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![Linus Torvalds](/assets/img/avatar_default.png)
Pull i2c updates from Wolfram Sang: "Features: - new drivers: Renesas EMEV2, register based MUX, NXP LPC2xxx - core: scans DT and assigns wakeup interrupts. no driver changes needed. - core: some refcouting issues fixed and better API for that - core: new helper function for best effort block read emulation - slave framework: proper DT bindings and userspace instantiation - some bigger work for xiic, pxa, omap drivers .. and quite a number of smaller driver fixes, cleanups, improvements" * 'i2c/for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (65 commits) i2c: mux: reg Change ioread endianness for readback i2c: mux: reg: fix compilation warnings i2c: mux: reg: simplify register size checking i2c: muxes: fix leaked i2c adapter device node references i2c: allow specifying separate wakeup interrupt in device tree of/irq: export of_get_irq_byname() i2c: xgene-slimpro: dma_mapping_error() doesn't return an error code i2c: Replace I2C_CROS_EC_TUNNEL dependency eeprom: at24: use i2c_smbus_read_i2c_block_data_or_emulated i2c: core: Add support for best effort block read emulation i2c: lpc2k: add driver i2c: mux: Add register-based mux i2c-mux-reg i2c: dt: describe generic bindings i2c: slave: print warning if slave flag not set i2c: support 10 bit and slave addresses in sysfs 'new_device' i2c: take address space into account when checking for used addresses i2c: apply DT flags when probing i2c: make address check indpendent from client struct i2c: rename address check functions i2c: apply address offset for slaves, too ...
209 lines
5.1 KiB
C
209 lines
5.1 KiB
C
/*
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* max6875.c - driver for MAX6874/MAX6875
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*
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* Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
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*
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* Based on eeprom.c
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*
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* The MAX6875 has a bank of registers and two banks of EEPROM.
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* Address ranges are defined as follows:
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* * 0x0000 - 0x0046 = configuration registers
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* * 0x8000 - 0x8046 = configuration EEPROM
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* * 0x8100 - 0x82FF = user EEPROM
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*
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* This driver makes the user EEPROM available for read.
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*
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* The registers & config EEPROM should be accessed via i2c-dev.
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*
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* The MAX6875 ignores the lowest address bit, so each chip responds to
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* two addresses - 0x50/0x51 and 0x52/0x53.
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*
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* Note that the MAX6875 uses i2c_smbus_write_byte_data() to set the read
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* address, so this driver is destructive if loaded for the wrong EEPROM chip.
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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; version 2 of the License.
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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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/* The MAX6875 can only read/write 16 bytes at a time */
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#define SLICE_SIZE 16
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#define SLICE_BITS 4
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/* USER EEPROM is at addresses 0x8100 - 0x82FF */
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#define USER_EEPROM_BASE 0x8100
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#define USER_EEPROM_SIZE 0x0200
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#define USER_EEPROM_SLICES 32
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/* MAX6875 commands */
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#define MAX6875_CMD_BLK_READ 0x84
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/* Each client has this additional data */
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struct max6875_data {
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struct i2c_client *fake_client;
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struct mutex update_lock;
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u32 valid;
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u8 data[USER_EEPROM_SIZE];
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unsigned long last_updated[USER_EEPROM_SLICES];
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};
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static void max6875_update_slice(struct i2c_client *client, int slice)
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{
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struct max6875_data *data = i2c_get_clientdata(client);
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int i, j, addr;
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u8 *buf;
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if (slice >= USER_EEPROM_SLICES)
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return;
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mutex_lock(&data->update_lock);
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buf = &data->data[slice << SLICE_BITS];
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if (!(data->valid & (1 << slice)) ||
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time_after(jiffies, data->last_updated[slice])) {
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dev_dbg(&client->dev, "Starting update of slice %u\n", slice);
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data->valid &= ~(1 << slice);
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addr = USER_EEPROM_BASE + (slice << SLICE_BITS);
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/* select the eeprom address */
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if (i2c_smbus_write_byte_data(client, addr >> 8, addr & 0xFF)) {
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dev_err(&client->dev, "address set failed\n");
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goto exit_up;
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}
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if (i2c_check_functionality(client->adapter,
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I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
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if (i2c_smbus_read_i2c_block_data(client,
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MAX6875_CMD_BLK_READ,
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SLICE_SIZE,
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buf) != SLICE_SIZE) {
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goto exit_up;
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}
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} else {
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for (i = 0; i < SLICE_SIZE; i++) {
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j = i2c_smbus_read_byte(client);
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if (j < 0) {
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goto exit_up;
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}
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buf[i] = j;
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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_up:
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mutex_unlock(&data->update_lock);
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}
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static ssize_t max6875_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 max6875_data *data = i2c_get_clientdata(client);
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int slice, max_slice;
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/* refresh slices which contain requested bytes */
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max_slice = (off + count - 1) >> SLICE_BITS;
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for (slice = (off >> SLICE_BITS); slice <= max_slice; slice++)
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max6875_update_slice(client, slice);
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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 user_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 = USER_EEPROM_SIZE,
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.read = max6875_read,
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};
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static int max6875_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 max6875_data *data;
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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 -ENODEV;
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/* Only bind to even addresses */
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if (client->addr & 1)
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return -ENODEV;
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if (!(data = kzalloc(sizeof(struct max6875_data), GFP_KERNEL)))
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return -ENOMEM;
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/* A fake client is created on the odd address */
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data->fake_client = i2c_new_dummy(client->adapter, client->addr + 1);
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if (!data->fake_client) {
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err = -ENOMEM;
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goto exit_kfree;
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}
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/* Init real i2c_client */
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i2c_set_clientdata(client, data);
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mutex_init(&data->update_lock);
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err = sysfs_create_bin_file(&client->dev.kobj, &user_eeprom_attr);
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if (err)
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goto exit_remove_fake;
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return 0;
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exit_remove_fake:
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i2c_unregister_device(data->fake_client);
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exit_kfree:
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kfree(data);
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return err;
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}
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static int max6875_remove(struct i2c_client *client)
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{
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struct max6875_data *data = i2c_get_clientdata(client);
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i2c_unregister_device(data->fake_client);
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sysfs_remove_bin_file(&client->dev.kobj, &user_eeprom_attr);
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kfree(data);
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return 0;
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}
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static const struct i2c_device_id max6875_id[] = {
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{ "max6875", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, max6875_id);
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static struct i2c_driver max6875_driver = {
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.driver = {
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.name = "max6875",
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},
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.probe = max6875_probe,
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.remove = max6875_remove,
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.id_table = max6875_id,
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};
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module_i2c_driver(max6875_driver);
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MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
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MODULE_DESCRIPTION("MAX6875 driver");
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MODULE_LICENSE("GPL");
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