[PATCH 4/5] 1-wire: add ds2431 support
Jean-Christophe PLAGNIOL-VILLARD
plagnioj at jcrosoft.com
Sat Oct 27 16:03:44 EDT 2012
Based on linux implementation.
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
---
drivers/w1/slaves/Kconfig | 10 ++
drivers/w1/slaves/Makefile | 1 +
drivers/w1/slaves/w1_ds2431.c | 294 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 305 insertions(+)
create mode 100644 drivers/w1/slaves/w1_ds2431.c
diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
index f35eedf..26150a2 100644
--- a/drivers/w1/slaves/Kconfig
+++ b/drivers/w1/slaves/Kconfig
@@ -4,4 +4,14 @@
menu "1-wire Slaves"
+config W1_SLAVE_DS2431
+ bool "1kb EEPROM family support (DS2431)"
+ help
+ Say Y here if you want to use a 1-wire
+ 1kb EEPROM family device (DS2431)
+
+config W1_SLAVE_DS2431_WRITE
+ bool "write support"
+ depends on W1_SLAVE_DS2431
+
endmenu
diff --git a/drivers/w1/slaves/Makefile b/drivers/w1/slaves/Makefile
index ac9a5a7..65804e0 100644
--- a/drivers/w1/slaves/Makefile
+++ b/drivers/w1/slaves/Makefile
@@ -2,3 +2,4 @@
# Makefile for the Dallas's 1-wire slaves.
#
+obj-$(CONFIG_W1_SLAVE_DS2431) += w1_ds2431.o
diff --git a/drivers/w1/slaves/w1_ds2431.c b/drivers/w1/slaves/w1_ds2431.c
new file mode 100644
index 0000000..30e6e1d
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds2431.c
@@ -0,0 +1,294 @@
+/*
+ * w1_ds2431.c - w1 family 2d (DS2431) driver
+ *
+ * Copyright (c) 2008 Bernhard Weirich <bernhard.weirich at riedel.net>
+ * Copyright (c) 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
+ *
+ * Heavily inspired by w1_DS2433 driver from Ben Gardner <bgardner at wabtec.com>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#include <init.h>
+#include "../w1.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
+
+#define DRIVERNAME "ds2431"
+
+static int ds2431_count = 0;
+
+/*
+ * 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 ds2431_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.
+ */
+int ds2431_readblock(struct w1_device *dev, int off, int count, char *buf)
+{
+ struct w1_bus *bus = dev->bus;
+ 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(dev))
+ return -1;
+
+ w1_write_block(bus, wrbuf, 3);
+ w1_read_block(bus, buf, count);
+
+ if (w1_reset_select_slave(dev))
+ return -1;
+
+ w1_write_block(bus, wrbuf, 3);
+ w1_read_block(bus, cmp, count);
+
+ if (!memcmp(cmp, buf, count))
+ return 0;
+ } while (--tries);
+
+ dev_err(&dev->dev, "proof reading failed %d times\n",
+ W1_F2D_READ_RETRIES);
+
+ return -1;
+}
+
+static ssize_t ds2431_cdev_read(struct cdev *cdev, void *buf, size_t count,
+ loff_t off, ulong flags)
+{
+ struct w1_device *dev = cdev->priv;
+ int todo = count;
+
+ count = ds2431_fix_count(off, count, W1_F2D_EEPROM_SIZE);
+ if (count == 0)
+ return 0;
+
+ /* 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 (ds2431_readblock(dev, off, block_read, buf) < 0)
+ count = -EIO;
+
+ todo -= W1_F2D_READ_MAXLEN;
+ buf += W1_F2D_READ_MAXLEN;
+ off += W1_F2D_READ_MAXLEN;
+ }
+
+ return count;
+}
+
+#ifdef CONFIG_W1_SLAVE_DS2431_WRITE
+/*
+ * 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 ds2431_write(struct w1_device *dev, int addr, int len, const u8 *data)
+{
+ struct w1_bus *bus = dev->bus;
+ 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(dev))
+ return -1;
+
+ wrbuf[0] = W1_F2D_WRITE_SCRATCH;
+ wrbuf[1] = addr & 0xff;
+ wrbuf[2] = addr >> 8;
+
+ w1_write_block(bus, wrbuf, 3);
+ w1_write_block(bus, data, len);
+
+ /* Read the scratchpad and verify */
+ if (w1_reset_select_slave(dev))
+ return -1;
+
+ w1_write_8(bus, W1_F2D_READ_SCRATCH);
+ w1_read_block(bus, 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(&dev->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(dev))
+ return -1;
+
+ wrbuf[0] = W1_F2D_COPY_SCRATCH;
+ wrbuf[3] = es;
+ w1_write_block(bus, wrbuf, 4);
+
+ /* Sleep for tprog ms to wait for the write to complete */
+ mdelay(W1_F2D_TPROG_MS);
+
+ /* Reset the bus to wake up the EEPROM */
+ w1_reset_bus(bus);
+
+ return 0;
+}
+
+static ssize_t ds2431_cdev_write(struct cdev *cdev, const void *buf, size_t count,
+ loff_t off, ulong flags)
+{
+ struct w1_device *dev = cdev->priv;
+ int addr, len;
+ int copy;
+
+ count = ds2431_fix_count(off, count, W1_F2D_EEPROM_SIZE);
+ if (count == 0)
+ return 0;
+
+ /* 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 (ds2431_readblock(dev, 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 (ds2431_write(dev, addr & ~W1_F2D_SCRATCH_MASK,
+ W1_F2D_SCRATCH_SIZE, tmp) < 0) {
+ count = -EIO;
+ goto out_up;
+ }
+ } else {
+
+ copy = W1_F2D_SCRATCH_SIZE;
+ if (ds2431_write(dev, addr, copy, buf) < 0) {
+ count = -EIO;
+ goto out_up;
+ }
+ }
+ buf += copy;
+ addr += copy;
+ len -= copy;
+ }
+
+out_up:
+ return count;
+}
+#else
+#define ds2431_cdev_write NULL
+#endif
+
+static struct file_operations ds2431_ops = {
+ .read = ds2431_cdev_read,
+ .write = ds2431_cdev_write,
+ .lseek = dev_lseek_default,
+};
+
+static int ds2431_probe(struct w1_device *dev)
+{
+ struct cdev *cdev;
+
+ cdev = xzalloc(sizeof(*cdev));
+ cdev->dev = &dev->dev;
+ cdev->priv = dev;
+ cdev->ops = &ds2431_ops;
+ cdev->size = W1_F2D_EEPROM_SIZE;
+ cdev->name = asprintf(DRIVERNAME"%d", ds2431_count++);
+ if (cdev->name == NULL)
+ return -ENOMEM;
+
+ return devfs_create(cdev);
+}
+
+struct w1_driver ds2431_driver = {
+ .drv = {
+ .name = DRIVERNAME,
+ },
+ .probe = ds2431_probe,
+ .fid = 0x2d,
+};
+
+static int w1_ds2431_init(void)
+{
+ return w1_driver_register(&ds2431_driver);
+}
+device_initcall(w1_ds2431_init);
--
1.7.10.4
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