linux/drivers/w1/slaves/w1_ds2431.c
Andrew F. Davis de0d6dbdbd w1: Add subsystem kernel public interface
Like other subsystems we should be able to define slave devices outside
of the w1 directory. To do this we move public facing interface
definitions to include/linux/w1.h and rename the internal definition
file to w1_internal.h.

As w1_family.h and w1_int.h contained almost entirely public
driver interface definitions we simply removed these files and
moved the remaining definitions into w1_internal.h.

With this we can now start to move slave devices out of w1/slaves and
into the subsystem based on the function they implement, again like
other drivers.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:54:54 +02:00

297 lines
6.8 KiB
C

/*
* 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 <linux/w1.h>
#define W1_EEPROM_DS2431 0x2D
#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 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);
int todo = count;
count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE);
if (count == 0)
return 0;
mutex_lock(&sl->master->bus_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->bus_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 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;
int copy;
count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE);
if (count == 0)
return 0;
mutex_lock(&sl->master->bus_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->bus_mutex);
return count;
}
static BIN_ATTR_RW(eeprom, W1_F2D_EEPROM_SIZE);
static struct bin_attribute *w1_f2d_bin_attrs[] = {
&bin_attr_eeprom,
NULL,
};
static const struct attribute_group w1_f2d_group = {
.bin_attrs = w1_f2d_bin_attrs,
};
static const struct attribute_group *w1_f2d_groups[] = {
&w1_f2d_group,
NULL,
};
static struct w1_family_ops w1_f2d_fops = {
.groups = w1_f2d_groups,
};
static struct w1_family w1_family_2d = {
.fid = W1_EEPROM_DS2431,
.fops = &w1_f2d_fops,
};
module_w1_family(w1_family_2d);
MODULE_AUTHOR("Bernhard Weirich <bernhard.weirich@riedel.net>");
MODULE_DESCRIPTION("w1 family 2d driver for DS2431, 1kb EEPROM");
MODULE_LICENSE("GPL");
MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2431));