1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * w1_ds2413.c - w1 family 3a (DS2413) driver 4 * based on w1_ds2408.c by Jean-Francois Dagenais <dagenaisj@sonatest.com> 5 * 6 * Copyright (c) 2013 Mariusz Bialonczyk <manio@skyboo.net> 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/module.h> 11 #include <linux/moduleparam.h> 12 #include <linux/device.h> 13 #include <linux/types.h> 14 #include <linux/delay.h> 15 #include <linux/slab.h> 16 17 #include <linux/w1.h> 18 19 #define W1_FAMILY_DS2413 0x3A 20 21 #define W1_F3A_RETRIES 3 22 #define W1_F3A_FUNC_PIO_ACCESS_READ 0xF5 23 #define W1_F3A_FUNC_PIO_ACCESS_WRITE 0x5A 24 #define W1_F3A_SUCCESS_CONFIRM_BYTE 0xAA 25 #define W1_F3A_INVALID_PIO_STATE 0xFF 26 27 static ssize_t state_read(struct file *filp, struct kobject *kobj, 28 struct bin_attribute *bin_attr, char *buf, loff_t off, 29 size_t count) 30 { 31 struct w1_slave *sl = kobj_to_w1_slave(kobj); 32 unsigned int retries = W1_F3A_RETRIES; 33 ssize_t bytes_read = -EIO; 34 u8 state; 35 36 dev_dbg(&sl->dev, 37 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p", 38 bin_attr->attr.name, kobj, (unsigned int)off, count, buf); 39 40 if (off != 0) 41 return 0; 42 if (!buf) 43 return -EINVAL; 44 45 mutex_lock(&sl->master->bus_mutex); 46 dev_dbg(&sl->dev, "mutex locked"); 47 48 next: 49 if (w1_reset_select_slave(sl)) 50 goto out; 51 52 while (retries--) { 53 w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ); 54 55 state = w1_read_8(sl->master); 56 if ((state & 0x0F) == ((~state >> 4) & 0x0F)) { 57 /* complement is correct */ 58 *buf = state; 59 bytes_read = 1; 60 goto out; 61 } else if (state == W1_F3A_INVALID_PIO_STATE) { 62 /* slave didn't respond, try to select it again */ 63 dev_warn(&sl->dev, "slave device did not respond to PIO_ACCESS_READ, " \ 64 "reselecting, retries left: %d\n", retries); 65 goto next; 66 } 67 68 if (w1_reset_resume_command(sl->master)) 69 goto out; /* unrecoverable error */ 70 71 dev_warn(&sl->dev, "PIO_ACCESS_READ error, retries left: %d\n", retries); 72 } 73 74 out: 75 mutex_unlock(&sl->master->bus_mutex); 76 dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n", 77 (bytes_read > 0) ? "succeeded" : "error", retries); 78 return bytes_read; 79 } 80 81 static BIN_ATTR_RO(state, 1); 82 83 static ssize_t output_write(struct file *filp, struct kobject *kobj, 84 struct bin_attribute *bin_attr, char *buf, 85 loff_t off, size_t count) 86 { 87 struct w1_slave *sl = kobj_to_w1_slave(kobj); 88 u8 w1_buf[3]; 89 unsigned int retries = W1_F3A_RETRIES; 90 ssize_t bytes_written = -EIO; 91 92 if (count != 1 || off != 0) 93 return -EFAULT; 94 95 dev_dbg(&sl->dev, "locking mutex for write_output"); 96 mutex_lock(&sl->master->bus_mutex); 97 dev_dbg(&sl->dev, "mutex locked"); 98 99 if (w1_reset_select_slave(sl)) 100 goto out; 101 102 /* according to the DS2413 datasheet the most significant 6 bits 103 should be set to "1"s, so do it now */ 104 *buf = *buf | 0xFC; 105 106 while (retries--) { 107 w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE; 108 w1_buf[1] = *buf; 109 w1_buf[2] = ~(*buf); 110 w1_write_block(sl->master, w1_buf, 3); 111 112 if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) { 113 bytes_written = 1; 114 goto out; 115 } 116 if (w1_reset_resume_command(sl->master)) 117 goto out; /* unrecoverable error */ 118 119 dev_warn(&sl->dev, "PIO_ACCESS_WRITE error, retries left: %d\n", retries); 120 } 121 122 out: 123 mutex_unlock(&sl->master->bus_mutex); 124 dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n", 125 (bytes_written > 0) ? "succeeded" : "error", retries); 126 return bytes_written; 127 } 128 129 static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1); 130 131 static struct bin_attribute *w1_f3a_bin_attrs[] = { 132 &bin_attr_state, 133 &bin_attr_output, 134 NULL, 135 }; 136 137 static const struct attribute_group w1_f3a_group = { 138 .bin_attrs = w1_f3a_bin_attrs, 139 }; 140 141 static const struct attribute_group *w1_f3a_groups[] = { 142 &w1_f3a_group, 143 NULL, 144 }; 145 146 static const struct w1_family_ops w1_f3a_fops = { 147 .groups = w1_f3a_groups, 148 }; 149 150 static struct w1_family w1_family_3a = { 151 .fid = W1_FAMILY_DS2413, 152 .fops = &w1_f3a_fops, 153 }; 154 module_w1_family(w1_family_3a); 155 156 MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>"); 157 MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO"); 158 MODULE_LICENSE("GPL"); 159 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413)); 160