#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/w1.h>
#include <linux/nvmem-provider.h>
#define W1_DS2501_UNW_FAMILY 0x91
#define W1_DS2501_SIZE 64
#define W1_DS2502_FAMILY 0x09
#define W1_DS2502_UNW_FAMILY 0x89
#define W1_DS2502_SIZE 128
#define W1_DS2505_FAMILY 0x0b
#define W1_DS2505_SIZE 2048
#define W1_PAGE_SIZE 32
#define W1_EXT_READ_MEMORY 0xA5
#define W1_READ_DATA_CRC 0xC3
#define OFF2PG(off) ((off) / W1_PAGE_SIZE)
#define CRC16_INIT 0
#define CRC16_VALID 0xb001
struct w1_eprom_data {
size_t size;
int (*read)(struct w1_slave *sl, int pageno);
u8 eprom[W1_DS2505_SIZE];
DECLARE_BITMAP(page_present, W1_DS2505_SIZE / W1_PAGE_SIZE);
char nvmem_name[64];
};
static int w1_ds2502_read_page(struct w1_slave *sl, int pageno)
{
struct w1_eprom_data *data = sl->family_data;
int pgoff = pageno * W1_PAGE_SIZE;
int ret = -EIO;
u8 buf[3];
u8 crc8;
if (test_bit(pageno, data->page_present))
return 0;
mutex_lock(&sl->master->bus_mutex);
if (w1_reset_select_slave(sl))
goto err;
buf[0] = W1_READ_DATA_CRC;
buf[1] = pgoff & 0xff;
buf[2] = pgoff >> 8;
w1_write_block(sl->master, buf, 3);
crc8 = w1_read_8(sl->master);
if (w1_calc_crc8(buf, 3) != crc8)
goto err;
w1_read_block(sl->master, &data->eprom[pgoff], W1_PAGE_SIZE);
crc8 = w1_read_8(sl->master);
if (w1_calc_crc8(&data->eprom[pgoff], W1_PAGE_SIZE) != crc8)
goto err;
set_bit(pageno, data->page_present);
ret = 0;
err:
mutex_unlock(&sl->master->bus_mutex);
return ret;
}
static int w1_ds2505_read_page(struct w1_slave *sl, int pageno)
{
struct w1_eprom_data *data = sl->family_data;
int redir_retries = 16;
int pgoff, epoff;
int ret = -EIO;
u8 buf[6];
u8 redir;
u16 crc;
if (test_bit(pageno, data->page_present))
return 0;
epoff = pgoff = pageno * W1_PAGE_SIZE;
mutex_lock(&sl->master->bus_mutex);
retry:
if (w1_reset_select_slave(sl))
goto err;
buf[0] = W1_EXT_READ_MEMORY;
buf[1] = pgoff & 0xff;
buf[2] = pgoff >> 8;
w1_write_block(sl->master, buf, 3);
w1_read_block(sl->master, buf + 3, 3);
redir = buf[3];
crc = crc16(CRC16_INIT, buf, 6);
if (crc != CRC16_VALID)
goto err;
if (redir != 0xff) {
redir_retries--;
if (redir_retries < 0)
goto err;
pgoff = (redir ^ 0xff) * W1_PAGE_SIZE;
goto retry;
}
w1_read_block(sl->master, &data->eprom[epoff], W1_PAGE_SIZE);
w1_read_block(sl->master, buf, 2);
crc = crc16(CRC16_INIT, &data->eprom[epoff], W1_PAGE_SIZE);
crc = crc16(crc, buf, 2);
if (crc != CRC16_VALID)
goto err;
set_bit(pageno, data->page_present);
ret = 0;
err:
mutex_unlock(&sl->master->bus_mutex);
return ret;
}
static int w1_nvmem_read(void *priv, unsigned int off, void *buf, size_t count)
{
struct w1_slave *sl = priv;
struct w1_eprom_data *data = sl->family_data;
size_t eprom_size = data->size;
int ret;
int i;
if (off > eprom_size)
return -EINVAL;
if ((off + count) > eprom_size)
count = eprom_size - off;
i = OFF2PG(off);
do {
ret = data->read(sl, i++);
if (ret < 0)
return ret;
} while (i < OFF2PG(off + count));
memcpy(buf, &data->eprom[off], count);
return 0;
}
static int w1_eprom_add_slave(struct w1_slave *sl)
{
struct w1_eprom_data *data;
struct nvmem_device *nvmem;
struct nvmem_config nvmem_cfg = {
.dev = &sl->dev,
.add_legacy_fixed_of_cells = true,
.reg_read = w1_nvmem_read,
.type = NVMEM_TYPE_OTP,
.read_only = true,
.word_size = 1,
.priv = sl,
.id = -1
};
data = devm_kzalloc(&sl->dev, sizeof(struct w1_eprom_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
sl->family_data = data;
switch (sl->family->fid) {
case W1_DS2501_UNW_FAMILY:
data->size = W1_DS2501_SIZE;
data->read = w1_ds2502_read_page;
break;
case W1_DS2502_FAMILY:
case W1_DS2502_UNW_FAMILY:
data->size = W1_DS2502_SIZE;
data->read = w1_ds2502_read_page;
break;
case W1_DS2505_FAMILY:
data->size = W1_DS2505_SIZE;
data->read = w1_ds2505_read_page;
break;
}
if (sl->master->bus_master->dev_id)
snprintf(data->nvmem_name, sizeof(data->nvmem_name),
"%s-%02x-%012llx",
sl->master->bus_master->dev_id, sl->reg_num.family,
(unsigned long long)sl->reg_num.id);
else
snprintf(data->nvmem_name, sizeof(data->nvmem_name),
"%02x-%012llx",
sl->reg_num.family,
(unsigned long long)sl->reg_num.id);
nvmem_cfg.name = data->nvmem_name;
nvmem_cfg.size = data->size;
nvmem = devm_nvmem_register(&sl->dev, &nvmem_cfg);
return PTR_ERR_OR_ZERO(nvmem);
}
static const struct w1_family_ops w1_eprom_fops = {
.add_slave = w1_eprom_add_slave,
};
static struct w1_family w1_family_09 = {
.fid = W1_DS2502_FAMILY,
.fops = &w1_eprom_fops,
};
static struct w1_family w1_family_0b = {
.fid = W1_DS2505_FAMILY,
.fops = &w1_eprom_fops,
};
static struct w1_family w1_family_89 = {
.fid = W1_DS2502_UNW_FAMILY,
.fops = &w1_eprom_fops,
};
static struct w1_family w1_family_91 = {
.fid = W1_DS2501_UNW_FAMILY,
.fops = &w1_eprom_fops,
};
static int __init w1_ds250x_init(void)
{
int err;
err = w1_register_family(&w1_family_09);
if (err)
return err;
err = w1_register_family(&w1_family_0b);
if (err)
goto err_0b;
err = w1_register_family(&w1_family_89);
if (err)
goto err_89;
err = w1_register_family(&w1_family_91);
if (err)
goto err_91;
return 0;
err_91:
w1_unregister_family(&w1_family_89);
err_89:
w1_unregister_family(&w1_family_0b);
err_0b:
w1_unregister_family(&w1_family_09);
return err;
}
static void __exit w1_ds250x_exit(void)
{
w1_unregister_family(&w1_family_09);
w1_unregister_family(&w1_family_0b);
w1_unregister_family(&w1_family_89);
w1_unregister_family(&w1_family_91);
}
module_init(w1_ds250x_init);
module_exit(w1_ds250x_exit);
MODULE_AUTHOR("Thomas Bogendoerfer <tbogendoerfe@suse.de>");
MODULE_DESCRIPTION("w1 family driver for DS250x Add Only Memory");
MODULE_LICENSE("GPL");
MODULE_ALIAS("w1-family-" __stringify(W1_DS2502_FAMILY));
MODULE_ALIAS("w1-family-" __stringify(W1_DS2505_FAMILY));
MODULE_ALIAS("w1-family-" __stringify(W1_DS2501_UNW_FAMILY));
MODULE_ALIAS("w1-family-" __stringify(W1_DS2502_UNW_FAMILY));
