1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * 1-Wire implementation for the ds2780 chip 4 * 5 * Copyright (C) 2010 Indesign, LLC 6 * 7 * Author: Clifton Barnes <cabarnes@indesign-llc.com> 8 * 9 * Based on w1-ds2760 driver 10 */ 11 12 #include <linux/kernel.h> 13 #include <linux/module.h> 14 #include <linux/device.h> 15 #include <linux/types.h> 16 #include <linux/platform_device.h> 17 #include <linux/mutex.h> 18 #include <linux/idr.h> 19 20 #include <linux/w1.h> 21 22 #include "w1_ds2780.h" 23 24 #define W1_FAMILY_DS2780 0x32 25 26 static int w1_ds2780_do_io(struct device *dev, char *buf, int addr, 27 size_t count, int io) 28 { 29 struct w1_slave *sl = container_of(dev, struct w1_slave, dev); 30 31 if (addr > DS2780_DATA_SIZE || addr < 0) 32 return 0; 33 34 count = min_t(int, count, DS2780_DATA_SIZE - addr); 35 36 if (w1_reset_select_slave(sl) == 0) { 37 if (io) { 38 w1_write_8(sl->master, W1_DS2780_WRITE_DATA); 39 w1_write_8(sl->master, addr); 40 w1_write_block(sl->master, buf, count); 41 } else { 42 w1_write_8(sl->master, W1_DS2780_READ_DATA); 43 w1_write_8(sl->master, addr); 44 count = w1_read_block(sl->master, buf, count); 45 } 46 } 47 48 return count; 49 } 50 51 int w1_ds2780_io(struct device *dev, char *buf, int addr, size_t count, 52 int io) 53 { 54 struct w1_slave *sl = container_of(dev, struct w1_slave, dev); 55 int ret; 56 57 if (!dev) 58 return -ENODEV; 59 60 mutex_lock(&sl->master->bus_mutex); 61 62 ret = w1_ds2780_do_io(dev, buf, addr, count, io); 63 64 mutex_unlock(&sl->master->bus_mutex); 65 66 return ret; 67 } 68 EXPORT_SYMBOL(w1_ds2780_io); 69 70 int w1_ds2780_eeprom_cmd(struct device *dev, int addr, int cmd) 71 { 72 struct w1_slave *sl = container_of(dev, struct w1_slave, dev); 73 74 if (!dev) 75 return -EINVAL; 76 77 mutex_lock(&sl->master->bus_mutex); 78 79 if (w1_reset_select_slave(sl) == 0) { 80 w1_write_8(sl->master, cmd); 81 w1_write_8(sl->master, addr); 82 } 83 84 mutex_unlock(&sl->master->bus_mutex); 85 return 0; 86 } 87 EXPORT_SYMBOL(w1_ds2780_eeprom_cmd); 88 89 static ssize_t w1_slave_read(struct file *filp, struct kobject *kobj, 90 struct bin_attribute *bin_attr, char *buf, 91 loff_t off, size_t count) 92 { 93 struct device *dev = container_of(kobj, struct device, kobj); 94 return w1_ds2780_io(dev, buf, off, count, 0); 95 } 96 97 static BIN_ATTR_RO(w1_slave, DS2780_DATA_SIZE); 98 99 static struct bin_attribute *w1_ds2780_bin_attrs[] = { 100 &bin_attr_w1_slave, 101 NULL, 102 }; 103 104 static const struct attribute_group w1_ds2780_group = { 105 .bin_attrs = w1_ds2780_bin_attrs, 106 }; 107 108 static const struct attribute_group *w1_ds2780_groups[] = { 109 &w1_ds2780_group, 110 NULL, 111 }; 112 113 static int w1_ds2780_add_slave(struct w1_slave *sl) 114 { 115 int ret; 116 struct platform_device *pdev; 117 118 pdev = platform_device_alloc("ds2780-battery", PLATFORM_DEVID_AUTO); 119 if (!pdev) 120 return -ENOMEM; 121 pdev->dev.parent = &sl->dev; 122 123 ret = platform_device_add(pdev); 124 if (ret) 125 goto pdev_add_failed; 126 127 dev_set_drvdata(&sl->dev, pdev); 128 129 return 0; 130 131 pdev_add_failed: 132 platform_device_put(pdev); 133 134 return ret; 135 } 136 137 static void w1_ds2780_remove_slave(struct w1_slave *sl) 138 { 139 struct platform_device *pdev = dev_get_drvdata(&sl->dev); 140 141 platform_device_unregister(pdev); 142 } 143 144 static const struct w1_family_ops w1_ds2780_fops = { 145 .add_slave = w1_ds2780_add_slave, 146 .remove_slave = w1_ds2780_remove_slave, 147 .groups = w1_ds2780_groups, 148 }; 149 150 static struct w1_family w1_ds2780_family = { 151 .fid = W1_FAMILY_DS2780, 152 .fops = &w1_ds2780_fops, 153 }; 154 module_w1_family(w1_ds2780_family); 155 156 MODULE_AUTHOR("Clifton Barnes <cabarnes@indesign-llc.com>"); 157 MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2780 Stand-Alone Fuel Gauge IC"); 158 MODULE_LICENSE("GPL"); 159 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2780)); 160