i2c: stub: Add support for banked register ranges
Some chips implement banked register ranges. This allows implementing more registers than the limited 8-bit address space originally allows. In order to access a register on these chips, you must first select the proper bank. Add support for this mechanism to the i2c-stub driver so that such chips can be emulated. All the bank settings are passed as module parameters. Signed-off-by: Jean Delvare <jdelvare@suse.de> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Jean Delvare
Wolfram Sang
Родитель
1dff59831b
Коммит
2408c17fce
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@ -47,15 +47,18 @@ unsigned long functionality:
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value 0x1f0000 would only enable the quick, byte and byte data
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commands.
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u8 bank_reg[10]
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u8 bank_mask[10]
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u8 bank_start[10]
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u8 bank_end[10]:
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Optional bank settings. They tell which bits in which register
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select the active bank, as well as the range of banked registers.
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CAVEATS:
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If your target driver polls some byte or word waiting for it to change, the
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stub could lock it up. Use i2cset to unlock it.
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If the hardware for your driver has banked registers (e.g. Winbond sensors
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chips) this module will not work well - although it could be extended to
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support that pretty easily.
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If you spam it hard enough, printk can be lossy. This module really wants
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something like relayfs.
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@ -2,7 +2,7 @@
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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, 2012 Jean Delvare <jdelvare@suse.de>
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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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@ -53,6 +53,24 @@ 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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@ -65,6 +83,16 @@ struct stub_chip {
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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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@ -92,6 +120,17 @@ static struct smbus_block_data *stub_find_block(struct device *dev,
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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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@ -100,6 +139,7 @@ static s32 stub_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
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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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@ -125,7 +165,8 @@ static s32 stub_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
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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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data->byte = chip->words[chip->pointer++] & 0xff;
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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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@ -135,14 +176,25 @@ static s32 stub_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
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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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chip->words[command] &= 0xff00;
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chip->words[command] |= data->byte;
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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 = chip->words[command] & 0xff;
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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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@ -153,13 +205,14 @@ static s32 stub_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
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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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chip->words[command] = data->word;
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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 = chip->words[command];
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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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@ -169,6 +222,10 @@ static s32 stub_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
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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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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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@ -192,6 +249,10 @@ static s32 stub_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
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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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@ -262,6 +323,43 @@ static struct i2c_adapter stub_adapter = {
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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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@ -289,19 +387,32 @@ static int __init i2c_stub_init(void)
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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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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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kfree(stub_chips);
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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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kfree(stub_chips);
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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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