/* * w1_ds2431.c - w1 family 2d (DS2431) driver * * Copyright (c) 2008 Bernhard Weirich * Copyright (c) 2012 Jean-Christophe PLAGNIOL-VILLARD * * Heavily inspired by w1_DS2433 driver from Ben Gardner * * This source code is licensed under the GNU General Public License, * Version 2. See the file COPYING for more details. */ #include #include "../w1.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 #define DRIVERNAME "ds2431" static int ds2431_count = 0; /* * 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 ds2431_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 ds2431_readblock(struct w1_device *dev, int off, int count, char *buf) { struct w1_bus *bus = dev->bus; 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(dev)) return -1; w1_write_block(bus, wrbuf, 3); w1_read_block(bus, buf, count); if (w1_reset_select_slave(dev)) return -1; w1_write_block(bus, wrbuf, 3); w1_read_block(bus, cmp, count); if (!memcmp(cmp, buf, count)) return 0; } while (--tries); dev_err(&dev->dev, "proof reading failed %d times\n", W1_F2D_READ_RETRIES); return -1; } static ssize_t ds2431_cdev_read(struct cdev *cdev, void *buf, size_t count, loff_t off, ulong flags) { struct w1_device *dev = cdev->priv; int todo = count; count = ds2431_fix_count(off, count, W1_F2D_EEPROM_SIZE); if (count == 0) return 0; /* 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 (ds2431_readblock(dev, off, block_read, buf) < 0) count = -EIO; todo -= W1_F2D_READ_MAXLEN; buf += W1_F2D_READ_MAXLEN; off += W1_F2D_READ_MAXLEN; } return count; } #ifdef CONFIG_W1_SLAVE_DS2431_WRITE /* * 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 ds2431_write(struct w1_device *dev, int addr, int len, const u8 *data) { struct w1_bus *bus = dev->bus; 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(dev)) return -1; wrbuf[0] = W1_F2D_WRITE_SCRATCH; wrbuf[1] = addr & 0xff; wrbuf[2] = addr >> 8; w1_write_block(bus, wrbuf, 3); w1_write_block(bus, data, len); /* Read the scratchpad and verify */ if (w1_reset_select_slave(dev)) return -1; w1_write_8(bus, W1_F2D_READ_SCRATCH); w1_read_block(bus, 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(&dev->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(dev)) return -1; wrbuf[0] = W1_F2D_COPY_SCRATCH; wrbuf[3] = es; w1_write_block(bus, wrbuf, 4); /* Sleep for tprog ms to wait for the write to complete */ mdelay(W1_F2D_TPROG_MS); /* Reset the bus to wake up the EEPROM */ w1_reset_bus(bus); return 0; } static ssize_t ds2431_cdev_write(struct cdev *cdev, const void *buf, size_t count, loff_t off, ulong flags) { struct w1_device *dev = cdev->priv; int addr, len; int copy; count = ds2431_fix_count(off, count, W1_F2D_EEPROM_SIZE); if (count == 0) return 0; /* 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 (ds2431_readblock(dev, 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 (ds2431_write(dev, addr & ~W1_F2D_SCRATCH_MASK, W1_F2D_SCRATCH_SIZE, tmp) < 0) { count = -EIO; goto out_up; } } else { copy = W1_F2D_SCRATCH_SIZE; if (ds2431_write(dev, addr, copy, buf) < 0) { count = -EIO; goto out_up; } } buf += copy; addr += copy; len -= copy; } out_up: return count; } #else #define ds2431_cdev_write NULL #endif static struct cdev_operations ds2431_ops = { .read = ds2431_cdev_read, .write = ds2431_cdev_write, }; static int ds2431_probe(struct w1_device *dev) { struct cdev *cdev; cdev = xzalloc(sizeof(*cdev)); cdev->dev = &dev->dev; cdev->priv = dev; cdev->ops = &ds2431_ops; cdev->size = W1_F2D_EEPROM_SIZE; cdev->name = basprintf(DRIVERNAME"%d", ds2431_count++); if (cdev->name == NULL) return -ENOMEM; return devfs_create(cdev); } struct w1_driver ds2431_driver = { .drv = { .name = DRIVERNAME, }, .probe = ds2431_probe, .fid = 0x2d, }; static int w1_ds2431_init(void) { return w1_driver_register(&ds2431_driver); } device_initcall(w1_ds2431_init);