Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f6887531 authored by Andrew Worsley's avatar Andrew Worsley Committed by Greg Kroah-Hartman
Browse files

drivers: w1: Add 1w slave driver for DS28E05 EEPROM 



Add a one wire driver for the DS28E05 one wire slave chip. This chip
requires OverDrive support to talk to it.

Signed-off-by: default avatarAndrew Worsley <amworsley@gmail.com>
Acked-by: default avatarEvgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 54865314

drivers/w1/slaves/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -65,6 +65,14 @@ config W1_SLAVE_DS2423 
	  Say Y here if you want to use a 1-wire

	  counter family device (DS2423).



config W1_SLAVE_DS2805

	tristate "112-byte EEPROM support (DS28E05)"

	help

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

	  is a 112-byte user-programmable EEPROM is

          organized as 7 pages of 16 bytes each with 64bit

          unique number. Requires OverDrive Speed to talk to.



config W1_SLAVE_DS2431

	tristate "1kb EEPROM family support (DS2431)"

	help

drivers/w1/slaves/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ obj-$(CONFIG_W1_SLAVE_DS2413) += w1_ds2413.o 
obj-$(CONFIG_W1_SLAVE_DS2406)	+= w1_ds2406.o

obj-$(CONFIG_W1_SLAVE_DS2423)	+= w1_ds2423.o

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_DS2760)	+= w1_ds2760.o

drivers/w1/slaves/w1_ds2805.c

0 → 100644
+313 −0
Original line number Diff line number Diff line 
/*

 * w1_ds2805 - w1 family 0d (DS28E05) driver

 *

 * Copyright (c) 2016 Andrew Worsley amworsley@gmail.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_DS2805       0x0D



#define W1_F0D_EEPROM_SIZE		128

#define W1_F0D_PAGE_BITS		3

#define W1_F0D_PAGE_SIZE		(1<<W1_F0D_PAGE_BITS)

#define W1_F0D_PAGE_MASK		0x0F



#define W1_F0D_SCRATCH_BITS  1

#define W1_F0D_SCRATCH_SIZE  (1<<W1_F0D_SCRATCH_BITS)

#define W1_F0D_SCRATCH_MASK  (W1_F0D_SCRATCH_SIZE-1)



#define W1_F0D_READ_EEPROM	0xF0

#define W1_F0D_WRITE_EEPROM	0x55

#define W1_F0D_RELEASE		0xFF



#define W1_F0D_CS_OK		0xAA /* Chip Status Ok */



#define W1_F0D_TPROG_MS		16



#define W1_F0D_READ_RETRIES		10

#define W1_F0D_READ_MAXLEN		W1_F0D_EEPROM_SIZE



/*

 * 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_f0d_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_F0D_READ_RETRIES times.

 *

 * count must not exceed W1_F0D_READ_MAXLEN.

 */

static int w1_f0d_readblock(struct w1_slave *sl, int off, int count, char *buf)

{

	u8 wrbuf[3];

	u8 cmp[W1_F0D_READ_MAXLEN];

	int tries = W1_F0D_READ_RETRIES;



	do {

		wrbuf[0] = W1_F0D_READ_EEPROM;

		wrbuf[1] = off & 0x7f;

		wrbuf[2] = 0;



		if (w1_reset_select_slave(sl))

			return -1;



		w1_write_block(sl->master, wrbuf, sizeof(wrbuf));

		w1_read_block(sl->master, buf, count);



		if (w1_reset_select_slave(sl))

			return -1;



		w1_write_block(sl->master, wrbuf, sizeof(wrbuf));

		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_F0D_READ_RETRIES);



	return -1;

}



static ssize_t w1_f0d_read_bin(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_f0d_fix_count(off, count, W1_F0D_EEPROM_SIZE);

	if (count == 0)

		return 0;



	mutex_lock(&sl->master->mutex);



	/* read directly from the EEPROM in chunks of W1_F0D_READ_MAXLEN */

	while (todo > 0) {

		int block_read;



		if (todo >= W1_F0D_READ_MAXLEN)

			block_read = W1_F0D_READ_MAXLEN;

		else

			block_read = todo;



		if (w1_f0d_readblock(sl, off, block_read, buf) < 0) {

			count = -EIO;

			break;

		}



		todo -= W1_F0D_READ_MAXLEN;

		buf += W1_F0D_READ_MAXLEN;

		off += W1_F0D_READ_MAXLEN;

	}



	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 aligned at W1_F0D_SCRATCH_SIZE bytes and

 * must be W1_F0D_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_F0D_PAGE_SIZE - (addr & W1_F0D_PAGE_MASK))

 * @param data	The data to write

 * @return	0=Success -1=failure

 */

static int w1_f0d_write(struct w1_slave *sl, int addr, int len, const u8 *data)

{

	int tries = W1_F0D_READ_RETRIES;

	u8 wrbuf[3];

	u8 rdbuf[W1_F0D_SCRATCH_SIZE];

	u8 cs;



	if ((addr & 1) || (len != 2)) {

		dev_err(&sl->dev, "%s: bad addr/len -  addr=%#x len=%d\n",

		    __func__, addr, len);

		return -1;

	}



retry:



	/* Write the data to the scratchpad */

	if (w1_reset_select_slave(sl))

		return -1;



	wrbuf[0] = W1_F0D_WRITE_EEPROM;

	wrbuf[1] = addr & 0xff;

	wrbuf[2] = 0xff; /* ?? from Example */



	w1_write_block(sl->master, wrbuf, sizeof(wrbuf));

	w1_write_block(sl->master, data, len);



	w1_read_block(sl->master, rdbuf, sizeof(rdbuf));

	/* Compare what was read against the data written */

	if ((rdbuf[0] != data[0]) || (rdbuf[1] != data[1])) {



		if (--tries)

			goto retry;



		dev_err(&sl->dev,

			"could not write to eeprom, scratchpad compare failed %d times\n",

			W1_F0D_READ_RETRIES);

		pr_info("%s: rdbuf = %#x %#x data = %#x %#x\n",

		    __func__, rdbuf[0], rdbuf[1], data[0], data[1]);



		return -1;

	}



	/* Trigger write out to EEPROM */

	w1_write_8(sl->master, W1_F0D_RELEASE);



	/* Sleep for tprog ms to wait for the write to complete */

	msleep(W1_F0D_TPROG_MS);



	/* Check CS (Command Status) == 0xAA ? */

	cs = w1_read_8(sl->master);

	if (cs != W1_F0D_CS_OK) {

		dev_err(&sl->dev, "save to eeprom failed = CS=%#x\n", cs);

		return -1;

	}



	return 0;

}



static ssize_t w1_f0d_write_bin(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_f0d_fix_count(off, count, W1_F0D_EEPROM_SIZE);

	if (count == 0)

		return 0;



	mutex_lock(&sl->master->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_F0D_SCRATCH_SIZE || addr & W1_F0D_SCRATCH_MASK) {

			char tmp[W1_F0D_SCRATCH_SIZE];



			/* read the block and update the parts to be written */

			if (w1_f0d_readblock(sl, addr & ~W1_F0D_SCRATCH_MASK,

					W1_F0D_SCRATCH_SIZE, tmp)) {

				count = -EIO;

				goto out_up;

			}



			/* copy at most to the boundary of the PAGE or len */

			copy = W1_F0D_SCRATCH_SIZE -

				(addr & W1_F0D_SCRATCH_MASK);



			if (copy > len)

				copy = len;



			memcpy(&tmp[addr & W1_F0D_SCRATCH_MASK], buf, copy);

			if (w1_f0d_write(sl, addr & ~W1_F0D_SCRATCH_MASK,

					W1_F0D_SCRATCH_SIZE, tmp) < 0) {

				count = -EIO;

				goto out_up;

			}

		} else {



			copy = W1_F0D_SCRATCH_SIZE;

			if (w1_f0d_write(sl, addr, copy, buf) < 0) {

				count = -EIO;

				goto out_up;

			}

		}

		buf += copy;

		addr += copy;

		len -= copy;

	}



out_up:

	mutex_unlock(&sl->master->mutex);



	return count;

}



static struct bin_attribute w1_f0d_bin_attr = {

	.attr = {

		.name = "eeprom",

		.mode = S_IRUGO | S_IWUSR,

	},

	.size = W1_F0D_EEPROM_SIZE,

	.read = w1_f0d_read_bin,

	.write = w1_f0d_write_bin,

};



static int w1_f0d_add_slave(struct w1_slave *sl)

{

	return sysfs_create_bin_file(&sl->dev.kobj, &w1_f0d_bin_attr);

}



static void w1_f0d_remove_slave(struct w1_slave *sl)

{

	sysfs_remove_bin_file(&sl->dev.kobj, &w1_f0d_bin_attr);

}



static struct w1_family_ops w1_f0d_fops = {

	.add_slave      = w1_f0d_add_slave,

	.remove_slave   = w1_f0d_remove_slave,

};



static struct w1_family w1_family_2d = {

	.fid = W1_EEPROM_DS2805,

	.fops = &w1_f0d_fops,

};



static int __init w1_f0d_init(void)

{

	pr_info("%s()\n", __func__);

	return w1_register_family(&w1_family_2d);

}



static void __exit w1_f0d_fini(void)

{

	pr_info("%s()\n", __func__);

	w1_unregister_family(&w1_family_2d);

}



module_init(w1_f0d_init);

module_exit(w1_f0d_fini);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Andrew Worsley amworsley@gmail.com");

MODULE_DESCRIPTION("w1 family 0d driver for DS2805, 1kb EEPROM");

drivers/w1/w1.c

+2 −0
Original line number Diff line number Diff line
@@ -729,6 +729,8 @@ int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn) 
	atomic_set(&sl->refcnt, 1);

	atomic_inc(&sl->master->refcnt);

	dev->slave_count++;

	dev_info(&dev->dev, "Attaching one wire slave %02x.%012llx crc %02x\n",

		  rn->family, (unsigned long long)rn->id, rn->crc);



	/* slave modules need to be loaded in a context with unlocked mutex */

	mutex_unlock(&dev->mutex);