drivers/misc/eeprom/eeprom_93xx46.c - kernel/bruno - Git at Google

 /*
  * Driver for 93xx46 EEPROMs
  *
  * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
 #include <linux/sysfs.h>
 #include <linux/eeprom_93xx46.h>

 #define OP_START	0x4
 #define OP_WRITE	(OP_START | 0x1)
 #define OP_READ		(OP_START | 0x2)
 #define ADDR_EWDS	0x00
 #define ADDR_ERAL	0x20
 #define ADDR_EWEN	0x30

 struct eeprom_93xx46_dev {
 	struct spi_device *spi;
 	struct eeprom_93xx46_platform_data *pdata;
 	struct bin_attribute bin;
 	struct mutex lock;
 	int addrlen;
 };

 static ssize_t
 eeprom_93xx46_bin_read(struct file *filp, struct kobject *kobj,
 		       struct bin_attribute *bin_attr,
 		       char *buf, loff_t off, size_t count)
 {
 	struct eeprom_93xx46_dev *edev;
 	struct device *dev;
 	struct spi_message m;
 	struct spi_transfer t[2];
 	int bits, ret;
 	u16 cmd_addr;

 	dev = container_of(kobj, struct device, kobj);
 	edev = dev_get_drvdata(dev);

 	cmd_addr = OP_READ << edev->addrlen;

 	if (edev->addrlen == 7) {
 		cmd_addr |= off & 0x7f;
 		bits = 10;
 	} else {
 		cmd_addr |= off & 0x3f;
 		bits = 9;
 	}

 	dev_dbg(&edev->spi->dev, "read cmd 0x%x, %d Hz\n",
 		cmd_addr, edev->spi->max_speed_hz);

 	spi_message_init(&m);
 	memset(t, 0, sizeof(t));

 	t[0].tx_buf = (char *)&cmd_addr;
 	t[0].len = 2;
 	t[0].bits_per_word = bits;
 	spi_message_add_tail(&t[0], &m);

 	t[1].rx_buf = buf;
 	t[1].len = count;
 	t[1].bits_per_word = 8;
 	spi_message_add_tail(&t[1], &m);

 	mutex_lock(&edev->lock);

 	if (edev->pdata->prepare)
 		edev->pdata->prepare(edev);

 	ret = spi_sync(edev->spi, &m);
 	/* have to wait at least Tcsl ns */
 	ndelay(250);
 	if (ret) {
 		dev_err(&edev->spi->dev, "read %zu bytes at %d: err. %d\n",
 			count, (int)off, ret);
 	}

 	if (edev->pdata->finish)
 		edev->pdata->finish(edev);

 	mutex_unlock(&edev->lock);
 	return ret ? : count;
 }

 static int eeprom_93xx46_ew(struct eeprom_93xx46_dev *edev, int is_on)
 {
 	struct spi_message m;
 	struct spi_transfer t;
 	int bits, ret;
 	u16 cmd_addr;

 	cmd_addr = OP_START << edev->addrlen;
 	if (edev->addrlen == 7) {
 		cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS) << 1;
 		bits = 10;
 	} else {
 		cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS);
 		bits = 9;
 	}

 	dev_dbg(&edev->spi->dev, "ew cmd 0x%04x\n", cmd_addr);

 	spi_message_init(&m);
 	memset(&t, 0, sizeof(t));

 	t.tx_buf = &cmd_addr;
 	t.len = 2;
 	t.bits_per_word = bits;
 	spi_message_add_tail(&t, &m);

 	mutex_lock(&edev->lock);

 	if (edev->pdata->prepare)
 		edev->pdata->prepare(edev);

 	ret = spi_sync(edev->spi, &m);
 	/* have to wait at least Tcsl ns */
 	ndelay(250);
 	if (ret)
 		dev_err(&edev->spi->dev, "erase/write %sable error %d\n",
 			is_on ? "en" : "dis", ret);

 	if (edev->pdata->finish)
 		edev->pdata->finish(edev);

 	mutex_unlock(&edev->lock);
 	return ret;
 }

 static ssize_t
 eeprom_93xx46_write_word(struct eeprom_93xx46_dev *edev,
 			 const char *buf, unsigned off)
 {
 	struct spi_message m;
 	struct spi_transfer t[2];
 	int bits, data_len, ret;
 	u16 cmd_addr;

 	cmd_addr = OP_WRITE << edev->addrlen;

 	if (edev->addrlen == 7) {
 		cmd_addr |= off & 0x7f;
 		bits = 10;
 		data_len = 1;
 	} else {
 		cmd_addr |= off & 0x3f;
 		bits = 9;
 		data_len = 2;
 	}

 	dev_dbg(&edev->spi->dev, "write cmd 0x%x\n", cmd_addr);

 	spi_message_init(&m);
 	memset(t, 0, sizeof(t));

 	t[0].tx_buf = (char *)&cmd_addr;
 	t[0].len = 2;
 	t[0].bits_per_word = bits;
 	spi_message_add_tail(&t[0], &m);

 	t[1].tx_buf = buf;
 	t[1].len = data_len;
 	t[1].bits_per_word = 8;
 	spi_message_add_tail(&t[1], &m);

 	ret = spi_sync(edev->spi, &m);
 	/* have to wait program cycle time Twc ms */
 	mdelay(6);
 	return ret;
 }

 static ssize_t
 eeprom_93xx46_bin_write(struct file *filp, struct kobject *kobj,
 			struct bin_attribute *bin_attr,
 			char *buf, loff_t off, size_t count)
 {
 	struct eeprom_93xx46_dev *edev;
 	struct device *dev;
 	int i, ret, step = 1;

 	dev = container_of(kobj, struct device, kobj);
 	edev = dev_get_drvdata(dev);

 	/* only write even number of bytes on 16-bit devices */
 	if (edev->addrlen == 6) {
 		step = 2;
 		count &= ~1;
 	}

 	/* erase/write enable */
 	ret = eeprom_93xx46_ew(edev, 1);
 	if (ret)
 		return ret;

 	mutex_lock(&edev->lock);

 	if (edev->pdata->prepare)
 		edev->pdata->prepare(edev);

 	for (i = 0; i < count; i += step) {
 		ret = eeprom_93xx46_write_word(edev, &buf[i], off + i);
 		if (ret) {
 			dev_err(&edev->spi->dev, "write failed at %d: %d\n",
 				(int)off + i, ret);
 			break;
 		}
 	}

 	if (edev->pdata->finish)
 		edev->pdata->finish(edev);

 	mutex_unlock(&edev->lock);

 	/* erase/write disable */
 	eeprom_93xx46_ew(edev, 0);
 	return ret ? : count;
 }

 static int eeprom_93xx46_eral(struct eeprom_93xx46_dev *edev)
 {
 	struct eeprom_93xx46_platform_data *pd = edev->pdata;
 	struct spi_message m;
 	struct spi_transfer t;
 	int bits, ret;
 	u16 cmd_addr;

 	cmd_addr = OP_START << edev->addrlen;
 	if (edev->addrlen == 7) {
 		cmd_addr |= ADDR_ERAL << 1;
 		bits = 10;
 	} else {
 		cmd_addr |= ADDR_ERAL;
 		bits = 9;
 	}

 	spi_message_init(&m);
 	memset(&t, 0, sizeof(t));

 	t.tx_buf = &cmd_addr;
 	t.len = 2;
 	t.bits_per_word = bits;
 	spi_message_add_tail(&t, &m);

 	mutex_lock(&edev->lock);

 	if (edev->pdata->prepare)
 		edev->pdata->prepare(edev);

 	ret = spi_sync(edev->spi, &m);
 	if (ret)
 		dev_err(&edev->spi->dev, "erase error %d\n", ret);
 	/* have to wait erase cycle time Tec ms */
 	mdelay(6);

 	if (pd->finish)
 		pd->finish(edev);

 	mutex_unlock(&edev->lock);
 	return ret;
 }

 static ssize_t eeprom_93xx46_store_erase(struct device *dev,
 					 struct device_attribute *attr,
 					 const char *buf, size_t count)
 {
 	struct eeprom_93xx46_dev *edev = dev_get_drvdata(dev);
 	int erase = 0, ret;

 	sscanf(buf, "%d", &erase);
 	if (erase) {
 		ret = eeprom_93xx46_ew(edev, 1);
 		if (ret)
 			return ret;
 		ret = eeprom_93xx46_eral(edev);
 		if (ret)
 			return ret;
 		ret = eeprom_93xx46_ew(edev, 0);
 		if (ret)
 			return ret;
 	}
 	return count;
 }
 static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase);

 static int eeprom_93xx46_probe(struct spi_device *spi)
 {
 	struct eeprom_93xx46_platform_data *pd;
 	struct eeprom_93xx46_dev *edev;
 	int err;

 	pd = spi->dev.platform_data;
 	if (!pd) {
 		dev_err(&spi->dev, "missing platform data\n");
 		return -ENODEV;
 	}

 	edev = kzalloc(sizeof(*edev), GFP_KERNEL);
 	if (!edev)
 		return -ENOMEM;

 	if (pd->flags & EE_ADDR8)
 		edev->addrlen = 7;
 	else if (pd->flags & EE_ADDR16)
 		edev->addrlen = 6;
 	else {
 		dev_err(&spi->dev, "unspecified address type\n");
 		err = -EINVAL;
 		goto fail;
 	}

 	mutex_init(&edev->lock);

 	edev->spi = spi_dev_get(spi);
 	edev->pdata = pd;

 	sysfs_bin_attr_init(&edev->bin);
 	edev->bin.attr.name = "eeprom";
 	edev->bin.attr.mode = S_IRUSR;
 	edev->bin.read = eeprom_93xx46_bin_read;
 	edev->bin.size = 128;
 	if (!(pd->flags & EE_READONLY)) {
 		edev->bin.write = eeprom_93xx46_bin_write;
 		edev->bin.attr.mode |= S_IWUSR;
 	}

 	err = sysfs_create_bin_file(&spi->dev.kobj, &edev->bin);
 	if (err)
 		goto fail;

 	dev_info(&spi->dev, "%d-bit eeprom %s\n",
 		(pd->flags & EE_ADDR8) ? 8 : 16,
 		(pd->flags & EE_READONLY) ? "(readonly)" : "");

 	if (!(pd->flags & EE_READONLY)) {
 		if (device_create_file(&spi->dev, &dev_attr_erase))
 			dev_err(&spi->dev, "can't create erase interface\n");
 	}

 	spi_set_drvdata(spi, edev);
 	return 0;
 fail:
 	kfree(edev);
 	return err;
 }

 static int eeprom_93xx46_remove(struct spi_device *spi)
 {
 	struct eeprom_93xx46_dev *edev = spi_get_drvdata(spi);

 	if (!(edev->pdata->flags & EE_READONLY))
 		device_remove_file(&spi->dev, &dev_attr_erase);

 	sysfs_remove_bin_file(&spi->dev.kobj, &edev->bin);
 	kfree(edev);
 	return 0;
 }

 static struct spi_driver eeprom_93xx46_driver = {
 	.driver = {
 		.name	= "93xx46",
 	},
 	.probe		= eeprom_93xx46_probe,
 	.remove		= eeprom_93xx46_remove,
 };

 module_spi_driver(eeprom_93xx46_driver);

 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Driver for 93xx46 EEPROMs");
 MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>");
 MODULE_ALIAS("spi:93xx46");
	/*
	* Driver for 93xx46 EEPROMs
	*
	* (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/delay.h>
	#include <linux/device.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/slab.h>
	#include <linux/spi/spi.h>
	#include <linux/sysfs.h>
	#include <linux/eeprom_93xx46.h>

	#define OP_START 0x4
	#define OP_WRITE (OP_START \| 0x1)
	#define OP_READ (OP_START \| 0x2)
	#define ADDR_EWDS 0x00
	#define ADDR_ERAL 0x20
	#define ADDR_EWEN 0x30

	struct eeprom_93xx46_dev {
	struct spi_device *spi;
	struct eeprom_93xx46_platform_data *pdata;
	struct bin_attribute bin;
	struct mutex lock;
	int addrlen;
	};

	static ssize_t
	eeprom_93xx46_bin_read(struct file filp, struct kobject kobj,
	struct bin_attribute *bin_attr,
	char *buf, loff_t off, size_t count)
	{
	struct eeprom_93xx46_dev *edev;
	struct device *dev;
	struct spi_message m;
	struct spi_transfer t[2];
	int bits, ret;
	u16 cmd_addr;

	dev = container_of(kobj, struct device, kobj);
	edev = dev_get_drvdata(dev);

	cmd_addr = OP_READ << edev->addrlen;

	if (edev->addrlen == 7) {
	cmd_addr \|= off & 0x7f;
	bits = 10;
	} else {
	cmd_addr \|= off & 0x3f;
	bits = 9;
	}

	dev_dbg(&edev->spi->dev, "read cmd 0x%x, %d Hz\n",
	cmd_addr, edev->spi->max_speed_hz);

	spi_message_init(&m);
	memset(t, 0, sizeof(t));

	t[0].tx_buf = (char *)&cmd_addr;
	t[0].len = 2;
	t[0].bits_per_word = bits;
	spi_message_add_tail(&t[0], &m);

	t[1].rx_buf = buf;
	t[1].len = count;
	t[1].bits_per_word = 8;
	spi_message_add_tail(&t[1], &m);

	mutex_lock(&edev->lock);

	if (edev->pdata->prepare)
	edev->pdata->prepare(edev);

	ret = spi_sync(edev->spi, &m);
	/* have to wait at least Tcsl ns */
	ndelay(250);
	if (ret) {
	dev_err(&edev->spi->dev, "read %zu bytes at %d: err. %d\n",
	count, (int)off, ret);
	}

	if (edev->pdata->finish)
	edev->pdata->finish(edev);

	mutex_unlock(&edev->lock);
	return ret ? : count;
	}

	static int eeprom_93xx46_ew(struct eeprom_93xx46_dev *edev, int is_on)
	{
	struct spi_message m;
	struct spi_transfer t;
	int bits, ret;
	u16 cmd_addr;

	cmd_addr = OP_START << edev->addrlen;
	if (edev->addrlen == 7) {
	cmd_addr \|= (is_on ? ADDR_EWEN : ADDR_EWDS) << 1;
	bits = 10;
	} else {
	cmd_addr \|= (is_on ? ADDR_EWEN : ADDR_EWDS);
	bits = 9;
	}

	dev_dbg(&edev->spi->dev, "ew cmd 0x%04x\n", cmd_addr);

	spi_message_init(&m);
	memset(&t, 0, sizeof(t));

	t.tx_buf = &cmd_addr;
	t.len = 2;
	t.bits_per_word = bits;
	spi_message_add_tail(&t, &m);

	mutex_lock(&edev->lock);

	if (edev->pdata->prepare)
	edev->pdata->prepare(edev);

	ret = spi_sync(edev->spi, &m);
	/* have to wait at least Tcsl ns */
	ndelay(250);
	if (ret)
	dev_err(&edev->spi->dev, "erase/write %sable error %d\n",
	is_on ? "en" : "dis", ret);

	if (edev->pdata->finish)
	edev->pdata->finish(edev);

	mutex_unlock(&edev->lock);
	return ret;
	}

	static ssize_t
	eeprom_93xx46_write_word(struct eeprom_93xx46_dev *edev,
	const char *buf, unsigned off)
	{
	struct spi_message m;
	struct spi_transfer t[2];
	int bits, data_len, ret;
	u16 cmd_addr;

	cmd_addr = OP_WRITE << edev->addrlen;

	if (edev->addrlen == 7) {
	cmd_addr \|= off & 0x7f;
	bits = 10;
	data_len = 1;
	} else {
	cmd_addr \|= off & 0x3f;
	bits = 9;
	data_len = 2;
	}

	dev_dbg(&edev->spi->dev, "write cmd 0x%x\n", cmd_addr);

	spi_message_init(&m);
	memset(t, 0, sizeof(t));

	t[0].tx_buf = (char *)&cmd_addr;
	t[0].len = 2;
	t[0].bits_per_word = bits;
	spi_message_add_tail(&t[0], &m);

	t[1].tx_buf = buf;
	t[1].len = data_len;
	t[1].bits_per_word = 8;
	spi_message_add_tail(&t[1], &m);

	ret = spi_sync(edev->spi, &m);
	/* have to wait program cycle time Twc ms */
	mdelay(6);
	return ret;
	}

	static ssize_t
	eeprom_93xx46_bin_write(struct file filp, struct kobject kobj,
	struct bin_attribute *bin_attr,
	char *buf, loff_t off, size_t count)
	{
	struct eeprom_93xx46_dev *edev;
	struct device *dev;
	int i, ret, step = 1;

	dev = container_of(kobj, struct device, kobj);
	edev = dev_get_drvdata(dev);

	/* only write even number of bytes on 16-bit devices */
	if (edev->addrlen == 6) {
	step = 2;
	count &= ~1;
	}

	/* erase/write enable */
	ret = eeprom_93xx46_ew(edev, 1);
	if (ret)
	return ret;

	mutex_lock(&edev->lock);

	if (edev->pdata->prepare)
	edev->pdata->prepare(edev);

	for (i = 0; i < count; i += step) {
	ret = eeprom_93xx46_write_word(edev, &buf[i], off + i);
	if (ret) {
	dev_err(&edev->spi->dev, "write failed at %d: %d\n",
	(int)off + i, ret);
	break;
	}
	}

	if (edev->pdata->finish)
	edev->pdata->finish(edev);

	mutex_unlock(&edev->lock);

	/* erase/write disable */
	eeprom_93xx46_ew(edev, 0);
	return ret ? : count;
	}

	static int eeprom_93xx46_eral(struct eeprom_93xx46_dev *edev)
	{
	struct eeprom_93xx46_platform_data *pd = edev->pdata;
	struct spi_message m;
	struct spi_transfer t;
	int bits, ret;
	u16 cmd_addr;

	cmd_addr = OP_START << edev->addrlen;
	if (edev->addrlen == 7) {
	cmd_addr \|= ADDR_ERAL << 1;
	bits = 10;
	} else {
	cmd_addr \|= ADDR_ERAL;
	bits = 9;
	}

	spi_message_init(&m);
	memset(&t, 0, sizeof(t));

	t.tx_buf = &cmd_addr;
	t.len = 2;
	t.bits_per_word = bits;
	spi_message_add_tail(&t, &m);

	mutex_lock(&edev->lock);

	if (edev->pdata->prepare)
	edev->pdata->prepare(edev);

	ret = spi_sync(edev->spi, &m);
	if (ret)
	dev_err(&edev->spi->dev, "erase error %d\n", ret);
	/* have to wait erase cycle time Tec ms */
	mdelay(6);

	if (pd->finish)
	pd->finish(edev);

	mutex_unlock(&edev->lock);
	return ret;
	}

	static ssize_t eeprom_93xx46_store_erase(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t count)
	{
	struct eeprom_93xx46_dev *edev = dev_get_drvdata(dev);
	int erase = 0, ret;

	sscanf(buf, "%d", &erase);
	if (erase) {
	ret = eeprom_93xx46_ew(edev, 1);
	if (ret)
	return ret;
	ret = eeprom_93xx46_eral(edev);
	if (ret)
	return ret;
	ret = eeprom_93xx46_ew(edev, 0);
	if (ret)
	return ret;
	}
	return count;
	}
	static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase);

	static int eeprom_93xx46_probe(struct spi_device *spi)
	{
	struct eeprom_93xx46_platform_data *pd;
	struct eeprom_93xx46_dev *edev;
	int err;

	pd = spi->dev.platform_data;
	if (!pd) {
	dev_err(&spi->dev, "missing platform data\n");
	return -ENODEV;
	}

	edev = kzalloc(sizeof(*edev), GFP_KERNEL);
	if (!edev)
	return -ENOMEM;

	if (pd->flags & EE_ADDR8)
	edev->addrlen = 7;
	else if (pd->flags & EE_ADDR16)
	edev->addrlen = 6;
	else {
	dev_err(&spi->dev, "unspecified address type\n");
	err = -EINVAL;
	goto fail;
	}

	mutex_init(&edev->lock);

	edev->spi = spi_dev_get(spi);
	edev->pdata = pd;

	sysfs_bin_attr_init(&edev->bin);
	edev->bin.attr.name = "eeprom";
	edev->bin.attr.mode = S_IRUSR;
	edev->bin.read = eeprom_93xx46_bin_read;
	edev->bin.size = 128;
	if (!(pd->flags & EE_READONLY)) {
	edev->bin.write = eeprom_93xx46_bin_write;
	edev->bin.attr.mode \|= S_IWUSR;
	}

	err = sysfs_create_bin_file(&spi->dev.kobj, &edev->bin);
	if (err)
	goto fail;

	dev_info(&spi->dev, "%d-bit eeprom %s\n",
	(pd->flags & EE_ADDR8) ? 8 : 16,
	(pd->flags & EE_READONLY) ? "(readonly)" : "");

	if (!(pd->flags & EE_READONLY)) {
	if (device_create_file(&spi->dev, &dev_attr_erase))
	dev_err(&spi->dev, "can't create erase interface\n");
	}

	spi_set_drvdata(spi, edev);
	return 0;
	fail:
	kfree(edev);
	return err;
	}

	static int eeprom_93xx46_remove(struct spi_device *spi)
	{
	struct eeprom_93xx46_dev *edev = spi_get_drvdata(spi);

	if (!(edev->pdata->flags & EE_READONLY))
	device_remove_file(&spi->dev, &dev_attr_erase);

	sysfs_remove_bin_file(&spi->dev.kobj, &edev->bin);
	kfree(edev);
	return 0;
	}

	static struct spi_driver eeprom_93xx46_driver = {
	.driver = {
	.name = "93xx46",
	},
	.probe = eeprom_93xx46_probe,
	.remove = eeprom_93xx46_remove,
	};

	module_spi_driver(eeprom_93xx46_driver);

	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("Driver for 93xx46 EEPROMs");
	MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>");
	MODULE_ALIAS("spi:93xx46");