summaryrefslogtreecommitdiffstats
path: root/drivers/w1/slaves/w1_ds2423.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/w1/slaves/w1_ds2423.c')
-rw-r--r--drivers/w1/slaves/w1_ds2423.c133
1 files changed, 133 insertions, 0 deletions
diff --git a/drivers/w1/slaves/w1_ds2423.c b/drivers/w1/slaves/w1_ds2423.c
new file mode 100644
index 000000000..b6bd18d5b
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds2423.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * w1_ds2423.c
+ *
+ * Copyright (c) 2010 Mika Laitio <lamikr@pilppa.org>
+ *
+ * This driver will read and write the value of 4 counters to w1_slave file in
+ * sys filesystem.
+ * Inspired by the w1_therm and w1_ds2431 drivers.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/crc16.h>
+
+#include <linux/w1.h>
+
+#define W1_COUNTER_DS2423 0x1D
+
+#define CRC16_VALID 0xb001
+#define CRC16_INIT 0
+
+#define COUNTER_COUNT 4
+#define READ_BYTE_COUNT 42
+
+static ssize_t w1_slave_show(struct device *device,
+ struct device_attribute *attr, char *out_buf)
+{
+ struct w1_slave *sl = dev_to_w1_slave(device);
+ struct w1_master *dev = sl->master;
+ u8 rbuf[COUNTER_COUNT * READ_BYTE_COUNT];
+ u8 wrbuf[3];
+ int rom_addr;
+ int read_byte_count;
+ int result;
+ ssize_t c;
+ int ii;
+ int p;
+ int crc;
+
+ c = PAGE_SIZE;
+ rom_addr = (12 << 5) + 31;
+ wrbuf[0] = 0xA5;
+ wrbuf[1] = rom_addr & 0xFF;
+ wrbuf[2] = rom_addr >> 8;
+ mutex_lock(&dev->bus_mutex);
+ if (!w1_reset_select_slave(sl)) {
+ w1_write_block(dev, wrbuf, 3);
+ read_byte_count = 0;
+ for (p = 0; p < 4; p++) {
+ /*
+ * 1 byte for first bytes in ram page read
+ * 4 bytes for counter
+ * 4 bytes for zero bits
+ * 2 bytes for crc
+ * 31 remaining bytes from the ram page
+ */
+ read_byte_count += w1_read_block(dev,
+ rbuf + (p * READ_BYTE_COUNT), READ_BYTE_COUNT);
+ for (ii = 0; ii < READ_BYTE_COUNT; ++ii)
+ c -= snprintf(out_buf + PAGE_SIZE - c,
+ c, "%02x ",
+ rbuf[(p * READ_BYTE_COUNT) + ii]);
+ if (read_byte_count != (p + 1) * READ_BYTE_COUNT) {
+ dev_warn(device,
+ "w1_counter_read() returned %u bytes "
+ "instead of %d bytes wanted.\n",
+ read_byte_count,
+ READ_BYTE_COUNT);
+ c -= snprintf(out_buf + PAGE_SIZE - c,
+ c, "crc=NO\n");
+ } else {
+ if (p == 0) {
+ crc = crc16(CRC16_INIT, wrbuf, 3);
+ crc = crc16(crc, rbuf, 11);
+ } else {
+ /*
+ * DS2423 calculates crc from all bytes
+ * read after the previous crc bytes.
+ */
+ crc = crc16(CRC16_INIT,
+ (rbuf + 11) +
+ ((p - 1) * READ_BYTE_COUNT),
+ READ_BYTE_COUNT);
+ }
+ if (crc == CRC16_VALID) {
+ result = 0;
+ for (ii = 4; ii > 0; ii--) {
+ result <<= 8;
+ result |= rbuf[(p *
+ READ_BYTE_COUNT) + ii];
+ }
+ c -= snprintf(out_buf + PAGE_SIZE - c,
+ c, "crc=YES c=%d\n", result);
+ } else {
+ c -= snprintf(out_buf + PAGE_SIZE - c,
+ c, "crc=NO\n");
+ }
+ }
+ }
+ } else {
+ c -= snprintf(out_buf + PAGE_SIZE - c, c, "Connection error");
+ }
+ mutex_unlock(&dev->bus_mutex);
+ return PAGE_SIZE - c;
+}
+
+static DEVICE_ATTR_RO(w1_slave);
+
+static struct attribute *w1_f1d_attrs[] = {
+ &dev_attr_w1_slave.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(w1_f1d);
+
+static const struct w1_family_ops w1_f1d_fops = {
+ .groups = w1_f1d_groups,
+};
+
+static struct w1_family w1_family_1d = {
+ .fid = W1_COUNTER_DS2423,
+ .fops = &w1_f1d_fops,
+};
+module_w1_family(w1_family_1d);
+
+MODULE_AUTHOR("Mika Laitio <lamikr@pilppa.org>");
+MODULE_DESCRIPTION("w1 family 1d driver for DS2423, 4 counters and 4kb ram");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("w1-family-" __stringify(W1_COUNTER_DS2423));