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![Wolfram Sang](/assets/img/avatar_default.png)
I request this for drivers, so the core should adhere to sorted includes as well. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
421 lines
10 KiB
C
421 lines
10 KiB
C
/*
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i2c-stub.c - I2C/SMBus chip emulator
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Copyright (c) 2004 Mark M. Hoffman <mhoffman@lightlink.com>
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Copyright (C) 2007-2014 Jean Delvare <jdelvare@suse.de>
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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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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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#define DEBUG 1
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#include <linux/errno.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#define MAX_CHIPS 10
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/*
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* Support for I2C_FUNC_SMBUS_BLOCK_DATA is disabled by default and must
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* be enabled explicitly by setting the I2C_FUNC_SMBUS_BLOCK_DATA bits
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* in the 'functionality' module parameter.
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*/
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#define STUB_FUNC_DEFAULT \
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(I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | \
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I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | \
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I2C_FUNC_SMBUS_I2C_BLOCK)
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#define STUB_FUNC_ALL \
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(STUB_FUNC_DEFAULT | I2C_FUNC_SMBUS_BLOCK_DATA)
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static unsigned short chip_addr[MAX_CHIPS];
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module_param_array(chip_addr, ushort, NULL, S_IRUGO);
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MODULE_PARM_DESC(chip_addr,
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"Chip addresses (up to 10, between 0x03 and 0x77)");
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static unsigned long functionality = STUB_FUNC_DEFAULT;
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module_param(functionality, ulong, S_IRUGO | S_IWUSR);
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MODULE_PARM_DESC(functionality, "Override functionality bitfield");
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/* Some chips have banked register ranges */
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static u8 bank_reg[MAX_CHIPS];
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module_param_array(bank_reg, byte, NULL, S_IRUGO);
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MODULE_PARM_DESC(bank_reg, "Bank register");
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static u8 bank_mask[MAX_CHIPS];
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module_param_array(bank_mask, byte, NULL, S_IRUGO);
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MODULE_PARM_DESC(bank_mask, "Bank value mask");
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static u8 bank_start[MAX_CHIPS];
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module_param_array(bank_start, byte, NULL, S_IRUGO);
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MODULE_PARM_DESC(bank_start, "First banked register");
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static u8 bank_end[MAX_CHIPS];
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module_param_array(bank_end, byte, NULL, S_IRUGO);
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MODULE_PARM_DESC(bank_end, "Last banked register");
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struct smbus_block_data {
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struct list_head node;
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u8 command;
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u8 len;
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u8 block[I2C_SMBUS_BLOCK_MAX];
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};
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struct stub_chip {
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u8 pointer;
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u16 words[256]; /* Byte operations use the LSB as per SMBus
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specification */
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struct list_head smbus_blocks;
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/* For chips with banks, extra registers are allocated dynamically */
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u8 bank_reg;
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u8 bank_shift;
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u8 bank_mask;
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u8 bank_sel; /* Currently selected bank */
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u8 bank_start;
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u8 bank_end;
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u16 bank_size;
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u16 *bank_words; /* Room for bank_mask * bank_size registers */
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};
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static struct stub_chip *stub_chips;
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static int stub_chips_nr;
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static struct smbus_block_data *stub_find_block(struct device *dev,
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struct stub_chip *chip,
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u8 command, bool create)
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{
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struct smbus_block_data *b, *rb = NULL;
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list_for_each_entry(b, &chip->smbus_blocks, node) {
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if (b->command == command) {
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rb = b;
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break;
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}
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}
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if (rb == NULL && create) {
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rb = devm_kzalloc(dev, sizeof(*rb), GFP_KERNEL);
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if (rb == NULL)
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return rb;
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rb->command = command;
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list_add(&rb->node, &chip->smbus_blocks);
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}
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return rb;
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}
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static u16 *stub_get_wordp(struct stub_chip *chip, u8 offset)
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{
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if (chip->bank_sel &&
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offset >= chip->bank_start && offset <= chip->bank_end)
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return chip->bank_words +
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(chip->bank_sel - 1) * chip->bank_size +
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offset - chip->bank_start;
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else
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return chip->words + offset;
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}
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/* Return negative errno on error. */
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static s32 stub_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
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char read_write, u8 command, int size, union i2c_smbus_data *data)
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{
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s32 ret;
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int i, len;
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struct stub_chip *chip = NULL;
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struct smbus_block_data *b;
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u16 *wordp;
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/* Search for the right chip */
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for (i = 0; i < stub_chips_nr; i++) {
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if (addr == chip_addr[i]) {
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chip = stub_chips + i;
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break;
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}
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}
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if (!chip)
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return -ENODEV;
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switch (size) {
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case I2C_SMBUS_QUICK:
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dev_dbg(&adap->dev, "smbus quick - addr 0x%02x\n", addr);
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ret = 0;
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break;
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case I2C_SMBUS_BYTE:
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if (read_write == I2C_SMBUS_WRITE) {
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chip->pointer = command;
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dev_dbg(&adap->dev,
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"smbus byte - addr 0x%02x, wrote 0x%02x.\n",
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addr, command);
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} else {
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wordp = stub_get_wordp(chip, chip->pointer++);
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data->byte = *wordp & 0xff;
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dev_dbg(&adap->dev,
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"smbus byte - addr 0x%02x, read 0x%02x.\n",
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addr, data->byte);
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}
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ret = 0;
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break;
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case I2C_SMBUS_BYTE_DATA:
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wordp = stub_get_wordp(chip, command);
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if (read_write == I2C_SMBUS_WRITE) {
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*wordp &= 0xff00;
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*wordp |= data->byte;
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dev_dbg(&adap->dev,
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"smbus byte data - addr 0x%02x, wrote 0x%02x at 0x%02x.\n",
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addr, data->byte, command);
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/* Set the bank as needed */
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if (chip->bank_words && command == chip->bank_reg) {
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chip->bank_sel =
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(data->byte >> chip->bank_shift)
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& chip->bank_mask;
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dev_dbg(&adap->dev,
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"switching to bank %u.\n",
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chip->bank_sel);
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}
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} else {
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data->byte = *wordp & 0xff;
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dev_dbg(&adap->dev,
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"smbus byte data - addr 0x%02x, read 0x%02x at 0x%02x.\n",
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addr, data->byte, command);
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}
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chip->pointer = command + 1;
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ret = 0;
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break;
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case I2C_SMBUS_WORD_DATA:
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wordp = stub_get_wordp(chip, command);
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if (read_write == I2C_SMBUS_WRITE) {
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*wordp = data->word;
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dev_dbg(&adap->dev,
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"smbus word data - addr 0x%02x, wrote 0x%04x at 0x%02x.\n",
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addr, data->word, command);
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} else {
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data->word = *wordp;
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dev_dbg(&adap->dev,
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"smbus word data - addr 0x%02x, read 0x%04x at 0x%02x.\n",
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addr, data->word, command);
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}
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ret = 0;
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break;
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case I2C_SMBUS_I2C_BLOCK_DATA:
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/*
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* We ignore banks here, because banked chips don't use I2C
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* block transfers
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*/
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if (data->block[0] > 256 - command) /* Avoid overrun */
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data->block[0] = 256 - command;
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len = data->block[0];
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if (read_write == I2C_SMBUS_WRITE) {
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for (i = 0; i < len; i++) {
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chip->words[command + i] &= 0xff00;
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chip->words[command + i] |= data->block[1 + i];
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}
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dev_dbg(&adap->dev,
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"i2c block data - addr 0x%02x, wrote %d bytes at 0x%02x.\n",
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addr, len, command);
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} else {
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for (i = 0; i < len; i++) {
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data->block[1 + i] =
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chip->words[command + i] & 0xff;
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}
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dev_dbg(&adap->dev,
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"i2c block data - addr 0x%02x, read %d bytes at 0x%02x.\n",
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addr, len, command);
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}
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ret = 0;
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break;
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case I2C_SMBUS_BLOCK_DATA:
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/*
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* We ignore banks here, because chips typically don't use both
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* banks and SMBus block transfers
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*/
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b = stub_find_block(&adap->dev, chip, command, false);
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if (read_write == I2C_SMBUS_WRITE) {
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len = data->block[0];
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if (len == 0 || len > I2C_SMBUS_BLOCK_MAX) {
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ret = -EINVAL;
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break;
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}
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if (b == NULL) {
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b = stub_find_block(&adap->dev, chip, command,
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true);
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if (b == NULL) {
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ret = -ENOMEM;
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break;
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}
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}
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/* Largest write sets read block length */
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if (len > b->len)
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b->len = len;
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for (i = 0; i < len; i++)
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b->block[i] = data->block[i + 1];
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/* update for byte and word commands */
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chip->words[command] = (b->block[0] << 8) | b->len;
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dev_dbg(&adap->dev,
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"smbus block data - addr 0x%02x, wrote %d bytes at 0x%02x.\n",
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addr, len, command);
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} else {
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if (b == NULL) {
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dev_dbg(&adap->dev,
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"SMBus block read command without prior block write not supported\n");
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ret = -EOPNOTSUPP;
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break;
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}
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len = b->len;
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data->block[0] = len;
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for (i = 0; i < len; i++)
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data->block[i + 1] = b->block[i];
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dev_dbg(&adap->dev,
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"smbus block data - addr 0x%02x, read %d bytes at 0x%02x.\n",
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addr, len, command);
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}
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ret = 0;
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break;
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default:
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dev_dbg(&adap->dev, "Unsupported I2C/SMBus command\n");
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ret = -EOPNOTSUPP;
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break;
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} /* switch (size) */
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return ret;
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}
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static u32 stub_func(struct i2c_adapter *adapter)
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{
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return STUB_FUNC_ALL & functionality;
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}
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static const struct i2c_algorithm smbus_algorithm = {
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.functionality = stub_func,
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.smbus_xfer = stub_xfer,
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};
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static struct i2c_adapter stub_adapter = {
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.owner = THIS_MODULE,
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.class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
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.algo = &smbus_algorithm,
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.name = "SMBus stub driver",
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};
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static int __init i2c_stub_allocate_banks(int i)
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{
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struct stub_chip *chip = stub_chips + i;
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chip->bank_reg = bank_reg[i];
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chip->bank_start = bank_start[i];
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chip->bank_end = bank_end[i];
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chip->bank_size = bank_end[i] - bank_start[i] + 1;
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/* We assume that all bits in the mask are contiguous */
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chip->bank_mask = bank_mask[i];
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while (!(chip->bank_mask & 1)) {
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chip->bank_shift++;
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chip->bank_mask >>= 1;
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}
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chip->bank_words = kzalloc(chip->bank_mask * chip->bank_size *
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sizeof(u16), GFP_KERNEL);
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if (!chip->bank_words)
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return -ENOMEM;
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pr_debug("i2c-stub: Allocated %u banks of %u words each (registers 0x%02x to 0x%02x)\n",
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chip->bank_mask, chip->bank_size, chip->bank_start,
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chip->bank_end);
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return 0;
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}
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static void i2c_stub_free(void)
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{
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int i;
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for (i = 0; i < stub_chips_nr; i++)
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kfree(stub_chips[i].bank_words);
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kfree(stub_chips);
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}
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static int __init i2c_stub_init(void)
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{
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int i, ret;
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if (!chip_addr[0]) {
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pr_err("i2c-stub: Please specify a chip address\n");
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return -ENODEV;
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}
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for (i = 0; i < MAX_CHIPS && chip_addr[i]; i++) {
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if (chip_addr[i] < 0x03 || chip_addr[i] > 0x77) {
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pr_err("i2c-stub: Invalid chip address 0x%02x\n",
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chip_addr[i]);
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return -EINVAL;
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}
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pr_info("i2c-stub: Virtual chip at 0x%02x\n", chip_addr[i]);
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}
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/* Allocate memory for all chips at once */
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stub_chips_nr = i;
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stub_chips = kcalloc(stub_chips_nr, sizeof(struct stub_chip),
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GFP_KERNEL);
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if (!stub_chips) {
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pr_err("i2c-stub: Out of memory\n");
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return -ENOMEM;
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}
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for (i = 0; i < stub_chips_nr; i++) {
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INIT_LIST_HEAD(&stub_chips[i].smbus_blocks);
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/* Allocate extra memory for banked register ranges */
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if (bank_mask[i]) {
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ret = i2c_stub_allocate_banks(i);
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if (ret)
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goto fail_free;
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}
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}
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ret = i2c_add_adapter(&stub_adapter);
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if (ret)
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goto fail_free;
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return 0;
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fail_free:
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i2c_stub_free();
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return ret;
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}
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static void __exit i2c_stub_exit(void)
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{
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i2c_del_adapter(&stub_adapter);
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i2c_stub_free();
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}
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MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
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MODULE_DESCRIPTION("I2C stub driver");
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MODULE_LICENSE("GPL");
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module_init(i2c_stub_init);
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module_exit(i2c_stub_exit);
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