1 /* 2 * w1_ds2413.c - w1 family 3a (DS2413) driver 3 * based on w1_ds2408.c by Jean-Francois Dagenais <dagenaisj@sonatest.com> 4 * 5 * Copyright (c) 2013 Mariusz Bialonczyk <manio@skyboo.net> 6 * 7 * This source code is licensed under the GNU General Public License, 8 * Version 2. See the file COPYING for more details. 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/module.h> 13 #include <linux/moduleparam.h> 14 #include <linux/device.h> 15 #include <linux/types.h> 16 #include <linux/delay.h> 17 #include <linux/slab.h> 18 19 #include "../w1.h" 20 #include "../w1_int.h" 21 #include "../w1_family.h" 22 23 MODULE_LICENSE("GPL"); 24 MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>"); 25 MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO"); 26 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413)); 27 28 #define W1_F3A_RETRIES 3 29 #define W1_F3A_FUNC_PIO_ACCESS_READ 0xF5 30 #define W1_F3A_FUNC_PIO_ACCESS_WRITE 0x5A 31 #define W1_F3A_SUCCESS_CONFIRM_BYTE 0xAA 32 33 static ssize_t state_read(struct file *filp, struct kobject *kobj, 34 struct bin_attribute *bin_attr, char *buf, loff_t off, 35 size_t count) 36 { 37 struct w1_slave *sl = kobj_to_w1_slave(kobj); 38 dev_dbg(&sl->dev, 39 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p", 40 bin_attr->attr.name, kobj, (unsigned int)off, count, buf); 41 42 if (off != 0) 43 return 0; 44 if (!buf) 45 return -EINVAL; 46 47 mutex_lock(&sl->master->bus_mutex); 48 dev_dbg(&sl->dev, "mutex locked"); 49 50 if (w1_reset_select_slave(sl)) { 51 mutex_unlock(&sl->master->bus_mutex); 52 return -EIO; 53 } 54 55 w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ); 56 *buf = w1_read_8(sl->master); 57 58 mutex_unlock(&sl->master->bus_mutex); 59 dev_dbg(&sl->dev, "mutex unlocked"); 60 61 /* check for correct complement */ 62 if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F)) 63 return -EIO; 64 else 65 return 1; 66 } 67 68 static BIN_ATTR_RO(state, 1); 69 70 static ssize_t output_write(struct file *filp, struct kobject *kobj, 71 struct bin_attribute *bin_attr, char *buf, 72 loff_t off, size_t count) 73 { 74 struct w1_slave *sl = kobj_to_w1_slave(kobj); 75 u8 w1_buf[3]; 76 unsigned int retries = W1_F3A_RETRIES; 77 78 if (count != 1 || off != 0) 79 return -EFAULT; 80 81 dev_dbg(&sl->dev, "locking mutex for write_output"); 82 mutex_lock(&sl->master->bus_mutex); 83 dev_dbg(&sl->dev, "mutex locked"); 84 85 if (w1_reset_select_slave(sl)) 86 goto error; 87 88 /* according to the DS2413 datasheet the most significant 6 bits 89 should be set to "1"s, so do it now */ 90 *buf = *buf | 0xFC; 91 92 while (retries--) { 93 w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE; 94 w1_buf[1] = *buf; 95 w1_buf[2] = ~(*buf); 96 w1_write_block(sl->master, w1_buf, 3); 97 98 if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) { 99 mutex_unlock(&sl->master->bus_mutex); 100 dev_dbg(&sl->dev, "mutex unlocked, retries:%d", retries); 101 return 1; 102 } 103 if (w1_reset_resume_command(sl->master)) 104 goto error; 105 } 106 107 error: 108 mutex_unlock(&sl->master->bus_mutex); 109 dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries); 110 return -EIO; 111 } 112 113 static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1); 114 115 static struct bin_attribute *w1_f3a_bin_attrs[] = { 116 &bin_attr_state, 117 &bin_attr_output, 118 NULL, 119 }; 120 121 static const struct attribute_group w1_f3a_group = { 122 .bin_attrs = w1_f3a_bin_attrs, 123 }; 124 125 static const struct attribute_group *w1_f3a_groups[] = { 126 &w1_f3a_group, 127 NULL, 128 }; 129 130 static struct w1_family_ops w1_f3a_fops = { 131 .groups = w1_f3a_groups, 132 }; 133 134 static struct w1_family w1_family_3a = { 135 .fid = W1_FAMILY_DS2413, 136 .fops = &w1_f3a_fops, 137 }; 138 139 static int __init w1_f3a_init(void) 140 { 141 return w1_register_family(&w1_family_3a); 142 } 143 144 static void __exit w1_f3a_exit(void) 145 { 146 w1_unregister_family(&w1_family_3a); 147 } 148 149 module_init(w1_f3a_init); 150 module_exit(w1_f3a_exit); 151