, + unsigned int writeval, unsigned int *readval); }; It defines the following operations. @@ -152,6 +154,13 @@ It defines the following operations. Pointer to a function for writing a value to the chip. This function is optional, but must be provided if any writeable attributes exist. +* reg_access: + Pointer to a function for writing or reading a register to the chip. + This function is optional. + WARNING: Drivers implementing this function must block any access that + may cause issues such as power loss, board resets, flash corruption or + bricking. + Each sensor channel is described with struct hwmon_channel_info, which is defined as follows:: diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c index 3501a3ead4ba..027e5fc33114 100644 --- a/drivers/hwmon/hwmon.c +++ b/drivers/hwmon/hwmon.c @@ -10,6 +10,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include +#include #include #include #include @@ -35,6 +36,9 @@ struct hwmon_device { struct list_head tzdata; struct attribute_group group; const struct attribute_group **groups; + unsigned int cached_reg_addr; + char read_buf[20]; + unsigned int read_buf_len; }; #define to_hwmon_device(d) container_of(d, struct hwmon_device, dev) @@ -64,6 +68,90 @@ struct hwmon_thermal_data { struct thermal_zone_device *tzd;/* thermal zone device */ }; +static struct dentry *hwmon_debugfs_dentry; + +static ssize_t hwmon_debugfs_read_reg(struct file *file, + char __user *userbuf, + size_t count, loff_t *ppos) +{ + struct hwmon_device *hwdev = file->private_data; + unsigned int val; + int ret; + + if (*ppos > 0) + return simple_read_from_buffer(userbuf, count, ppos, + hwdev->read_buf, + hwdev->read_buf_len); + + ret = hwdev->chip->ops->reg_access(&hwdev->dev, hwdev->cached_reg_addr, + 0, &val); + if (ret) + return ret; + + hwdev->read_buf_len = snprintf(hwdev->read_buf, sizeof(hwdev->read_buf), + "0x%X\n", val); + + return simple_read_from_buffer(userbuf, count, ppos, hwdev->read_buf, + hwdev->read_buf_len); +} + +static ssize_t hwmon_debugfs_write_reg(struct file *file, + const char __user *userbuf, + size_t count, loff_t *ppos) +{ + struct hwmon_device *hwdev = file->private_data; + unsigned int reg, val; + char buf[80]; + int ret; + + count = min_t(size_t, count, sizeof(buf) - 1); + if (copy_from_user(buf, userbuf, count)) + return -EFAULT; + + buf[count] = 0; + + ret = sscanf(buf, "%i %i", ®, &val); + + switch (ret) { + case 1: + hwdev->cached_reg_addr = reg; + break; + case 2: + hwdev->cached_reg_addr = reg; + ret = hwdev->chip->ops->reg_access(&hwdev->dev, reg, val, NULL); + if (ret) + return ret; + break; + default: + return -EINVAL; + } + + return count; +} + +static const struct file_operations hwmon_debugfs_reg_fops = { + .open = simple_open, + .read = hwmon_debugfs_read_reg, + .write = hwmon_debugfs_write_reg, +}; + +static void hwmon_device_register_debugfs(struct hwmon_device *hwdev) +{ + struct dentry *dir = debugfs_create_dir(dev_name(&hwdev->dev), + hwmon_debugfs_dentry); + + debugfs_create_file("direct_reg_access", 0644, dir, hwdev, + &hwmon_debugfs_reg_fops); +} + +static void hwmon_device_unregister_debugfs(struct hwmon_device *hwdev) +{ + struct dentry *dir = debugfs_lookup(dev_name(&hwdev->dev), + hwmon_debugfs_dentry); + + debugfs_remove_recursive(dir); +} + static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -114,6 +202,8 @@ static void hwmon_dev_release(struct device *dev) { struct hwmon_device *hwdev = to_hwmon_device(dev); + hwmon_device_unregister_debugfs(hwdev); + if (hwdev->group.attrs) hwmon_free_attrs(hwdev->group.attrs); kfree(hwdev->groups); @@ -817,6 +907,9 @@ __hwmon_device_register(struct device *dev, const char *name, void *drvdata, } } + if (chip && chip->ops->reg_access) + hwmon_device_register_debugfs(hwdev); + return hdev; free_hwmon: @@ -1062,12 +1155,16 @@ static int __init hwmon_init(void) pr_err("couldn't register hwmon sysfs class\n"); return err; } + + hwmon_debugfs_dentry = debugfs_create_dir("hwmon", NULL); + return 0; } static void __exit hwmon_exit(void) { class_unregister(&hwmon_class); + debugfs_remove(hwmon_debugfs_dentry); } subsys_initcall(hwmon_init); diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h index fad1f1df26df..587fb2931ac1 100644 --- a/include/linux/hwmon.h +++ b/include/linux/hwmon.h @@ -390,6 +390,16 @@ enum hwmon_intrusion_attributes { * Channel number * @val: Value to write * The function returns 0 on success or a negative error number. + * @reg_access: + * Callback to read or write register values. + * Parameters are: + * @dev: Pointer to hardware monitoring device + * @reg: Register address to read or write + * @writeval: + * Value to write to register. 0 when reading. + * @readval: + * Pointer to value read from register. NULL when writing. + * The function returns 0 on success or a negative error number. */ struct hwmon_ops { umode_t (*is_visible)(const void *drvdata, enum hwmon_sensor_types type, @@ -400,6 +410,8 @@ struct hwmon_ops { u32 attr, int channel, const char **str); int (*write)(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long val); + int (*reg_access)(struct device *dev, unsigned int reg, + unsigned int writeval, unsigned int *readval); }; /**