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[147.75.80.249]) by mx.google.com with ESMTPS id dt17-20020a170906b79100b00a3d1190865esi1018437ejb.185.2024.02.15.13.14.31 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Feb 2024 13:14:31 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-67685-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249; Authentication-Results: mx.google.com; arc=pass (i=1 spf=pass spfdomain=pengutronix.de); spf=pass (google.com: domain of linux-kernel+bounces-67685-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) smtp.mailfrom="linux-kernel+bounces-67685-ouuuleilei=gmail.com@vger.kernel.org" Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id 519381F23B1A for ; Thu, 15 Feb 2024 21:14:31 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 90DEB13DBA5; Thu, 15 Feb 2024 21:14:18 +0000 (UTC) Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (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 92A2B132461 for ; Thu, 15 Feb 2024 21:14:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708031657; cv=none; b=VccMJpe60yCfpkpNEphBxxGSishxt2gLF16YN4I3RH+A+RXPND1A0hr5saV56C6bEmALCIO3zy9T6E34hxkG0BADS14bo2WHdWrJfL3T/tYAClh7ME9q7ykzJw90/D0JqmXUd2AxYiHqIWTcHEaHOSM+iVthaK3CmVWsdTlbbQM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708031657; c=relaxed/simple; bh=XVy3hOobm6zUM/uUVP4IVcxxMoT0bKOg5SLpDVCDiZE=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=X/EJwnXo2dZAO9cUSx+TK22RYj5DS85FjpzBC6r1os6huJv7wllWXUYmk8dnvceWAoaff8Jyb3PBvLIBSZtno2DdOFe5QqbHm+hfAM/J9GufmTO3hUBFO1XlIZ7T42wXORIRu84tupwxzRSRTXh/aB0lyRs0E51D38CRUVSIxTE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from dude02.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::28]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1raj3W-0001Cg-Ff; Thu, 15 Feb 2024 22:14:06 +0100 From: Marco Felsch To: srinivas.kandagatla@linaro.org, gregkh@linuxfoundation.org, miquel.raynal@bootlin.com, michael@walle.cc, rafal@milecki.pl Cc: linux-kernel@vger.kernel.org, kernel@pengutronix.de Subject: [RFC PATCH] nvmem: core: add sysfs cell write support Date: Thu, 15 Feb 2024 22:14:01 +0100 Message-Id: <20240215211401.1201004-1-m.felsch@pengutronix.de> X-Mailer: git-send-email 2.39.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:1101:1d::28 X-SA-Exim-Mail-From: m.felsch@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1791001018152060472 X-GMAIL-MSGID: 1791001018152060472 Add the sysfs cell write support to make it possible to write to exposed cells from sysfs as well e.g. for device provisioning. Signed-off-by: Marco Felsch --- Hi, the purpose of this patch is to make the NVMEM cells exposed via the testing ABI sysfs writeable, to allow changes during devie life-time. Regards, Marco drivers/nvmem/core.c | 40 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-) diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index 980123fb4dde..5a497188cfea 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -336,6 +336,40 @@ static ssize_t nvmem_cell_attr_read(struct file *filp, struct kobject *kobj, return read_len; } +static ssize_t nvmem_cell_attr_write(struct file *filp, struct kobject *kobj, + struct bin_attribute *attr, char *buf, + loff_t pos, size_t count) +{ + struct nvmem_cell_entry *entry; + struct nvmem_cell *cell; + int ret; + + entry = attr->private; + + if (!entry->nvmem->reg_write) + return -EPERM; + + if (pos >= entry->bytes) + return -EFBIG; + + if (pos + count > entry->bytes) + count = entry->bytes - pos; + + cell = nvmem_create_cell(entry, entry->name, 0); + if (IS_ERR(cell)) + return PTR_ERR(cell); + + if (!cell) + return -EINVAL; + + ret = nvmem_cell_write(cell, buf, count); + + kfree_const(cell->id); + kfree(cell); + + return ret; +} + /* default read/write permissions */ static struct bin_attribute bin_attr_rw_nvmem = { .attr = { @@ -432,6 +466,7 @@ static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem) struct bin_attribute **cells_attrs, *attrs; struct nvmem_cell_entry *entry; unsigned int ncells = 0, i = 0; + umode_t mode; int ret = 0; mutex_lock(&nvmem_mutex); @@ -456,15 +491,18 @@ static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem) goto unlock_mutex; } + mode = nvmem_bin_attr_get_umode(nvmem); + /* Initialize each attribute to take the name and size of the cell */ list_for_each_entry(entry, &nvmem->cells, node) { sysfs_bin_attr_init(&attrs[i]); attrs[i].attr.name = devm_kasprintf(&nvmem->dev, GFP_KERNEL, "%s@%x", entry->name, entry->offset); - attrs[i].attr.mode = 0444; + attrs[i].attr.mode = mode; attrs[i].size = entry->bytes; attrs[i].read = &nvmem_cell_attr_read; + attrs[i].write = &nvmem_cell_attr_write; attrs[i].private = entry; if (!attrs[i].attr.name) { ret = -ENOMEM;