--- /dev/null
+/*
+ * 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");
+MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS28E04));
+
+/* 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 eeprom_read(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 eeprom_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);
+ 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 BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
+
+static ssize_t pio_read(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 pio_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 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 BIN_ATTR_RW(pio, 1);
+
+static ssize_t crccheck_show(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 crccheck_store(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);
+}
+
+static DEVICE_ATTR_RW(crccheck);
+
+static struct attribute *w1_f1C_attrs[] = {
+ &dev_attr_crccheck.attr,
+ NULL,
+};
+
+static struct bin_attribute *w1_f1C_bin_attrs[] = {
+ &bin_attr_eeprom,
+ &bin_attr_pio,
+ NULL,
+};
+
+static const struct attribute_group w1_f1C_group = {
+ .attrs = w1_f1C_attrs,
+ .bin_attrs = w1_f1C_bin_attrs,
+};
+
+static const struct attribute_group *w1_f1C_groups[] = {
+ &w1_f1C_group,
+ NULL,
+};
+
+static int w1_f1C_add_slave(struct w1_slave *sl)
+{
+ 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;
+ }
+
+ return 0;
+}
+
+static void w1_f1C_remove_slave(struct w1_slave *sl)
+{
+ kfree(sl->family_data);
+ sl->family_data = NULL;
+}
+
+static struct w1_family_ops w1_f1C_fops = {
+ .add_slave = w1_f1C_add_slave,
+ .remove_slave = w1_f1C_remove_slave,
+ .groups = w1_f1C_groups,
+};
+
+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);
Code Review / kvmfornfv.git / blobdiff