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 <linux/w1.h> 20 21 #define W1_FAMILY_DS2413 0x3A 22 23 #define W1_F3A_RETRIES 3 24 #define W1_F3A_FUNC_PIO_ACCESS_READ 0xF5 25 #define W1_F3A_FUNC_PIO_ACCESS_WRITE 0x5A 26 #define W1_F3A_SUCCESS_CONFIRM_BYTE 0xAA 27 28 static ssize_t state_read(struct file *filp, struct kobject *kobj, 29 struct bin_attribute *bin_attr, char *buf, loff_t off, 30 size_t count) 31 { 32 struct w1_slave *sl = kobj_to_w1_slave(kobj); 33 dev_dbg(&sl->dev, 34 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p", 35 bin_attr->attr.name, kobj, (unsigned int)off, count, buf); 36 37 if (off != 0) 38 return 0; 39 if (!buf) 40 return -EINVAL; 41 42 mutex_lock(&sl->master->bus_mutex); 43 dev_dbg(&sl->dev, "mutex locked"); 44 45 if (w1_reset_select_slave(sl)) { 46 mutex_unlock(&sl->master->bus_mutex); 47 return -EIO; 48 } 49 50 w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ); 51 *buf = w1_read_8(sl->master); 52 53 mutex_unlock(&sl->master->bus_mutex); 54 dev_dbg(&sl->dev, "mutex unlocked"); 55 56 /* check for correct complement */ 57 if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F)) 58 return -EIO; 59 else 60 return 1; 61 } 62 63 static BIN_ATTR_RO(state, 1); 64 65 static ssize_t output_write(struct file *filp, struct kobject *kobj, 66 struct bin_attribute *bin_attr, char *buf, 67 loff_t off, size_t count) 68 { 69 struct w1_slave *sl = kobj_to_w1_slave(kobj); 70 u8 w1_buf[3]; 71 unsigned int retries = W1_F3A_RETRIES; 72 73 if (count != 1 || off != 0) 74 return -EFAULT; 75 76 dev_dbg(&sl->dev, "locking mutex for write_output"); 77 mutex_lock(&sl->master->bus_mutex); 78 dev_dbg(&sl->dev, "mutex locked"); 79 80 if (w1_reset_select_slave(sl)) 81 goto error; 82 83 /* according to the DS2413 datasheet the most significant 6 bits 84 should be set to "1"s, so do it now */ 85 *buf = *buf | 0xFC; 86 87 while (retries--) { 88 w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE; 89 w1_buf[1] = *buf; 90 w1_buf[2] = ~(*buf); 91 w1_write_block(sl->master, w1_buf, 3); 92 93 if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) { 94 mutex_unlock(&sl->master->bus_mutex); 95 dev_dbg(&sl->dev, "mutex unlocked, retries:%d", retries); 96 return 1; 97 } 98 if (w1_reset_resume_command(sl->master)) 99 goto error; 100 } 101 102 error: 103 mutex_unlock(&sl->master->bus_mutex); 104 dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries); 105 return -EIO; 106 } 107 108 static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1); 109 110 static struct bin_attribute *w1_f3a_bin_attrs[] = { 111 &bin_attr_state, 112 &bin_attr_output, 113 NULL, 114 }; 115 116 static const struct attribute_group w1_f3a_group = { 117 .bin_attrs = w1_f3a_bin_attrs, 118 }; 119 120 static const struct attribute_group *w1_f3a_groups[] = { 121 &w1_f3a_group, 122 NULL, 123 }; 124 125 static struct w1_family_ops w1_f3a_fops = { 126 .groups = w1_f3a_groups, 127 }; 128 129 static struct w1_family w1_family_3a = { 130 .fid = W1_FAMILY_DS2413, 131 .fops = &w1_f3a_fops, 132 }; 133 module_w1_family(w1_family_3a); 134 135 MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>"); 136 MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO"); 137 MODULE_LICENSE("GPL"); 138 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413)); 139