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));