w1/slaves/w1_ds2781.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * 1-Wire implementation for the ds2781 chip
0004  *
0005  * Author: Renata Sayakhova <renata@oktetlabs.ru>
0006  *
0007  * Based on w1-ds2780 driver
0008  */
0009
0010 #include <linux/kernel.h>
0011 #include <linux/module.h>
0012 #include <linux/device.h>
0013 #include <linux/types.h>
0014 #include <linux/platform_device.h>
0015 #include <linux/mutex.h>
0016
0017 #include <linux/w1.h>
0018
0019 #include "w1_ds2781.h"
0020
0021 #define W1_FAMILY_DS2781    0x3D
0022
0023 static int w1_ds2781_do_io(struct device *dev, char *buf, int addr,
0024             size_t count, int io)
0025 {
0026     struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
0027
0028     if (addr > DS2781_DATA_SIZE || addr < 0)
0029         return 0;
0030
0031     count = min_t(int, count, DS2781_DATA_SIZE - addr);
0032
0033     if (w1_reset_select_slave(sl) == 0) {
0034         if (io) {
0035             w1_write_8(sl->master, W1_DS2781_WRITE_DATA);
0036             w1_write_8(sl->master, addr);
0037             w1_write_block(sl->master, buf, count);
0038         } else {
0039             w1_write_8(sl->master, W1_DS2781_READ_DATA);
0040             w1_write_8(sl->master, addr);
0041             count = w1_read_block(sl->master, buf, count);
0042         }
0043     }
0044
0045     return count;
0046 }
0047
0048 int w1_ds2781_io(struct device *dev, char *buf, int addr, size_t count,
0049             int io)
0050 {
0051     struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
0052     int ret;
0053
0054     if (!dev)
0055         return -ENODEV;
0056
0057     mutex_lock(&sl->master->bus_mutex);
0058
0059     ret = w1_ds2781_do_io(dev, buf, addr, count, io);
0060
0061     mutex_unlock(&sl->master->bus_mutex);
0062
0063     return ret;
0064 }
0065 EXPORT_SYMBOL(w1_ds2781_io);
0066
0067 int w1_ds2781_eeprom_cmd(struct device *dev, int addr, int cmd)
0068 {
0069     struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
0070
0071     if (!dev)
0072         return -EINVAL;
0073
0074     mutex_lock(&sl->master->bus_mutex);
0075
0076     if (w1_reset_select_slave(sl) == 0) {
0077         w1_write_8(sl->master, cmd);
0078         w1_write_8(sl->master, addr);
0079     }
0080
0081     mutex_unlock(&sl->master->bus_mutex);
0082     return 0;
0083 }
0084 EXPORT_SYMBOL(w1_ds2781_eeprom_cmd);
0085
0086 static ssize_t w1_slave_read(struct file *filp, struct kobject *kobj,
0087                  struct bin_attribute *bin_attr, char *buf,
0088                  loff_t off, size_t count)
0089 {
0090     struct device *dev = kobj_to_dev(kobj);
0091     return w1_ds2781_io(dev, buf, off, count, 0);
0092 }
0093
0094 static BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE);
0095
0096 static struct bin_attribute *w1_ds2781_bin_attrs[] = {
0097     &bin_attr_w1_slave,
0098     NULL,
0099 };
0100
0101 static const struct attribute_group w1_ds2781_group = {
0102     .bin_attrs = w1_ds2781_bin_attrs,
0103 };
0104
0105 static const struct attribute_group *w1_ds2781_groups[] = {
0106     &w1_ds2781_group,
0107     NULL,
0108 };
0109
0110 static int w1_ds2781_add_slave(struct w1_slave *sl)
0111 {
0112     int ret;
0113     struct platform_device *pdev;
0114
0115     pdev = platform_device_alloc("ds2781-battery", PLATFORM_DEVID_AUTO);
0116     if (!pdev)
0117         return -ENOMEM;
0118     pdev->dev.parent = &sl->dev;
0119
0120     ret = platform_device_add(pdev);
0121     if (ret)
0122         goto pdev_add_failed;
0123
0124     dev_set_drvdata(&sl->dev, pdev);
0125
0126     return 0;
0127
0128 pdev_add_failed:
0129     platform_device_put(pdev);
0130
0131     return ret;
0132 }
0133
0134 static void w1_ds2781_remove_slave(struct w1_slave *sl)
0135 {
0136     struct platform_device *pdev = dev_get_drvdata(&sl->dev);
0137
0138     platform_device_unregister(pdev);
0139 }
0140
0141 static const struct w1_family_ops w1_ds2781_fops = {
0142     .add_slave    = w1_ds2781_add_slave,
0143     .remove_slave = w1_ds2781_remove_slave,
0144     .groups       = w1_ds2781_groups,
0145 };
0146
0147 static struct w1_family w1_ds2781_family = {
0148     .fid = W1_FAMILY_DS2781,
0149     .fops = &w1_ds2781_fops,
0150 };
0151 module_w1_family(w1_ds2781_family);
0152
0153 MODULE_AUTHOR("Renata Sayakhova <renata@oktetlabs.ru>");
0154 MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC");
0155 MODULE_LICENSE("GPL");
0156 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781));