diff options
Diffstat (limited to 'drivers/w1/w1_ds2433.c')
| -rw-r--r-- | drivers/w1/w1_ds2433.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/drivers/w1/w1_ds2433.c b/drivers/w1/w1_ds2433.c new file mode 100644 index 0000000..9ec9163 --- /dev/null +++ b/drivers/w1/w1_ds2433.c @@ -0,0 +1,222 @@ +/* + * w1_ds2433.c - w1 family 23 (DS2433) driver + * + * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the smems of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + */ + +#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 "w1.h" +#include "w1_io.h" +#include "w1_int.h" +#include "w1_family.h" + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>"); +MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM"); + +#define W1_EEPROM_SIZE 512 +#define W1_PAGE_SIZE 32 +#define W1_PAGE_BITS 5 +#define W1_PAGE_MASK 0x1F + +#define W1_F23_READ_EEPROM 0xF0 +#define W1_F23_WRITE_SCRATCH 0x0F +#define W1_F23_READ_SCRATCH 0xAA +#define W1_F23_COPY_SCRATCH 0x55 + +/** + * Check the file size bounds and adjusts count as needed. + * This may not be needed if the sysfs layer checks bounds. + */ +static inline size_t w1_f23_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; +} + +static ssize_t w1_f23_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count) +{ + struct w1_slave *sl = kobj_to_w1_slave(kobj); + u8 wrbuf[3]; + + if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0) + return 0; + + atomic_inc(&sl->refcnt); + if (down_interruptible(&sl->master->mutex)) { + count = 0; + goto out_dec; + } + + /* read directly from the EEPROM */ + if (w1_reset_select_slave(sl)) { + count = -EIO; + goto out_up; + } + + wrbuf[0] = W1_F23_READ_EEPROM; + wrbuf[1] = off & 0xff; + wrbuf[2] = off >> 8; + w1_write_block(sl->master, wrbuf, 3); + w1_read_block(sl->master, buf, count); + +out_up: + up(&sl->master->mutex); +out_dec: + atomic_dec(&sl->refcnt); + + return count; +} + +/** + * Writes to the scratchpad and reads it back for verification. + * The master must be locked. + * + * @param sl The slave structure + * @param addr Address for the write + * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK)) + * @param data The data to write + * @return 0=Success -1=failure + */ +static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data) +{ + u8 wrbuf[4]; + u8 rdbuf[W1_PAGE_SIZE + 3]; + u8 es = (addr + len - 1) & 0x1f; + + /* Write the data to the scratchpad */ + if (w1_reset_select_slave(sl)) + return -1; + + wrbuf[0] = W1_F23_WRITE_SCRATCH; + wrbuf[1] = addr & 0xff; + wrbuf[2] = addr >> 8; + + w1_write_block(sl->master, wrbuf, 3); + w1_write_block(sl->master, data, len); + + /* Read the scratchpad and verify */ + if (w1_reset_select_slave(sl)) + return -1; + + w1_write_8(sl->master, W1_F23_READ_SCRATCH); + w1_read_block(sl->master, rdbuf, len + 3); + + /* Compare what was read against the data written */ + if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) || + (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) + return -1; + + /* Copy the scratchpad to EEPROM */ + if (w1_reset_select_slave(sl)) + return -1; + + wrbuf[0] = W1_F23_COPY_SCRATCH; + wrbuf[3] = es; + w1_write_block(sl->master, wrbuf, 4); + + /* Sleep for 5 ms to wait for the write to complete */ + msleep(5); + + /* Reset the bus to wake up the EEPROM (this may not be needed) */ + w1_reset_bus(sl->master); + + return 0; +} + +static ssize_t w1_f23_write_bin(struct kobject *kobj, char *buf, loff_t off, + size_t count) +{ + struct w1_slave *sl = kobj_to_w1_slave(kobj); + int addr, len, idx; + + if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0) + return 0; + + atomic_inc(&sl->refcnt); + if (down_interruptible(&sl->master->mutex)) { + count = 0; + goto out_dec; + } + + /* Can only write data to one page at a time */ + idx = 0; + while (idx < count) { + addr = off + idx; + len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK); + if (len > (count - idx)) + len = count - idx; + + if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) { + count = -EIO; + goto out_up; + } + idx += len; + } + +out_up: + up(&sl->master->mutex); +out_dec: + atomic_dec(&sl->refcnt); + + return count; +} + +static struct bin_attribute w1_f23_bin_attr = { + .attr = { + .name = "eeprom", + .mode = S_IRUGO | S_IWUSR, + .owner = THIS_MODULE, + }, + .size = W1_EEPROM_SIZE, + .read = w1_f23_read_bin, + .write = w1_f23_write_bin, +}; + +static int w1_f23_add_slave(struct w1_slave *sl) +{ + return sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr); +} + +static void w1_f23_remove_slave(struct w1_slave *sl) +{ + sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr); +} + +static struct w1_family_ops w1_f23_fops = { + .add_slave = w1_f23_add_slave, + .remove_slave = w1_f23_remove_slave, +}; + +static struct w1_family w1_family_23 = { + .fid = W1_EEPROM_DS2433, + .fops = &w1_f23_fops, +}; + +static int __init w1_f23_init(void) +{ + return w1_register_family(&w1_family_23); +} + +static void __exit w1_f23_fini(void) +{ + w1_unregister_family(&w1_family_23); +} + +module_init(w1_f23_init); +module_exit(w1_f23_fini); |