w1: Add 1-wire slave device driver for DS28E04-100

This patch adds a 1-wire slave device driver for the DS28E04-100.

Signed-off-by: Markus Franke <franm@hrz.tu-chemnitz.de>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4 files changed, 471 insertions, 0 deletions

diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
index eb9e376d6244..605ee36c96f8 100644
--- a/drivers/w1/slaves/Kconfig
+++ b/drivers/w1/slaves/Kconfig
@@ -94,6 +94,13 @@ config W1_SLAVE_DS2781
 
           If you are unsure, say N.
 
+config W1_SLAVE_DS28E04
+        tristate "4096-Bit Addressable 1-Wire EEPROM with PIO (DS28E04-100)"
+        depends on W1
+        help
+          Say Y here if you want to use a 1-wire
+          4kb EEPROM with PIO family device (DS28E04).
+
 config W1_SLAVE_BQ27000
         tristate "BQ27000 slave support"
         depends on W1
diff --git a/drivers/w1/slaves/Makefile b/drivers/w1/slaves/Makefile
index c4f1859fb520..05188f6aab5a 100644
--- a/drivers/w1/slaves/Makefile
+++ b/drivers/w1/slaves/Makefile
@@ -12,3 +12,4 @@ obj-$(CONFIG_W1_SLAVE_DS2760)	+= w1_ds2760.o
 obj-$(CONFIG_W1_SLAVE_DS2780)   += w1_ds2780.o
 obj-$(CONFIG_W1_SLAVE_DS2781)   += w1_ds2781.o
 obj-$(CONFIG_W1_SLAVE_BQ27000)  += w1_bq27000.o
+obj-$(CONFIG_W1_SLAVE_DS28E04)  += w1_ds28e04.o
diff --git a/drivers/w1/slaves/w1_ds28e04.c b/drivers/w1/slaves/w1_ds28e04.c
new file mode 100644
index 000000000000..f652db3782bf
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds28e04.c
@@ -0,0 +1,462 @@
+/*
+ *      w1_ds28e04.c - w1 family 1C (DS28E04) driver
+ *
+ * Copyright (c) 2012 Markus Franke <franke.m@sebakmt.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>
+#include <linux/crc16.h>
+#include <linux/uaccess.h>
+
+#define CRC16_INIT              0
+#define CRC16_VALID             0xb001
+
+#include "../w1.h"
+#include "../w1_int.h"
+#include "../w1_family.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Markus Franke <franke.m@sebakmt.com>, <franm@hrz.tu-chemnitz.de>");
+MODULE_DESCRIPTION("w1 family 1C driver for DS28E04, 4kb EEPROM and PIO");
+
+/* Allow the strong pullup to be disabled, but default to enabled.
+ * If it was disabled a parasite powered device might not get the required
+ * current to copy the data from the scratchpad to EEPROM.  If it is enabled parasite powered
+ * devices have a better chance of getting the current required.
+ */
+static int w1_strong_pullup = 1;
+module_param_named(strong_pullup, w1_strong_pullup, int, 0);
+
+/* enable/disable CRC checking on DS28E04-100 memory accesses */
+static char w1_enable_crccheck = 1;
+
+#define W1_EEPROM_SIZE          512
+#define W1_PAGE_COUNT           16
+#define W1_PAGE_SIZE            32
+#define W1_PAGE_BITS            5
+#define W1_PAGE_MASK            0x1F
+
+#define W1_F1C_READ_EEPROM      0xF0
+#define W1_F1C_WRITE_SCRATCH    0x0F
+#define W1_F1C_READ_SCRATCH     0xAA
+#define W1_F1C_COPY_SCRATCH     0x55
+#define W1_F1C_ACCESS_WRITE     0x5A
+
+#define W1_1C_REG_LOGIC_STATE   0x220
+
+struct w1_f1C_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_f1C_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;
+}
+
+static int w1_f1C_refresh_block(struct w1_slave *sl, struct w1_f1C_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_F1C_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;
+}
+
+static int w1_f1C_read(struct w1_slave *sl, int addr, int len, char *data)
+{
+        u8 wrbuf[3];
+
+        /* read directly from the EEPROM */
+        if (w1_reset_select_slave(sl))
+                return -EIO;
+
+        wrbuf[0] = W1_F1C_READ_EEPROM;
+        wrbuf[1] = addr & 0xff;
+        wrbuf[2] = addr >> 8;
+        
+        w1_write_block(sl->master, wrbuf, sizeof(wrbuf));
+        return w1_read_block(sl->master, data, len);
+}
+
+static ssize_t w1_f1C_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);
+        struct w1_f1C_data *data = sl->family_data;
+        int i, min_page, max_page;
+
+        if ((count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
+                return 0;
+
+        mutex_lock(&sl->master->mutex);
+
+        if(w1_enable_crccheck) {
+                min_page = (off >> W1_PAGE_BITS);
+                max_page = (off + count - 1) >> W1_PAGE_BITS;
+                for (i = min_page; i <= max_page; i++) {
+                        if (w1_f1C_refresh_block(sl, data, i)) {
+                                count = -EIO;
+                                goto out_up;
+                        }
+                }
+                memcpy(buf, &data->memory[off], count);
+        }
+        else {
+                count = w1_f1C_read(sl, off, count, buf);
+        }
+
+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_f1C_write(struct w1_slave *sl, int addr, int len, const u8 *data)
+{
+        u8 wrbuf[4];
+        u8 rdbuf[W1_PAGE_SIZE + 3];
+        u8 es = (addr + len - 1) & 0x1f;
+        unsigned int tm = 10;
+        int i;
+        struct w1_f1C_data *f1C = sl->family_data;
+
+        /* Write the data to the scratchpad */
+        if (w1_reset_select_slave(sl))
+                return -1;
+
+        wrbuf[0] = W1_F1C_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_F1C_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_F1C_COPY_SCRATCH;
+        wrbuf[3] = es;
+
+        for(i = 0; i < sizeof(wrbuf); ++i) {
+                /* issue 10ms strong pullup (or delay) on the last byte for writing the data from the scratchpad to EEPROM */
+                if(w1_strong_pullup && i == sizeof(wrbuf)-1)
+                        w1_next_pullup(sl->master, tm);
+                
+                w1_write_8(sl->master, wrbuf[i]);
+        }
+
+        if(!w1_strong_pullup)
+                msleep(tm);
+
+        if(w1_enable_crccheck) {
+                /* invalidate cached data */
+                f1C->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
+        }
+
+        /* Reset the bus to wake up the EEPROM (this may not be needed) */
+        w1_reset_bus(sl->master);
+
+        return 0;
+}
+
+static ssize_t w1_f1C_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_f1C_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
+                return 0;
+
+        if(w1_enable_crccheck) {
+                /* 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;
+                        }
+                }
+        }
+
+        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_f1C_write(sl, addr, len, &buf[idx]) < 0) {
+                        count = -EIO;
+                        goto out_up;
+                }
+                idx += len;
+        }
+
+out_up:
+        mutex_unlock(&sl->master->mutex);
+
+        return count;
+}
+
+static ssize_t w1_f1C_read_pio(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 ret;
+
+        /* check arguments */
+        if(off != 0 || count != 1 || buf == NULL)
+                return -EINVAL;
+
+        mutex_lock(&sl->master->mutex);
+        ret = w1_f1C_read(sl, W1_1C_REG_LOGIC_STATE, count, buf);
+        mutex_unlock(&sl->master->mutex);
+
+        return ret;
+}
+
+static ssize_t w1_f1C_write_pio(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);
+        u8 wrbuf[3];
+        u8 ack;
+
+        /* check arguments */
+        if(off != 0 || count != 1 || buf == NULL)
+                return -EINVAL;
+
+        mutex_lock(&sl->master->mutex);
+
+        /* Write the PIO data */
+        if (w1_reset_select_slave(sl))
+                return -1;
+
+        /* set bit 7..2 to value '1' */
+        *buf = *buf | 0xFC;
+
+        wrbuf[0] = W1_F1C_ACCESS_WRITE;
+        wrbuf[1] = *buf;
+        wrbuf[2] = ~(*buf);
+        w1_write_block(sl->master, wrbuf, 3);
+
+        w1_read_block(sl->master, &ack, sizeof(ack));
+
+        mutex_unlock(&sl->master->mutex);
+
+        /* check for acknowledgement */
+        if(ack != 0xAA) return -EIO;
+
+        return count;
+}
+
+static ssize_t w1_f1C_show_crccheck(struct device *dev, struct device_attribute *attr,  
+                               char *buf)
+{
+        if(put_user(w1_enable_crccheck + 0x30, buf))
+                return -EFAULT;
+        
+        return sizeof(w1_enable_crccheck);
+}
+
+static ssize_t w1_f1C_store_crccheck(struct device *dev, struct device_attribute *attr, 
+                               const char *buf, size_t count)
+{
+        char val;
+        
+        if(count != 1 || !buf) return -EINVAL;
+
+        if(get_user(val, buf))
+                return -EFAULT;
+        
+        /* convert to decimal */
+        val = val - 0x30;
+        if(val != 0 && val != 1) return -EINVAL;
+
+        /* set the new value */
+        w1_enable_crccheck = val;
+
+        return sizeof(w1_enable_crccheck);
+}
+
+#define NB_SYSFS_BIN_FILES 2
+static struct bin_attribute w1_f1C_bin_attr[NB_SYSFS_BIN_FILES] = {
+        {
+                .attr = {
+                        .name = "eeprom",
+                        .mode = S_IRUGO | S_IWUSR,
+                },
+                .size = W1_EEPROM_SIZE,
+                .read = w1_f1C_read_bin,
+                .write = w1_f1C_write_bin,
+        },
+        {
+                .attr = {
+                        .name = "pio",
+                        .mode = S_IRUGO | S_IWUSR,
+                },
+                .size = 1,
+                .read = w1_f1C_read_pio,
+                .write = w1_f1C_write_pio,
+        }
+};
+
+static DEVICE_ATTR(crccheck, S_IWUSR | S_IRUGO, w1_f1C_show_crccheck, w1_f1C_store_crccheck);
+
+static int w1_f1C_add_slave(struct w1_slave *sl)
+{
+        int err = 0;
+        int i;
+        struct w1_f1C_data *data = NULL;
+
+        if(w1_enable_crccheck) {
+                data = kzalloc(sizeof(struct w1_f1C_data), GFP_KERNEL);
+                if (!data)
+                        return -ENOMEM;
+                sl->family_data = data;
+        }
+
+        /* create binary sysfs attributes */
+        for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
+                err = sysfs_create_bin_file(&sl->dev.kobj, &(w1_f1C_bin_attr[i]));
+
+        if(err)
+                goto out;
+
+        /* create device attributes */
+        err = device_create_file(&sl->dev, &dev_attr_crccheck); 
+
+        if(err) {
+                /* remove binary sysfs attributes */
+                for (i = 0; i < NB_SYSFS_BIN_FILES; ++i)
+                        sysfs_remove_bin_file(&sl->dev.kobj, &(w1_f1C_bin_attr[i]));
+        }
+
+out:
+        if(err) {
+                if(w1_enable_crccheck)
+                        kfree(data);
+        }
+
+        return err;
+}
+
+static void w1_f1C_remove_slave(struct w1_slave *sl)
+{
+        int i;
+
+        if(w1_enable_crccheck) {
+                kfree(sl->family_data);
+                sl->family_data = NULL;
+        }
+
+        /* remove device attributes */
+        device_remove_file(&sl->dev, &dev_attr_crccheck);
+
+        /* remove binary sysfs attributes */
+        for (i = 0; i < NB_SYSFS_BIN_FILES; ++i)
+                sysfs_remove_bin_file(&sl->dev.kobj, &(w1_f1C_bin_attr[i]));
+}
+
+static struct w1_family_ops w1_f1C_fops = {
+        .add_slave      = w1_f1C_add_slave,
+        .remove_slave   = w1_f1C_remove_slave,
+};
+
+static struct w1_family w1_family_1C = {
+        .fid = W1_FAMILY_DS28E04,
+        .fops = &w1_f1C_fops,
+};
+
+static int __init w1_f1C_init(void)
+{
+        return w1_register_family(&w1_family_1C);
+}
+
+static void __exit w1_f1C_fini(void)
+{
+        w1_unregister_family(&w1_family_1C);
+}
+
+module_init(w1_f1C_init);
+module_exit(w1_f1C_fini);
diff --git a/drivers/w1/w1_family.h b/drivers/w1/w1_family.h
index 874aeb05011b..b00ada44a89b 100644
--- a/drivers/w1/w1_family.h
+++ b/drivers/w1/w1_family.h
@@ -30,6 +30,7 @@
 #define W1_FAMILY_SMEM_01       0x01
 #define W1_FAMILY_SMEM_81       0x81
 #define W1_THERM_DS18S20        0x10
+#define W1_FAMILY_DS28E04       0x1C
 #define W1_COUNTER_DS2423       0x1D
 #define W1_THERM_DS1822         0x22
 #define W1_EEPROM_DS2433        0x23