143 lines
3.9 KiB
C
143 lines
3.9 KiB
C
/*
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* mc24lc64t.c - driver for Microchip 24LC64T
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*
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* Copyright (C) 2017 Celestica Corp.
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*
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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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#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/i2c.h>
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#include <linux/mutex.h>
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#include <linux/types.h>
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#include <linux/delay.h>
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#include <linux/jiffies.h>
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struct mc24lc64t_data {
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struct i2c_client *fake_client;
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struct mutex update_lock;
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};
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static ssize_t mc24lc64t_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 = kobj_to_i2c_client(kobj);
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struct mc24lc64t_data *drvdata = i2c_get_clientdata(client);
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unsigned long timeout, read_time, i = 0;
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int status;
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mutex_lock(&drvdata->update_lock);
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if (i2c_smbus_write_byte_data(client, off>>8, off))
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{
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status = -EIO;
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goto exit;
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}
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msleep(1);
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begin:
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if (i < count)
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{
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timeout = jiffies + msecs_to_jiffies(25); /* 25 mS timeout*/
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do {
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read_time = jiffies;
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status = i2c_smbus_read_byte(client);
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if (status >= 0)
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{
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buf[i++] = status;
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goto begin;
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}
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} while (time_before(read_time, timeout));
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status = -ETIMEDOUT;
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goto exit;
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}
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status = count;
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exit:
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mutex_unlock(&drvdata->update_lock);
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return status;
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}
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static struct bin_attribute mc24lc64t_bit_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 = 65536,
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.read = mc24lc64t_read,
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};
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static int mc24lc64t_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct i2c_adapter *adapter = client->adapter;
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struct mc24lc64t_data *drvdata;
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int err;
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE_DATA
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| I2C_FUNC_SMBUS_READ_BYTE))
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return -EPFNOSUPPORT;
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if (!(drvdata = devm_kzalloc(&client->dev,
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sizeof(struct mc24lc64t_data), GFP_KERNEL)))
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return -ENOMEM;
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drvdata->fake_client = i2c_new_dummy_device(client->adapter, client->addr + 1);
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if (!drvdata->fake_client)
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return -ENOMEM;
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i2c_set_clientdata(client, drvdata);
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mutex_init(&drvdata->update_lock);
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err = sysfs_create_bin_file(&client->dev.kobj, &mc24lc64t_bit_attr);
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if (err)
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i2c_unregister_device(drvdata->fake_client);
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return err;
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}
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static int mc24lc64t_remove(struct i2c_client *client)
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{
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struct mc24lc64t_data *drvdata = i2c_get_clientdata(client);
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i2c_unregister_device(drvdata->fake_client);
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sysfs_remove_bin_file(&client->dev.kobj, &mc24lc64t_bit_attr);
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return 0;
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}
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static const struct i2c_device_id mc24lc64t_id[] = {
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{ "24lc64t", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, mc24lc64t_id);
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static struct i2c_driver mc24lc64t_driver = {
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.driver = {
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.name = "mc24lc64t",
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.owner = THIS_MODULE,
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},
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.probe = mc24lc64t_probe,
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.remove = mc24lc64t_remove,
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.id_table = mc24lc64t_id,
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};
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module_i2c_driver(mc24lc64t_driver);
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MODULE_AUTHOR("Abhisit Sangjan <asang@celestica.com>");
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MODULE_DESCRIPTION("Microchip 24LC64T Driver");
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MODULE_LICENSE("GPL");
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