/* * w1_ds2431.c - w1 family 2d (DS2431) driver * * Copyright (c) 2008 Bernhard Weirich <bernhard.weirich@riedel.net> * * Heavily inspired by w1_DS2433 driver from Ben Gardner <bgardner@wabtec.com> * * This source code is licensed under the GNU General Public License, * Version 2. See the file COPYING for more details. */ #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_int.h" #include "../w1_family.h" #define W1_F2D_EEPROM_SIZE 128 #define W1_F2D_PAGE_COUNT 4 #define W1_F2D_PAGE_BITS 5 #define W1_F2D_PAGE_SIZE (1<<W1_F2D_PAGE_BITS) #define W1_F2D_PAGE_MASK 0x1F #define W1_F2D_SCRATCH_BITS 3 #define W1_F2D_SCRATCH_SIZE (1<<W1_F2D_SCRATCH_BITS) #define W1_F2D_SCRATCH_MASK (W1_F2D_SCRATCH_SIZE-1) #define W1_F2D_READ_EEPROM 0xF0 #define W1_F2D_WRITE_SCRATCH 0x0F #define W1_F2D_READ_SCRATCH 0xAA #define W1_F2D_COPY_SCRATCH 0x55 #define W1_F2D_TPROG_MS 11 #define W1_F2D_READ_RETRIES 10 #define W1_F2D_READ_MAXLEN 8 /* * Check the file size bounds and adjusts count as needed. * This would not be needed if the file size didn't reset to 0 after a write. */ static inline size_t w1_f2d_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; } /* * Read a block from W1 ROM two times and compares the results. * If they are equal they are returned, otherwise the read * is repeated W1_F2D_READ_RETRIES times. * * count must not exceed W1_F2D_READ_MAXLEN. */ static int w1_f2d_readblock(struct w1_slave *sl, int off, int count, char *buf) { u8 wrbuf[3]; u8 cmp[W1_F2D_READ_MAXLEN]; int tries = W1_F2D_READ_RETRIES; do { wrbuf[0] = W1_F2D_READ_EEPROM; wrbuf[1] = off & 0xff; wrbuf[2] = off >> 8; if (w1_reset_select_slave(sl)) return -1; w1_write_block(sl->master, wrbuf, 3); w1_read_block(sl->master, buf, count); if (w1_reset_select_slave(sl)) return -1; w1_write_block(sl->master, wrbuf, 3); w1_read_block(sl->master, cmp, count); if (!memcmp(cmp, buf, count)) return 0; } while (--tries); dev_err(&sl->dev, "proof reading failed %d times\n", W1_F2D_READ_RETRIES); return -1; } static ssize_t eeprom_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count) { struct w1_slave *sl = kobj_to_w1_slave(kobj); int todo = count; count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE); if (count == 0) return 0; mutex_lock(&sl->master->bus_mutex); /* read directly from the EEPROM in chunks of W1_F2D_READ_MAXLEN */ while (todo > 0) { int block_read; if (todo >= W1_F2D_READ_MAXLEN) block_read = W1_F2D_READ_MAXLEN; else block_read = todo; if (w1_f2d_readblock(sl, off, block_read, buf) < 0) count = -EIO; todo -= W1_F2D_READ_MAXLEN; buf += W1_F2D_READ_MAXLEN; off += W1_F2D_READ_MAXLEN; } mutex_unlock(&sl->master->bus_mutex); return count; } /* * Writes to the scratchpad and reads it back for verification. * Then copies the scratchpad to EEPROM. * The data must be aligned at W1_F2D_SCRATCH_SIZE bytes and * must be W1_F2D_SCRATCH_SIZE bytes long. * The master must be locked. * * @param sl The slave structure * @param addr Address for the write * @param len length must be <= (W1_F2D_PAGE_SIZE - (addr & W1_F2D_PAGE_MASK)) * @param data The data to write * @return 0=Success -1=failure */ static int w1_f2d_write(struct w1_slave *sl, int addr, int len, const u8 *data) { int tries = W1_F2D_READ_RETRIES; u8 wrbuf[4]; u8 rdbuf[W1_F2D_SCRATCH_SIZE + 3]; u8 es = (addr + len - 1) % W1_F2D_SCRATCH_SIZE; retry: /* Write the data to the scratchpad */ if (w1_reset_select_slave(sl)) return -1; wrbuf[0] = W1_F2D_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_F2D_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)) { if (--tries) goto retry; dev_err(&sl->dev, "could not write to eeprom, scratchpad compare failed %d times\n", W1_F2D_READ_RETRIES); return -1; } /* Copy the scratchpad to EEPROM */ if (w1_reset_select_slave(sl)) return -1; wrbuf[0] = W1_F2D_COPY_SCRATCH; wrbuf[3] = es; w1_write_block(sl->master, wrbuf, 4); /* Sleep for tprog ms to wait for the write to complete */ msleep(W1_F2D_TPROG_MS); /* Reset the bus to wake up the EEPROM */ w1_reset_bus(sl->master); return 0; } static ssize_t eeprom_write(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count) { struct w1_slave *sl = kobj_to_w1_slave(kobj); int addr, len; int copy; count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE); if (count == 0) return 0; mutex_lock(&sl->master->bus_mutex); /* Can only write data in blocks of the size of the scratchpad */ addr = off; len = count; while (len > 0) { /* if len too short or addr not aligned */ if (len < W1_F2D_SCRATCH_SIZE || addr & W1_F2D_SCRATCH_MASK) { char tmp[W1_F2D_SCRATCH_SIZE]; /* read the block and update the parts to be written */ if (w1_f2d_readblock(sl, addr & ~W1_F2D_SCRATCH_MASK, W1_F2D_SCRATCH_SIZE, tmp)) { count = -EIO; goto out_up; } /* copy at most to the boundary of the PAGE or len */ copy = W1_F2D_SCRATCH_SIZE - (addr & W1_F2D_SCRATCH_MASK); if (copy > len) copy = len; memcpy(&tmp[addr & W1_F2D_SCRATCH_MASK], buf, copy); if (w1_f2d_write(sl, addr & ~W1_F2D_SCRATCH_MASK, W1_F2D_SCRATCH_SIZE, tmp) < 0) { count = -EIO; goto out_up; } } else { copy = W1_F2D_SCRATCH_SIZE; if (w1_f2d_write(sl, addr, copy, buf) < 0) { count = -EIO; goto out_up; } } buf += copy; addr += copy; len -= copy; } out_up: mutex_unlock(&sl->master->bus_mutex); return count; } static BIN_ATTR_RW(eeprom, W1_F2D_EEPROM_SIZE); static struct bin_attribute *w1_f2d_bin_attrs[] = { &bin_attr_eeprom, NULL, }; static const struct attribute_group w1_f2d_group = { .bin_attrs = w1_f2d_bin_attrs, }; static const struct attribute_group *w1_f2d_groups[] = { &w1_f2d_group, NULL, }; static struct w1_family_ops w1_f2d_fops = { .groups = w1_f2d_groups, }; static struct w1_family w1_family_2d = { .fid = W1_EEPROM_DS2431, .fops = &w1_f2d_fops, }; static int __init w1_f2d_init(void) { return w1_register_family(&w1_family_2d); } static void __exit w1_f2d_fini(void) { w1_unregister_family(&w1_family_2d); } module_init(w1_f2d_init); module_exit(w1_f2d_fini); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Bernhard Weirich <bernhard.weirich@riedel.net>"); MODULE_DESCRIPTION("w1 family 2d driver for DS2431, 1kb EEPROM"); MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2431));