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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * 1-Wire implementation for the ds2781 chip4 *5 * Author: Renata Sayakhova <renata@oktetlabs.ru>6 *7 * Based on w1-ds2780 driver8 */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 0x3D22 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 92 return w1_ds2781_io(dev, buf, off, count, 0);93}94 95static BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE);96 97static struct bin_attribute *w1_ds2781_bin_attrs[] = {98 &bin_attr_w1_slave,99 NULL,100};101 102static const struct attribute_group w1_ds2781_group = {103 .bin_attrs = w1_ds2781_bin_attrs,104};105 106static const struct attribute_group *w1_ds2781_groups[] = {107 &w1_ds2781_group,108 NULL,109};110 111static int w1_ds2781_add_slave(struct w1_slave *sl)112{113 int ret;114 struct platform_device *pdev;115 116 pdev = platform_device_alloc("ds2781-battery", PLATFORM_DEVID_AUTO);117 if (!pdev)118 return -ENOMEM;119 pdev->dev.parent = &sl->dev;120 121 ret = platform_device_add(pdev);122 if (ret)123 goto pdev_add_failed;124 125 dev_set_drvdata(&sl->dev, pdev);126 127 return 0;128 129pdev_add_failed:130 platform_device_put(pdev);131 132 return ret;133}134 135static void w1_ds2781_remove_slave(struct w1_slave *sl)136{137 struct platform_device *pdev = dev_get_drvdata(&sl->dev);138 139 platform_device_unregister(pdev);140}141 142static const struct w1_family_ops w1_ds2781_fops = {143 .add_slave = w1_ds2781_add_slave,144 .remove_slave = w1_ds2781_remove_slave,145 .groups = w1_ds2781_groups,146};147 148static struct w1_family w1_ds2781_family = {149 .fid = W1_FAMILY_DS2781,150 .fops = &w1_ds2781_fops,151};152module_w1_family(w1_ds2781_family);153 154MODULE_AUTHOR("Renata Sayakhova <renata@oktetlabs.ru>");155MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC");156MODULE_LICENSE("GPL");157MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781));158