w1: Add 1-wire slave device driver for DS28E04-100
authorMarkus Franke <franm@hrz.tu-chemnitz.de>
Fri, 25 May 2012 22:45:12 +0000 (00:45 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 13 Jun 2012 23:47:10 +0000 (16:47 -0700)
Signed-off-by: Markus Franke <franm@hrz.tu-chemnitz.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Documentation/ABI/stable/sysfs-driver-w1_ds28e04 [new file with mode: 0644]
Documentation/w1/slaves/w1_ds28e04 [new file with mode: 0644]
drivers/w1/slaves/Kconfig
drivers/w1/slaves/Makefile
drivers/w1/slaves/w1_ds28e04.c [new file with mode: 0644]
drivers/w1/w1_family.h

diff --git a/Documentation/ABI/stable/sysfs-driver-w1_ds28e04 b/Documentation/ABI/stable/sysfs-driver-w1_ds28e04
new file mode 100644 (file)
index 0000000..26579ee
--- /dev/null
@@ -0,0 +1,15 @@
+What:          /sys/bus/w1/devices/.../pio
+Date:          May 2012
+Contact:       Markus Franke <franm@hrz.tu-chemnitz.de>
+Description:   read/write the contents of the two PIO's of the DS28E04-100
+               see Documentation/w1/slaves/w1_ds28e04 for detailed information
+Users:         any user space application which wants to communicate with DS28E04-100
+
+
+
+What:          /sys/bus/w1/devices/.../eeprom
+Date:          May 2012
+Contact:       Markus Franke <franm@hrz.tu-chemnitz.de>
+Description:   read/write the contents of the EEPROM memory of the DS28E04-100
+               see Documentation/w1/slaves/w1_ds28e04 for detailed information
+Users:         any user space application which wants to communicate with DS28E04-100
diff --git a/Documentation/w1/slaves/w1_ds28e04 b/Documentation/w1/slaves/w1_ds28e04
new file mode 100644 (file)
index 0000000..85bc9a7
--- /dev/null
@@ -0,0 +1,36 @@
+Kernel driver w1_ds28e04
+========================
+
+Supported chips:
+  * Maxim DS28E04-100 4096-Bit Addressable 1-Wire EEPROM with PIO
+
+supported family codes:
+       W1_FAMILY_DS28E04       0x1C
+
+Author: Markus Franke, <franke.m@sebakmt.com> <franm@hrz.tu-chemnitz.de>
+
+Description
+-----------
+
+Support is provided through the sysfs files "eeprom" and "pio". CRC checking
+during memory accesses can optionally be enabled/disabled via the device
+attribute "crccheck". The strong pull-up can optionally be enabled/disabled
+via the module parameter "w1_strong_pullup".
+
+Memory Access
+
+       A read operation on the "eeprom" file reads the given amount of bytes
+       from the EEPROM of the DS28E04.
+
+       A write operation on the "eeprom" file writes the given byte sequence
+       to the EEPROM of the DS28E04. If CRC checking mode is enabled only
+       fully alligned blocks of 32 bytes with valid CRC16 values (in bytes 30
+       and 31) are allowed to be written.
+
+PIO Access
+
+       The 2 PIOs of the DS28E04-100 are accessible via the "pio" sysfs file.
+
+       The current status of the PIO's is returned as an 8 bit value. Bit 0/1
+       represent the state of PIO_0/PIO_1. Bits 2..7 do not care. The PIO's are
+       driven low-active, i.e. the driver delivers/expects low-active values.
index eb9e376d624478bb143238970ffb54c2791c0917..67526690acbcb85ad211459a39a7f36ac65e5d4e 100644 (file)
@@ -94,6 +94,19 @@ 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
+       select CRC16
+       help
+         If you enable this you will have the DS28E04-100
+         chip support.
+
+         Say Y here if you want to use a 1-wire
+         4kb EEPROM with PIO family device (DS28E04).
+
+         If you are unsure, say N.
+
 config W1_SLAVE_BQ27000
        tristate "BQ27000 slave support"
        depends on W1
index c4f1859fb520ad5218b0ab40f32b102ac2db35d9..05188f6aab5ab3dc6bcd32565a7ca17de42fffad 100644 (file)
@@ -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 (file)
index 0000000..98117db
--- /dev/null
@@ -0,0 +1,469 @@
+/*
+ *     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;
+
+       count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE);
+       if (count == 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;
+
+       count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE);
+       if (count == 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)) {
+               mutex_unlock(&sl->master->mutex);
+               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) {
+               /* 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]));
+
+               kfree(data);
+       }
+
+       return err;
+}
+
+static void w1_f1C_remove_slave(struct w1_slave *sl)
+{
+       int i;
+
+       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);
index 874aeb05011b04d2b83145627436a56755425623..b00ada44a89be8989a46912fb85e976624d5e586 100644 (file)
@@ -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