w1: new driver. DS2431 chip

[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>

1 files changed, 312 insertions, 0 deletions

diff --git a/drivers/w1/slaves/w1_ds2431.c b/drivers/w1/slaves/w1_ds2431.c
new file mode 100644
index 000000000000..2c6c0cf6a20f
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds2431.c
@@ -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");