1 files changed, 295 insertions, 0 deletions
diff --git a/drivers/w1/slaves/w1_ds2430.c b/drivers/w1/slaves/w1_ds2430.c
new file mode 100644
index 000000000..0ea7d779d
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds2430.c
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * w1_ds2430.c - w1 family 14 (DS2430) driver
+ **
+ * Copyright (c) 2019 Angelo Dureghello <angelo.dureghello@timesys.com>
+ *
+ * Cloned and modified from ds2431
+ * Copyright (c) 2008 Bernhard Weirich <bernhard.weirich@riedel.net>
+ *
+ */
+
+#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/w1.h>
+
+#define W1_EEPROM_DS2430	0x14
+
+#define W1_F14_EEPROM_SIZE	32
+#define W1_F14_PAGE_COUNT	1
+#define W1_F14_PAGE_BITS	5
+#define W1_F14_PAGE_SIZE	(1 << W1_F14_PAGE_BITS)
+#define W1_F14_PAGE_MASK	0x1F
+
+#define W1_F14_SCRATCH_BITS	5
+#define W1_F14_SCRATCH_SIZE	(1 << W1_F14_SCRATCH_BITS)
+#define W1_F14_SCRATCH_MASK	(W1_F14_SCRATCH_SIZE-1)
+
+#define W1_F14_READ_EEPROM	0xF0
+#define W1_F14_WRITE_SCRATCH	0x0F
+#define W1_F14_READ_SCRATCH	0xAA
+#define W1_F14_COPY_SCRATCH	0x55
+#define W1_F14_VALIDATION_KEY	0xa5
+
+#define W1_F14_TPROG_MS		11
+#define W1_F14_READ_RETRIES	10
+#define W1_F14_READ_MAXLEN	W1_F14_SCRATCH_SIZE
+
+/*
+ * 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_f14_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_F14_READ_RETRIES times.
+ *
+ * count must not exceed W1_F14_READ_MAXLEN.
+ */
+static int w1_f14_readblock(struct w1_slave *sl, int off, int count, char *buf)
+{
+	u8 wrbuf[2];
+	u8 cmp[W1_F14_READ_MAXLEN];
+	int tries = W1_F14_READ_RETRIES;
+
+	do {
+		wrbuf[0] = W1_F14_READ_EEPROM;
+		wrbuf[1] = off & 0xff;
+
+		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_F14_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_f14_fix_count(off, count, W1_F14_EEPROM_SIZE);
+	if (count == 0)
+		return 0;
+
+	mutex_lock(&sl->master->bus_mutex);
+
+	/* read directly from the EEPROM in chunks of W1_F14_READ_MAXLEN */
+	while (todo > 0) {
+		int block_read;
+
+		if (todo >= W1_F14_READ_MAXLEN)
+			block_read = W1_F14_READ_MAXLEN;
+		else
+			block_read = todo;
+
+		if (w1_f14_readblock(sl, off, block_read, buf) < 0)
+			count = -EIO;
+
+		todo -= W1_F14_READ_MAXLEN;
+		buf += W1_F14_READ_MAXLEN;
+		off += W1_F14_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_F14_SCRATCH_SIZE bytes and
+ * must be W1_F14_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_F14_PAGE_SIZE - (addr & W1_F14_PAGE_MASK))
+ * @param data	The data to write
+ * @return	0=Success -1=failure
+ */
+static int w1_f14_write(struct w1_slave *sl, int addr, int len, const u8 *data)
+{
+	int tries = W1_F14_READ_RETRIES;
+	u8 wrbuf[2];
+	u8 rdbuf[W1_F14_SCRATCH_SIZE + 3];
+
+retry:
+
+	/* Write the data to the scratchpad */
+	if (w1_reset_select_slave(sl))
+		return -1;
+
+	wrbuf[0] = W1_F14_WRITE_SCRATCH;
+	wrbuf[1] = addr & 0xff;
+
+	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;
+
+	w1_write_8(sl->master, W1_F14_READ_SCRATCH);
+	w1_read_block(sl->master, rdbuf, len + 2);
+
+	/*
+	 * Compare what was read against the data written
+	 * Note: on read scratchpad, device returns 2 bulk 0xff bytes,
+	 * to be discarded.
+	 */
+	if ((memcmp(data, &rdbuf[2], len) != 0)) {
+
+		if (--tries)
+			goto retry;
+
+		dev_err(&sl->dev,
+			"could not write to eeprom, scratchpad compare failed %d times\n",
+			W1_F14_READ_RETRIES);
+
+		return -1;
+	}
+
+	/* Copy the scratchpad to EEPROM */
+	if (w1_reset_select_slave(sl))
+		return -1;
+
+	wrbuf[0] = W1_F14_COPY_SCRATCH;
+	wrbuf[1] = W1_F14_VALIDATION_KEY;
+	w1_write_block(sl->master, wrbuf, 2);
+
+	/* Sleep for tprog ms to wait for the write to complete */
+	msleep(W1_F14_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_f14_fix_count(off, count, W1_F14_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_F14_SCRATCH_SIZE || addr & W1_F14_SCRATCH_MASK) {
+			char tmp[W1_F14_SCRATCH_SIZE];
+
+			/* read the block and update the parts to be written */
+			if (w1_f14_readblock(sl, addr & ~W1_F14_SCRATCH_MASK,
+					W1_F14_SCRATCH_SIZE, tmp)) {
+				count = -EIO;
+				goto out_up;
+			}
+
+			/* copy at most to the boundary of the PAGE or len */
+			copy = W1_F14_SCRATCH_SIZE -
+				(addr & W1_F14_SCRATCH_MASK);
+
+			if (copy > len)
+				copy = len;
+
+			memcpy(&tmp[addr & W1_F14_SCRATCH_MASK], buf, copy);
+			if (w1_f14_write(sl, addr & ~W1_F14_SCRATCH_MASK,
+					W1_F14_SCRATCH_SIZE, tmp) < 0) {
+				count = -EIO;
+				goto out_up;
+			}
+		} else {
+
+			copy = W1_F14_SCRATCH_SIZE;
+			if (w1_f14_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;
+}
+
+static BIN_ATTR_RW(eeprom, W1_F14_EEPROM_SIZE);
+
+static struct bin_attribute *w1_f14_bin_attrs[] = {
+	&bin_attr_eeprom,
+	NULL,
+};
+
+static const struct attribute_group w1_f14_group = {
+	.bin_attrs = w1_f14_bin_attrs,
+};
+
+static const struct attribute_group *w1_f14_groups[] = {
+	&w1_f14_group,
+	NULL,
+};
+
+static const struct w1_family_ops w1_f14_fops = {
+	.groups	= w1_f14_groups,
+};
+
+static struct w1_family w1_family_14 = {
+	.fid = W1_EEPROM_DS2430,
+	.fops = &w1_f14_fops,
+};
+module_w1_family(w1_family_14);
+
+MODULE_AUTHOR("Angelo Dureghello <angelo.dureghello@timesys.com>");
+MODULE_DESCRIPTION("w1 family 14 driver for DS2430, 256b EEPROM");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2430));