354 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * w1_ds2408.c - w1 family 29 (DS2408) driver4 *5 * Copyright (c) 2010 Jean-Francois Dagenais <dagenaisj@sonatest.com>6 */7 8#include <linux/kernel.h>9#include <linux/module.h>10#include <linux/moduleparam.h>11#include <linux/device.h>12#include <linux/types.h>13#include <linux/delay.h>14#include <linux/slab.h>15 16#include <linux/w1.h>17 18#define W1_FAMILY_DS2408 0x2919 20#define W1_F29_RETRIES 321 22#define W1_F29_REG_LOGIG_STATE 0x88 /* R */23#define W1_F29_REG_OUTPUT_LATCH_STATE 0x89 /* R */24#define W1_F29_REG_ACTIVITY_LATCH_STATE 0x8A /* R */25#define W1_F29_REG_COND_SEARCH_SELECT_MASK 0x8B /* RW */26#define W1_F29_REG_COND_SEARCH_POL_SELECT 0x8C /* RW */27#define W1_F29_REG_CONTROL_AND_STATUS 0x8D /* RW */28 29#define W1_F29_FUNC_READ_PIO_REGS 0xF030#define W1_F29_FUNC_CHANN_ACCESS_READ 0xF531#define W1_F29_FUNC_CHANN_ACCESS_WRITE 0x5A32/* also used to write the control/status reg (0x8D): */33#define W1_F29_FUNC_WRITE_COND_SEARCH_REG 0xCC34#define W1_F29_FUNC_RESET_ACTIVITY_LATCHES 0xC335 36#define W1_F29_SUCCESS_CONFIRM_BYTE 0xAA37 38static int _read_reg(struct w1_slave *sl, u8 address, unsigned char *buf)39{40 u8 wrbuf[3];41 42 dev_dbg(&sl->dev, "Reading with slave: %p, reg addr: %0#4x, buff addr: %p",43 sl, (unsigned int)address, buf);44 45 if (!buf)46 return -EINVAL;47 48 mutex_lock(&sl->master->bus_mutex);49 dev_dbg(&sl->dev, "mutex locked");50 51 if (w1_reset_select_slave(sl)) {52 mutex_unlock(&sl->master->bus_mutex);53 return -EIO;54 }55 56 wrbuf[0] = W1_F29_FUNC_READ_PIO_REGS;57 wrbuf[1] = address;58 wrbuf[2] = 0;59 w1_write_block(sl->master, wrbuf, 3);60 *buf = w1_read_8(sl->master);61 62 mutex_unlock(&sl->master->bus_mutex);63 dev_dbg(&sl->dev, "mutex unlocked");64 return 1;65}66 67static ssize_t state_read(struct file *filp, struct kobject *kobj,68 struct bin_attribute *bin_attr, char *buf, loff_t off,69 size_t count)70{71 dev_dbg(&kobj_to_w1_slave(kobj)->dev,72 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",73 bin_attr->attr.name, kobj, (unsigned int)off, count, buf);74 if (count != 1 || off != 0)75 return -EFAULT;76 return _read_reg(kobj_to_w1_slave(kobj), W1_F29_REG_LOGIG_STATE, buf);77}78 79static ssize_t output_read(struct file *filp, struct kobject *kobj,80 struct bin_attribute *bin_attr, char *buf,81 loff_t off, size_t count)82{83 dev_dbg(&kobj_to_w1_slave(kobj)->dev,84 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",85 bin_attr->attr.name, kobj, (unsigned int)off, count, buf);86 if (count != 1 || off != 0)87 return -EFAULT;88 return _read_reg(kobj_to_w1_slave(kobj),89 W1_F29_REG_OUTPUT_LATCH_STATE, buf);90}91 92static ssize_t activity_read(struct file *filp, struct kobject *kobj,93 struct bin_attribute *bin_attr, char *buf,94 loff_t off, size_t count)95{96 dev_dbg(&kobj_to_w1_slave(kobj)->dev,97 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",98 bin_attr->attr.name, kobj, (unsigned int)off, count, buf);99 if (count != 1 || off != 0)100 return -EFAULT;101 return _read_reg(kobj_to_w1_slave(kobj),102 W1_F29_REG_ACTIVITY_LATCH_STATE, buf);103}104 105static ssize_t cond_search_mask_read(struct file *filp, struct kobject *kobj,106 struct bin_attribute *bin_attr, char *buf,107 loff_t off, size_t count)108{109 dev_dbg(&kobj_to_w1_slave(kobj)->dev,110 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",111 bin_attr->attr.name, kobj, (unsigned int)off, count, buf);112 if (count != 1 || off != 0)113 return -EFAULT;114 return _read_reg(kobj_to_w1_slave(kobj),115 W1_F29_REG_COND_SEARCH_SELECT_MASK, buf);116}117 118static ssize_t cond_search_polarity_read(struct file *filp,119 struct kobject *kobj,120 struct bin_attribute *bin_attr,121 char *buf, loff_t off, size_t count)122{123 if (count != 1 || off != 0)124 return -EFAULT;125 return _read_reg(kobj_to_w1_slave(kobj),126 W1_F29_REG_COND_SEARCH_POL_SELECT, buf);127}128 129static ssize_t status_control_read(struct file *filp, struct kobject *kobj,130 struct bin_attribute *bin_attr, char *buf,131 loff_t off, size_t count)132{133 if (count != 1 || off != 0)134 return -EFAULT;135 return _read_reg(kobj_to_w1_slave(kobj),136 W1_F29_REG_CONTROL_AND_STATUS, buf);137}138 139#ifdef CONFIG_W1_SLAVE_DS2408_READBACK140static bool optional_read_back_valid(struct w1_slave *sl, u8 expected)141{142 u8 w1_buf[3];143 144 if (w1_reset_resume_command(sl->master))145 return false;146 147 w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;148 w1_buf[1] = W1_F29_REG_OUTPUT_LATCH_STATE;149 w1_buf[2] = 0;150 151 w1_write_block(sl->master, w1_buf, 3);152 153 return (w1_read_8(sl->master) == expected);154}155#else156static bool optional_read_back_valid(struct w1_slave *sl, u8 expected)157{158 return true;159}160#endif161 162static ssize_t output_write(struct file *filp, struct kobject *kobj,163 struct bin_attribute *bin_attr, char *buf,164 loff_t off, size_t count)165{166 struct w1_slave *sl = kobj_to_w1_slave(kobj);167 u8 w1_buf[3];168 unsigned int retries = W1_F29_RETRIES;169 ssize_t bytes_written = -EIO;170 171 if (count != 1 || off != 0)172 return -EFAULT;173 174 dev_dbg(&sl->dev, "locking mutex for write_output");175 mutex_lock(&sl->master->bus_mutex);176 dev_dbg(&sl->dev, "mutex locked");177 178 if (w1_reset_select_slave(sl))179 goto out;180 181 do {182 w1_buf[0] = W1_F29_FUNC_CHANN_ACCESS_WRITE;183 w1_buf[1] = *buf;184 w1_buf[2] = ~(*buf);185 186 w1_write_block(sl->master, w1_buf, 3);187 188 if (w1_read_8(sl->master) == W1_F29_SUCCESS_CONFIRM_BYTE &&189 optional_read_back_valid(sl, *buf)) {190 bytes_written = 1;191 goto out;192 }193 194 if (w1_reset_resume_command(sl->master))195 goto out; /* unrecoverable error */196 /* try again, the slave is ready for a command */197 } while (--retries);198 199out:200 mutex_unlock(&sl->master->bus_mutex);201 202 dev_dbg(&sl->dev, "%s, mutex unlocked retries:%d\n",203 (bytes_written > 0) ? "succeeded" : "error", retries);204 205 return bytes_written;206}207 208 209/*210 * Writing to the activity file resets the activity latches.211 */212static ssize_t activity_write(struct file *filp, struct kobject *kobj,213 struct bin_attribute *bin_attr, char *buf,214 loff_t off, size_t count)215{216 struct w1_slave *sl = kobj_to_w1_slave(kobj);217 unsigned int retries = W1_F29_RETRIES;218 219 if (count != 1 || off != 0)220 return -EFAULT;221 222 mutex_lock(&sl->master->bus_mutex);223 224 if (w1_reset_select_slave(sl))225 goto error;226 227 while (retries--) {228 w1_write_8(sl->master, W1_F29_FUNC_RESET_ACTIVITY_LATCHES);229 if (w1_read_8(sl->master) == W1_F29_SUCCESS_CONFIRM_BYTE) {230 mutex_unlock(&sl->master->bus_mutex);231 return 1;232 }233 if (w1_reset_resume_command(sl->master))234 goto error;235 }236 237error:238 mutex_unlock(&sl->master->bus_mutex);239 return -EIO;240}241 242static ssize_t status_control_write(struct file *filp, struct kobject *kobj,243 struct bin_attribute *bin_attr, char *buf,244 loff_t off, size_t count)245{246 struct w1_slave *sl = kobj_to_w1_slave(kobj);247 u8 w1_buf[4];248 unsigned int retries = W1_F29_RETRIES;249 250 if (count != 1 || off != 0)251 return -EFAULT;252 253 mutex_lock(&sl->master->bus_mutex);254 255 if (w1_reset_select_slave(sl))256 goto error;257 258 while (retries--) {259 w1_buf[0] = W1_F29_FUNC_WRITE_COND_SEARCH_REG;260 w1_buf[1] = W1_F29_REG_CONTROL_AND_STATUS;261 w1_buf[2] = 0;262 w1_buf[3] = *buf;263 264 w1_write_block(sl->master, w1_buf, 4);265 if (w1_reset_resume_command(sl->master))266 goto error;267 268 w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;269 w1_buf[1] = W1_F29_REG_CONTROL_AND_STATUS;270 w1_buf[2] = 0;271 272 w1_write_block(sl->master, w1_buf, 3);273 if (w1_read_8(sl->master) == *buf) {274 /* success! */275 mutex_unlock(&sl->master->bus_mutex);276 return 1;277 }278 }279error:280 mutex_unlock(&sl->master->bus_mutex);281 282 return -EIO;283}284 285/*286 * This is a special sequence we must do to ensure the P0 output is not stuck287 * in test mode. This is described in rev 2 of the ds2408's datasheet288 * (http://datasheets.maximintegrated.com/en/ds/DS2408.pdf) under289 * "APPLICATION INFORMATION/Power-up timing".290 */291static int w1_f29_disable_test_mode(struct w1_slave *sl)292{293 int res;294 u8 magic[10] = {0x96, };295 u64 rn = le64_to_cpu(*((u64 *)&sl->reg_num));296 297 memcpy(&magic[1], &rn, 8);298 magic[9] = 0x3C;299 300 mutex_lock(&sl->master->bus_mutex);301 302 res = w1_reset_bus(sl->master);303 if (res)304 goto out;305 w1_write_block(sl->master, magic, ARRAY_SIZE(magic));306 307 res = w1_reset_bus(sl->master);308out:309 mutex_unlock(&sl->master->bus_mutex);310 return res;311}312 313static BIN_ATTR_RO(state, 1);314static BIN_ATTR_RW(output, 1);315static BIN_ATTR_RW(activity, 1);316static BIN_ATTR_RO(cond_search_mask, 1);317static BIN_ATTR_RO(cond_search_polarity, 1);318static BIN_ATTR_RW(status_control, 1);319 320static struct bin_attribute *w1_f29_bin_attrs[] = {321 &bin_attr_state,322 &bin_attr_output,323 &bin_attr_activity,324 &bin_attr_cond_search_mask,325 &bin_attr_cond_search_polarity,326 &bin_attr_status_control,327 NULL,328};329 330static const struct attribute_group w1_f29_group = {331 .bin_attrs = w1_f29_bin_attrs,332};333 334static const struct attribute_group *w1_f29_groups[] = {335 &w1_f29_group,336 NULL,337};338 339static const struct w1_family_ops w1_f29_fops = {340 .add_slave = w1_f29_disable_test_mode,341 .groups = w1_f29_groups,342};343 344static struct w1_family w1_family_29 = {345 .fid = W1_FAMILY_DS2408,346 .fops = &w1_f29_fops,347};348module_w1_family(w1_family_29);349 350MODULE_AUTHOR("Jean-Francois Dagenais <dagenaisj@sonatest.com>");351MODULE_DESCRIPTION("w1 family 29 driver for DS2408 8 Pin IO");352MODULE_LICENSE("GPL");353MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2408));354