misc/eeprom: add driver for microwire 93xx46 EEPROMs
Anatolij Gustschin [Tue, 26 Jul 2011 00:13:27 +0000 (17:13 -0700)]
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 <agust@denx.de>
Cc: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/misc/eeprom/Kconfig
drivers/misc/eeprom/Makefile
drivers/misc/eeprom/eeprom_93xx46.c [new file with mode: 0644]
include/linux/eeprom_93xx46.h [new file with mode: 0644]

index 9118613..620de28 100644 (file)
@@ -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
index df3d68f..ec55aad 100644 (file)
@@ -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 (file)
index 0000000..0c7ebb1
--- /dev/null
@@ -0,0 +1,410 @@
+/*
+ * 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");
diff --git a/include/linux/eeprom_93xx46.h b/include/linux/eeprom_93xx46.h
new file mode 100644 (file)
index 0000000..0679181
--- /dev/null
@@ -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 *);
+};