w1: new driver. DS2431 chip
authorBernhard Weirich <bernhard.weirich@riedel.net>
Thu, 16 Oct 2008 05:05:11 +0000 (22:05 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 16 Oct 2008 18:21:51 +0000 (11:21 -0700)
[akpm@linux-foundation.org: minor fixlets and cleanups]
Signed-off-by: Bernhard Weirich <bernhard.weirich@riedel.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/w1/slaves/w1_ds2431.c [new file with mode: 0644]
drivers/w1/w1_family.h

diff --git a/drivers/w1/slaves/w1_ds2431.c b/drivers/w1/slaves/w1_ds2431.c
new file mode 100644 (file)
index 0000000..2c6c0cf
--- /dev/null
@@ -0,0 +1,312 @@
+/*
+ * w1_ds2431.c - w1 family 2d (DS2431) driver
+ *
+ * Copyright (c) 2008 Bernhard Weirich <bernhard.weirich@riedel.net>
+ *
+ * Heavily inspired by w1_DS2433 driver 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 "../w1.h"
+#include "../w1_int.h"
+#include "../w1_family.h"
+
+#define W1_F2D_EEPROM_SIZE             128
+#define W1_F2D_PAGE_COUNT              4
+#define W1_F2D_PAGE_BITS               5
+#define W1_F2D_PAGE_SIZE               (1<<W1_F2D_PAGE_BITS)
+#define W1_F2D_PAGE_MASK               0x1F
+
+#define W1_F2D_SCRATCH_BITS  3
+#define W1_F2D_SCRATCH_SIZE  (1<<W1_F2D_SCRATCH_BITS)
+#define W1_F2D_SCRATCH_MASK  (W1_F2D_SCRATCH_SIZE-1)
+
+#define W1_F2D_READ_EEPROM     0xF0
+#define W1_F2D_WRITE_SCRATCH   0x0F
+#define W1_F2D_READ_SCRATCH    0xAA
+#define W1_F2D_COPY_SCRATCH    0x55
+
+
+#define W1_F2D_TPROG_MS                11
+
+#define W1_F2D_READ_RETRIES            10
+#define W1_F2D_READ_MAXLEN             8
+
+/*
+ * 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_f2d_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_F2D_READ_RETRIES times.
+ *
+ * count must not exceed W1_F2D_READ_MAXLEN.
+ */
+static int w1_f2d_readblock(struct w1_slave *sl, int off, int count, char *buf)
+{
+       u8 wrbuf[3];
+       u8 cmp[W1_F2D_READ_MAXLEN];
+       int tries = W1_F2D_READ_RETRIES;
+
+       do {
+               wrbuf[0] = W1_F2D_READ_EEPROM;
+               wrbuf[1] = off & 0xff;
+               wrbuf[2] = off >> 8;
+
+               if (w1_reset_select_slave(sl))
+                       return -1;
+
+               w1_write_block(sl->master, wrbuf, 3);
+               w1_read_block(sl->master, buf, count);
+
+               if (w1_reset_select_slave(sl))
+                       return -1;
+
+               w1_write_block(sl->master, wrbuf, 3);
+               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_F2D_READ_RETRIES);
+
+       return -1;
+}
+
+static ssize_t w1_f2d_read_bin(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_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE);
+       if (count == 0)
+               return 0;
+
+       mutex_lock(&sl->master->mutex);
+
+       /* read directly from the EEPROM in chunks of W1_F2D_READ_MAXLEN */
+       while (todo > 0) {
+               int block_read;
+
+               if (todo >= W1_F2D_READ_MAXLEN)
+                       block_read = W1_F2D_READ_MAXLEN;
+               else
+                       block_read = todo;
+
+               if (w1_f2d_readblock(sl, off, block_read, buf) < 0)
+                       count = -EIO;
+
+               todo -= W1_F2D_READ_MAXLEN;
+               buf += W1_F2D_READ_MAXLEN;
+               off += W1_F2D_READ_MAXLEN;
+       }
+
+       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 aligned at W1_F2D_SCRATCH_SIZE bytes and
+ * must be W1_F2D_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_F2D_PAGE_SIZE - (addr & W1_F2D_PAGE_MASK))
+ * @param data The data to write
+ * @return     0=Success -1=failure
+ */
+static int w1_f2d_write(struct w1_slave *sl, int addr, int len, const u8 *data)
+{
+       int tries = W1_F2D_READ_RETRIES;
+       u8 wrbuf[4];
+       u8 rdbuf[W1_F2D_SCRATCH_SIZE + 3];
+       u8 es = (addr + len - 1) % W1_F2D_SCRATCH_SIZE;
+
+retry:
+
+       /* Write the data to the scratchpad */
+       if (w1_reset_select_slave(sl))
+               return -1;
+
+       wrbuf[0] = W1_F2D_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_F2D_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)) {
+
+               if (--tries)
+                       goto retry;
+
+               dev_err(&sl->dev,
+                       "could not write to eeprom, scratchpad compare failed %d times\n",
+                       W1_F2D_READ_RETRIES);
+
+               return -1;
+       }
+
+       /* Copy the scratchpad to EEPROM */
+       if (w1_reset_select_slave(sl))
+               return -1;
+
+       wrbuf[0] = W1_F2D_COPY_SCRATCH;
+       wrbuf[3] = es;
+       w1_write_block(sl->master, wrbuf, 4);
+
+       /* Sleep for tprog ms to wait for the write to complete */
+       msleep(W1_F2D_TPROG_MS);
+
+       /* Reset the bus to wake up the EEPROM  */
+       w1_reset_bus(sl->master);
+
+       return 0;
+}
+
+static ssize_t w1_f2d_write_bin(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_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE);
+       if (count == 0)
+               return 0;
+
+       mutex_lock(&sl->master->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_F2D_SCRATCH_SIZE || addr & W1_F2D_SCRATCH_MASK) {
+                       char tmp[W1_F2D_SCRATCH_SIZE];
+
+                       /* read the block and update the parts to be written */
+                       if (w1_f2d_readblock(sl, addr & ~W1_F2D_SCRATCH_MASK,
+                                       W1_F2D_SCRATCH_SIZE, tmp)) {
+                               count = -EIO;
+                               goto out_up;
+                       }
+
+                       /* copy at most to the boundary of the PAGE or len */
+                       copy = W1_F2D_SCRATCH_SIZE -
+                               (addr & W1_F2D_SCRATCH_MASK);
+
+                       if (copy > len)
+                               copy = len;
+
+                       memcpy(&tmp[addr & W1_F2D_SCRATCH_MASK], buf, copy);
+                       if (w1_f2d_write(sl, addr & ~W1_F2D_SCRATCH_MASK,
+                                       W1_F2D_SCRATCH_SIZE, tmp) < 0) {
+                               count = -EIO;
+                               goto out_up;
+                       }
+               } else {
+
+                       copy = W1_F2D_SCRATCH_SIZE;
+                       if (w1_f2d_write(sl, addr, copy, buf) < 0) {
+                               count = -EIO;
+                               goto out_up;
+                       }
+               }
+               buf += copy;
+               addr += copy;
+               len -= copy;
+       }
+
+out_up:
+       mutex_unlock(&sl->master->mutex);
+
+       return count;
+}
+
+static struct bin_attribute w1_f2d_bin_attr = {
+       .attr = {
+               .name = "eeprom",
+               .mode = S_IRUGO | S_IWUSR,
+       },
+       .size = W1_F2D_EEPROM_SIZE,
+       .read = w1_f2d_read_bin,
+       .write = w1_f2d_write_bin,
+};
+
+static int w1_f2d_add_slave(struct w1_slave *sl)
+{
+       return sysfs_create_bin_file(&sl->dev.kobj, &w1_f2d_bin_attr);
+}
+
+static void w1_f2d_remove_slave(struct w1_slave *sl)
+{
+       sysfs_remove_bin_file(&sl->dev.kobj, &w1_f2d_bin_attr);
+}
+
+static struct w1_family_ops w1_f2d_fops = {
+       .add_slave      = w1_f2d_add_slave,
+       .remove_slave   = w1_f2d_remove_slave,
+};
+
+static struct w1_family w1_family_2d = {
+       .fid = W1_EEPROM_DS2431,
+       .fops = &w1_f2d_fops,
+};
+
+static int __init w1_f2d_init(void)
+{
+       return w1_register_family(&w1_family_2d);
+}
+
+static void __exit w1_f2d_fini(void)
+{
+       w1_unregister_family(&w1_family_2d);
+}
+
+module_init(w1_f2d_init);
+module_exit(w1_f2d_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Bernhard Weirich <bernhard.weirich@riedel.net>");
+MODULE_DESCRIPTION("w1 family 2d driver for DS2431, 1kb EEPROM");
index 30531331a643527860415450341a104df40543ab..3ca1b9298f2143dea98a2973021cdafe254bad38 100644 (file)
@@ -33,6 +33,7 @@
 #define W1_THERM_DS1822        0x22
 #define W1_EEPROM_DS2433       0x23
 #define W1_THERM_DS18B20       0x28
+#define W1_EEPROM_DS2431       0x2D
 #define W1_FAMILY_DS2760       0x30
 
 #define MAXNAMELEN             32