|  | /* | 
|  | * 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/init.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); | 
|  |  | 
|  | if (unlikely(off >= edev->bin.size)) | 
|  | return 0; | 
|  | if ((off + count) > edev->bin.size) | 
|  | count = edev->bin.size - off; | 
|  | if (unlikely(!count)) | 
|  | return count; | 
|  |  | 
|  | 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); | 
|  |  | 
|  | if (unlikely(off >= edev->bin.size)) | 
|  | return 0; | 
|  | if ((off + count) > edev->bin.size) | 
|  | count = edev->bin.size - off; | 
|  | if (unlikely(!count)) | 
|  | return count; | 
|  |  | 
|  | /* 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 __devinit 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"); | 
|  | } | 
|  |  | 
|  | dev_set_drvdata(&spi->dev, edev); | 
|  | return 0; | 
|  | fail: | 
|  | kfree(edev); | 
|  | return err; | 
|  | } | 
|  |  | 
|  | static int __devexit eeprom_93xx46_remove(struct spi_device *spi) | 
|  | { | 
|  | struct eeprom_93xx46_dev *edev = dev_get_drvdata(&spi->dev); | 
|  |  | 
|  | if (!(edev->pdata->flags & EE_READONLY)) | 
|  | device_remove_file(&spi->dev, &dev_attr_erase); | 
|  |  | 
|  | sysfs_remove_bin_file(&spi->dev.kobj, &edev->bin); | 
|  | dev_set_drvdata(&spi->dev, NULL); | 
|  | kfree(edev); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static struct spi_driver eeprom_93xx46_driver = { | 
|  | .driver = { | 
|  | .name	= "93xx46", | 
|  | .owner	= THIS_MODULE, | 
|  | }, | 
|  | .probe		= eeprom_93xx46_probe, | 
|  | .remove		= __devexit_p(eeprom_93xx46_remove), | 
|  | }; | 
|  |  | 
|  | static int __init eeprom_93xx46_init(void) | 
|  | { | 
|  | return spi_register_driver(&eeprom_93xx46_driver); | 
|  | } | 
|  | module_init(eeprom_93xx46_init); | 
|  |  | 
|  | static void __exit eeprom_93xx46_exit(void) | 
|  | { | 
|  | spi_unregister_driver(&eeprom_93xx46_driver); | 
|  | } | 
|  | module_exit(eeprom_93xx46_exit); | 
|  |  | 
|  | MODULE_LICENSE("GPL"); | 
|  | MODULE_DESCRIPTION("Driver for 93xx46 EEPROMs"); | 
|  | MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>"); | 
|  | MODULE_ALIAS("spi:93xx46"); |