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path: root/drivers/w1/slaves/w1_ds2408.c
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Diffstat (limited to 'drivers/w1/slaves/w1_ds2408.c')
-rw-r--r--drivers/w1/slaves/w1_ds2408.c366
1 files changed, 366 insertions, 0 deletions
diff --git a/drivers/w1/slaves/w1_ds2408.c b/drivers/w1/slaves/w1_ds2408.c
new file mode 100644
index 000000000..7dfa0e116
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds2408.c
@@ -0,0 +1,366 @@
+/*
+ * w1_ds2408.c - w1 family 29 (DS2408) driver
+ *
+ * Copyright (c) 2010 Jean-Francois Dagenais <dagenaisj@sonatest.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 "../w1.h"
+#include "../w1_int.h"
+#include "../w1_family.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jean-Francois Dagenais <dagenaisj@sonatest.com>");
+MODULE_DESCRIPTION("w1 family 29 driver for DS2408 8 Pin IO");
+MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2408));
+
+
+#define W1_F29_RETRIES 3
+
+#define W1_F29_REG_LOGIG_STATE 0x88 /* R */
+#define W1_F29_REG_OUTPUT_LATCH_STATE 0x89 /* R */
+#define W1_F29_REG_ACTIVITY_LATCH_STATE 0x8A /* R */
+#define W1_F29_REG_COND_SEARCH_SELECT_MASK 0x8B /* RW */
+#define W1_F29_REG_COND_SEARCH_POL_SELECT 0x8C /* RW */
+#define W1_F29_REG_CONTROL_AND_STATUS 0x8D /* RW */
+
+#define W1_F29_FUNC_READ_PIO_REGS 0xF0
+#define W1_F29_FUNC_CHANN_ACCESS_READ 0xF5
+#define W1_F29_FUNC_CHANN_ACCESS_WRITE 0x5A
+/* also used to write the control/status reg (0x8D): */
+#define W1_F29_FUNC_WRITE_COND_SEARCH_REG 0xCC
+#define W1_F29_FUNC_RESET_ACTIVITY_LATCHES 0xC3
+
+#define W1_F29_SUCCESS_CONFIRM_BYTE 0xAA
+
+static int _read_reg(struct w1_slave *sl, u8 address, unsigned char* buf)
+{
+ u8 wrbuf[3];
+ dev_dbg(&sl->dev,
+ "Reading with slave: %p, reg addr: %0#4x, buff addr: %p",
+ sl, (unsigned int)address, buf);
+
+ if (!buf)
+ return -EINVAL;
+
+ mutex_lock(&sl->master->bus_mutex);
+ dev_dbg(&sl->dev, "mutex locked");
+
+ if (w1_reset_select_slave(sl)) {
+ mutex_unlock(&sl->master->bus_mutex);
+ return -EIO;
+ }
+
+ wrbuf[0] = W1_F29_FUNC_READ_PIO_REGS;
+ wrbuf[1] = address;
+ wrbuf[2] = 0;
+ w1_write_block(sl->master, wrbuf, 3);
+ *buf = w1_read_8(sl->master);
+
+ mutex_unlock(&sl->master->bus_mutex);
+ dev_dbg(&sl->dev, "mutex unlocked");
+ return 1;
+}
+
+static ssize_t state_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *buf, loff_t off,
+ size_t count)
+{
+ dev_dbg(&kobj_to_w1_slave(kobj)->dev,
+ "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
+ bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
+ if (count != 1 || off != 0)
+ return -EFAULT;
+ return _read_reg(kobj_to_w1_slave(kobj), W1_F29_REG_LOGIG_STATE, buf);
+}
+
+static ssize_t output_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *buf,
+ loff_t off, size_t count)
+{
+ dev_dbg(&kobj_to_w1_slave(kobj)->dev,
+ "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
+ bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
+ if (count != 1 || off != 0)
+ return -EFAULT;
+ return _read_reg(kobj_to_w1_slave(kobj),
+ W1_F29_REG_OUTPUT_LATCH_STATE, buf);
+}
+
+static ssize_t activity_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *buf,
+ loff_t off, size_t count)
+{
+ dev_dbg(&kobj_to_w1_slave(kobj)->dev,
+ "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
+ bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
+ if (count != 1 || off != 0)
+ return -EFAULT;
+ return _read_reg(kobj_to_w1_slave(kobj),
+ W1_F29_REG_ACTIVITY_LATCH_STATE, buf);
+}
+
+static ssize_t cond_search_mask_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *buf,
+ loff_t off, size_t count)
+{
+ dev_dbg(&kobj_to_w1_slave(kobj)->dev,
+ "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
+ bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
+ if (count != 1 || off != 0)
+ return -EFAULT;
+ return _read_reg(kobj_to_w1_slave(kobj),
+ W1_F29_REG_COND_SEARCH_SELECT_MASK, buf);
+}
+
+static ssize_t cond_search_polarity_read(struct file *filp,
+ struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t count)
+{
+ if (count != 1 || off != 0)
+ return -EFAULT;
+ return _read_reg(kobj_to_w1_slave(kobj),
+ W1_F29_REG_COND_SEARCH_POL_SELECT, buf);
+}
+
+static ssize_t status_control_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *buf,
+ loff_t off, size_t count)
+{
+ if (count != 1 || off != 0)
+ return -EFAULT;
+ return _read_reg(kobj_to_w1_slave(kobj),
+ W1_F29_REG_CONTROL_AND_STATUS, buf);
+}
+
+static ssize_t output_write(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 w1_buf[3];
+ u8 readBack;
+ unsigned int retries = W1_F29_RETRIES;
+
+ if (count != 1 || off != 0)
+ return -EFAULT;
+
+ dev_dbg(&sl->dev, "locking mutex for write_output");
+ mutex_lock(&sl->master->bus_mutex);
+ dev_dbg(&sl->dev, "mutex locked");
+
+ if (w1_reset_select_slave(sl))
+ goto error;
+
+ while (retries--) {
+ w1_buf[0] = W1_F29_FUNC_CHANN_ACCESS_WRITE;
+ w1_buf[1] = *buf;
+ w1_buf[2] = ~(*buf);
+ w1_write_block(sl->master, w1_buf, 3);
+
+ readBack = w1_read_8(sl->master);
+
+ if (readBack != W1_F29_SUCCESS_CONFIRM_BYTE) {
+ if (w1_reset_resume_command(sl->master))
+ goto error;
+ /* try again, the slave is ready for a command */
+ continue;
+ }
+
+#ifdef CONFIG_W1_SLAVE_DS2408_READBACK
+ /* here the master could read another byte which
+ would be the PIO reg (the actual pin logic state)
+ since in this driver we don't know which pins are
+ in and outs, there's no value to read the state and
+ compare. with (*buf) so end this command abruptly: */
+ if (w1_reset_resume_command(sl->master))
+ goto error;
+
+ /* go read back the output latches */
+ /* (the direct effect of the write above) */
+ w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;
+ w1_buf[1] = W1_F29_REG_OUTPUT_LATCH_STATE;
+ w1_buf[2] = 0;
+ w1_write_block(sl->master, w1_buf, 3);
+ /* read the result of the READ_PIO_REGS command */
+ if (w1_read_8(sl->master) == *buf)
+#endif
+ {
+ /* success! */
+ mutex_unlock(&sl->master->bus_mutex);
+ dev_dbg(&sl->dev,
+ "mutex unlocked, retries:%d", retries);
+ return 1;
+ }
+ }
+error:
+ mutex_unlock(&sl->master->bus_mutex);
+ dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
+
+ return -EIO;
+}
+
+
+/**
+ * Writing to the activity file resets the activity latches.
+ */
+static ssize_t activity_write(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);
+ unsigned int retries = W1_F29_RETRIES;
+
+ if (count != 1 || off != 0)
+ return -EFAULT;
+
+ mutex_lock(&sl->master->bus_mutex);
+
+ if (w1_reset_select_slave(sl))
+ goto error;
+
+ while (retries--) {
+ w1_write_8(sl->master, W1_F29_FUNC_RESET_ACTIVITY_LATCHES);
+ if (w1_read_8(sl->master) == W1_F29_SUCCESS_CONFIRM_BYTE) {
+ mutex_unlock(&sl->master->bus_mutex);
+ return 1;
+ }
+ if (w1_reset_resume_command(sl->master))
+ goto error;
+ }
+
+error:
+ mutex_unlock(&sl->master->bus_mutex);
+ return -EIO;
+}
+
+static ssize_t status_control_write(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 w1_buf[4];
+ unsigned int retries = W1_F29_RETRIES;
+
+ if (count != 1 || off != 0)
+ return -EFAULT;
+
+ mutex_lock(&sl->master->bus_mutex);
+
+ if (w1_reset_select_slave(sl))
+ goto error;
+
+ while (retries--) {
+ w1_buf[0] = W1_F29_FUNC_WRITE_COND_SEARCH_REG;
+ w1_buf[1] = W1_F29_REG_CONTROL_AND_STATUS;
+ w1_buf[2] = 0;
+ w1_buf[3] = *buf;
+
+ w1_write_block(sl->master, w1_buf, 4);
+ if (w1_reset_resume_command(sl->master))
+ goto error;
+
+ w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;
+ w1_buf[1] = W1_F29_REG_CONTROL_AND_STATUS;
+ w1_buf[2] = 0;
+
+ w1_write_block(sl->master, w1_buf, 3);
+ if (w1_read_8(sl->master) == *buf) {
+ /* success! */
+ mutex_unlock(&sl->master->bus_mutex);
+ return 1;
+ }
+ }
+error:
+ mutex_unlock(&sl->master->bus_mutex);
+
+ return -EIO;
+}
+
+/*
+ * This is a special sequence we must do to ensure the P0 output is not stuck
+ * in test mode. This is described in rev 2 of the ds2408's datasheet
+ * (http://datasheets.maximintegrated.com/en/ds/DS2408.pdf) under
+ * "APPLICATION INFORMATION/Power-up timing".
+ */
+static int w1_f29_disable_test_mode(struct w1_slave *sl)
+{
+ int res;
+ u8 magic[10] = {0x96, };
+ u64 rn = le64_to_cpu(*((u64*)&sl->reg_num));
+
+ memcpy(&magic[1], &rn, 8);
+ magic[9] = 0x3C;
+
+ mutex_lock(&sl->master->bus_mutex);
+
+ res = w1_reset_bus(sl->master);
+ if (res)
+ goto out;
+ w1_write_block(sl->master, magic, ARRAY_SIZE(magic));
+
+ res = w1_reset_bus(sl->master);
+out:
+ mutex_unlock(&sl->master->bus_mutex);
+ return res;
+}
+
+static BIN_ATTR_RO(state, 1);
+static BIN_ATTR_RW(output, 1);
+static BIN_ATTR_RW(activity, 1);
+static BIN_ATTR_RO(cond_search_mask, 1);
+static BIN_ATTR_RO(cond_search_polarity, 1);
+static BIN_ATTR_RW(status_control, 1);
+
+static struct bin_attribute *w1_f29_bin_attrs[] = {
+ &bin_attr_state,
+ &bin_attr_output,
+ &bin_attr_activity,
+ &bin_attr_cond_search_mask,
+ &bin_attr_cond_search_polarity,
+ &bin_attr_status_control,
+ NULL,
+};
+
+static const struct attribute_group w1_f29_group = {
+ .bin_attrs = w1_f29_bin_attrs,
+};
+
+static const struct attribute_group *w1_f29_groups[] = {
+ &w1_f29_group,
+ NULL,
+};
+
+static struct w1_family_ops w1_f29_fops = {
+ .add_slave = w1_f29_disable_test_mode,
+ .groups = w1_f29_groups,
+};
+
+static struct w1_family w1_family_29 = {
+ .fid = W1_FAMILY_DS2408,
+ .fops = &w1_f29_fops,
+};
+
+static int __init w1_f29_init(void)
+{
+ return w1_register_family(&w1_family_29);
+}
+
+static void __exit w1_f29_exit(void)
+{
+ w1_unregister_family(&w1_family_29);
+}
+
+module_init(w1_f29_init);
+module_exit(w1_f29_exit);
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