--- /dev/null
+/*
+ * w1_therm.c
+ *
+ * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the therms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <asm/types.h>
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/sched.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+
+#include "../w1.h"
+#include "../w1_int.h"
+#include "../w1_family.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
+MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
+MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18S20));
+MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1822));
+MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18B20));
+MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1825));
+MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS28EA00));
+
+/* Allow the strong pullup to be disabled, but default to enabled.
+ * If it was disabled a parasite powered device might not get the require
+ * current to do a temperature conversion. If it is enabled parasite powered
+ * devices have a better chance of getting the current required.
+ * In case the parasite power-detection is not working (seems to be the case
+ * for some DS18S20) the strong pullup can also be forced, regardless of the
+ * power state of the devices.
+ *
+ * Summary of options:
+ * - strong_pullup = 0 Disable strong pullup completely
+ * - strong_pullup = 1 Enable automatic strong pullup detection
+ * - strong_pullup = 2 Force strong pullup
+ */
+static int w1_strong_pullup = 1;
+module_param_named(strong_pullup, w1_strong_pullup, int, 0);
+
+static int w1_therm_add_slave(struct w1_slave *sl)
+{
+ sl->family_data = kzalloc(9, GFP_KERNEL);
+ if (!sl->family_data)
+ return -ENOMEM;
+ return 0;
+}
+
+static void w1_therm_remove_slave(struct w1_slave *sl)
+{
+ kfree(sl->family_data);
+ sl->family_data = NULL;
+}
+
+static ssize_t w1_slave_show(struct device *device,
+ struct device_attribute *attr, char *buf);
+
+static DEVICE_ATTR_RO(w1_slave);
+
+static struct attribute *w1_therm_attrs[] = {
+ &dev_attr_w1_slave.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(w1_therm);
+
+static struct w1_family_ops w1_therm_fops = {
+ .add_slave = w1_therm_add_slave,
+ .remove_slave = w1_therm_remove_slave,
+ .groups = w1_therm_groups,
+};
+
+static struct w1_family w1_therm_family_DS18S20 = {
+ .fid = W1_THERM_DS18S20,
+ .fops = &w1_therm_fops,
+};
+
+static struct w1_family w1_therm_family_DS18B20 = {
+ .fid = W1_THERM_DS18B20,
+ .fops = &w1_therm_fops,
+};
+
+static struct w1_family w1_therm_family_DS1822 = {
+ .fid = W1_THERM_DS1822,
+ .fops = &w1_therm_fops,
+};
+
+static struct w1_family w1_therm_family_DS28EA00 = {
+ .fid = W1_THERM_DS28EA00,
+ .fops = &w1_therm_fops,
+};
+
+static struct w1_family w1_therm_family_DS1825 = {
+ .fid = W1_THERM_DS1825,
+ .fops = &w1_therm_fops,
+};
+
+struct w1_therm_family_converter
+{
+ u8 broken;
+ u16 reserved;
+ struct w1_family *f;
+ int (*convert)(u8 rom[9]);
+};
+
+/* The return value is millidegrees Centigrade. */
+static inline int w1_DS18B20_convert_temp(u8 rom[9]);
+static inline int w1_DS18S20_convert_temp(u8 rom[9]);
+
+static struct w1_therm_family_converter w1_therm_families[] = {
+ {
+ .f = &w1_therm_family_DS18S20,
+ .convert = w1_DS18S20_convert_temp
+ },
+ {
+ .f = &w1_therm_family_DS1822,
+ .convert = w1_DS18B20_convert_temp
+ },
+ {
+ .f = &w1_therm_family_DS18B20,
+ .convert = w1_DS18B20_convert_temp
+ },
+ {
+ .f = &w1_therm_family_DS28EA00,
+ .convert = w1_DS18B20_convert_temp
+ },
+ {
+ .f = &w1_therm_family_DS1825,
+ .convert = w1_DS18B20_convert_temp
+ }
+};
+
+static inline int w1_DS18B20_convert_temp(u8 rom[9])
+{
+ s16 t = le16_to_cpup((__le16 *)rom);
+ return t*1000/16;
+}
+
+static inline int w1_DS18S20_convert_temp(u8 rom[9])
+{
+ int t, h;
+
+ if (!rom[7])
+ return 0;
+
+ if (rom[1] == 0)
+ t = ((s32)rom[0] >> 1)*1000;
+ else
+ t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
+
+ t -= 250;
+ h = 1000*((s32)rom[7] - (s32)rom[6]);
+ h /= (s32)rom[7];
+ t += h;
+
+ return t;
+}
+
+static inline int w1_convert_temp(u8 rom[9], u8 fid)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
+ if (w1_therm_families[i].f->fid == fid)
+ return w1_therm_families[i].convert(rom);
+
+ return 0;
+}
+
+
+static ssize_t w1_slave_show(struct device *device,
+ struct device_attribute *attr, char *buf)
+{
+ struct w1_slave *sl = dev_to_w1_slave(device);
+ struct w1_master *dev = sl->master;
+ u8 rom[9], crc, verdict, external_power;
+ int i, max_trying = 10;
+ ssize_t c = PAGE_SIZE;
+
+ i = mutex_lock_interruptible(&dev->bus_mutex);
+ if (i != 0)
+ return i;
+
+ memset(rom, 0, sizeof(rom));
+
+ while (max_trying--) {
+
+ verdict = 0;
+ crc = 0;
+
+ if (!w1_reset_select_slave(sl)) {
+ int count = 0;
+ unsigned int tm = 750;
+ unsigned long sleep_rem;
+
+ w1_write_8(dev, W1_READ_PSUPPLY);
+ external_power = w1_read_8(dev);
+
+ if (w1_reset_select_slave(sl))
+ continue;
+
+ /* 750ms strong pullup (or delay) after the convert */
+ if (w1_strong_pullup == 2 ||
+ (!external_power && w1_strong_pullup))
+ w1_next_pullup(dev, tm);
+
+ w1_write_8(dev, W1_CONVERT_TEMP);
+
+ if (external_power) {
+ mutex_unlock(&dev->bus_mutex);
+
+ sleep_rem = msleep_interruptible(tm);
+ if (sleep_rem != 0)
+ return -EINTR;
+
+ i = mutex_lock_interruptible(&dev->bus_mutex);
+ if (i != 0)
+ return i;
+ } else if (!w1_strong_pullup) {
+ sleep_rem = msleep_interruptible(tm);
+ if (sleep_rem != 0) {
+ mutex_unlock(&dev->bus_mutex);
+ return -EINTR;
+ }
+ }
+
+ if (!w1_reset_select_slave(sl)) {
+
+ w1_write_8(dev, W1_READ_SCRATCHPAD);
+ if ((count = w1_read_block(dev, rom, 9)) != 9) {
+ dev_warn(device, "w1_read_block() "
+ "returned %u instead of 9.\n",
+ count);
+ }
+
+ crc = w1_calc_crc8(rom, 8);
+
+ if (rom[8] == crc)
+ verdict = 1;
+ }
+ }
+
+ if (verdict)
+ break;
+ }
+
+ for (i = 0; i < 9; ++i)
+ c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]);
+ c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
+ crc, (verdict) ? "YES" : "NO");
+ if (verdict)
+ memcpy(sl->family_data, rom, sizeof(rom));
+ else
+ dev_warn(device, "Read failed CRC check\n");
+
+ for (i = 0; i < 9; ++i)
+ c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ",
+ ((u8 *)sl->family_data)[i]);
+
+ c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
+ w1_convert_temp(rom, sl->family->fid));
+ mutex_unlock(&dev->bus_mutex);
+
+ return PAGE_SIZE - c;
+}
+
+static int __init w1_therm_init(void)
+{
+ int err, i;
+
+ for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
+ err = w1_register_family(w1_therm_families[i].f);
+ if (err)
+ w1_therm_families[i].broken = 1;
+ }
+
+ return 0;
+}
+
+static void __exit w1_therm_fini(void)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
+ if (!w1_therm_families[i].broken)
+ w1_unregister_family(w1_therm_families[i].f);
+}
+
+module_init(w1_therm_init);
+module_exit(w1_therm_fini);
Code Review / kvmfornfv.git / blobdiff