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 23 static 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 48 int 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 } 65 EXPORT_SYMBOL(w1_ds2781_io); 66 67 int 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 } 84 EXPORT_SYMBOL(w1_ds2781_eeprom_cmd); 85 86 static 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 95 static BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE); 96 97 static struct bin_attribute *w1_ds2781_bin_attrs[] = { 98 &bin_attr_w1_slave, 99 NULL, 100 }; 101 102 static const struct attribute_group w1_ds2781_group = { 103 .bin_attrs = w1_ds2781_bin_attrs, 104 }; 105 106 static const struct attribute_group *w1_ds2781_groups[] = { 107 &w1_ds2781_group, 108 NULL, 109 }; 110 111 static 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; 128 129 pdev_add_failed: 130 platform_device_put(pdev); 131 132 return ret; 133 } 134 135 static 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 } 141 142 static 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 }; 147 148 static struct w1_family w1_ds2781_family = { 149 .fid = W1_FAMILY_DS2781, 150 .fops = &w1_ds2781_fops, 151 }; 152 module_w1_family(w1_ds2781_family); 153 154 MODULE_AUTHOR("Renata Sayakhova <renata@oktetlabs.ru>"); 155 MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC"); 156 MODULE_LICENSE("GPL"); 157 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781)); 158