162 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * w1_ds2413.c - w1 family 3a (DS2413) driver4 * 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 0x3A20 21#define W1_F3A_RETRIES 322#define W1_F3A_FUNC_PIO_ACCESS_READ 0xF523#define W1_F3A_FUNC_PIO_ACCESS_WRITE 0x5A24#define W1_F3A_SUCCESS_CONFIRM_BYTE 0xAA25#define W1_F3A_INVALID_PIO_STATE 0xFF26 27static 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 48next: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 74out: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 81static BIN_ATTR_RO(state, 1);82 83static 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 /*103 * according to the DS2413 datasheet the most significant 6 bits104 * should be set to "1"s, so do it now105 */106 *buf = *buf | 0xFC;107 108 while (retries--) {109 w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;110 w1_buf[1] = *buf;111 w1_buf[2] = ~(*buf);112 w1_write_block(sl->master, w1_buf, 3);113 114 if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {115 bytes_written = 1;116 goto out;117 }118 if (w1_reset_resume_command(sl->master))119 goto out; /* unrecoverable error */120 121 dev_warn(&sl->dev, "PIO_ACCESS_WRITE error, retries left: %d\n", retries);122 }123 124out:125 mutex_unlock(&sl->master->bus_mutex);126 dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",127 (bytes_written > 0) ? "succeeded" : "error", retries);128 return bytes_written;129}130 131static BIN_ATTR(output, 0664, NULL, output_write, 1);132 133static struct bin_attribute *w1_f3a_bin_attrs[] = {134 &bin_attr_state,135 &bin_attr_output,136 NULL,137};138 139static const struct attribute_group w1_f3a_group = {140 .bin_attrs = w1_f3a_bin_attrs,141};142 143static const struct attribute_group *w1_f3a_groups[] = {144 &w1_f3a_group,145 NULL,146};147 148static const struct w1_family_ops w1_f3a_fops = {149 .groups = w1_f3a_groups,150};151 152static struct w1_family w1_family_3a = {153 .fid = W1_FAMILY_DS2413,154 .fops = &w1_f3a_fops,155};156module_w1_family(w1_family_3a);157 158MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");159MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");160MODULE_LICENSE("GPL");161MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));162