307 строки
7.0 KiB
C
307 строки
7.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* w1_ds2433.c - w1 family 23 (DS2433) driver
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*
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* Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
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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/slab.h>
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#ifdef CONFIG_W1_SLAVE_DS2433_CRC
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#include <linux/crc16.h>
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#define CRC16_INIT 0
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#define CRC16_VALID 0xb001
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#endif
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#include <linux/w1.h>
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#define W1_EEPROM_DS2433 0x23
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#define W1_EEPROM_SIZE 512
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#define W1_PAGE_COUNT 16
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#define W1_PAGE_SIZE 32
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#define W1_PAGE_BITS 5
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#define W1_PAGE_MASK 0x1F
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#define W1_F23_TIME 300
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#define W1_F23_READ_EEPROM 0xF0
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#define W1_F23_WRITE_SCRATCH 0x0F
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#define W1_F23_READ_SCRATCH 0xAA
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#define W1_F23_COPY_SCRATCH 0x55
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struct w1_f23_data {
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u8 memory[W1_EEPROM_SIZE];
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u32 validcrc;
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};
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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_f23_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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#ifdef CONFIG_W1_SLAVE_DS2433_CRC
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static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
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int block)
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{
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u8 wrbuf[3];
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int off = block * W1_PAGE_SIZE;
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if (data->validcrc & (1 << block))
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return 0;
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if (w1_reset_select_slave(sl)) {
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data->validcrc = 0;
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return -EIO;
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}
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wrbuf[0] = W1_F23_READ_EEPROM;
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wrbuf[1] = off & 0xff;
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wrbuf[2] = off >> 8;
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w1_write_block(sl->master, wrbuf, 3);
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w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
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/* cache the block if the CRC is valid */
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if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
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data->validcrc |= (1 << block);
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return 0;
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}
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#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
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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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#ifdef CONFIG_W1_SLAVE_DS2433_CRC
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struct w1_f23_data *data = sl->family_data;
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int i, min_page, max_page;
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#else
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u8 wrbuf[3];
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#endif
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if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
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return 0;
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mutex_lock(&sl->master->bus_mutex);
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#ifdef CONFIG_W1_SLAVE_DS2433_CRC
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min_page = (off >> W1_PAGE_BITS);
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max_page = (off + count - 1) >> W1_PAGE_BITS;
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for (i = min_page; i <= max_page; i++) {
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if (w1_f23_refresh_block(sl, data, i)) {
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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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memcpy(buf, &data->memory[off], count);
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#else /* CONFIG_W1_SLAVE_DS2433_CRC */
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/* read directly from the EEPROM */
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if (w1_reset_select_slave(sl)) {
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count = -EIO;
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goto out_up;
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}
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wrbuf[0] = W1_F23_READ_EEPROM;
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wrbuf[1] = off & 0xff;
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wrbuf[2] = off >> 8;
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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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#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
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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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/**
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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 on one page.
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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_PAGE_SIZE - (addr & W1_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_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
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{
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#ifdef CONFIG_W1_SLAVE_DS2433_CRC
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struct w1_f23_data *f23 = sl->family_data;
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#endif
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u8 wrbuf[4];
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u8 rdbuf[W1_PAGE_SIZE + 3];
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u8 es = (addr + len - 1) & 0x1f;
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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_F23_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_F23_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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return -1;
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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_F23_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 5 ms to wait for the write to complete */
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msleep(5);
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/* Reset the bus to wake up the EEPROM (this may not be needed) */
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w1_reset_bus(sl->master);
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#ifdef CONFIG_W1_SLAVE_DS2433_CRC
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f23->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
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#endif
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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, idx;
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if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
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return 0;
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#ifdef CONFIG_W1_SLAVE_DS2433_CRC
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/* can only write full blocks in cached mode */
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if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
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dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
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(int)off, count);
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return -EINVAL;
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}
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/* make sure the block CRCs are valid */
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for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
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if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
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dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
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return -EINVAL;
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}
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}
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#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
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mutex_lock(&sl->master->bus_mutex);
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/* Can only write data to one page at a time */
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idx = 0;
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while (idx < count) {
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addr = off + idx;
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len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
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if (len > (count - idx))
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len = count - idx;
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if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
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count = -EIO;
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goto out_up;
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}
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idx += len;
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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_EEPROM_SIZE);
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static struct bin_attribute *w1_f23_bin_attributes[] = {
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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_f23_group = {
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.bin_attrs = w1_f23_bin_attributes,
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};
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static const struct attribute_group *w1_f23_groups[] = {
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&w1_f23_group,
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NULL,
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};
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static int w1_f23_add_slave(struct w1_slave *sl)
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{
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#ifdef CONFIG_W1_SLAVE_DS2433_CRC
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struct w1_f23_data *data;
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data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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sl->family_data = data;
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#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
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return 0;
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}
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static void w1_f23_remove_slave(struct w1_slave *sl)
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{
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#ifdef CONFIG_W1_SLAVE_DS2433_CRC
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kfree(sl->family_data);
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sl->family_data = NULL;
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#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
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}
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static struct w1_family_ops w1_f23_fops = {
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.add_slave = w1_f23_add_slave,
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.remove_slave = w1_f23_remove_slave,
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.groups = w1_f23_groups,
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};
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static struct w1_family w1_family_23 = {
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.fid = W1_EEPROM_DS2433,
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.fops = &w1_f23_fops,
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};
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module_w1_family(w1_family_23);
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MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
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MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2433));
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