[PATCH v2 5/5] w1: ds2433: add support for ds28ec20 eeprom

From: marc . ferland
Date: Mon Nov 27 2023 - 15:19:34 EST


From: Marc Ferland <marc.ferland@xxxxxxxxxxxx>

The ds28ec20 eeprom is (almost) backward compatible with the
ds2433. The only differences are:

- the eeprom size is now 2560 bytes instead of 512;
- the number of pages is now 80 (same page size as the ds2433: 256 bits);
- the programming time has increased from 5ms to 10ms;

This patch adds support for the ds28ec20 to the ds2433 driver. From
the datasheet: The DS28EC20 provides a high degree of backward
compatibility with the DS2433. Besides the different family codes, the
only protocol change that is required on an existing DS2433
implementation is a lengthening of the programming duration (tPROG)
from 5ms to 10ms.

dmesg now returns:

w1_master_driver w1_bus_master1: Attaching one wire slave 43.000000478756 crc e0

instead of:

w1_master_driver w1_bus_master1: Attaching one wire slave 43.000000478756 crc e0
w1_master_driver w1_bus_master1: Family 43 for 43.000000478756.e0 is not registered.

Test script writing/reading random data (CONFIG_W1_SLAVE_DS2433_CRC is
not set):

#!/bin/sh

EEPROM=/sys/bus/w1/devices/43-000000478756/eeprom
BINFILE1=/home/root/file1.bin
BINFILE2=/home/root/file2.bin

for BS in 1 2 3 4 8 16 32 64 128 256 512 1024 2560; do
dd if=/dev/random of=${BINFILE1} bs=${BS} count=1 status=none
dd if=${BINFILE1} of=${EEPROM} status=none
dd if=${EEPROM} of=${BINFILE2} bs=${BS} count=1 status=none
if ! cmp --silent ${BINFILE1} ${BINFILE2}; then
echo file1
hexdump ${BINFILE1}
echo file2
hexdump ${BINFILE2}
echo FAIL
exit 1
fi
echo "${BS} OK!"
done

Results:

# ./test.sh
1 OK!
2 OK!
3 OK!
4 OK!
8 OK!
16 OK!
32 OK!
64 OK!
128 OK!
256 OK!
512 OK!
1024 OK!
2560 OK!

Tests with CONFIG_W1_SLAVE_DS2433_CRC=y:

$ cat /proc/config.gz | gunzip | grep CONFIG_W1_SLAVE_DS2433
CONFIG_W1_SLAVE_DS2433=m
CONFIG_W1_SLAVE_DS2433_CRC=y

# create a 32 bytes block with a crc, i.e.:
00000000 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 40 |123456789:;<=>?@|
00000010 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e ba 63 |ABCDEFGHIJKLMN.c|

# fill all 80 blocks
$ dd if=test.bin of=/sys/bus/w1/devices/43-000000478756/eeprom bs=32 count=80

# read back all blocks, i.e.:
$ hexdump -C /sys/bus/w1/devices/43-000000478756/eeprom
00000000 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 40 |123456789:;<=>?@|
00000010 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e ba 63 |ABCDEFGHIJKLMN.c|
00000020 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 40 |123456789:;<=>?@|
00000030 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e ba 63 |ABCDEFGHIJKLMN.c|
...
000009e0 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 40 |123456789:;<=>?@|
000009f0 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e ba 63 |ABCDEFGHIJKLMN.c|
00000a00

Note: both memories (ds2433 and ds28ec20) have been tested with the
new driver.

Signed-off-by: Marc Ferland <marc.ferland@xxxxxxxxxxxx>
Co-developed-by: Jean-Francois Dagenais <jeff.dagenais@xxxxxxxxx>
Signed-off-by: Jean-Francois Dagenais <jeff.dagenais@xxxxxxxxx>
---
drivers/w1/slaves/w1_ds2433.c | 98 ++++++++++++++++++++++++++++++++---
1 file changed, 90 insertions(+), 8 deletions(-)

diff --git a/drivers/w1/slaves/w1_ds2433.c b/drivers/w1/slaves/w1_ds2433.c
index 63ed03191137..ab1491a7854a 100644
--- a/drivers/w1/slaves/w1_ds2433.c
+++ b/drivers/w1/slaves/w1_ds2433.c
@@ -1,8 +1,9 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
- * w1_ds2433.c - w1 family 23 (DS2433) driver
+ * w1_ds2433.c - w1 family 23 (DS2433) & 43 (DS28EC20) eeprom driver
*
* Copyright (c) 2005 Ben Gardner <bgardner@xxxxxxxxxx>
+ * Copyright (c) 2023 Marc Ferland <marc.ferland@xxxxxxxxxxxx>
*/

#include <linux/kernel.h>
@@ -23,8 +24,10 @@
#include <linux/w1.h>

#define W1_EEPROM_DS2433 0x23
+#define W1_EEPROM_DS28EC20 0x43

-#define W1_EEPROM_SIZE 512
+#define W1_EEPROM_DS2433_SIZE 512
+#define W1_EEPROM_DS28EC20_SIZE 2560

#define W1_PAGE_SIZE 32
#define W1_PAGE_BITS 5
@@ -42,11 +45,17 @@ struct ds2433_config {
};

static const struct ds2433_config config_f23 = {
- .eeprom_size = W1_EEPROM_SIZE,
+ .eeprom_size = W1_EEPROM_DS2433_SIZE,
.page_count = 16,
.tprog = 5,
};

+static const struct ds2433_config config_f43 = {
+ .eeprom_size = W1_EEPROM_DS28EC20_SIZE,
+ .page_count = 80,
+ .tprog = 10,
+};
+
struct w1_f23_data {
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
u8 *memory;
@@ -264,10 +273,22 @@ static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
return count;
}

-static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
+static struct bin_attribute bin_attr_f23_eeprom = {
+ .attr = { .name = "eeprom", .mode = 0644 },
+ .read = eeprom_read,
+ .write = eeprom_write,
+ .size = W1_EEPROM_DS2433_SIZE,
+};
+
+static struct bin_attribute bin_attr_f43_eeprom = {
+ .attr = { .name = "eeprom", .mode = 0644 },
+ .read = eeprom_read,
+ .write = eeprom_write,
+ .size = W1_EEPROM_DS28EC20_SIZE,
+};

static struct bin_attribute *w1_f23_bin_attributes[] = {
- &bin_attr_eeprom,
+ &bin_attr_f23_eeprom,
NULL,
};

@@ -280,6 +301,20 @@ static const struct attribute_group *w1_f23_groups[] = {
NULL,
};

+static struct bin_attribute *w1_f43_bin_attributes[] = {
+ &bin_attr_f43_eeprom,
+ NULL,
+};
+
+static const struct attribute_group w1_f43_group = {
+ .bin_attrs = w1_f43_bin_attributes,
+};
+
+static const struct attribute_group *w1_f43_groups[] = {
+ &w1_f43_group,
+ NULL,
+};
+
static int w1_f23_add_slave(struct w1_slave *sl)
{
struct w1_f23_data *data;
@@ -288,7 +323,14 @@ static int w1_f23_add_slave(struct w1_slave *sl)
if (!data)
return -ENOMEM;

- data->cfg = &config_f23;
+ switch (sl->family->fid) {
+ case W1_EEPROM_DS2433:
+ data->cfg = &config_f23;
+ break;
+ case W1_EEPROM_DS28EC20:
+ data->cfg = &config_f43;
+ break;
+ }

#ifdef CONFIG_W1_SLAVE_DS2433_CRC
data->memory = kzalloc(data->cfg->eeprom_size, GFP_KERNEL);
@@ -326,13 +368,53 @@ static const struct w1_family_ops w1_f23_fops = {
.groups = w1_f23_groups,
};

+static const struct w1_family_ops w1_f43_fops = {
+ .add_slave = w1_f23_add_slave,
+ .remove_slave = w1_f23_remove_slave,
+ .groups = w1_f43_groups,
+};
+
static struct w1_family w1_family_23 = {
.fid = W1_EEPROM_DS2433,
.fops = &w1_f23_fops,
};
-module_w1_family(w1_family_23);
+
+static struct w1_family w1_family_43 = {
+ .fid = W1_EEPROM_DS28EC20,
+ .fops = &w1_f43_fops,
+};
+
+static int __init w1_ds2433_init(void)
+{
+ int err;
+
+ err = w1_register_family(&w1_family_23);
+ if (err)
+ return err;
+
+ err = w1_register_family(&w1_family_43);
+ if (err)
+ goto err_43;
+
+ return 0;
+
+err_43:
+ w1_unregister_family(&w1_family_23);
+ return err;
+}
+
+static void __exit w1_ds2433_exit(void)
+{
+ w1_unregister_family(&w1_family_23);
+ w1_unregister_family(&w1_family_43);
+}
+
+module_init(w1_ds2433_init);
+module_exit(w1_ds2433_exit);

MODULE_AUTHOR("Ben Gardner <bgardner@xxxxxxxxxx>");
-MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
+MODULE_AUTHOR("Marc Ferland <marc.ferland@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("w1 family 23/43 driver for DS2433 (4kb) and DS28EC20 (20kb)");
MODULE_LICENSE("GPL");
MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2433));
+MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS28EC20));
--
2.34.1