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306 lines
7.0 KiB
306 lines
7.0 KiB
// 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 <[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/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 const 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 <[email protected]>"); |
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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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