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linux/drivers/w1/slaves/w1_ds250x.c
Rafał Miłecki 2cc3b37f5b nvmem: add explicit config option to read old syntax fixed OF cells 
Binding for fixed NVMEM cells defined directly as NVMEM device subnodes
has been deprecated. It has been replaced by the "fixed-layout" NVMEM
layout binding.

New syntax is meant to be clearer and should help avoiding imprecise
bindings.

NVMEM subsystem already supports the new binding. It should be a good
idea to limit support for old syntax to existing drivers that actually
support & use it (we can't break backward compatibility!). That way we
additionally encourage new bindings & drivers to ignore deprecated
binding.

It wasn't clear (to me) if rtc and w1 code actually uses old syntax
fixed cells. I enabled them to don't risk any breakage.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
[for meson-{efuse,mx-efuse}.c]
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
[for mtk-efuse.c, nvmem/core.c, nvmem-provider.h]
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
[MT8192, MT8195 Chromebooks]
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
[for microchip-otpc.c]
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
[SAMA7G5-EK]
Tested-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20231020105545.216052-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-10-21 19:19:06 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* w1_ds250x.c - w1 family 09/0b/89/91 (DS250x) driver
*/
#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; /* page already present */
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); /* mark 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; /* page already present */
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, crc16 */
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); /* crc16 */
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));
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