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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * w1_ds2405.c4 *5 * Copyright (c) 2017 Maciej S. Szmigiero <mail@maciej.szmigiero.name>6 * Based on w1_therm.c copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>7 */8 9#include <linux/device.h>10#include <linux/kernel.h>11#include <linux/module.h>12#include <linux/moduleparam.h>13#include <linux/mutex.h>14#include <linux/string.h>15#include <linux/types.h>16 17#include <linux/w1.h>18 19#define W1_FAMILY_DS2405 0x0520 21MODULE_LICENSE("GPL");22MODULE_AUTHOR("Maciej S. Szmigiero <mail@maciej.szmigiero.name>");23MODULE_DESCRIPTION("Driver for 1-wire Dallas DS2405 PIO.");24MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2405));25 26static int w1_ds2405_select(struct w1_slave *sl, bool only_active)27{28 struct w1_master *dev = sl->master;29 30 u64 dev_addr = le64_to_cpu(*(u64 *)&sl->reg_num);31 unsigned int bit_ctr;32 33 if (w1_reset_bus(dev) != 0)34 return 0;35 36 /*37 * We cannot use a normal Match ROM command38 * since doing so would toggle PIO state39 */40 w1_write_8(dev, only_active ? W1_ALARM_SEARCH : W1_SEARCH);41 42 for (bit_ctr = 0; bit_ctr < 64; bit_ctr++) {43 int bit2send = !!(dev_addr & BIT(bit_ctr));44 u8 ret;45 46 ret = w1_triplet(dev, bit2send);47 48 if ((ret & (BIT(0) | BIT(1))) ==49 (BIT(0) | BIT(1))) /* no devices found */50 return 0;51 52 if (!!(ret & BIT(2)) != bit2send)53 /* wrong direction taken - no such device */54 return 0;55 }56 57 return 1;58}59 60static int w1_ds2405_read_pio(struct w1_slave *sl)61{62 if (w1_ds2405_select(sl, true))63 return 0; /* "active" means PIO is low */64 65 if (w1_ds2405_select(sl, false))66 return 1;67 68 return -ENODEV;69}70 71static ssize_t state_show(struct device *device,72 struct device_attribute *attr, char *buf)73{74 struct w1_slave *sl = dev_to_w1_slave(device);75 struct w1_master *dev = sl->master;76 77 int ret;78 ssize_t f_retval;79 u8 state;80 81 ret = mutex_lock_interruptible(&dev->bus_mutex);82 if (ret)83 return ret;84 85 if (!w1_ds2405_select(sl, false)) {86 f_retval = -ENODEV;87 goto out_unlock;88 }89 90 state = w1_read_8(dev);91 if (state != 0 &&92 state != 0xff) {93 dev_err(device, "non-consistent state %x\n", state);94 f_retval = -EIO;95 goto out_unlock;96 }97 98 *buf = state ? '1' : '0';99 f_retval = 1;100 101out_unlock:102 w1_reset_bus(dev);103 mutex_unlock(&dev->bus_mutex);104 105 return f_retval;106}107 108static ssize_t output_show(struct device *device,109 struct device_attribute *attr, char *buf)110{111 struct w1_slave *sl = dev_to_w1_slave(device);112 struct w1_master *dev = sl->master;113 114 int ret;115 ssize_t f_retval;116 117 ret = mutex_lock_interruptible(&dev->bus_mutex);118 if (ret)119 return ret;120 121 ret = w1_ds2405_read_pio(sl);122 if (ret < 0) {123 f_retval = ret;124 goto out_unlock;125 }126 127 *buf = ret ? '1' : '0';128 f_retval = 1;129 130out_unlock:131 w1_reset_bus(dev);132 mutex_unlock(&dev->bus_mutex);133 134 return f_retval;135}136 137static ssize_t output_store(struct device *device,138 struct device_attribute *attr,139 const char *buf, size_t count)140{141 struct w1_slave *sl = dev_to_w1_slave(device);142 struct w1_master *dev = sl->master;143 144 int ret, current_pio;145 unsigned int val;146 ssize_t f_retval;147 148 if (count < 1)149 return -EINVAL;150 151 if (sscanf(buf, " %u%n", &val, &ret) < 1)152 return -EINVAL;153 154 if (val != 0 && val != 1)155 return -EINVAL;156 157 f_retval = ret;158 159 ret = mutex_lock_interruptible(&dev->bus_mutex);160 if (ret)161 return ret;162 163 current_pio = w1_ds2405_read_pio(sl);164 if (current_pio < 0) {165 f_retval = current_pio;166 goto out_unlock;167 }168 169 if (current_pio == val)170 goto out_unlock;171 172 if (w1_reset_bus(dev) != 0) {173 f_retval = -ENODEV;174 goto out_unlock;175 }176 177 /*178 * can't use w1_reset_select_slave() here since it uses Skip ROM if179 * there is only one device on bus180 */181 do {182 u64 dev_addr = le64_to_cpu(*(u64 *)&sl->reg_num);183 u8 cmd[9];184 185 cmd[0] = W1_MATCH_ROM;186 memcpy(&cmd[1], &dev_addr, sizeof(dev_addr));187 188 w1_write_block(dev, cmd, sizeof(cmd));189 } while (0);190 191out_unlock:192 w1_reset_bus(dev);193 mutex_unlock(&dev->bus_mutex);194 195 return f_retval;196}197 198static DEVICE_ATTR_RO(state);199static DEVICE_ATTR_RW(output);200 201static struct attribute *w1_ds2405_attrs[] = {202 &dev_attr_state.attr,203 &dev_attr_output.attr,204 NULL205};206 207ATTRIBUTE_GROUPS(w1_ds2405);208 209static const struct w1_family_ops w1_ds2405_fops = {210 .groups = w1_ds2405_groups211};212 213static struct w1_family w1_family_ds2405 = {214 .fid = W1_FAMILY_DS2405,215 .fops = &w1_ds2405_fops216};217 218module_w1_family(w1_family_ds2405);219