From 06b4501e88ad10f02849a3f9d7408ed6ae15a53f Mon Sep 17 00:00:00 2001 From: Anatolij Gustschin Date: Mon, 25 Jul 2011 17:13:27 -0700 Subject: [PATCH] misc/eeprom: add driver for microwire 93xx46 EEPROMs Add EEPROM driver for 93xx46 chips. It can also be used with spi_gpio driver to access 93xx46 EEPROMs connected over GPIO lines. This driver supports read/write/erase access to the EEPROM chips over sysfs files. [rdunlap@xenotime.net: fix printk format] Signed-off-by: Anatolij Gustschin Cc: Jonathan Cameron Cc: Grant Likely Signed-off-by: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/misc/eeprom/Kconfig | 13 + drivers/misc/eeprom/Makefile | 1 + drivers/misc/eeprom/eeprom_93xx46.c | 410 ++++++++++++++++++++++++++++ include/linux/eeprom_93xx46.h | 18 ++ 4 files changed, 442 insertions(+) create mode 100644 drivers/misc/eeprom/eeprom_93xx46.c create mode 100644 include/linux/eeprom_93xx46.h diff --git a/drivers/misc/eeprom/Kconfig b/drivers/misc/eeprom/Kconfig index 9118613af321..620de283b40b 100644 --- a/drivers/misc/eeprom/Kconfig +++ b/drivers/misc/eeprom/Kconfig @@ -70,4 +70,17 @@ config EEPROM_93CX6 If unsure, say N. +config EEPROM_93XX46 + tristate "Microwire EEPROM 93XX46 support" + depends on SPI && SYSFS + help + Driver for the microwire EEPROM chipsets 93xx46x. The driver + supports both read and write commands and also the command to + erase the whole EEPROM. + + This driver can also be built as a module. If so, the module + will be called eeprom_93xx46. + + If unsure, say N. + endmenu diff --git a/drivers/misc/eeprom/Makefile b/drivers/misc/eeprom/Makefile index df3d68ffa9d1..ec55aad24cfb 100644 --- a/drivers/misc/eeprom/Makefile +++ b/drivers/misc/eeprom/Makefile @@ -3,3 +3,4 @@ obj-$(CONFIG_EEPROM_AT25) += at25.o obj-$(CONFIG_EEPROM_LEGACY) += eeprom.o obj-$(CONFIG_EEPROM_MAX6875) += max6875.o obj-$(CONFIG_EEPROM_93CX6) += eeprom_93cx6.o +obj-$(CONFIG_EEPROM_93XX46) += eeprom_93xx46.o diff --git a/drivers/misc/eeprom/eeprom_93xx46.c b/drivers/misc/eeprom/eeprom_93xx46.c new file mode 100644 index 000000000000..0c7ebb1e19e5 --- /dev/null +++ b/drivers/misc/eeprom/eeprom_93xx46.c @@ -0,0 +1,410 @@ +/* + * Driver for 93xx46 EEPROMs + * + * (C) 2011 DENX Software Engineering, Anatolij Gustschin + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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 "); +MODULE_ALIAS("spi:93xx46"); diff --git a/include/linux/eeprom_93xx46.h b/include/linux/eeprom_93xx46.h new file mode 100644 index 000000000000..06791811e49d --- /dev/null +++ b/include/linux/eeprom_93xx46.h @@ -0,0 +1,18 @@ +/* + * Module: eeprom_93xx46 + * platform description for 93xx46 EEPROMs. + */ + +struct eeprom_93xx46_platform_data { + unsigned char flags; +#define EE_ADDR8 0x01 /* 8 bit addr. cfg */ +#define EE_ADDR16 0x02 /* 16 bit addr. cfg */ +#define EE_READONLY 0x08 /* forbid writing */ + + /* + * optional hooks to control additional logic + * before and after spi transfer. + */ + void (*prepare)(void *); + void (*finish)(void *); +};