cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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w1_ds2781.c (3457B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * 1-Wire implementation for the ds2781 chip
      4 *
      5 * Author: Renata Sayakhova <renata@oktetlabs.ru>
      6 *
      7 * Based on w1-ds2780 driver
      8 */
      9
     10#include <linux/kernel.h>
     11#include <linux/module.h>
     12#include <linux/device.h>
     13#include <linux/types.h>
     14#include <linux/platform_device.h>
     15#include <linux/mutex.h>
     16
     17#include <linux/w1.h>
     18
     19#include "w1_ds2781.h"
     20
     21#define W1_FAMILY_DS2781	0x3D
     22
     23static int w1_ds2781_do_io(struct device *dev, char *buf, int addr,
     24			size_t count, int io)
     25{
     26	struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
     27
     28	if (addr > DS2781_DATA_SIZE || addr < 0)
     29		return 0;
     30
     31	count = min_t(int, count, DS2781_DATA_SIZE - addr);
     32
     33	if (w1_reset_select_slave(sl) == 0) {
     34		if (io) {
     35			w1_write_8(sl->master, W1_DS2781_WRITE_DATA);
     36			w1_write_8(sl->master, addr);
     37			w1_write_block(sl->master, buf, count);
     38		} else {
     39			w1_write_8(sl->master, W1_DS2781_READ_DATA);
     40			w1_write_8(sl->master, addr);
     41			count = w1_read_block(sl->master, buf, count);
     42		}
     43	}
     44
     45	return count;
     46}
     47
     48int w1_ds2781_io(struct device *dev, char *buf, int addr, size_t count,
     49			int io)
     50{
     51	struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
     52	int ret;
     53
     54	if (!dev)
     55		return -ENODEV;
     56
     57	mutex_lock(&sl->master->bus_mutex);
     58
     59	ret = w1_ds2781_do_io(dev, buf, addr, count, io);
     60
     61	mutex_unlock(&sl->master->bus_mutex);
     62
     63	return ret;
     64}
     65EXPORT_SYMBOL(w1_ds2781_io);
     66
     67int w1_ds2781_eeprom_cmd(struct device *dev, int addr, int cmd)
     68{
     69	struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
     70
     71	if (!dev)
     72		return -EINVAL;
     73
     74	mutex_lock(&sl->master->bus_mutex);
     75
     76	if (w1_reset_select_slave(sl) == 0) {
     77		w1_write_8(sl->master, cmd);
     78		w1_write_8(sl->master, addr);
     79	}
     80
     81	mutex_unlock(&sl->master->bus_mutex);
     82	return 0;
     83}
     84EXPORT_SYMBOL(w1_ds2781_eeprom_cmd);
     85
     86static ssize_t w1_slave_read(struct file *filp, struct kobject *kobj,
     87			     struct bin_attribute *bin_attr, char *buf,
     88			     loff_t off, size_t count)
     89{
     90	struct device *dev = kobj_to_dev(kobj);
     91	return w1_ds2781_io(dev, buf, off, count, 0);
     92}
     93
     94static BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE);
     95
     96static struct bin_attribute *w1_ds2781_bin_attrs[] = {
     97	&bin_attr_w1_slave,
     98	NULL,
     99};
    100
    101static const struct attribute_group w1_ds2781_group = {
    102	.bin_attrs = w1_ds2781_bin_attrs,
    103};
    104
    105static const struct attribute_group *w1_ds2781_groups[] = {
    106	&w1_ds2781_group,
    107	NULL,
    108};
    109
    110static int w1_ds2781_add_slave(struct w1_slave *sl)
    111{
    112	int ret;
    113	struct platform_device *pdev;
    114
    115	pdev = platform_device_alloc("ds2781-battery", PLATFORM_DEVID_AUTO);
    116	if (!pdev)
    117		return -ENOMEM;
    118	pdev->dev.parent = &sl->dev;
    119
    120	ret = platform_device_add(pdev);
    121	if (ret)
    122		goto pdev_add_failed;
    123
    124	dev_set_drvdata(&sl->dev, pdev);
    125
    126	return 0;
    127
    128pdev_add_failed:
    129	platform_device_put(pdev);
    130
    131	return ret;
    132}
    133
    134static void w1_ds2781_remove_slave(struct w1_slave *sl)
    135{
    136	struct platform_device *pdev = dev_get_drvdata(&sl->dev);
    137
    138	platform_device_unregister(pdev);
    139}
    140
    141static const struct w1_family_ops w1_ds2781_fops = {
    142	.add_slave    = w1_ds2781_add_slave,
    143	.remove_slave = w1_ds2781_remove_slave,
    144	.groups       = w1_ds2781_groups,
    145};
    146
    147static struct w1_family w1_ds2781_family = {
    148	.fid = W1_FAMILY_DS2781,
    149	.fops = &w1_ds2781_fops,
    150};
    151module_w1_family(w1_ds2781_family);
    152
    153MODULE_AUTHOR("Renata Sayakhova <renata@oktetlabs.ru>");
    154MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC");
    155MODULE_LICENSE("GPL");
    156MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781));