ac75779b72
Switch the parent of the nvmem device to the parent of the rtc device so it can be registered before the RTC. This is a small change in the ABI as the nvmem moves out of the /sys/class/rtc/rtcX folder to be under the parent device folder (that is where the previous nvram files where registered). However, it is still available under its correct location, /sys/bus/nvmem/devices which is the one that should be used by userspace applications. The other benefit is that the nvmem device can stay registered even if the rtc registration fails. Or it is possible to not register the rtc if the nvmem registration failed. Finally, it makes a lot of sense for devices that actually have different i2c or spi addresses for the RTC and the EEPROM. That is basically how it would end up when using MFD or even completely separate devices. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
119 lines
2.6 KiB
C
119 lines
2.6 KiB
C
/*
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* RTC subsystem, nvmem interface
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*
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* Copyright (C) 2017 Alexandre Belloni
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/err.h>
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#include <linux/types.h>
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#include <linux/nvmem-consumer.h>
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#include <linux/rtc.h>
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#include <linux/sysfs.h>
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#include "rtc-core.h"
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/*
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* Deprecated ABI compatibility, this should be removed at some point
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*/
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static const char nvram_warning[] = "Deprecated ABI, please use nvmem";
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static ssize_t
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rtc_nvram_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *attr,
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char *buf, loff_t off, size_t count)
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{
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struct rtc_device *rtc = attr->private;
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dev_warn_once(kobj_to_dev(kobj), nvram_warning);
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return nvmem_device_read(rtc->nvmem, off, count, buf);
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}
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static ssize_t
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rtc_nvram_write(struct file *filp, struct kobject *kobj,
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struct bin_attribute *attr,
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char *buf, loff_t off, size_t count)
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{
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struct rtc_device *rtc = attr->private;
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dev_warn_once(kobj_to_dev(kobj), nvram_warning);
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return nvmem_device_write(rtc->nvmem, off, count, buf);
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}
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static int rtc_nvram_register(struct rtc_device *rtc, size_t size)
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{
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int err;
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rtc->nvram = devm_kzalloc(rtc->dev.parent,
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sizeof(struct bin_attribute),
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GFP_KERNEL);
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if (!rtc->nvram)
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return -ENOMEM;
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rtc->nvram->attr.name = "nvram";
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rtc->nvram->attr.mode = 0644;
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rtc->nvram->private = rtc;
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sysfs_bin_attr_init(rtc->nvram);
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rtc->nvram->read = rtc_nvram_read;
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rtc->nvram->write = rtc_nvram_write;
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rtc->nvram->size = size;
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err = sysfs_create_bin_file(&rtc->dev.parent->kobj,
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rtc->nvram);
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if (err) {
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devm_kfree(rtc->dev.parent, rtc->nvram);
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rtc->nvram = NULL;
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}
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return err;
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}
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static void rtc_nvram_unregister(struct rtc_device *rtc)
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{
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sysfs_remove_bin_file(&rtc->dev.parent->kobj, rtc->nvram);
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}
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/*
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* New ABI, uses nvmem
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*/
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int rtc_nvmem_register(struct rtc_device *rtc,
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struct nvmem_config *nvmem_config)
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{
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if (!IS_ERR_OR_NULL(rtc->nvmem))
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return -EBUSY;
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if (!nvmem_config)
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return -ENODEV;
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nvmem_config->dev = rtc->dev.parent;
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nvmem_config->owner = rtc->owner;
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rtc->nvmem = nvmem_register(nvmem_config);
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if (IS_ERR_OR_NULL(rtc->nvmem))
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return PTR_ERR(rtc->nvmem);
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/* Register the old ABI */
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if (rtc->nvram_old_abi)
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rtc_nvram_register(rtc, nvmem_config->size);
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return 0;
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}
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void rtc_nvmem_unregister(struct rtc_device *rtc)
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{
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if (IS_ERR_OR_NULL(rtc->nvmem))
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return;
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/* unregister the old ABI */
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if (rtc->nvram)
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rtc_nvram_unregister(rtc);
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nvmem_unregister(rtc->nvmem);
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}
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