From: "Lad, Prabhakar" <[email protected]>
this patch adds support for max31826 temperature sensor with
1Kb eeprom.
the temprature values can be read from file:
/sys/bus/w1/devices/3b-0000003c0cfe/w1_slave
and the eeprom can be read/written from file:
/sys/bus/w1/devices/3b-0000003c0cfe/eeprom
Signed-off-by: Lad, Prabhakar <[email protected]>
---
Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX31826.pdf
Temperature reading example:
/sys/bus/w1/devices/3b-0000003c0cfe$ cat w1_slave
87 02 ff ff f0 ff ff ff b0 : crc=b0 YES
87 02 ff ff f0 ff ff ff b0 t=40437
Reading the eeprom contents:
/sys/bus/w1/devices/3b-0000003c0cfe$ cat eeprom | hexdump -Cv
00000000 48 65 6c 6c 6f 20 57 6f 72 6c 64 20 4d 41 78 33 |Hello World MAx3|
00000010 31 38 32 36 20 74 65 6d 70 65 72 61 74 75 72 65 |1826 temperature|
00000020 20 73 65 6e 73 6f 72 20 77 69 74 68 20 31 4b 20 | sensor with 1K |
00000030 65 65 70 72 6f 6d 20 0a 00 00 00 00 00 00 00 00 |eeprom .........|
00000040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000070 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000080
drivers/w1/slaves/Kconfig | 9 +
drivers/w1/slaves/Makefile | 1 +
drivers/w1/slaves/w1_max31826.c | 490 ++++++++++++++++++++++++++++++++++++++++
drivers/w1/w1_family.h | 1 +
4 files changed, 501 insertions(+)
create mode 100644 drivers/w1/slaves/w1_max31826.c
diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
index cfe74d0..fcac213 100644
--- a/drivers/w1/slaves/Kconfig
+++ b/drivers/w1/slaves/Kconfig
@@ -132,4 +132,13 @@ config W1_SLAVE_BQ27000
Say Y here if you want to use a hdq
bq27000 slave support.
+config W1_SLAVE_MAX31826
+ tristate "MAX31826 slave support"
+ help
+ If you enable this you will have the MAX31826
+ chip support.
+
+ Say Y here if you want to use a 1-wire
+ digital temperature sensor with 1kb EEPROM
+
endmenu
diff --git a/drivers/w1/slaves/Makefile b/drivers/w1/slaves/Makefile
index 1e9989a..2b31d99 100644
--- a/drivers/w1/slaves/Makefile
+++ b/drivers/w1/slaves/Makefile
@@ -15,3 +15,4 @@ obj-$(CONFIG_W1_SLAVE_DS2780) += w1_ds2780.o
obj-$(CONFIG_W1_SLAVE_DS2781) += w1_ds2781.o
obj-$(CONFIG_W1_SLAVE_BQ27000) += w1_bq27000.o
obj-$(CONFIG_W1_SLAVE_DS28E04) += w1_ds28e04.o
+obj-$(CONFIG_W1_SLAVE_MAX31826) += w1_max31826.o
diff --git a/drivers/w1/slaves/w1_max31826.c b/drivers/w1/slaves/w1_max31826.c
new file mode 100644
index 0000000..6ff544b
--- /dev/null
+++ b/drivers/w1/slaves/w1_max31826.c
@@ -0,0 +1,490 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * w1_max31826.c - w1 family 2d (MAX31826) driver
+ *
+ * Copyright (c) 2019 Lad, Prabhakar <[email protected]>
+ *
+ * Heavily inspired by w1_ds2413 and w1_therm driver from
+ * Bernhard Weirich <[email protected]> and
+ * Evgeniy Polyakov <[email protected]>
+ *
+ */
+
+#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"
+
+/* 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);
+
+#define W1_F2D_EEPROM_SIZE 128
+#define W1_F2D_PAGE_COUNT 4
+#define W1_F2D_PAGE_BITS 5
+#define W1_F2D_PAGE_SIZE (1<<W1_F2D_PAGE_BITS)
+#define W1_F2D_PAGE_MASK 0x1F
+
+#define W1_F2D_SCRATCH_BITS 3
+#define W1_F2D_SCRATCH_SIZE (1<<W1_F2D_SCRATCH_BITS)
+#define W1_F2D_SCRATCH_MASK (W1_F2D_SCRATCH_SIZE-1)
+
+#define W1_F2D_READ_EEPROM 0xF0
+#define W1_F2D_WRITE_SCRATCH 0x0F
+#define W1_F2D_READ_SCRATCH 0xAA
+#define W1_F2D_COPY_SCRATCH 0x55
+#define W1_F2D_COPY_SCRATCHPAD2_DO 0xA5
+
+
+#define W1_F2D_TPROG_MS 25
+#define W1_F2D_READ_RETRIES 10
+#define W1_F2D_READ_MAXLEN 8
+
+/*
+ * Check the file size bounds and adjusts count as needed.
+ * This would not be needed if the file size didn't reset to 0 after a write.
+ */
+static inline size_t w1_f2d_fix_count(loff_t off, size_t count, size_t size)
+{
+ if (off > size)
+ return 0;
+
+ if ((off + count) > size)
+ return size - off;
+
+ return count;
+}
+
+/*
+ * Read a block from W1 ROM two times and compares the results.
+ * If they are equal they are returned, otherwise the read
+ * is repeated W1_F2D_READ_RETRIES times.
+ *
+ * count must not exceed W1_F2D_READ_MAXLEN.
+ */
+static int w1_f2d_readblock(struct w1_slave *sl, int off, int count, char *buf)
+{
+ u8 wrbuf[3];
+ u8 cmp[W1_F2D_READ_MAXLEN];
+ int tries = W1_F2D_READ_RETRIES;
+
+ do {
+ wrbuf[0] = W1_F2D_READ_EEPROM;
+ wrbuf[1] = off;
+
+ if (w1_reset_select_slave(sl))
+ return -1;
+
+ w1_write_block(sl->master, wrbuf, 2);
+ w1_read_block(sl->master, buf, count);
+
+ if (w1_reset_select_slave(sl))
+ return -1;
+
+ w1_write_block(sl->master, wrbuf, 2);
+ w1_read_block(sl->master, cmp, count);
+
+ if (!memcmp(cmp, buf, count))
+ return 0;
+ } while (--tries);
+
+ dev_err(&sl->dev, "proof reading failed %d times\n",
+ W1_F2D_READ_RETRIES);
+
+ return -1;
+}
+
+static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *buf,
+ loff_t off, size_t count)
+{
+ struct w1_slave *sl = kobj_to_w1_slave(kobj);
+ int todo = count;
+
+ count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE);
+ if (count == 0)
+ return 0;
+
+ mutex_lock(&sl->master->bus_mutex);
+
+ /* read directly from the EEPROM in chunks of W1_F2D_READ_MAXLEN */
+ while (todo > 0) {
+ int block_read;
+
+ if (todo >= W1_F2D_READ_MAXLEN)
+ block_read = W1_F2D_READ_MAXLEN;
+ else
+ block_read = todo;
+
+ if (w1_f2d_readblock(sl, off, block_read, buf) < 0)
+ count = -EIO;
+
+ todo -= W1_F2D_READ_MAXLEN;
+ buf += W1_F2D_READ_MAXLEN;
+ off += W1_F2D_READ_MAXLEN;
+ }
+
+ mutex_unlock(&sl->master->bus_mutex);
+
+ return count;
+}
+
+/*
+ * Writes to the scratchpad and reads it back for verification.
+ * Then copies the scratchpad to EEPROM.
+ * The data must be aligned at W1_F2D_SCRATCH_SIZE bytes and
+ * must be W1_F2D_SCRATCH_SIZE bytes long.
+ * The master must be locked.
+ *
+ * @param sl The slave structure
+ * @param addr Address for the write
+ * @param len length must be <= (W1_F2D_PAGE_SIZE - (addr & W1_F2D_PAGE_MASK))
+ * @param data The data to write
+ * @return 0=Success -1=failure
+ */
+static int w1_f2d_write(struct w1_slave *sl, int addr, int len, const u8 *data)
+{
+ int tries = W1_F2D_READ_RETRIES;
+ u8 rdbuf[W1_F2D_SCRATCH_SIZE + 3];
+ u8 wrbuf[4];
+
+retry:
+ /* Write the data to the scratchpad */
+ if (w1_reset_select_slave(sl))
+ return -1;
+
+ wrbuf[0] = W1_F2D_WRITE_SCRATCH;
+ wrbuf[1] = addr;
+ w1_write_block(sl->master, wrbuf, 2);
+ w1_write_block(sl->master, data, len);
+
+ /* Read the scratchpad and verify */
+ if (w1_reset_select_slave(sl))
+ return -1;
+
+ wrbuf[0] = W1_F2D_READ_SCRATCH;
+ wrbuf[1] = addr;
+ w1_write_block(sl->master, wrbuf, 2);
+ w1_read_block(sl->master, rdbuf, len);
+
+ /* Compare what was read against the data written */
+ if ((memcmp(data, &rdbuf, len) != 0)) {
+ if (--tries)
+ goto retry;
+
+ dev_err(&sl->dev,
+ "could not write to eeprom, scratchpad compare failed %d times\n",
+ W1_F2D_READ_RETRIES);
+
+ return -1;
+ }
+
+ /* Copy the scratchpad to EEPROM */
+ if (w1_reset_select_slave(sl))
+ return -1;
+
+ wrbuf[0] = W1_F2D_COPY_SCRATCH;
+ wrbuf[1] = W1_F2D_COPY_SCRATCHPAD2_DO;
+ w1_write_block(sl->master, wrbuf, 2);
+
+ /* Sleep for tprog ms to wait for the write to complete */
+ msleep(W1_F2D_TPROG_MS);
+
+ /* Reset the bus to wake up the EEPROM */
+ w1_reset_bus(sl->master);
+
+ return 0;
+}
+
+static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *buf,
+ loff_t off, size_t count)
+{
+ struct w1_slave *sl = kobj_to_w1_slave(kobj);
+ int addr, len;
+ int copy;
+
+ count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE);
+ if (count == 0)
+ return 0;
+
+ mutex_lock(&sl->master->bus_mutex);
+
+ /* Can only write data in blocks of the size of the scratchpad */
+ addr = off;
+ len = count;
+ while (len > 0) {
+
+ /* if len too short or addr not aligned */
+ if (len < W1_F2D_SCRATCH_SIZE || addr & W1_F2D_SCRATCH_MASK) {
+ char tmp[W1_F2D_SCRATCH_SIZE];
+
+ /* read the block and update the parts to be written */
+ if (w1_f2d_readblock(sl, addr & ~W1_F2D_SCRATCH_MASK,
+ W1_F2D_SCRATCH_SIZE, tmp)) {
+ count = -EIO;
+ goto out_up;
+ }
+
+ /* copy at most to the boundary of the PAGE or len */
+ copy = W1_F2D_SCRATCH_SIZE -
+ (addr & W1_F2D_SCRATCH_MASK);
+
+ if (copy > len)
+ copy = len;
+
+ memcpy(&tmp, buf, copy);
+ if (w1_f2d_write(sl, addr & ~W1_F2D_SCRATCH_MASK,
+ W1_F2D_SCRATCH_SIZE, tmp) < 0) {
+ count = -EIO;
+ goto out_up;
+ }
+ } else {
+
+ copy = W1_F2D_SCRATCH_SIZE;
+ if (w1_f2d_write(sl, addr, copy, buf) < 0) {
+ count = -EIO;
+ goto out_up;
+ }
+ }
+ buf += copy;
+ addr += copy;
+ len -= copy;
+ }
+
+out_up:
+ mutex_unlock(&sl->master->bus_mutex);
+
+ return count;
+}
+
+struct w1_therm_family_data {
+ uint8_t rom[9];
+ atomic_t refcnt;
+};
+
+/* return the address of the refcnt in the family data */
+#define THERM_REFCNT(family_data) \
+ (&((struct w1_therm_family_data *)family_data)->refcnt)
+
+static int w1_therm_add_slave(struct w1_slave *sl)
+{
+ sl->family_data = kzalloc(sizeof(struct w1_therm_family_data),
+ GFP_KERNEL);
+ if (!sl->family_data)
+ return -ENOMEM;
+ atomic_set(THERM_REFCNT(sl->family_data), 1);
+ return 0;
+}
+
+static void w1_therm_remove_slave(struct w1_slave *sl)
+{
+ int refcnt = atomic_sub_return(1, THERM_REFCNT(sl->family_data));
+
+ while (refcnt) {
+ msleep(1000);
+ refcnt = atomic_read(THERM_REFCNT(sl->family_data));
+ }
+ kfree(sl->family_data);
+ sl->family_data = NULL;
+}
+
+#define MILLIDEGREES_C (1000 / 16)
+
+static inline int w1_convert_temp(u8 rom[9])
+{
+ s16 t = le16_to_cpup((__le16 *)rom);
+
+ return t * MILLIDEGREES_C;
+}
+
+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, ret, max_trying = 10;
+ ssize_t c = PAGE_SIZE;
+ u8 *family_data = sl->family_data;
+
+ ret = mutex_lock_interruptible(&dev->bus_mutex);
+ if (ret != 0)
+ goto post_unlock;
+
+ if (!sl->family_data) {
+ ret = -ENODEV;
+ goto pre_unlock;
+ }
+
+ /* prevent the slave from going away in sleep */
+ atomic_inc(THERM_REFCNT(family_data));
+ 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) {
+ ret = -EINTR;
+ goto post_unlock;
+ }
+
+ ret = mutex_lock_interruptible(&dev->bus_mutex);
+ if (ret != 0)
+ goto post_unlock;
+ } else if (!w1_strong_pullup) {
+ sleep_rem = msleep_interruptible(tm);
+ if (sleep_rem != 0) {
+ ret = -EINTR;
+ goto pre_unlock;
+ }
+ }
+
+ if (!w1_reset_select_slave(sl)) {
+
+ w1_write_8(dev, W1_READ_SCRATCHPAD);
+ count = w1_read_block(dev, rom, 9);
+ if (count != 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(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 *)family_data)[i]);
+
+ c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
+ w1_convert_temp(rom));
+ ret = PAGE_SIZE - c;
+
+pre_unlock:
+ mutex_unlock(&dev->bus_mutex);
+
+post_unlock:
+ atomic_dec(THERM_REFCNT(family_data));
+ return ret;
+}
+
+static DEVICE_ATTR_RO(w1_slave);
+
+static struct attribute *w1_therm_attrs[] = {
+ &dev_attr_w1_slave.attr,
+ NULL,
+};
+static const struct attribute_group w1_therm_group = {
+ .attrs = w1_therm_attrs,
+};
+
+static BIN_ATTR_RW(eeprom, W1_F2D_EEPROM_SIZE);
+
+static struct bin_attribute *w1_f2d_bin_attrs[] = {
+ &bin_attr_eeprom,
+ NULL,
+};
+
+static const struct attribute_group w1_f2d_group = {
+ .bin_attrs = w1_f2d_bin_attrs,
+};
+
+static const struct attribute_group *w1_f2d_groups[] = {
+ &w1_f2d_group,
+ &w1_therm_group,
+ NULL,
+};
+
+static struct w1_family_ops w1_f2d_fops = {
+ .add_slave = w1_therm_add_slave,
+ .remove_slave = w1_therm_remove_slave,
+ .groups = w1_f2d_groups,
+};
+
+
+static struct w1_family w1_family_2d = {
+ .fid = W1_FAMILY_MAX31826,
+ .fops = &w1_f2d_fops,
+};
+
+static int __init w1_f2d_init(void)
+{
+ return w1_register_family(&w1_family_2d);
+}
+
+static void __exit w1_f2d_fini(void)
+{
+ w1_unregister_family(&w1_family_2d);
+}
+
+module_init(w1_f2d_init);
+module_exit(w1_f2d_fini);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Lad, Prabhakar <[email protected]>");
+MODULE_DESCRIPTION("w1 family 2d driver for MAX31826, Digital Temperature Sensor with 1kb EEPROM");
+MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_MAX31826));
diff --git a/drivers/w1/w1_family.h b/drivers/w1/w1_family.h
index ed5dcb8..47243b8 100644
--- a/drivers/w1/w1_family.h
+++ b/drivers/w1/w1_family.h
@@ -43,6 +43,7 @@
#define W1_FAMILY_DS2413 0x3A
#define W1_FAMILY_DS2406 0x12
#define W1_THERM_DS1825 0x3B
+#define W1_FAMILY_MAX31826 0x3B
#define W1_FAMILY_DS2781 0x3D
#define W1_THERM_DS28EA00 0x42
--
2.7.4