w1/slaves/w1_ds2413.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * w1_ds2413.c - w1 family 3a (DS2413) driver
0004  * based on w1_ds2408.c by Jean-Francois Dagenais <dagenaisj@sonatest.com>
0005  *
0006  * Copyright (c) 2013 Mariusz Bialonczyk <manio@skyboo.net>
0007  */
0008
0009 #include <linux/kernel.h>
0010 #include <linux/module.h>
0011 #include <linux/moduleparam.h>
0012 #include <linux/device.h>
0013 #include <linux/types.h>
0014 #include <linux/delay.h>
0015 #include <linux/slab.h>
0016
0017 #include <linux/w1.h>
0018
0019 #define W1_FAMILY_DS2413    0x3A
0020
0021 #define W1_F3A_RETRIES                     3
0022 #define W1_F3A_FUNC_PIO_ACCESS_READ        0xF5
0023 #define W1_F3A_FUNC_PIO_ACCESS_WRITE       0x5A
0024 #define W1_F3A_SUCCESS_CONFIRM_BYTE        0xAA
0025 #define W1_F3A_INVALID_PIO_STATE           0xFF
0026
0027 static ssize_t state_read(struct file *filp, struct kobject *kobj,
0028               struct bin_attribute *bin_attr, char *buf, loff_t off,
0029               size_t count)
0030 {
0031     struct w1_slave *sl = kobj_to_w1_slave(kobj);
0032     unsigned int retries = W1_F3A_RETRIES;
0033     ssize_t bytes_read = -EIO;
0034     u8 state;
0035
0036     dev_dbg(&sl->dev,
0037         "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
0038         bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
0039
0040     if (off != 0)
0041         return 0;
0042     if (!buf)
0043         return -EINVAL;
0044
0045     mutex_lock(&sl->master->bus_mutex);
0046     dev_dbg(&sl->dev, "mutex locked");
0047
0048 next:
0049     if (w1_reset_select_slave(sl))
0050         goto out;
0051
0052     while (retries--) {
0053         w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
0054
0055         state = w1_read_8(sl->master);
0056         if ((state & 0x0F) == ((~state >> 4) & 0x0F)) {
0057             /* complement is correct */
0058             *buf = state;
0059             bytes_read = 1;
0060             goto out;
0061         } else if (state == W1_F3A_INVALID_PIO_STATE) {
0062             /* slave didn't respond, try to select it again */
0063             dev_warn(&sl->dev, "slave device did not respond to PIO_ACCESS_READ, " \
0064                         "reselecting, retries left: %d\n", retries);
0065             goto next;
0066         }
0067
0068         if (w1_reset_resume_command(sl->master))
0069             goto out; /* unrecoverable error */
0070
0071         dev_warn(&sl->dev, "PIO_ACCESS_READ error, retries left: %d\n", retries);
0072     }
0073
0074 out:
0075     mutex_unlock(&sl->master->bus_mutex);
0076     dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
0077         (bytes_read > 0) ? "succeeded" : "error", retries);
0078     return bytes_read;
0079 }
0080
0081 static BIN_ATTR_RO(state, 1);
0082
0083 static ssize_t output_write(struct file *filp, struct kobject *kobj,
0084                 struct bin_attribute *bin_attr, char *buf,
0085                 loff_t off, size_t count)
0086 {
0087     struct w1_slave *sl = kobj_to_w1_slave(kobj);
0088     u8 w1_buf[3];
0089     unsigned int retries = W1_F3A_RETRIES;
0090     ssize_t bytes_written = -EIO;
0091
0092     if (count != 1 || off != 0)
0093         return -EFAULT;
0094
0095     dev_dbg(&sl->dev, "locking mutex for write_output");
0096     mutex_lock(&sl->master->bus_mutex);
0097     dev_dbg(&sl->dev, "mutex locked");
0098
0099     if (w1_reset_select_slave(sl))
0100         goto out;
0101
0102     /* according to the DS2413 datasheet the most significant 6 bits
0103        should be set to "1"s, so do it now */
0104     *buf = *buf | 0xFC;
0105
0106     while (retries--) {
0107         w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;
0108         w1_buf[1] = *buf;
0109         w1_buf[2] = ~(*buf);
0110         w1_write_block(sl->master, w1_buf, 3);
0111
0112         if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
0113             bytes_written = 1;
0114             goto out;
0115         }
0116         if (w1_reset_resume_command(sl->master))
0117             goto out; /* unrecoverable error */
0118
0119         dev_warn(&sl->dev, "PIO_ACCESS_WRITE error, retries left: %d\n", retries);
0120     }
0121
0122 out:
0123     mutex_unlock(&sl->master->bus_mutex);
0124     dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
0125         (bytes_written > 0) ? "succeeded" : "error", retries);
0126     return bytes_written;
0127 }
0128
0129 static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1);
0130
0131 static struct bin_attribute *w1_f3a_bin_attrs[] = {
0132     &bin_attr_state,
0133     &bin_attr_output,
0134     NULL,
0135 };
0136
0137 static const struct attribute_group w1_f3a_group = {
0138     .bin_attrs = w1_f3a_bin_attrs,
0139 };
0140
0141 static const struct attribute_group *w1_f3a_groups[] = {
0142     &w1_f3a_group,
0143     NULL,
0144 };
0145
0146 static const struct w1_family_ops w1_f3a_fops = {
0147     .groups     = w1_f3a_groups,
0148 };
0149
0150 static struct w1_family w1_family_3a = {
0151     .fid = W1_FAMILY_DS2413,
0152     .fops = &w1_f3a_fops,
0153 };
0154 module_w1_family(w1_family_3a);
0155
0156 MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
0157 MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");
0158 MODULE_LICENSE("GPL");
0159 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));