diff options
Diffstat (limited to 'drivers/w1/slaves/w1_ds2431.c')
| -rw-r--r-- | drivers/w1/slaves/w1_ds2431.c | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/drivers/w1/slaves/w1_ds2431.c b/drivers/w1/slaves/w1_ds2431.c new file mode 100644 index 000000000..6856b1c29 --- /dev/null +++ b/drivers/w1/slaves/w1_ds2431.c @@ -0,0 +1,294 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * w1_ds2431.c - w1 family 2d (DS2431) driver + * + * Copyright (c) 2008 Bernhard Weirich <bernhard.weirich@riedel.net> + * + * Heavily inspired by w1_DS2433 driver from Ben Gardner <bgardner@wabtec.com> + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/device.h> +#include <linux/types.h> +#include <linux/delay.h> + +#include <linux/w1.h> + +#define W1_EEPROM_DS2431 0x2D + +#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 + +/* + * 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 w1_f2d_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 w1_f2d_readblock(struct w1_slave *sl, int off, int count, char *buf) +{ + 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(sl)) + return -1; + + w1_write_block(sl->master, wrbuf, 3); + w1_read_block(sl->master, buf, count); + + if (w1_reset_select_slave(sl)) + return -1; + + w1_write_block(sl->master, wrbuf, 3); + 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_F2D_READ_RETRIES); + + return -1; +} + +static ssize_t eeprom_read(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_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE); + if (count == 0) + return 0; + + mutex_lock(&sl->master->bus_mutex); + + /* 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 (w1_f2d_readblock(sl, off, block_read, buf) < 0) + count = -EIO; + + todo -= W1_F2D_READ_MAXLEN; + buf += W1_F2D_READ_MAXLEN; + off += W1_F2D_READ_MAXLEN; + } + + mutex_unlock(&sl->master->bus_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_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 w1_f2d_write(struct w1_slave *sl, int addr, int len, const u8 *data) +{ + 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(sl)) + return -1; + + wrbuf[0] = W1_F2D_WRITE_SCRATCH; + wrbuf[1] = addr & 0xff; + wrbuf[2] = addr >> 8; + + w1_write_block(sl->master, wrbuf, 3); + w1_write_block(sl->master, data, len); + + /* Read the scratchpad and verify */ + if (w1_reset_select_slave(sl)) + return -1; + + w1_write_8(sl->master, W1_F2D_READ_SCRATCH); + w1_read_block(sl->master, 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(&sl->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(sl)) + return -1; + + wrbuf[0] = W1_F2D_COPY_SCRATCH; + wrbuf[3] = es; + w1_write_block(sl->master, wrbuf, 4); + + /* Sleep for tprog ms to wait for the write to complete */ + msleep(W1_F2D_TPROG_MS); + + /* Reset the bus to wake up the EEPROM */ + w1_reset_bus(sl->master); + + return 0; +} + +static ssize_t eeprom_write(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_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE); + if (count == 0) + return 0; + + mutex_lock(&sl->master->bus_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_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 (w1_f2d_readblock(sl, 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 (w1_f2d_write(sl, addr & ~W1_F2D_SCRATCH_MASK, + W1_F2D_SCRATCH_SIZE, tmp) < 0) { + count = -EIO; + goto out_up; + } + } else { + + copy = W1_F2D_SCRATCH_SIZE; + if (w1_f2d_write(sl, addr, copy, buf) < 0) { + count = -EIO; + goto out_up; + } + } + buf += copy; + addr += copy; + len -= copy; + } + +out_up: + mutex_unlock(&sl->master->bus_mutex); + + return count; +} + +static BIN_ATTR_RW(eeprom, W1_F2D_EEPROM_SIZE); + +static struct bin_attribute *w1_f2d_bin_attrs[] = { + &bin_attr_eeprom, + NULL, +}; + +static const struct attribute_group w1_f2d_group = { + .bin_attrs = w1_f2d_bin_attrs, +}; + +static const struct attribute_group *w1_f2d_groups[] = { + &w1_f2d_group, + NULL, +}; + +static const struct w1_family_ops w1_f2d_fops = { + .groups = w1_f2d_groups, +}; + +static struct w1_family w1_family_2d = { + .fid = W1_EEPROM_DS2431, + .fops = &w1_f2d_fops, +}; +module_w1_family(w1_family_2d); + +MODULE_AUTHOR("Bernhard Weirich <bernhard.weirich@riedel.net>"); +MODULE_DESCRIPTION("w1 family 2d driver for DS2431, 1kb EEPROM"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2431)); |