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294 lines
6.7 KiB
294 lines
6.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* w1_ds2431.c - w1 family 2d (DS2431) driver |
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* |
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* Copyright (c) 2008 Bernhard Weirich <[email protected]> |
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* |
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* Heavily inspired by w1_DS2433 driver from Ben Gardner <[email protected]> |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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#include <linux/device.h> |
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#include <linux/types.h> |
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#include <linux/delay.h> |
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#include <linux/w1.h> |
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#define W1_EEPROM_DS2431 0x2D |
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#define W1_F2D_EEPROM_SIZE 128 |
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#define W1_F2D_PAGE_COUNT 4 |
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#define W1_F2D_PAGE_BITS 5 |
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#define W1_F2D_PAGE_SIZE (1<<W1_F2D_PAGE_BITS) |
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#define W1_F2D_PAGE_MASK 0x1F |
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#define W1_F2D_SCRATCH_BITS 3 |
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#define W1_F2D_SCRATCH_SIZE (1<<W1_F2D_SCRATCH_BITS) |
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#define W1_F2D_SCRATCH_MASK (W1_F2D_SCRATCH_SIZE-1) |
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#define W1_F2D_READ_EEPROM 0xF0 |
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#define W1_F2D_WRITE_SCRATCH 0x0F |
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#define W1_F2D_READ_SCRATCH 0xAA |
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#define W1_F2D_COPY_SCRATCH 0x55 |
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#define W1_F2D_TPROG_MS 11 |
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#define W1_F2D_READ_RETRIES 10 |
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#define W1_F2D_READ_MAXLEN 8 |
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/* |
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* Check the file size bounds and adjusts count as needed. |
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* This would not be needed if the file size didn't reset to 0 after a write. |
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*/ |
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static inline size_t w1_f2d_fix_count(loff_t off, size_t count, size_t size) |
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{ |
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if (off > size) |
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return 0; |
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if ((off + count) > size) |
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return size - off; |
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return count; |
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} |
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/* |
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* Read a block from W1 ROM two times and compares the results. |
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* If they are equal they are returned, otherwise the read |
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* is repeated W1_F2D_READ_RETRIES times. |
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* |
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* count must not exceed W1_F2D_READ_MAXLEN. |
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*/ |
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static int w1_f2d_readblock(struct w1_slave *sl, int off, int count, char *buf) |
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{ |
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u8 wrbuf[3]; |
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u8 cmp[W1_F2D_READ_MAXLEN]; |
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int tries = W1_F2D_READ_RETRIES; |
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do { |
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wrbuf[0] = W1_F2D_READ_EEPROM; |
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wrbuf[1] = off & 0xff; |
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wrbuf[2] = off >> 8; |
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if (w1_reset_select_slave(sl)) |
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return -1; |
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w1_write_block(sl->master, wrbuf, 3); |
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w1_read_block(sl->master, buf, count); |
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if (w1_reset_select_slave(sl)) |
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return -1; |
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w1_write_block(sl->master, wrbuf, 3); |
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w1_read_block(sl->master, cmp, count); |
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if (!memcmp(cmp, buf, count)) |
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return 0; |
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} while (--tries); |
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dev_err(&sl->dev, "proof reading failed %d times\n", |
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W1_F2D_READ_RETRIES); |
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return -1; |
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} |
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static ssize_t eeprom_read(struct file *filp, struct kobject *kobj, |
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struct bin_attribute *bin_attr, char *buf, |
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loff_t off, size_t count) |
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{ |
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struct w1_slave *sl = kobj_to_w1_slave(kobj); |
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int todo = count; |
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count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE); |
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if (count == 0) |
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return 0; |
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mutex_lock(&sl->master->bus_mutex); |
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/* read directly from the EEPROM in chunks of W1_F2D_READ_MAXLEN */ |
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while (todo > 0) { |
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int block_read; |
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if (todo >= W1_F2D_READ_MAXLEN) |
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block_read = W1_F2D_READ_MAXLEN; |
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else |
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block_read = todo; |
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if (w1_f2d_readblock(sl, off, block_read, buf) < 0) |
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count = -EIO; |
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todo -= W1_F2D_READ_MAXLEN; |
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buf += W1_F2D_READ_MAXLEN; |
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off += W1_F2D_READ_MAXLEN; |
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} |
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mutex_unlock(&sl->master->bus_mutex); |
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return count; |
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} |
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/* |
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* Writes to the scratchpad and reads it back for verification. |
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* Then copies the scratchpad to EEPROM. |
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* The data must be aligned at W1_F2D_SCRATCH_SIZE bytes and |
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* must be W1_F2D_SCRATCH_SIZE bytes long. |
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* The master must be locked. |
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* |
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* @param sl The slave structure |
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* @param addr Address for the write |
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* @param len length must be <= (W1_F2D_PAGE_SIZE - (addr & W1_F2D_PAGE_MASK)) |
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* @param data The data to write |
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* @return 0=Success -1=failure |
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*/ |
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static int w1_f2d_write(struct w1_slave *sl, int addr, int len, const u8 *data) |
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{ |
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int tries = W1_F2D_READ_RETRIES; |
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u8 wrbuf[4]; |
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u8 rdbuf[W1_F2D_SCRATCH_SIZE + 3]; |
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u8 es = (addr + len - 1) % W1_F2D_SCRATCH_SIZE; |
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retry: |
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/* Write the data to the scratchpad */ |
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if (w1_reset_select_slave(sl)) |
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return -1; |
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wrbuf[0] = W1_F2D_WRITE_SCRATCH; |
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wrbuf[1] = addr & 0xff; |
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wrbuf[2] = addr >> 8; |
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w1_write_block(sl->master, wrbuf, 3); |
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w1_write_block(sl->master, data, len); |
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/* Read the scratchpad and verify */ |
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if (w1_reset_select_slave(sl)) |
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return -1; |
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w1_write_8(sl->master, W1_F2D_READ_SCRATCH); |
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w1_read_block(sl->master, rdbuf, len + 3); |
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/* Compare what was read against the data written */ |
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if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) || |
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(rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) { |
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if (--tries) |
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goto retry; |
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dev_err(&sl->dev, |
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"could not write to eeprom, scratchpad compare failed %d times\n", |
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W1_F2D_READ_RETRIES); |
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return -1; |
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} |
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/* Copy the scratchpad to EEPROM */ |
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if (w1_reset_select_slave(sl)) |
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return -1; |
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wrbuf[0] = W1_F2D_COPY_SCRATCH; |
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wrbuf[3] = es; |
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w1_write_block(sl->master, wrbuf, 4); |
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/* Sleep for tprog ms to wait for the write to complete */ |
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msleep(W1_F2D_TPROG_MS); |
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/* Reset the bus to wake up the EEPROM */ |
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w1_reset_bus(sl->master); |
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return 0; |
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} |
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static ssize_t eeprom_write(struct file *filp, struct kobject *kobj, |
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struct bin_attribute *bin_attr, char *buf, |
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loff_t off, size_t count) |
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{ |
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struct w1_slave *sl = kobj_to_w1_slave(kobj); |
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int addr, len; |
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int copy; |
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count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE); |
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if (count == 0) |
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return 0; |
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mutex_lock(&sl->master->bus_mutex); |
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/* Can only write data in blocks of the size of the scratchpad */ |
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addr = off; |
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len = count; |
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while (len > 0) { |
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/* if len too short or addr not aligned */ |
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if (len < W1_F2D_SCRATCH_SIZE || addr & W1_F2D_SCRATCH_MASK) { |
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char tmp[W1_F2D_SCRATCH_SIZE]; |
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/* read the block and update the parts to be written */ |
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if (w1_f2d_readblock(sl, addr & ~W1_F2D_SCRATCH_MASK, |
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W1_F2D_SCRATCH_SIZE, tmp)) { |
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count = -EIO; |
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goto out_up; |
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} |
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/* copy at most to the boundary of the PAGE or len */ |
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copy = W1_F2D_SCRATCH_SIZE - |
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(addr & W1_F2D_SCRATCH_MASK); |
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if (copy > len) |
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copy = len; |
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memcpy(&tmp[addr & W1_F2D_SCRATCH_MASK], buf, copy); |
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if (w1_f2d_write(sl, addr & ~W1_F2D_SCRATCH_MASK, |
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W1_F2D_SCRATCH_SIZE, tmp) < 0) { |
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count = -EIO; |
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goto out_up; |
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} |
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} else { |
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copy = W1_F2D_SCRATCH_SIZE; |
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if (w1_f2d_write(sl, addr, copy, buf) < 0) { |
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count = -EIO; |
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goto out_up; |
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} |
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} |
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buf += copy; |
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addr += copy; |
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len -= copy; |
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} |
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out_up: |
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mutex_unlock(&sl->master->bus_mutex); |
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return count; |
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} |
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static BIN_ATTR_RW(eeprom, W1_F2D_EEPROM_SIZE); |
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static struct bin_attribute *w1_f2d_bin_attrs[] = { |
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&bin_attr_eeprom, |
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NULL, |
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}; |
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static const struct attribute_group w1_f2d_group = { |
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.bin_attrs = w1_f2d_bin_attrs, |
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}; |
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static const struct attribute_group *w1_f2d_groups[] = { |
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&w1_f2d_group, |
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NULL, |
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}; |
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static const struct w1_family_ops w1_f2d_fops = { |
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.groups = w1_f2d_groups, |
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}; |
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static struct w1_family w1_family_2d = { |
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.fid = W1_EEPROM_DS2431, |
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.fops = &w1_f2d_fops, |
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}; |
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module_w1_family(w1_family_2d); |
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MODULE_AUTHOR("Bernhard Weirich <[email protected]>"); |
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MODULE_DESCRIPTION("w1 family 2d driver for DS2431, 1kb EEPROM"); |
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MODULE_LICENSE("GPL"); |
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MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2431));
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