181 lines
4.1 KiB
C
181 lines
4.1 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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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/slab.h>
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#include <linux/delay.h>
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#include <linux/jiffies.h>
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#include <linux/i2c.h>
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#include <linux/mutex.h>
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/* Size of EEPROM in bytes */
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#define EEPROM_SIZE 256
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#define SLICE_BITS (6)
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#define SLICE_SIZE (1 << SLICE_BITS)
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#define SLICE_NUM (EEPROM_SIZE/SLICE_SIZE)
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/* Each client has this additional data */
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struct eeprom_data {
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struct mutex update_lock;
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u8 valid; /* bitfield, bit!=0 if slice is valid */
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unsigned long last_updated[SLICE_NUM]; /* In jiffies, 8 slices */
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u8 data[EEPROM_SIZE]; /* Register values */
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};
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static void inv_eeprom_update_client(struct i2c_client *client, u8 slice)
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{
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struct eeprom_data *data = i2c_get_clientdata(client);
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int i, j;
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int ret;
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int addr;
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mutex_lock(&data->update_lock);
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if (!(data->valid & (1 << slice)) ||
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time_after(jiffies, data->last_updated[slice] + 300 * HZ)) {
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dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
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addr = slice << SLICE_BITS;
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ret = i2c_smbus_write_byte_data(client, ((u8)addr >> 8) & 0xFF, (u8)addr & 0xFF);
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/* select the eeprom address */
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if (ret < 0) {
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dev_err(&client->dev, "address set failed\n");
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goto exit;
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}
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE)) {
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goto exit;
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}
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for (i = slice << SLICE_BITS; i < (slice + 1) << SLICE_BITS; i+= SLICE_SIZE) {
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for (j = i; j < (i+SLICE_SIZE); j++) {
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int res;
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res = i2c_smbus_read_byte(client);
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if (res < 0) {
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goto exit;
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}
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data->data[j] = res & 0xFF;
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}
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}
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data->last_updated[slice] = jiffies;
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data->valid |= (1 << slice);
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}
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exit:
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mutex_unlock(&data->update_lock);
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}
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static ssize_t inv_eeprom_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr,
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char *buf, loff_t off, size_t count)
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{
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struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj));
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struct eeprom_data *data = i2c_get_clientdata(client);
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u8 slice;
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if (off > EEPROM_SIZE) {
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return 0;
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}
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if (off + count > EEPROM_SIZE) {
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count = EEPROM_SIZE - off;
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}
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if (count == 0) {
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return 0;
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}
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/* Only refresh slices which contain requested bytes */
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for (slice = off >> SLICE_BITS; slice <= (off + count - 1) >> SLICE_BITS; slice++) {
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inv_eeprom_update_client(client, slice);
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}
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memcpy(buf, &data->data[off], count);
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return count;
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}
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static struct bin_attribute inv_eeprom_attr = {
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.attr = {
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.name = "eeprom",
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.mode = S_IRUGO,
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},
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.size = EEPROM_SIZE,
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.read = inv_eeprom_read,
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};
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static int inv_eeprom_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct eeprom_data *data;
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int err;
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if (!(data = kzalloc(sizeof(struct eeprom_data), GFP_KERNEL))) {
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err = -ENOMEM;
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goto exit;
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}
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memset(data->data, 0xff, EEPROM_SIZE);
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i2c_set_clientdata(client, data);
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mutex_init(&data->update_lock);
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/* create the sysfs eeprom file */
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err = sysfs_create_bin_file(&client->dev.kobj, &inv_eeprom_attr);
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if (err) {
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goto exit_kfree;
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}
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return 0;
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exit_kfree:
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kfree(data);
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exit:
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return err;
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}
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static int inv_eeprom_remove(struct i2c_client *client)
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{
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sysfs_remove_bin_file(&client->dev.kobj, &inv_eeprom_attr);
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kfree(i2c_get_clientdata(client));
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return 0;
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}
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static const struct i2c_device_id inv_eeprom_id[] = {
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{ "inv_eeprom", 0 },
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{ }
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};
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static struct i2c_driver inv_eeprom_driver = {
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.driver = {
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.name = "inv_eeprom",
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},
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.probe = inv_eeprom_probe,
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.remove = inv_eeprom_remove,
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.id_table = inv_eeprom_id,
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};
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module_i2c_driver(inv_eeprom_driver);
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MODULE_AUTHOR("Inventec");
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MODULE_DESCRIPTION("Inventec D6556 Mother Board EEPROM driver");
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MODULE_LICENSE("GPL");
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