linux/drivers/w1/slaves/w1_ds2433.c

317 lines
7.1 KiB
C
Raw Normal View History

/*
* w1_ds2433.c - w1 family 23 (DS2433) driver
*
* Copyright (c) 2005 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>
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
#include <linux/crc16.h>
#define CRC16_INIT 0
#define CRC16_VALID 0xb001
#endif
#include "../w1.h"
#include "../w1_int.h"
#include "../w1_family.h"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
#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_F23_TIME 300
#define W1_F23_READ_EEPROM 0xF0
#define W1_F23_WRITE_SCRATCH 0x0F
#define W1_F23_READ_SCRATCH 0xAA
#define W1_F23_COPY_SCRATCH 0x55
struct w1_f23_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_f23_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;
}
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_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_F23_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;
}
#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
sysfs: add parameter "struct bin_attribute *" in .read/.write methods for sysfs binary attributes Well, first of all, I don't want to change so many files either. What I do: Adding a new parameter "struct bin_attribute *" in the .read/.write methods for the sysfs binary attributes. In fact, only the four lines change in fs/sysfs/bin.c and include/linux/sysfs.h do the real work. But I have to update all the files that use binary attributes to make them compatible with the new .read and .write methods. I'm not sure if I missed any. :( Why I do this: For a sysfs attribute, we can get a pointer pointing to the struct attribute in the .show/.store method, while we can't do this for the binary attributes. I don't know why this is different, but this does make it not so handy to use the binary attributes as the regular ones. So I think this patch is reasonable. :) Who benefits from it: The patch that exposes ACPI tables in sysfs requires such an improvement. All the table binary attributes share the same .read method. Parameter "struct bin_attribute *" is used to get the table signature and instance number which are used to distinguish different ACPI table binary attributes. Without this parameter, we need to offer different .read methods for different ACPI table binary attributes. This is impossible as there are various ACPI tables on different platforms, and we don't know what they are until they are loaded. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-06-09 05:57:22 +00:00
static ssize_t w1_f23_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);
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
struct w1_f23_data *data = sl->family_data;
int i, min_page, max_page;
#else
u8 wrbuf[3];
#endif
if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
return 0;
mutex_lock(&sl->master->mutex);
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
min_page = (off >> W1_PAGE_BITS);
max_page = (off + count - 1) >> W1_PAGE_BITS;
for (i = min_page; i <= max_page; i++) {
if (w1_f23_refresh_block(sl, data, i)) {
count = -EIO;
goto out_up;
}
}
memcpy(buf, &data->memory[off], count);
#else /* CONFIG_W1_SLAVE_DS2433_CRC */
/* read directly from the EEPROM */
if (w1_reset_select_slave(sl)) {
count = -EIO;
goto out_up;
}
wrbuf[0] = W1_F23_READ_EEPROM;
wrbuf[1] = off & 0xff;
wrbuf[2] = off >> 8;
w1_write_block(sl->master, wrbuf, 3);
w1_read_block(sl->master, buf, count);
#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
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_f23_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;
/* Write the data to the scratchpad */
if (w1_reset_select_slave(sl))
return -1;
wrbuf[0] = W1_F23_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_F23_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_F23_COPY_SCRATCH;
wrbuf[3] = es;
w1_write_block(sl->master, wrbuf, 4);
/* Sleep for 5 ms to wait for the write to complete */
msleep(5);
/* Reset the bus to wake up the EEPROM (this may not be needed) */
w1_reset_bus(sl->master);
return 0;
}
sysfs: add parameter "struct bin_attribute *" in .read/.write methods for sysfs binary attributes Well, first of all, I don't want to change so many files either. What I do: Adding a new parameter "struct bin_attribute *" in the .read/.write methods for the sysfs binary attributes. In fact, only the four lines change in fs/sysfs/bin.c and include/linux/sysfs.h do the real work. But I have to update all the files that use binary attributes to make them compatible with the new .read and .write methods. I'm not sure if I missed any. :( Why I do this: For a sysfs attribute, we can get a pointer pointing to the struct attribute in the .show/.store method, while we can't do this for the binary attributes. I don't know why this is different, but this does make it not so handy to use the binary attributes as the regular ones. So I think this patch is reasonable. :) Who benefits from it: The patch that exposes ACPI tables in sysfs requires such an improvement. All the table binary attributes share the same .read method. Parameter "struct bin_attribute *" is used to get the table signature and instance number which are used to distinguish different ACPI table binary attributes. Without this parameter, we need to offer different .read methods for different ACPI table binary attributes. This is impossible as there are various ACPI tables on different platforms, and we don't know what they are until they are loaded. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-06-09 05:57:22 +00:00
static ssize_t w1_f23_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, idx;
if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
return 0;
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
/* 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;
}
}
#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
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_f23_write(sl, addr, len, &buf[idx]) < 0) {
count = -EIO;
goto out_up;
}
idx += len;
}
out_up:
mutex_unlock(&sl->master->mutex);
return count;
}
static struct bin_attribute w1_f23_bin_attr = {
.attr = {
.name = "eeprom",
.mode = S_IRUGO | S_IWUSR,
},
.size = W1_EEPROM_SIZE,
.read = w1_f23_read_bin,
.write = w1_f23_write_bin,
};
static int w1_f23_add_slave(struct w1_slave *sl)
{
int err;
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
struct w1_f23_data *data;
2007-07-19 08:49:03 +00:00
data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
sl->family_data = data;
#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
if (err)
kfree(data);
#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
return err;
}
static void w1_f23_remove_slave(struct w1_slave *sl)
{
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
kfree(sl->family_data);
sl->family_data = NULL;
#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
}
static struct w1_family_ops w1_f23_fops = {
.add_slave = w1_f23_add_slave,
.remove_slave = w1_f23_remove_slave,
};
static struct w1_family w1_family_23 = {
.fid = W1_EEPROM_DS2433,
.fops = &w1_f23_fops,
};
static int __init w1_f23_init(void)
{
return w1_register_family(&w1_family_23);
}
static void __exit w1_f23_fini(void)
{
w1_unregister_family(&w1_family_23);
}
module_init(w1_f23_init);
module_exit(w1_f23_fini);