/* * w1_ds2805 - w1 family 0d (DS28E05) driver * * Copyright (c) 2016 Andrew Worsley amworsley@gmail.com * * This source code is licensed under the GNU General Public License, * Version 2. See the file COPYING for more details. */ #include #include #include #include #include #include #include #define W1_EEPROM_DS2805 0x0D #define W1_F0D_EEPROM_SIZE 128 #define W1_F0D_PAGE_BITS 3 #define W1_F0D_PAGE_SIZE (1< 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_F0D_READ_RETRIES times. * * count must not exceed W1_F0D_READ_MAXLEN. */ static int w1_f0d_readblock(struct w1_slave *sl, int off, int count, char *buf) { u8 wrbuf[3]; u8 cmp[W1_F0D_READ_MAXLEN]; int tries = W1_F0D_READ_RETRIES; do { wrbuf[0] = W1_F0D_READ_EEPROM; wrbuf[1] = off & 0x7f; wrbuf[2] = 0; if (w1_reset_select_slave(sl)) return -1; w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); w1_read_block(sl->master, buf, count); if (w1_reset_select_slave(sl)) return -1; w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); 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_F0D_READ_RETRIES); return -1; } static ssize_t w1_f0d_read_bin(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_f0d_fix_count(off, count, W1_F0D_EEPROM_SIZE); if (count == 0) return 0; mutex_lock(&sl->master->mutex); /* read directly from the EEPROM in chunks of W1_F0D_READ_MAXLEN */ while (todo > 0) { int block_read; if (todo >= W1_F0D_READ_MAXLEN) block_read = W1_F0D_READ_MAXLEN; else block_read = todo; if (w1_f0d_readblock(sl, off, block_read, buf) < 0) { count = -EIO; break; } todo -= W1_F0D_READ_MAXLEN; buf += W1_F0D_READ_MAXLEN; off += W1_F0D_READ_MAXLEN; } mutex_unlock(&sl->master->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_F0D_SCRATCH_SIZE bytes and * must be W1_F0D_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_F0D_PAGE_SIZE - (addr & W1_F0D_PAGE_MASK)) * @param data The data to write * @return 0=Success -1=failure */ static int w1_f0d_write(struct w1_slave *sl, int addr, int len, const u8 *data) { int tries = W1_F0D_READ_RETRIES; u8 wrbuf[3]; u8 rdbuf[W1_F0D_SCRATCH_SIZE]; u8 cs; if ((addr & 1) || (len != 2)) { dev_err(&sl->dev, "%s: bad addr/len - addr=%#x len=%d\n", __func__, addr, len); return -1; } retry: /* Write the data to the scratchpad */ if (w1_reset_select_slave(sl)) return -1; wrbuf[0] = W1_F0D_WRITE_EEPROM; wrbuf[1] = addr & 0xff; wrbuf[2] = 0xff; /* ?? from Example */ w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); w1_write_block(sl->master, data, len); w1_read_block(sl->master, rdbuf, sizeof(rdbuf)); /* Compare what was read against the data written */ if ((rdbuf[0] != data[0]) || (rdbuf[1] != data[1])) { if (--tries) goto retry; dev_err(&sl->dev, "could not write to eeprom, scratchpad compare failed %d times\n", W1_F0D_READ_RETRIES); pr_info("%s: rdbuf = %#x %#x data = %#x %#x\n", __func__, rdbuf[0], rdbuf[1], data[0], data[1]); return -1; } /* Trigger write out to EEPROM */ w1_write_8(sl->master, W1_F0D_RELEASE); /* Sleep for tprog ms to wait for the write to complete */ msleep(W1_F0D_TPROG_MS); /* Check CS (Command Status) == 0xAA ? */ cs = w1_read_8(sl->master); if (cs != W1_F0D_CS_OK) { dev_err(&sl->dev, "save to eeprom failed = CS=%#x\n", cs); return -1; } return 0; } static ssize_t w1_f0d_write_bin(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_f0d_fix_count(off, count, W1_F0D_EEPROM_SIZE); if (count == 0) return 0; mutex_lock(&sl->master->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_F0D_SCRATCH_SIZE || addr & W1_F0D_SCRATCH_MASK) { char tmp[W1_F0D_SCRATCH_SIZE]; /* read the block and update the parts to be written */ if (w1_f0d_readblock(sl, addr & ~W1_F0D_SCRATCH_MASK, W1_F0D_SCRATCH_SIZE, tmp)) { count = -EIO; goto out_up; } /* copy at most to the boundary of the PAGE or len */ copy = W1_F0D_SCRATCH_SIZE - (addr & W1_F0D_SCRATCH_MASK); if (copy > len) copy = len; memcpy(&tmp[addr & W1_F0D_SCRATCH_MASK], buf, copy); if (w1_f0d_write(sl, addr & ~W1_F0D_SCRATCH_MASK, W1_F0D_SCRATCH_SIZE, tmp) < 0) { count = -EIO; goto out_up; } } else { copy = W1_F0D_SCRATCH_SIZE; if (w1_f0d_write(sl, addr, copy, buf) < 0) { count = -EIO; goto out_up; } } buf += copy; addr += copy; len -= copy; } out_up: mutex_unlock(&sl->master->mutex); return count; } static struct bin_attribute w1_f0d_bin_attr = { .attr = { .name = "eeprom", .mode = S_IRUGO | S_IWUSR, }, .size = W1_F0D_EEPROM_SIZE, .read = w1_f0d_read_bin, .write = w1_f0d_write_bin, }; static int w1_f0d_add_slave(struct w1_slave *sl) { return sysfs_create_bin_file(&sl->dev.kobj, &w1_f0d_bin_attr); } static void w1_f0d_remove_slave(struct w1_slave *sl) { sysfs_remove_bin_file(&sl->dev.kobj, &w1_f0d_bin_attr); } static struct w1_family_ops w1_f0d_fops = { .add_slave = w1_f0d_add_slave, .remove_slave = w1_f0d_remove_slave, }; static struct w1_family w1_family_2d = { .fid = W1_EEPROM_DS2805, .fops = &w1_f0d_fops, }; static int __init w1_f0d_init(void) { pr_info("%s()\n", __func__); return w1_register_family(&w1_family_2d); } static void __exit w1_f0d_fini(void) { pr_info("%s()\n", __func__); w1_unregister_family(&w1_family_2d); } module_init(w1_f0d_init); module_exit(w1_f0d_fini); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Andrew Worsley amworsley@gmail.com"); MODULE_DESCRIPTION("w1 family 0d driver for DS2805, 1kb EEPROM");