diff options
Diffstat (limited to 'drivers/i2c/chips/max6875.c')
| -rw-r--r-- | drivers/i2c/chips/max6875.c | 462 |
1 files changed, 122 insertions, 340 deletions
diff --git a/drivers/i2c/chips/max6875.c b/drivers/i2c/chips/max6875.c index 0230375f72e5..9e1aeb69abf9 100644 --- a/drivers/i2c/chips/max6875.c +++ b/drivers/i2c/chips/max6875.c @@ -5,97 +5,60 @@ Based on i2c/chips/eeprom.c - The MAX6875 has two EEPROM sections: config and user. - At reset, the config EEPROM is read into the registers. + The MAX6875 has a bank of registers and two banks of EEPROM. + Address ranges are defined as follows: + * 0x0000 - 0x0046 = configuration registers + * 0x8000 - 0x8046 = configuration EEPROM + * 0x8100 - 0x82FF = user EEPROM - This driver make 3 binary files available in sysfs: - reg_config - direct access to the registers - eeprom_config - acesses configuration eeprom space - eeprom_user - free for application use + This driver makes the user EEPROM available for read. - In our application, we put device serial & model numbers in user eeprom. + The registers & config EEPROM should be accessed via i2c-dev. - Notes: - 1) The datasheet says that register 0x44 / EEPROM 0x8044 should NOT - be overwritten, so the driver explicitly prevents that. - 2) It's a good idea to keep the config (0x45) locked in config EEPROM. - You can temporarily enable config writes by changing register 0x45. + The MAX6875 ignores the lowest address bit, so each chip responds to + two addresses - 0x50/0x51 and 0x52/0x53. + + Note that the MAX6875 uses i2c_smbus_write_byte_data() to set the read + address, so this driver is destructive if loaded for the wrong EEPROM chip. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. */ -#include <linux/config.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/module.h> #include <linux/slab.h> -#include <linux/sched.h> -#include <linux/delay.h> #include <linux/i2c.h> -#include <linux/i2c-sensor.h> +#include <asm/semaphore.h> -/* Addresses to scan */ -/* No address scanned by default, as this could corrupt standard EEPROMS. */ +/* Do not scan - the MAX6875 access method will write to some EEPROM chips */ static unsigned short normal_i2c[] = {I2C_CLIENT_END}; -static unsigned int normal_isa[] = {I2C_CLIENT_ISA_END}; /* Insmod parameters */ -SENSORS_INSMOD_1(max6875); - -/* this param will prevent 'accidental' writes to the eeprom */ -static int allow_write = 0; -module_param(allow_write, int, 0); -MODULE_PARM_DESC(allow_write, - "Enable write access:\n" - "*0: Read only\n" - " 1: Read/Write access"); +I2C_CLIENT_INSMOD_1(max6875); /* The MAX6875 can only read/write 16 bytes at a time */ #define SLICE_SIZE 16 #define SLICE_BITS 4 -/* CONFIG EEPROM is at addresses 0x8000 - 0x8045, registers are at 0 - 0x45 */ -#define CONFIG_EEPROM_BASE 0x8000 -#define CONFIG_EEPROM_SIZE 0x0046 -#define CONFIG_EEPROM_SLICES 5 - /* USER EEPROM is at addresses 0x8100 - 0x82FF */ #define USER_EEPROM_BASE 0x8100 #define USER_EEPROM_SIZE 0x0200 #define USER_EEPROM_SLICES 32 /* MAX6875 commands */ -#define MAX6875_CMD_BLOCK_WRITE 0x83 -#define MAX6875_CMD_BLOCK_READ 0x84 -#define MAX6875_CMD_REBOOT 0x88 - -enum max6875_area_type { - max6875_register_config=0, - max6875_eeprom_config, - max6875_eeprom_user, - max6857_max -}; - -struct eeprom_block { - enum max6875_area_type type; - u8 slices; - u32 size; - u32 valid; - u32 base; - unsigned long *updated; - u8 *data; -}; +#define MAX6875_CMD_BLK_READ 0x84 /* Each client has this additional data */ struct max6875_data { struct i2c_client client; struct semaphore update_lock; - struct eeprom_block blocks[max6857_max]; - /* the above structs point into the arrays below */ - u8 data[USER_EEPROM_SIZE + (CONFIG_EEPROM_SIZE*2)]; - unsigned long last_updated[USER_EEPROM_SLICES + (CONFIG_EEPROM_SLICES*2)]; + + u32 valid; + u8 data[USER_EEPROM_SIZE]; + unsigned long last_updated[USER_EEPROM_SLICES]; }; static int max6875_attach_adapter(struct i2c_adapter *adapter); @@ -111,337 +74,160 @@ static struct i2c_driver max6875_driver = { .detach_client = max6875_detach_client, }; -static int max6875_update_slice(struct i2c_client *client, - struct eeprom_block *blk, - int slice) +static void max6875_update_slice(struct i2c_client *client, int slice) { struct max6875_data *data = i2c_get_clientdata(client); - int i, j, addr, count; - u8 rdbuf[SLICE_SIZE]; - int retval = 0; + int i, j, addr; + u8 *buf; - if (slice >= blk->slices) - return -1; + if (slice >= USER_EEPROM_SLICES) + return; down(&data->update_lock); - if (!(blk->valid & (1 << slice)) || - (jiffies - blk->updated[slice] > 300 * HZ) || - (jiffies < blk->updated[slice])) { - dev_dbg(&client->dev, "Starting eeprom update, slice %u, base %u\n", - slice, blk->base); + buf = &data->data[slice << SLICE_BITS]; - addr = blk->base + (slice << SLICE_BITS); - count = blk->size - (slice << SLICE_BITS); - if (count > SLICE_SIZE) { - count = SLICE_SIZE; - } + if (!(data->valid & (1 << slice)) || + time_after(jiffies, data->last_updated[slice])) { - /* Preset the read address */ - if (addr < 0x100) { - /* select the register */ - if (i2c_smbus_write_byte(client, addr & 0xFF)) { - dev_dbg(&client->dev, "max6875 register select has failed!\n"); - retval = -1; - goto exit; - } - } else { - /* select the eeprom */ - if (i2c_smbus_write_byte_data(client, addr >> 8, addr & 0xFF)) { - dev_dbg(&client->dev, "max6875 address set has failed!\n"); - retval = -1; - goto exit; - } + dev_dbg(&client->dev, "Starting update of slice %u\n", slice); + + data->valid &= ~(1 << slice); + + addr = USER_EEPROM_BASE + (slice << SLICE_BITS); + + /* select the eeprom address */ + if (i2c_smbus_write_byte_data(client, addr >> 8, addr & 0xFF)) { + dev_err(&client->dev, "address set failed\n"); + goto exit_up; } - if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) { - if (i2c_smbus_read_i2c_block_data(client, MAX6875_CMD_BLOCK_READ, - rdbuf) != SLICE_SIZE) - { - retval = -1; - goto exit; + if (i2c_check_functionality(client->adapter, + I2C_FUNC_SMBUS_READ_I2C_BLOCK)) { + if (i2c_smbus_read_i2c_block_data(client, + MAX6875_CMD_BLK_READ, + buf) != SLICE_SIZE) { + goto exit_up; } - - memcpy(&blk->data[slice << SLICE_BITS], rdbuf, count); } else { - for (i = 0; i < count; i++) { + for (i = 0; i < SLICE_SIZE; i++) { j = i2c_smbus_read_byte(client); - if (j < 0) - { - retval = -1; - goto exit; + if (j < 0) { + goto exit_up; } - blk->data[(slice << SLICE_BITS) + i] = (u8) j; + buf[i] = j; } } - blk->updated[slice] = jiffies; - blk->valid |= (1 << slice); + data->last_updated[slice] = jiffies; + data->valid |= (1 << slice); } - exit: +exit_up: up(&data->update_lock); - return retval; } -static ssize_t max6875_read(struct kobject *kobj, char *buf, loff_t off, size_t count, - enum max6875_area_type area_type) +static ssize_t max6875_read(struct kobject *kobj, char *buf, loff_t off, + size_t count) { - struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj)); + struct i2c_client *client = kobj_to_i2c_client(kobj); struct max6875_data *data = i2c_get_clientdata(client); - struct eeprom_block *blk; - int slice; - - blk = &data->blocks[area_type]; + int slice, max_slice; - if (off > blk->size) + if (off > USER_EEPROM_SIZE) return 0; - if (off + count > blk->size) - count = blk->size - off; - /* Only refresh slices which contain requested bytes */ - for (slice = (off >> SLICE_BITS); slice <= ((off + count - 1) >> SLICE_BITS); slice++) - max6875_update_slice(client, blk, slice); + if (off + count > USER_EEPROM_SIZE) + count = USER_EEPROM_SIZE - off; - memcpy(buf, &blk->data[off], count); + /* refresh slices which contain requested bytes */ + max_slice = (off + count - 1) >> SLICE_BITS; + for (slice = (off >> SLICE_BITS); slice <= max_slice; slice++) + max6875_update_slice(client, slice); - return count; -} - -static ssize_t max6875_user_read(struct kobject *kobj, char *buf, loff_t off, size_t count) -{ - return max6875_read(kobj, buf, off, count, max6875_eeprom_user); -} - -static ssize_t max6875_config_read(struct kobject *kobj, char *buf, loff_t off, size_t count) -{ - return max6875_read(kobj, buf, off, count, max6875_eeprom_config); -} - -static ssize_t max6875_cfgreg_read(struct kobject *kobj, char *buf, loff_t off, size_t count) -{ - return max6875_read(kobj, buf, off, count, max6875_register_config); -} - - -static ssize_t max6875_write(struct kobject *kobj, char *buf, loff_t off, size_t count, - enum max6875_area_type area_type) -{ - struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj)); - struct max6875_data *data = i2c_get_clientdata(client); - struct eeprom_block *blk; - int slice, addr, retval; - ssize_t sent = 0; - - blk = &data->blocks[area_type]; - - if (off > blk->size) - return 0; - if ((off + count) > blk->size) - count = blk->size - off; - - if (down_interruptible(&data->update_lock)) - return -EAGAIN; - - /* writing to a register is done with i2c_smbus_write_byte_data() */ - if (blk->type == max6875_register_config) { - for (sent = 0; sent < count; sent++) { - addr = off + sent; - if (addr == 0x44) - continue; - - retval = i2c_smbus_write_byte_data(client, addr, buf[sent]); - } - } else { - int cmd, val; - - /* We are writing to EEPROM */ - for (sent = 0; sent < count; sent++) { - addr = blk->base + off + sent; - cmd = addr >> 8; - val = (addr & 0xff) | (buf[sent] << 8); // reversed - - if (addr == 0x8044) - continue; - - retval = i2c_smbus_write_word_data(client, cmd, val); - - if (retval) { - goto error_exit; - } + memcpy(buf, &data->data[off], count); - /* A write takes up to 11 ms */ - msleep(11); - } - } - - /* Invalidate the scratch buffer */ - for (slice = (off >> SLICE_BITS); slice <= ((off + count - 1) >> SLICE_BITS); slice++) - blk->valid &= ~(1 << slice); - - error_exit: - up(&data->update_lock); - - return sent; -} - -static ssize_t max6875_user_write(struct kobject *kobj, char *buf, loff_t off, size_t count) -{ - return max6875_write(kobj, buf, off, count, max6875_eeprom_user); -} - -static ssize_t max6875_config_write(struct kobject *kobj, char *buf, loff_t off, size_t count) -{ - return max6875_write(kobj, buf, off, count, max6875_eeprom_config); -} - -static ssize_t max6875_cfgreg_write(struct kobject *kobj, char *buf, loff_t off, size_t count) -{ - return max6875_write(kobj, buf, off, count, max6875_register_config); + return count; } static struct bin_attribute user_eeprom_attr = { .attr = { - .name = "eeprom_user", - .mode = S_IRUGO | S_IWUSR | S_IWGRP, - .owner = THIS_MODULE, - }, - .size = USER_EEPROM_SIZE, - .read = max6875_user_read, - .write = max6875_user_write, -}; - -static struct bin_attribute config_eeprom_attr = { - .attr = { - .name = "eeprom_config", - .mode = S_IRUGO | S_IWUSR, - .owner = THIS_MODULE, - }, - .size = CONFIG_EEPROM_SIZE, - .read = max6875_config_read, - .write = max6875_config_write, -}; - -static struct bin_attribute config_register_attr = { - .attr = { - .name = "reg_config", - .mode = S_IRUGO | S_IWUSR, + .name = "eeprom", + .mode = S_IRUGO, .owner = THIS_MODULE, }, - .size = CONFIG_EEPROM_SIZE, - .read = max6875_cfgreg_read, - .write = max6875_cfgreg_write, + .size = USER_EEPROM_SIZE, + .read = max6875_read, }; static int max6875_attach_adapter(struct i2c_adapter *adapter) { - return i2c_detect(adapter, &addr_data, max6875_detect); + return i2c_probe(adapter, &addr_data, max6875_detect); } -/* This function is called by i2c_detect */ +/* This function is called by i2c_probe */ static int max6875_detect(struct i2c_adapter *adapter, int address, int kind) { - struct i2c_client *new_client; + struct i2c_client *real_client; + struct i2c_client *fake_client; struct max6875_data *data; int err = 0; - /* Prevent 24RF08 corruption (in case of user error) */ - if (kind < 0) - i2c_smbus_xfer(adapter, address, 0, 0, 0, - I2C_SMBUS_QUICK, NULL); - - /* There are three ways we can read the EEPROM data: - (1) I2C block reads (faster, but unsupported by most adapters) - (2) Consecutive byte reads (100% overhead) - (3) Regular byte data reads (200% overhead) - The third method is not implemented by this driver because all - known adapters support at least the second. */ - if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA | - I2C_FUNC_SMBUS_BYTE | - I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) - goto exit; - - /* OK. For now, we presume we have a valid client. We now create the - client structure, even though we cannot fill it completely yet. - But it allows us to access eeprom_{read,write}_value. */ - if (!(data = kmalloc(sizeof(struct max6875_data), GFP_KERNEL))) { - err = -ENOMEM; - goto exit; - } + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE_DATA + | I2C_FUNC_SMBUS_READ_BYTE)) + return 0; + + /* Only check even addresses */ + if (address & 1) + return 0; + + if (!(data = kmalloc(sizeof(struct max6875_data), GFP_KERNEL))) + return -ENOMEM; memset(data, 0, sizeof(struct max6875_data)); - new_client = &data->client; - i2c_set_clientdata(new_client, data); - new_client->addr = address; - new_client->adapter = adapter; - new_client->driver = &max6875_driver; - new_client->flags = 0; - - /* Setup the user section */ - data->blocks[max6875_eeprom_user].type = max6875_eeprom_user; - data->blocks[max6875_eeprom_user].slices = USER_EEPROM_SLICES; - data->blocks[max6875_eeprom_user].size = USER_EEPROM_SIZE; - data->blocks[max6875_eeprom_user].base = USER_EEPROM_BASE; - data->blocks[max6875_eeprom_user].data = data->data; - data->blocks[max6875_eeprom_user].updated = data->last_updated; - - /* Setup the config section */ - data->blocks[max6875_eeprom_config].type = max6875_eeprom_config; - data->blocks[max6875_eeprom_config].slices = CONFIG_EEPROM_SLICES; - data->blocks[max6875_eeprom_config].size = CONFIG_EEPROM_SIZE; - data->blocks[max6875_eeprom_config].base = CONFIG_EEPROM_BASE; - data->blocks[max6875_eeprom_config].data = &data->data[USER_EEPROM_SIZE]; - data->blocks[max6875_eeprom_config].updated = &data->last_updated[USER_EEPROM_SLICES]; - - /* Setup the register section */ - data->blocks[max6875_register_config].type = max6875_register_config; - data->blocks[max6875_register_config].slices = CONFIG_EEPROM_SLICES; - data->blocks[max6875_register_config].size = CONFIG_EEPROM_SIZE; - data->blocks[max6875_register_config].base = 0; - data->blocks[max6875_register_config].data = &data->data[USER_EEPROM_SIZE+CONFIG_EEPROM_SIZE]; - data->blocks[max6875_register_config].updated = &data->last_updated[USER_EEPROM_SLICES+CONFIG_EEPROM_SLICES]; - - /* Init the data */ - memset(data->data, 0xff, sizeof(data->data)); - - /* Fill in the remaining client fields */ - strlcpy(new_client->name, "max6875", I2C_NAME_SIZE); + /* A fake client is created on the odd address */ + if (!(fake_client = kmalloc(sizeof(struct i2c_client), GFP_KERNEL))) { + err = -ENOMEM; + goto exit_kfree1; + } + memset(fake_client, 0, sizeof(struct i2c_client)); + + /* Init real i2c_client */ + real_client = &data->client; + i2c_set_clientdata(real_client, data); + real_client->addr = address; + real_client->adapter = adapter; + real_client->driver = &max6875_driver; + real_client->flags = 0; + strlcpy(real_client->name, "max6875", I2C_NAME_SIZE); init_MUTEX(&data->update_lock); - /* Verify that the chip is really what we think it is */ - if ((max6875_update_slice(new_client, &data->blocks[max6875_eeprom_config], 4) < 0) || - (max6875_update_slice(new_client, &data->blocks[max6875_register_config], 4) < 0)) - goto exit_kfree; - - /* 0x41,0x42 must be zero and 0x40 must match in eeprom and registers */ - if ((data->blocks[max6875_eeprom_config].data[0x41] != 0) || - (data->blocks[max6875_eeprom_config].data[0x42] != 0) || - (data->blocks[max6875_register_config].data[0x41] != 0) || - (data->blocks[max6875_register_config].data[0x42] != 0) || - (data->blocks[max6875_eeprom_config].data[0x40] != - data->blocks[max6875_register_config].data[0x40])) - goto exit_kfree; - - /* Tell the I2C layer a new client has arrived */ - if ((err = i2c_attach_client(new_client))) - goto exit_kfree; - - /* create the sysfs eeprom files with the correct permissions */ - if (allow_write == 0) { - user_eeprom_attr.attr.mode &= ~S_IWUGO; - user_eeprom_attr.write = NULL; - config_eeprom_attr.attr.mode &= ~S_IWUGO; - config_eeprom_attr.write = NULL; - config_register_attr.attr.mode &= ~S_IWUGO; - config_register_attr.write = NULL; - } - sysfs_create_bin_file(&new_client->dev.kobj, &user_eeprom_attr); - sysfs_create_bin_file(&new_client->dev.kobj, &config_eeprom_attr); - sysfs_create_bin_file(&new_client->dev.kobj, &config_register_attr); + /* Init fake client data */ + /* set the client data to the i2c_client so that it will get freed */ + i2c_set_clientdata(fake_client, fake_client); + fake_client->addr = address | 1; + fake_client->adapter = adapter; + fake_client->driver = &max6875_driver; + fake_client->flags = 0; + strlcpy(fake_client->name, "max6875 subclient", I2C_NAME_SIZE); + + /* Prevent 24RF08 corruption (in case of user error) */ + i2c_smbus_write_quick(real_client, 0); + + if ((err = i2c_attach_client(real_client)) != 0) + goto exit_kfree2; + + if ((err = i2c_attach_client(fake_client)) != 0) + goto exit_detach; + + sysfs_create_bin_file(&real_client->dev.kobj, &user_eeprom_attr); return 0; -exit_kfree: +exit_detach: + i2c_detach_client(real_client); +exit_kfree2: + kfree(fake_client); +exit_kfree1: kfree(data); -exit: return err; } @@ -450,13 +236,9 @@ static int max6875_detach_client(struct i2c_client *client) int err; err = i2c_detach_client(client); - if (err) { - dev_err(&client->dev, "Client deregistration failed, client not detached.\n"); + if (err) return err; - } - kfree(i2c_get_clientdata(client)); - return 0; } |