phytec ds28ec20

Signed-off-by: Christian Hemp <c.hemp@phytec.de>

4 files changed, 340 insertions, 0 deletions

diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
index d0cb01b42012..c1b529165b91 100644
--- a/drivers/w1/slaves/Kconfig
+++ b/drivers/w1/slaves/Kconfig
@@ -55,6 +55,21 @@ config W1_SLAVE_DS2433_CRC
 	  Each block has 30 bytes of data and a two byte CRC16.
 	  Full block writes are only allowed if the CRC is valid.
 
+config W1_SLAVE_DS28EC20
+	tristate "20kb EEPROM family support (DS28EC20)"
+	help
+	  Say Y here if you want to use a 1-wire
+	  20kb EEPROM family device (DS28EC20).
+
+config W1_SLAVE_DS28EC20_CRC
+	bool "Protect DS28EC20 data with a CRC16"
+	depends on W1_SLAVE_DS28EC20
+	select CRC16
+	help
+	  Say Y here to protect DS28EC20 data with a CRC16.
+	  Each block has 30 bytes of data and a two byte CRC16.
+	  Full block writes are only allowed if the CRC is valid.
+
 config W1_SLAVE_DS2760
 	tristate "Dallas 2760 battery monitor chip (HP iPAQ & others)"
 	depends on W1
diff --git a/drivers/w1/slaves/Makefile b/drivers/w1/slaves/Makefile
index 1f31e9fb0b25..224c1b1307b5 100644
--- a/drivers/w1/slaves/Makefile
+++ b/drivers/w1/slaves/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_W1_SLAVE_DS2433)	+= w1_ds2433.o
 obj-$(CONFIG_W1_SLAVE_DS2760)	+= w1_ds2760.o
 obj-$(CONFIG_W1_SLAVE_DS2780)	+= w1_ds2780.o
 obj-$(CONFIG_W1_SLAVE_BQ27000)	+= w1_bq27000.o
+obj-$(CONFIG_W1_SLAVE_DS28EC20)	+= w1_ds28ec20.o
diff --git a/drivers/w1/slaves/w1_ds28ec20.c b/drivers/w1/slaves/w1_ds28ec20.c
new file mode 100644
index 000000000000..5b141f8c1338
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds28ec20.c
@@ -0,0 +1,323 @@
+/*
+ *	w1_ds28ec20.c - w1 family 43 (DS28ec20) driver
+ *
+ * Copyright (c) 2012 Grigory Milev <g.milev@sam-solutions.net>
+ * Based on ds2433 from Ben Gardner <bgardner@wabtec.com>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#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/slab.h>
+#ifdef CONFIG_W1_SLAVE_DS28EC20_CRC
+#include <linux/crc16.h>
+
+#define CRC16_INIT		0
+#define CRC16_VALID		0xb001
+
+#endif
+
+#include "../w1.h"
+#include "../w1_int.h"
+#include "../w1_family.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Grigory Milev <g.milev@sam-solutions.net>");
+MODULE_DESCRIPTION("w1 family 43 driver for DS28EC20, 20kb EEPROM");
+
+#define W1_EEPROM_SIZE		2560
+#define W1_PAGE_COUNT		80
+#define W1_PAGE_SIZE		32
+#define W1_PAGE_BITS		5
+#define W1_PAGE_MASK		0x1F
+
+#define W1_F43_TIME		300
+
+#define W1_F43_READ_EEPROM	0xF0
+#define W1_F43_WRITE_SCRATCH	0x0F
+#define W1_F43_READ_SCRATCH	0xAA
+#define W1_F43_COPY_SCRATCH	0x55
+
+struct w1_f43_data {
+	u8	memory[W1_EEPROM_SIZE];
+	u32	validcrc;
+};
+
+/**
+ * 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_f43_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;
+}
+
+#ifdef CONFIG_W1_SLAVE_DS28EC20_CRC
+static int w1_f43_refresh_block(struct w1_slave *sl, struct w1_f43_data *data,
+				int block)
+{
+	u8	wrbuf[3];
+	int	off = block * W1_PAGE_SIZE;
+
+	if (data->validcrc & (1 << block))
+		return 0;
+
+	if (w1_reset_select_slave(sl)) {
+		data->validcrc = 0;
+		return -EIO;
+	}
+
+	wrbuf[0] = W1_F43_READ_EEPROM;
+	wrbuf[1] = off & 0xff;
+	wrbuf[2] = off >> 8;
+	w1_write_block(sl->master, wrbuf, 3);
+	w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
+
+	/* cache the block if the CRC is valid */
+	if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
+		data->validcrc |= (1 << block);
+
+	return 0;
+}
+#endif	/* CONFIG_W1_SLAVE_DS28EC20_CRC */
+
+static ssize_t w1_f43_read_bin(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);
+#ifdef CONFIG_W1_SLAVE_DS28EC20_CRC
+	struct w1_f43_data *data = sl->family_data;
+	int i, min_page, max_page;
+#else
+	u8 wrbuf[3];
+#endif
+
+	if ((count = w1_f43_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
+		return 0;
+
+	mutex_lock(&sl->master->mutex);
+
+#ifdef CONFIG_W1_SLAVE_DS28EC20_CRC
+
+	min_page = (off >> W1_PAGE_BITS);
+	max_page = (off + count - 1) >> W1_PAGE_BITS;
+	for (i = min_page; i <= max_page; i++) {
+		if (w1_f43_refresh_block(sl, data, i)) {
+			count = -EIO;
+			goto out_up;
+		}
+	}
+	memcpy(buf, &data->memory[off], count);
+
+#else 	/* CONFIG_W1_SLAVE_DS28EC20_CRC */
+
+	/* read directly from the EEPROM */
+	if (w1_reset_select_slave(sl)) {
+		count = -EIO;
+		goto out_up;
+	}
+
+	wrbuf[0] = W1_F43_READ_EEPROM;
+	wrbuf[1] = off & 0xff;
+	wrbuf[2] = off >> 8;
+	w1_write_block(sl->master, wrbuf, 3);
+	w1_read_block(sl->master, buf, count);
+
+#endif	/* CONFIG_W1_SLAVE_DS28EC20_CRC */
+
+out_up:
+	mutex_unlock(&sl->master->mutex);
+
+	return count;
+}
+
+/**
+ * Writes to the scratchpad and reads it back for verification.
+ * Then copies the scratchpad to EEPROM.
+ * The data must be on one page.
+ * The master must be locked.
+ *
+ * @param sl	The slave structure
+ * @param addr	Address for the write
+ * @param len   length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
+ * @param data	The data to write
+ * @return	0=Success -1=failure
+ */
+static int w1_f43_write(struct w1_slave *sl, int addr, int len, const u8 *data)
+{
+#ifdef CONFIG_W1_SLAVE_DS28EC20_CRC
+	struct w1_f43_data *f43 = sl->family_data;
+#endif
+	u8 wrbuf[4];
+	u8 rdbuf[W1_PAGE_SIZE + 3];
+	u8 es = (addr + len - 1) & 0x1f;
+
+	/* Write the data to the scratchpad */
+	if (w1_reset_select_slave(sl))
+		return -1;
+
+	wrbuf[0] = W1_F43_WRITE_SCRATCH;
+	wrbuf[1] = addr & 0xff;
+	wrbuf[2] = addr >> 8;
+
+	w1_write_block(sl->master, wrbuf, 3);
+	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_F43_READ_SCRATCH);
+	w1_read_block(sl->master, rdbuf, len + 3);
+
+	/* Compare what was read against the data written */
+	if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
+	    (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
+		return -1;
+
+	/* Copy the scratchpad to EEPROM */
+	if (w1_reset_select_slave(sl))
+		return -1;
+
+	wrbuf[0] = W1_F43_COPY_SCRATCH;
+	wrbuf[3] = es;
+	w1_write_block(sl->master, wrbuf, 4);
+
+	/* Sleep for 5 ms to wait for the write to complete */
+	msleep(5);
+
+	/* Reset the bus to wake up the EEPROM (this may not be needed) */
+	w1_reset_bus(sl->master);
+#ifdef CONFIG_W1_SLAVE_DS28EC20_CRC
+	f43->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
+#endif
+	return 0;
+}
+
+static ssize_t w1_f43_write_bin(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, idx;
+
+	if ((count = w1_f43_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
+		return 0;
+
+#ifdef CONFIG_W1_SLAVE_DS28EC20_CRC
+	/* can only write full blocks in cached mode */
+	if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
+		dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
+			(int)off, count);
+		return -EINVAL;
+	}
+
+	/* make sure the block CRCs are valid */
+	for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
+		if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
+			dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
+			return -EINVAL;
+		}
+	}
+#endif	/* CONFIG_W1_SLAVE_DS28EC20_CRC */
+
+	mutex_lock(&sl->master->mutex);
+
+	/* Can only write data to one page at a time */
+	idx = 0;
+	while (idx < count) {
+		addr = off + idx;
+		len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
+		if (len > (count - idx))
+			len = count - idx;
+
+		if (w1_f43_write(sl, addr, len, &buf[idx]) < 0) {
+			count = -EIO;
+			goto out_up;
+		}
+		idx += len;
+	}
+
+out_up:
+	mutex_unlock(&sl->master->mutex);
+
+	return count;
+}
+
+static struct bin_attribute w1_f43_bin_attr = {
+	.attr = {
+		.name = "eeprom",
+		.mode = S_IRUGO | S_IWUSR,
+	},
+	.size = W1_EEPROM_SIZE,
+	.read = w1_f43_read_bin,
+	.write = w1_f43_write_bin,
+};
+
+static int w1_f43_add_slave(struct w1_slave *sl)
+{
+	int err;
+#ifdef CONFIG_W1_SLAVE_DS28EC20_CRC
+	struct w1_f43_data *data;
+
+	data = kzalloc(sizeof(struct w1_f43_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	sl->family_data = data;
+
+#endif	/* CONFIG_W1_SLAVE_DS28EC20_CRC */
+
+	err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f43_bin_attr);
+
+#ifdef CONFIG_W1_SLAVE_DS28EC20_CRC
+	if (err)
+		kfree(data);
+#endif	/* CONFIG_W1_SLAVE_DS28EC20_CRC */
+
+	return err;
+}
+
+static void w1_f43_remove_slave(struct w1_slave *sl)
+{
+#ifdef CONFIG_W1_SLAVE_DS28EC20_CRC
+	kfree(sl->family_data);
+	sl->family_data = NULL;
+#endif	/* CONFIG_W1_SLAVE_DS28EC20_CRC */
+	sysfs_remove_bin_file(&sl->dev.kobj, &w1_f43_bin_attr);
+}
+
+static struct w1_family_ops w1_f43_fops = {
+	.add_slave      = w1_f43_add_slave,
+	.remove_slave   = w1_f43_remove_slave,
+};
+
+static struct w1_family w1_family_43 = {
+	.fid = W1_EEPROM_DS28EC20,
+	.fops = &w1_f43_fops,
+};
+
+static int __init w1_f43_init(void)
+{
+	return w1_register_family(&w1_family_43);
+}
+
+static void __exit w1_f43_fini(void)
+{
+	w1_unregister_family(&w1_family_43);
+}
+
+module_init(w1_f43_init);
+module_exit(w1_f43_fini);
diff --git a/drivers/w1/w1_family.h b/drivers/w1/w1_family.h
index 97479ae70b9c..2f086ef68869 100644
--- a/drivers/w1/w1_family.h
+++ b/drivers/w1/w1_family.h
@@ -38,6 +38,7 @@
 #define W1_EEPROM_DS2431	0x2D
 #define W1_FAMILY_DS2760	0x30
 #define W1_FAMILY_DS2780	0x32
+#define W1_EEPROM_DS28EC20  	0x43
 
 #define MAXNAMELEN		32