v4.19.13 snapshot.
diff --git a/drivers/i2c/i2c-stub.c b/drivers/i2c/i2c-stub.c
new file mode 100644
index 0000000..f31ec08
--- /dev/null
+++ b/drivers/i2c/i2c-stub.c
@@ -0,0 +1,422 @@
+/*
+ i2c-stub.c - I2C/SMBus chip emulator
+
+ Copyright (c) 2004 Mark M. Hoffman <mhoffman@lightlink.com>
+ Copyright (C) 2007-2014 Jean Delvare <jdelvare@suse.de>
+
+ 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
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+*/
+
+#define DEBUG 1
+#define pr_fmt(fmt) "i2c-stub: " fmt
+
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#define MAX_CHIPS 10
+
+/*
+ * Support for I2C_FUNC_SMBUS_BLOCK_DATA is disabled by default and must
+ * be enabled explicitly by setting the I2C_FUNC_SMBUS_BLOCK_DATA bits
+ * in the 'functionality' module parameter.
+ */
+#define STUB_FUNC_DEFAULT \
+ (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | \
+ I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | \
+ I2C_FUNC_SMBUS_I2C_BLOCK)
+
+#define STUB_FUNC_ALL \
+ (STUB_FUNC_DEFAULT | I2C_FUNC_SMBUS_BLOCK_DATA)
+
+static unsigned short chip_addr[MAX_CHIPS];
+module_param_array(chip_addr, ushort, NULL, S_IRUGO);
+MODULE_PARM_DESC(chip_addr,
+ "Chip addresses (up to 10, between 0x03 and 0x77)");
+
+static unsigned long functionality = STUB_FUNC_DEFAULT;
+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;
+ u8 len;
+ u8 block[I2C_SMBUS_BLOCK_MAX];
+};
+
+struct stub_chip {
+ u8 pointer;
+ 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;
+static int stub_chips_nr;
+
+static struct smbus_block_data *stub_find_block(struct device *dev,
+ struct stub_chip *chip,
+ u8 command, bool create)
+{
+ struct smbus_block_data *b, *rb = NULL;
+
+ list_for_each_entry(b, &chip->smbus_blocks, node) {
+ if (b->command == command) {
+ rb = b;
+ break;
+ }
+ }
+ if (rb == NULL && create) {
+ rb = devm_kzalloc(dev, sizeof(*rb), GFP_KERNEL);
+ if (rb == NULL)
+ return rb;
+ rb->command = command;
+ list_add(&rb->node, &chip->smbus_blocks);
+ }
+ 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)
+{
+ s32 ret;
+ 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++) {
+ if (addr == chip_addr[i]) {
+ chip = stub_chips + i;
+ break;
+ }
+ }
+ if (!chip)
+ return -ENODEV;
+
+ switch (size) {
+
+ case I2C_SMBUS_QUICK:
+ dev_dbg(&adap->dev, "smbus quick - addr 0x%02x\n", addr);
+ ret = 0;
+ break;
+
+ case I2C_SMBUS_BYTE:
+ if (read_write == I2C_SMBUS_WRITE) {
+ chip->pointer = command;
+ dev_dbg(&adap->dev,
+ "smbus byte - addr 0x%02x, wrote 0x%02x.\n",
+ addr, command);
+ } else {
+ 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);
+ }
+
+ ret = 0;
+ break;
+
+ case I2C_SMBUS_BYTE_DATA:
+ wordp = stub_get_wordp(chip, command);
+ if (read_write == I2C_SMBUS_WRITE) {
+ *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 = *wordp & 0xff;
+ dev_dbg(&adap->dev,
+ "smbus byte data - addr 0x%02x, read 0x%02x at 0x%02x.\n",
+ addr, data->byte, command);
+ }
+ chip->pointer = command + 1;
+
+ ret = 0;
+ break;
+
+ case I2C_SMBUS_WORD_DATA:
+ wordp = stub_get_wordp(chip, command);
+ if (read_write == I2C_SMBUS_WRITE) {
+ *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 = *wordp;
+ dev_dbg(&adap->dev,
+ "smbus word data - addr 0x%02x, read 0x%04x at 0x%02x.\n",
+ addr, data->word, command);
+ }
+
+ ret = 0;
+ break;
+
+ case I2C_SMBUS_I2C_BLOCK_DATA:
+ /*
+ * We ignore banks here, because banked chips don't use I2C
+ * block transfers
+ */
+ if (data->block[0] > 256 - command) /* Avoid overrun */
+ data->block[0] = 256 - command;
+ len = data->block[0];
+ if (read_write == I2C_SMBUS_WRITE) {
+ for (i = 0; i < len; i++) {
+ chip->words[command + i] &= 0xff00;
+ chip->words[command + i] |= data->block[1 + i];
+ }
+ dev_dbg(&adap->dev,
+ "i2c block data - addr 0x%02x, wrote %d bytes at 0x%02x.\n",
+ addr, len, command);
+ } else {
+ for (i = 0; i < len; i++) {
+ data->block[1 + i] =
+ chip->words[command + i] & 0xff;
+ }
+ dev_dbg(&adap->dev,
+ "i2c block data - addr 0x%02x, read %d bytes at 0x%02x.\n",
+ addr, len, command);
+ }
+
+ ret = 0;
+ 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];
+ if (len == 0 || len > I2C_SMBUS_BLOCK_MAX) {
+ ret = -EINVAL;
+ break;
+ }
+ if (b == NULL) {
+ b = stub_find_block(&adap->dev, chip, command,
+ true);
+ if (b == NULL) {
+ ret = -ENOMEM;
+ break;
+ }
+ }
+ /* Largest write sets read block length */
+ if (len > b->len)
+ b->len = len;
+ for (i = 0; i < len; i++)
+ b->block[i] = data->block[i + 1];
+ /* update for byte and word commands */
+ chip->words[command] = (b->block[0] << 8) | b->len;
+ dev_dbg(&adap->dev,
+ "smbus block data - addr 0x%02x, wrote %d bytes at 0x%02x.\n",
+ addr, len, command);
+ } else {
+ if (b == NULL) {
+ dev_dbg(&adap->dev,
+ "SMBus block read command without prior block write not supported\n");
+ ret = -EOPNOTSUPP;
+ break;
+ }
+ len = b->len;
+ data->block[0] = len;
+ for (i = 0; i < len; i++)
+ data->block[i + 1] = b->block[i];
+ dev_dbg(&adap->dev,
+ "smbus block data - addr 0x%02x, read %d bytes at 0x%02x.\n",
+ addr, len, command);
+ }
+
+ ret = 0;
+ break;
+
+ default:
+ dev_dbg(&adap->dev, "Unsupported I2C/SMBus command\n");
+ ret = -EOPNOTSUPP;
+ break;
+ } /* switch (size) */
+
+ return ret;
+}
+
+static u32 stub_func(struct i2c_adapter *adapter)
+{
+ return STUB_FUNC_ALL & functionality;
+}
+
+static const struct i2c_algorithm smbus_algorithm = {
+ .functionality = stub_func,
+ .smbus_xfer = stub_xfer,
+};
+
+static struct i2c_adapter stub_adapter = {
+ .owner = THIS_MODULE,
+ .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
+ .algo = &smbus_algorithm,
+ .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 = kcalloc(chip->bank_mask * chip->bank_size,
+ sizeof(u16),
+ GFP_KERNEL);
+ if (!chip->bank_words)
+ return -ENOMEM;
+
+ pr_debug("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;
+
+ if (!chip_addr[0]) {
+ pr_err("Please specify a chip address\n");
+ return -ENODEV;
+ }
+
+ for (i = 0; i < MAX_CHIPS && chip_addr[i]; i++) {
+ if (chip_addr[i] < 0x03 || chip_addr[i] > 0x77) {
+ pr_err("Invalid chip address 0x%02x\n",
+ chip_addr[i]);
+ return -EINVAL;
+ }
+
+ pr_info("Virtual chip at 0x%02x\n", chip_addr[i]);
+ }
+
+ /* Allocate memory for all chips at once */
+ stub_chips_nr = i;
+ stub_chips = kcalloc(stub_chips_nr, sizeof(struct stub_chip),
+ GFP_KERNEL);
+ if (!stub_chips)
+ return -ENOMEM;
+
+ 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)
+ goto fail_free;
+
+ return 0;
+
+ fail_free:
+ i2c_stub_free();
+ return ret;
+}
+
+static void __exit i2c_stub_exit(void)
+{
+ i2c_del_adapter(&stub_adapter);
+ i2c_stub_free();
+}
+
+MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
+MODULE_DESCRIPTION("I2C stub driver");
+MODULE_LICENSE("GPL");
+
+module_init(i2c_stub_init);
+module_exit(i2c_stub_exit);