From: "Lad, Prabhakar" <prabhakar.cse...@gmail.com> 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 <prabhakar.cse...@gmail.com> --- 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 <prabhakar.cse...@gmail.com> + * + * Heavily inspired by w1_ds2413 and w1_therm driver from + * Bernhard Weirich <bernhard.weir...@riedel.net> and + * Evgeniy Polyakov <z...@ioremap.net> + * + */ + +#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 <prabhakar.cse...@gmail.com>"); +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
