diff options
Diffstat (limited to 'drivers/w1/slaves/w1_ds2751.c')
| -rw-r--r-- | drivers/w1/slaves/w1_ds2751.c | 320 |
1 files changed, 320 insertions, 0 deletions
diff --git a/drivers/w1/slaves/w1_ds2751.c b/drivers/w1/slaves/w1_ds2751.c new file mode 100644 index 000000000000..9e5bf6faa4cb --- /dev/null +++ b/drivers/w1/slaves/w1_ds2751.c @@ -0,0 +1,320 @@ +/* + * Copyright 2005-2010 Freescale Semiconductor, Inc. All Rights Reserved. + */ + +/* + * The code contained herein is licensed under the GNU General Public + * License. You may obtain a copy of the GNU General Public License + * Version 2 or later at the following locations: + * + * http://www.opensource.org/licenses/gpl-license.html + * http://www.gnu.org/copyleft/gpl.html + */ +/* + * Implementation based on w1_ds2433.c + */ + +#include <linux/slab.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/device.h> +#include <linux/types.h> +#include <linux/delay.h> +#ifdef CONFIG_W1_F51_CRC +#include <linux/crc16.h> + +#define CRC16_INIT 0 +#define CRC16_VALID 0xb001 + +#endif + +#include "../w1.h" +#include "../w1_int.h" +#include "../w1_family.h" + +#define W1_EEPROM_SIZE 32 +#define W1_PAGE_SIZE 32 +#define W1_PAGE_BITS 5 +#define W1_PAGE_MASK 0x1F + +#define W1_F51_TIME 300 + +#define W1_F51_READ_EEPROM 0xB8 +#define W1_F51_WRITE_SCRATCH 0x6C +#define W1_F51_READ_SCRATCH 0x69 +#define W1_F51_COPY_SCRATCH 0x48 +#define W1_STATUS_OFFSET 0x0001 +#define W1_EEPROM_OFFSET 0x0007 +#define W1_SPECIAL_OFFSET 0x0008 +#define W1_EEPROM_BLOCK_0 0x0020 +#define W1_EEPROM_BLOCK_1 0x0030 +#define W1_SRAM 0x0080 +struct w1_f51_data { + u8 memory[W1_EEPROM_SIZE]; + u32 validcrc; +}; + +/** + * 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_f51_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; +} + +#ifdef CONFIG_W1_F51_CRC +static int w1_f51_refresh_block(struct w1_slave *sl, struct w1_f51_data *data, + int block) +{ + u8 wrbuf[3]; + int off = block * W1_PAGE_SIZE; + if (data->validcrc & (1 << block)) + return 0; + + if (w1_reset_select_slave(sl)) { + data->validcrc = 0; + return -EIO; + } + wrbuf[0] = W1_F51_READ_EEPROM; + wrbuf[1] = off & 0xff; + wrbuf[2] = off >> 8; + w1_write_block(sl->master, wrbuf, 3); + w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE); + + /* cache the block if the CRC is valid */ + if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID) + data->validcrc |= (1 << block); + + return 0; +} +#endif /* CONFIG_W1_F51_CRC */ + +static ssize_t w1_f51_read_bin(struct kobject *kobj, char *buf, loff_t off, + size_t count) +{ + struct w1_slave *sl = kobj_to_w1_slave(kobj); +#ifdef CONFIG_W1_F51_CRC + struct w1_f51_data *data = sl->family_data; + int i, min_page, max_page; +#else + u8 wrbuf[3]; +#endif + + count = w1_f51_fix_count(off, count, W1_EEPROM_SIZE) + if (count == 0) + return 0; + + mutex_lock(&sl->master->mutex); +#ifdef CONFIG_W1_F51_CRC + min_page = (off >> W1_PAGE_BITS); + max_page = (off + count - 1) >> W1_PAGE_BITS; + for (i = min_page; i <= max_page; i++) { + if (w1_f51_refresh_block(sl, data, i)) { + count = -EIO; + goto out_up; + } + } + memcpy(buf, &data->memory[off], count); + +#else /* CONFIG_W1_F51_CRC */ + + /* read directly from the EEPROM */ + if (w1_reset_select_slave(sl)) { + count = -EIO; + goto out_up; + } + off = (loff_t) W1_EEPROM_BLOCK_0; + wrbuf[0] = W1_F51_READ_EEPROM; + wrbuf[1] = off & 0xff; + wrbuf[2] = off >> 8; + w1_write_block(sl->master, wrbuf, 3); + if (w1_reset_select_slave(sl)) { + count = -EIO; + goto out_up; + } + + wrbuf[0] = W1_F51_READ_SCRATCH; + wrbuf[1] = off & 0xff; + wrbuf[2] = off >> 8; + w1_write_block(sl->master, wrbuf, 3); + w1_read_block(sl->master, buf, count); + +#endif /* CONFIG_W1_F51_CRC */ + + out_up: + mutex_unlock(&sl->master->mutex); + return count; +} + +/** + * Writes to the scratchpad and reads it back for verification. + * Then copies the scratchpad to EEPROM. + * The data must be on one page. + * The master must be locked. + * + * @param sl The slave structure + * @param addr Address for the write + * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK)) + * @param data The data to write + * @return 0=Success -1=failure + */ +static int w1_f51_write(struct w1_slave *sl, int addr, int len, const u8 * data) +{ + u8 wrbuf[4]; + u8 rdbuf[W1_EEPROM_SIZE + 3]; + u8 es = (addr + len - 1) & 0x1f; + /* Write the data to the scratchpad */ + if (w1_reset_select_slave(sl)) + return -1; + wrbuf[0] = W1_F51_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; + wrbuf[0] = W1_F51_READ_SCRATCH; + w1_write_block(sl->master, wrbuf, 3); + w1_read_block(sl->master, rdbuf, len + 3); + /* Compare what was read against the data written */ + if (memcmp(data, &rdbuf[0], len) != 0) { + printk("Error reading the scratch Pad\n"); + return -1; + } + /* Copy the scratchpad to EEPROM */ + if (w1_reset_select_slave(sl)) + return -1; + wrbuf[0] = W1_F51_COPY_SCRATCH; + wrbuf[3] = es; + w1_write_block(sl->master, wrbuf, 4); + /* Sleep for 5 ms to wait for the write to complete */ + msleep(5); + + /* Reset the bus to wake up the EEPROM (this may not be needed) */ + w1_reset_bus(sl->master); + + return 0; +} + +static ssize_t w1_f51_write_bin(struct kobject *kobj, char *buf, loff_t off, + size_t count) +{ + struct w1_slave *sl = kobj_to_w1_slave(kobj); + int addr; + + count = w1_f51_fix_count(off, count, W1_EEPROM_SIZE); + if (count == 0) + return 0; + off = (loff_t) 0x0020; +#ifdef CONFIG_W1_F51_CRC + /* can only write full blocks in cached mode */ + if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) { + dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n", + (int)off, count); + return -EINVAL; + } + + /* make sure the block CRCs are valid */ + for (idx = 0; idx < count; idx += W1_PAGE_SIZE) { + if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) { + dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off); + return -EINVAL; + } + } +#endif /* CONFIG_W1_F51_CRC */ + + mutex_lock(&sl->master->mutex); + + /* Can only write data to one page at a time */ + addr = off; + if (w1_f51_write(sl, addr, count, buf) < 0) { + count = -EIO; + goto out_up; + } + + out_up: + mutex_unlock(&sl->master->mutex); + + return count; +} + +static struct bin_attribute w1_f51_bin_attr = { + .attr = { + .name = "eeprom", + .mode = S_IRUGO | S_IWUSR, + .owner = THIS_MODULE, + }, + .size = W1_EEPROM_SIZE, + .read = w1_f51_read_bin, + .write = w1_f51_write_bin, +}; + +static int w1_f51_add_slave(struct w1_slave *sl) +{ + int err; +#ifdef CONFIG_W1_F51_CRC + struct w1_f51_data *data; + data = kmalloc(sizeof(struct w1_f51_data), GFP_KERNEL); + if (!data) + return -ENOMEM; + memset(data, 0, sizeof(struct w1_f51_data)); + sl->family_data = data; + +#endif /* CONFIG_W1_F51_CRC */ + + err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f51_bin_attr); + +#ifdef CONFIG_W1_F51_CRC + if (err) + kfree(data); +#endif /* CONFIG_W1_F51_CRC */ + + return err; +} + +static void w1_f51_remove_slave(struct w1_slave *sl) +{ +#ifdef CONFIG_W1_F51_CRC + kfree(sl->family_data); + sl->family_data = NULL; +#endif /* CONFIG_W1_F51_CRC */ + sysfs_remove_bin_file(&sl->dev.kobj, &w1_f51_bin_attr); +} + +static struct w1_family_ops w1_f51_fops = { + .add_slave = w1_f51_add_slave, + .remove_slave = w1_f51_remove_slave, +}; + +static struct w1_family w1_family_51 = { + .fid = W1_EEPROM_DS2751, + .fops = &w1_f51_fops, +}; + +static int __init w1_f51_init(void) +{ + return w1_register_family(&w1_family_51); +} + +static void __exit w1_f51_fini(void) +{ + w1_unregister_family(&w1_family_51); +} + +module_init(w1_f51_init); +module_exit(w1_f51_fini); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Freescale Semiconductors Inc"); +MODULE_DESCRIPTION + ("w1 family 51 driver for DS2751, Battery Level Sensing Device"); |