Commit 25ec8710 authored by Thomas Bogendoerfer's avatar Thomas Bogendoerfer Committed by Greg Kroah-Hartman
Browse files

w1: add DS2501, DS2502, DS2505 EPROM device driver 



Add a 1-Wire slave driver to support DS250x EPROM deivces. This
slave driver attaches the devices to the NVMEM subsystem for
an easy in-kernel usage.

Signed-off-by: default avatarThomas Bogendoerfer <tbogendoerfer@suse.de>
Link: https://lore.kernel.org/r/20190831082623.15627-3-tbogendoerfer@suse.de


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 74ded38a

drivers/w1/slaves/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -101,6 +101,12 @@ config W1_SLAVE_DS2438 
	  Say Y here if you want to use a 1-wire

	  DS2438 Smart Battery Monitor device support



config W1_SLAVE_DS250X

	tristate "512b/1kb/16kb EPROM family support"

	help

	  Say Y here if you want to use a 1-wire

	  512b/1kb/16kb EPROM family device (DS250x).



config W1_SLAVE_DS2780

	tristate "Dallas 2780 battery monitor chip"

	help

drivers/w1/slaves/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ obj-$(CONFIG_W1_SLAVE_DS2431) += w1_ds2431.o 
obj-$(CONFIG_W1_SLAVE_DS2805)	+= w1_ds2805.o

obj-$(CONFIG_W1_SLAVE_DS2433)	+= w1_ds2433.o

obj-$(CONFIG_W1_SLAVE_DS2438)	+= w1_ds2438.o

obj-$(CONFIG_W1_SLAVE_DS250X)	+= w1_ds250x.o

obj-$(CONFIG_W1_SLAVE_DS2780)	+= w1_ds2780.o

obj-$(CONFIG_W1_SLAVE_DS2781)	+= w1_ds2781.o

obj-$(CONFIG_W1_SLAVE_DS28E04)	+= w1_ds28e04.o

drivers/w1/slaves/w1_ds250x.c

0 → 100644
+290 −0
Original line number Diff line number Diff line 
// 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,

		.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 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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