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 <[email protected]> Cc: Guenter Roeck <[email protected]> --- Tested successfully with: http://jdelvare.nerim.net/devel/lm-sensors/dumps/w83793-for-stub.dump Documentation/i2c/i2c-stub | 11 ++- drivers/i2c/i2c-stub.c | 131 +++++++++++++++++++++++++++++++++++++++++---- 2 files changed, 128 insertions(+), 14 deletions(-) --- linux-3.16-rc3.orig/drivers/i2c/i2c-stub.c 2014-07-10 12:44:35.705936505 +0200 +++ linux-3.16-rc3/drivers/i2c/i2c-stub.c 2014-07-10 12:47:52.449819728 +0200 @@ -2,7 +2,7 @@ i2c-stub.c - I2C/SMBus chip emulator Copyright (c) 2004 Mark M. Hoffman <[email protected]> - Copyright (C) 2007, 2012 Jean Delvare <[email protected]> + Copyright (C) 2007-2014 Jean Delvare <[email protected]> This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -47,6 +47,24 @@ static unsigned long functionality = STU module_param(functionality, ulong, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(functionality, "Override functionality bitfield"); +/* Some chips have banked register ranges */ + +static u8 bank_reg[MAX_CHIPS]; +module_param_array(bank_reg, byte, NULL, S_IRUGO); +MODULE_PARM_DESC(bank_reg, "Bank register"); + +static u8 bank_mask[MAX_CHIPS]; +module_param_array(bank_mask, byte, NULL, S_IRUGO); +MODULE_PARM_DESC(bank_mask, "Bank value mask"); + +static u8 bank_start[MAX_CHIPS]; +module_param_array(bank_start, byte, NULL, S_IRUGO); +MODULE_PARM_DESC(bank_start, "First banked register"); + +static u8 bank_end[MAX_CHIPS]; +module_param_array(bank_end, byte, NULL, S_IRUGO); +MODULE_PARM_DESC(bank_end, "Last banked register"); + struct smbus_block_data { struct list_head node; u8 command; @@ -59,6 +77,16 @@ struct stub_chip { u16 words[256]; /* Byte operations use the LSB as per SMBus specification */ struct list_head smbus_blocks; + + /* For chips with banks, extra registers are allocated dynamically */ + u8 bank_reg; + u8 bank_shift; + u8 bank_mask; + u8 bank_sel; /* Currently selected bank */ + u8 bank_start; + u8 bank_end; + u16 bank_size; + u16 *bank_words; /* Room for bank_mask * bank_size registers */ }; static struct stub_chip *stub_chips; @@ -86,6 +114,17 @@ static struct smbus_block_data *stub_fin return rb; } +static u16 *stub_get_wordp(struct stub_chip *chip, u8 offset) +{ + if (chip->bank_sel && + offset >= chip->bank_start && offset <= chip->bank_end) + return chip->bank_words + + (chip->bank_sel - 1) * chip->bank_size + + offset - chip->bank_start; + else + return chip->words + offset; +} + /* Return negative errno on error. */ static s32 stub_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags, char read_write, u8 command, int size, union i2c_smbus_data *data) @@ -94,6 +133,7 @@ static s32 stub_xfer(struct i2c_adapter int i, len; struct stub_chip *chip = NULL; struct smbus_block_data *b; + u16 *wordp; /* Search for the right chip */ for (i = 0; i < stub_chips_nr; i++) { @@ -119,7 +159,8 @@ static s32 stub_xfer(struct i2c_adapter "smbus byte - addr 0x%02x, wrote 0x%02x.\n", addr, command); } else { - data->byte = chip->words[chip->pointer++] & 0xff; + wordp = stub_get_wordp(chip, chip->pointer++); + data->byte = *wordp & 0xff; dev_dbg(&adap->dev, "smbus byte - addr 0x%02x, read 0x%02x.\n", addr, data->byte); @@ -129,14 +170,25 @@ static s32 stub_xfer(struct i2c_adapter break; case I2C_SMBUS_BYTE_DATA: + wordp = stub_get_wordp(chip, command); if (read_write == I2C_SMBUS_WRITE) { - chip->words[command] &= 0xff00; - chip->words[command] |= data->byte; + *wordp &= 0xff00; + *wordp |= data->byte; dev_dbg(&adap->dev, "smbus byte data - addr 0x%02x, wrote 0x%02x at 0x%02x.\n", addr, data->byte, command); + + /* Set the bank as needed */ + if (chip->bank_words && command == chip->bank_reg) { + chip->bank_sel = + (data->byte >> chip->bank_shift) + & chip->bank_mask; + dev_dbg(&adap->dev, + "switching to bank %u.\n", + chip->bank_sel); + } } else { - data->byte = chip->words[command] & 0xff; + data->byte = *wordp & 0xff; dev_dbg(&adap->dev, "smbus byte data - addr 0x%02x, read 0x%02x at 0x%02x.\n", addr, data->byte, command); @@ -147,13 +199,14 @@ static s32 stub_xfer(struct i2c_adapter break; case I2C_SMBUS_WORD_DATA: + wordp = stub_get_wordp(chip, command); if (read_write == I2C_SMBUS_WRITE) { - chip->words[command] = data->word; + *wordp = data->word; dev_dbg(&adap->dev, "smbus word data - addr 0x%02x, wrote 0x%04x at 0x%02x.\n", addr, data->word, command); } else { - data->word = chip->words[command]; + data->word = *wordp; dev_dbg(&adap->dev, "smbus word data - addr 0x%02x, read 0x%04x at 0x%02x.\n", addr, data->word, command); @@ -163,6 +216,10 @@ static s32 stub_xfer(struct i2c_adapter break; case I2C_SMBUS_I2C_BLOCK_DATA: + /* + * We ignore banks here, because banked chips don't use I2C + * block transfers + */ len = data->block[0]; if (read_write == I2C_SMBUS_WRITE) { for (i = 0; i < len; i++) { @@ -186,6 +243,10 @@ static s32 stub_xfer(struct i2c_adapter break; case I2C_SMBUS_BLOCK_DATA: + /* + * We ignore banks here, because chips typically don't use both + * banks and SMBus block transfers + */ b = stub_find_block(&adap->dev, chip, command, false); if (read_write == I2C_SMBUS_WRITE) { len = data->block[0]; @@ -262,6 +323,43 @@ static struct i2c_adapter stub_adapter = .name = "SMBus stub driver", }; +static int __init i2c_stub_allocate_banks(int i) +{ + struct stub_chip *chip = stub_chips + i; + + chip->bank_reg = bank_reg[i]; + chip->bank_start = bank_start[i]; + chip->bank_end = bank_end[i]; + chip->bank_size = bank_end[i] - bank_start[i] + 1; + + /* We assume that all bits in the mask are contiguous */ + chip->bank_mask = bank_mask[i]; + while (!(chip->bank_mask & 1)) { + chip->bank_shift++; + chip->bank_mask >>= 1; + } + + chip->bank_words = kzalloc(chip->bank_mask * chip->bank_size * + sizeof(u16), GFP_KERNEL); + if (!chip->bank_words) + return -ENOMEM; + + pr_debug("i2c-stub: Allocated %u banks of %u words each (registers 0x%02x to 0x%02x)\n", + chip->bank_mask, chip->bank_size, chip->bank_start, + chip->bank_end); + + return 0; +} + +static void i2c_stub_free(void) +{ + int i; + + for (i = 0; i < stub_chips_nr; i++) + kfree(stub_chips[i].bank_words); + kfree(stub_chips); +} + static int __init i2c_stub_init(void) { int i, ret; @@ -289,19 +387,32 @@ static int __init i2c_stub_init(void) pr_err("i2c-stub: Out of memory\n"); return -ENOMEM; } - for (i = 0; i < stub_chips_nr; i++) + for (i = 0; i < stub_chips_nr; i++) { INIT_LIST_HEAD(&stub_chips[i].smbus_blocks); + /* Allocate extra memory for banked register ranges */ + if (bank_mask[i]) { + ret = i2c_stub_allocate_banks(i); + if (ret) + goto fail_free; + } + } + ret = i2c_add_adapter(&stub_adapter); if (ret) - kfree(stub_chips); + goto fail_free; + + return 0; + + fail_free: + i2c_stub_free(); return ret; } static void __exit i2c_stub_exit(void) { i2c_del_adapter(&stub_adapter); - kfree(stub_chips); + i2c_stub_free(); } MODULE_AUTHOR("Mark M. Hoffman <[email protected]>"); --- linux-3.16-rc3.orig/Documentation/i2c/i2c-stub 2014-07-10 12:44:33.275888638 +0200 +++ linux-3.16-rc3/Documentation/i2c/i2c-stub 2014-07-10 12:52:34.607411809 +0200 @@ -44,15 +44,18 @@ unsigned long functionality: value 0x1f0000 would only enable the quick, byte and byte data commands. +u8 bank_reg[10] +u8 bank_mask[10] +u8 bank_start[10] +u8 bank_end[10]: + Optional bank settings. They tell which bits in which register + select the active bank, as well as the range of banked registers. + CAVEATS: If your target driver polls some byte or word waiting for it to change, the stub could lock it up. Use i2cset to unlock it. -If the hardware for your driver has banked registers (e.g. Winbond sensors -chips) this module will not work well - although it could be extended to -support that pretty easily. - If you spam it hard enough, printk can be lossy. This module really wants something like relayfs. -- Jean Delvare SUSE L3 Support -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
