[v2,1/7] eeprom: Add a simple EEPROM framework for eeprom providers

Message ID	1426240214-2434-1-git-send-email-srinivas.kandagatla@linaro.org (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org> From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 1/7] eeprom: Add a simple EEPROM framework for eeprom providers Date: Fri, 13 Mar 2015 09:50:14 +0000 Message-Id: <1426240214-2434-1-git-send-email-srinivas.kandagatla@linaro.org> In-Reply-To: <1426240157-2383-1-git-send-email-srinivas.kandagatla@linaro.org> References: <1426240157-2383-1-git-send-email-srinivas.kandagatla@linaro.org> Cc: devicetree@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>, Pawel Moll <pawel.moll@arm.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, linux-api@vger.kernel.org, broonie@kernel.org, Stephen Boyd <sboyd@codeaurora.org>, linux-kernel@vger.kernel.org, Rob Herring <robh+dt@kernel.org>, Srinivas Kandagatla <srinivas.kandagatla@linaro.org>, Kumar Gala <galak@codeaurora.org>, Maxime Ripard <maxime.ripard@free-electrons.com>, linux-arm-msm@vger.kernel.org Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org

diff --git a/drivers/Kconfig b/drivers/Kconfig index c70d6e4..d7afc82 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -184,4 +184,6 @@ source "drivers/thunderbolt/Kconfig" source "drivers/android/Kconfig" +source "drivers/eeprom/Kconfig" + endmenu diff --git a/drivers/Makefile b/drivers/Makefile index 527a6da..57eb5b0 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -165,3 +165,4 @@ obj-$(CONFIG_RAS) += ras/ obj-$(CONFIG_THUNDERBOLT) += thunderbolt/ obj-$(CONFIG_CORESIGHT) += coresight/ obj-$(CONFIG_ANDROID) += android/ +obj-$(CONFIG_EEPROM) += eeprom/ diff --git a/drivers/eeprom/Kconfig b/drivers/eeprom/Kconfig new file mode 100644 index 0000000..21e1847 --- /dev/null +++ b/drivers/eeprom/Kconfig @@ -0,0 +1,11 @@ +menuconfig EEPROM + tristate "EEPROM Support" + depends on OF + select REGMAP + help + Support for EEPROM alike devices. + + This framework is designed to provide a generic interface to EEPROM + from both the Linux Kernel and the userspace. + + If unsure, say no. diff --git a/drivers/eeprom/Makefile b/drivers/eeprom/Makefile new file mode 100644 index 0000000..250c95a --- /dev/null +++ b/drivers/eeprom/Makefile @@ -0,0 +1,5 @@ +# +# Makefile for eeprom drivers. +# + +obj-$(CONFIG_EEPROM) += core.o diff --git a/drivers/eeprom/core.c b/drivers/eeprom/core.c new file mode 100644 index 0000000..a9839de --- /dev/null +++ b/drivers/eeprom/core.c @@ -0,0 +1,213 @@ +/* + * EEPROM framework core. + * + * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org> + * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/device.h> +#include <linux/eeprom-provider.h> +#include <linux/export.h> +#include <linux/fs.h> +#include <linux/idr.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/slab.h> +#include <linux/uaccess.h> + +struct eeprom_device { + struct regmap *regmap; + int stride; + size_t size; + + struct module *owner; + struct device dev; + int id; + int users; +}; + +static DEFINE_MUTEX(eeprom_mutex); +static DEFINE_IDA(eeprom_ida); + +#define to_eeprom(d) container_of(d, struct eeprom_device, dev) + +static ssize_t bin_attr_eeprom_read(struct file *filp, struct kobject *kobj, + struct bin_attribute *attr, + char *buf, loff_t offset, size_t count) +{ + struct device *dev = container_of(kobj, struct device, kobj); + struct eeprom_device *eeprom = to_eeprom(dev); + int rc; + + if (offset > eeprom->size) + return -EINVAL; + + if (offset + count > eeprom->size) + count = eeprom->size - offset; + + rc = regmap_bulk_read(eeprom->regmap, offset, + buf, count/eeprom->stride); + + if (IS_ERR_VALUE(rc)) + return rc; + + return count - count % eeprom->stride; +} + +static ssize_t bin_attr_eeprom_write(struct file *filp, struct kobject *kobj, + struct bin_attribute *attr, + char *buf, loff_t offset, size_t count) +{ + struct device *dev = container_of(kobj, struct device, kobj); + struct eeprom_device *eeprom = to_eeprom(dev); + int rc; + + if (offset > eeprom->size) + return -EINVAL; + + if (offset + count > eeprom->size) + count = eeprom->size - offset; + + rc = regmap_bulk_write(eeprom->regmap, offset, + buf, count/eeprom->stride); + + if (IS_ERR_VALUE(rc)) + return rc; + + return count - count % eeprom->stride; +} + +static struct bin_attribute bin_attr_eeprom = { + .attr = { + .name = "eeprom", + .mode = S_IWUSR | S_IRUGO, + }, + .read = bin_attr_eeprom_read, + .write = bin_attr_eeprom_write, +}; + +static struct bin_attribute *eeprom_bin_attributes[] = { + &bin_attr_eeprom, + NULL, +}; + +static const struct attribute_group eeprom_bin_group = { + .bin_attrs = eeprom_bin_attributes, +}; + +static const struct attribute_group *eeprom_dev_groups[] = { + &eeprom_bin_group, + NULL, +}; + +static void eeprom_release(struct device *dev) +{ + kfree(to_eeprom(dev)); +} + +static struct class eeprom_class = { + .name = "eeprom", + .dev_groups = eeprom_dev_groups, + .dev_release = eeprom_release, +}; + +/** + * eeprom_register(): Register a eeprom device for given eeprom. + * Also creates an binary entry in /sys/class/eeprom/name-id/eeprom + * + * @eeprom: eeprom device that needs to be created + * + * The return value will be an error code on error or a zero on success. + * The eeprom_device and sysfs entery will be freed by the eeprom_unregister(). + */ + +struct eeprom_device *eeprom_register(struct eeprom_config *config) +{ + struct eeprom_device *eeprom; + int rval; + + if (!config->regmap || !config->size) { + dev_err(config->dev, "Regmap not found\n"); + return ERR_PTR(-EINVAL); + } + + eeprom = kzalloc(sizeof(*eeprom), GFP_KERNEL); + if (!eeprom) + return ERR_PTR(-ENOMEM); + + eeprom->id = ida_simple_get(&eeprom_ida, 0, 0, GFP_KERNEL); + if (eeprom->id < 0) + return ERR_PTR(eeprom->id); + + eeprom->owner = config->owner; + eeprom->regmap = config->regmap; + eeprom->stride = config->stride; + eeprom->size = config->size; + eeprom->dev.class = &eeprom_class; + eeprom->dev.parent = config->dev; + eeprom->dev.of_node = config->dev ? config->dev->of_node : NULL; + dev_set_name(&eeprom->dev, "%s%d", + config->name ? : "eeprom", config->id); + + device_initialize(&eeprom->dev); + + dev_dbg(&eeprom->dev, "Registering eeprom device %s\n", + dev_name(&eeprom->dev)); + + rval = device_add(&eeprom->dev); + if (rval) + return ERR_PTR(rval); + + return eeprom; +} +EXPORT_SYMBOL_GPL(eeprom_register); + +/** + * eeprom_unregister(): Unregister previously registered eeprom device + * + * @eeprom: Pointer to previously registered eeprom device. + * + * The return value will be an non zero on error or a zero on success. + */ +int eeprom_unregister(struct eeprom_device *eeprom) +{ + mutex_lock(&eeprom_mutex); + if (eeprom->users) { + mutex_unlock(&eeprom_mutex); + return -EBUSY; + } + mutex_unlock(&eeprom_mutex); + + device_del(&eeprom->dev); + + return 0; +} +EXPORT_SYMBOL_GPL(eeprom_unregister); + +static int eeprom_init(void) +{ + return class_register(&eeprom_class); +} + +static void eeprom_exit(void) +{ + class_unregister(&eeprom_class); +} + +subsys_initcall(eeprom_init); +module_exit(eeprom_exit); + +MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org"); +MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com"); +MODULE_DESCRIPTION("EEPROM Driver Core"); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/eeprom-provider.h b/include/linux/eeprom-provider.h new file mode 100644 index 0000000..21afdaa --- /dev/null +++ b/include/linux/eeprom-provider.h @@ -0,0 +1,47 @@ +/* + * EEPROM framework provider. + * + * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org> + * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#ifndef _LINUX_EEPROM_PROVIDER_H +#define _LINUX_EEPROM_PROVIDER_H + +#include <linux/regmap.h> + +struct eeprom_device; + +struct eeprom_config { + struct device *dev; + struct regmap *regmap; + const char *name; + int id; + int stride; + size_t size; + struct module *owner; +}; + +#if IS_ENABLED(CONFIG_EEPROM) + +struct eeprom_device *eeprom_register(struct eeprom_config *cfg); +int eeprom_unregister(struct eeprom_device *eeprom); + +#else + +static inline struct eeprom_device *eeprom_register(struct eeprom_config *cfg) +{ + return NULL; +} +static inline int eeprom_unregister(struct eeprom_device *eeprom) +{ + return -ENOSYS; +} + +#endif /* CONFIG_EEPROM */ + +#endif /* ifndef _LINUX_EEPROM_PROVIDER_H */

[v2,1/7] eeprom: Add a simple EEPROM framework for eeprom providers

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