summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--Documentation/i2c/i2c-stub12
-rw-r--r--drivers/i2c/i2c-stub.c99
2 files changed, 104 insertions, 7 deletions
diff --git a/Documentation/i2c/i2c-stub b/Documentation/i2c/i2c-stub
index fa4b669c166b..a0fe7a04a3bd 100644
--- a/Documentation/i2c/i2c-stub
+++ b/Documentation/i2c/i2c-stub
@@ -2,9 +2,9 @@ MODULE: i2c-stub
DESCRIPTION:
-This module is a very simple fake I2C/SMBus driver. It implements five
+This module is a very simple fake I2C/SMBus driver. It implements six
types of SMBus commands: write quick, (r/w) byte, (r/w) byte data, (r/w)
-word data, and (r/w) I2C block data.
+word data, (r/w) I2C block data, and (r/w) SMBus block data.
You need to provide chip addresses as a module parameter when loading this
driver, which will then only react to SMBus commands to these addresses.
@@ -19,6 +19,14 @@ A pointer register with auto-increment is implemented for all byte
operations. This allows for continuous byte reads like those supported by
EEPROMs, among others.
+SMBus block command support is disabled by default, and must be enabled
+explicitly by setting the respective bits (0x03000000) in the functionality
+module parameter.
+
+SMBus block commands must be written to configure an SMBus command for
+SMBus block operations. Writes can be partial. Block read commands always
+return the number of bytes selected with the largest write so far.
+
The typical use-case is like this:
1. load this module
2. use i2cset (from the i2c-tools project) to pre-load some data
diff --git a/drivers/i2c/i2c-stub.c b/drivers/i2c/i2c-stub.c
index 77e4849d2f2a..e0bb4655661d 100644
--- a/drivers/i2c/i2c-stub.c
+++ b/drivers/i2c/i2c-stub.c
@@ -27,29 +27,70 @@
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/i2c.h>
+#include <linux/list.h>
#define MAX_CHIPS 10
-#define STUB_FUNC (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | \
- I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | \
- I2C_FUNC_SMBUS_I2C_BLOCK)
+
+/*
+ * 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;
+static unsigned long functionality = STUB_FUNC_DEFAULT;
module_param(functionality, ulong, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(functionality, "Override functionality bitfield");
+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;
};
static struct stub_chip *stub_chips;
+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;
+}
+
/* 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)
@@ -57,6 +98,7 @@ static s32 stub_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
s32 ret;
int i, len;
struct stub_chip *chip = NULL;
+ struct smbus_block_data *b;
/* Search for the right chip */
for (i = 0; i < MAX_CHIPS && chip_addr[i]; i++) {
@@ -148,6 +190,51 @@ static s32 stub_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
ret = 0;
break;
+ case I2C_SMBUS_BLOCK_DATA:
+ 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;
@@ -159,7 +246,7 @@ static s32 stub_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
static u32 stub_func(struct i2c_adapter *adapter)
{
- return STUB_FUNC & functionality;
+ return STUB_FUNC_ALL & functionality;
}
static const struct i2c_algorithm smbus_algorithm = {
@@ -199,6 +286,8 @@ static int __init i2c_stub_init(void)
pr_err("i2c-stub: Out of memory\n");
return -ENOMEM;
}
+ for (i--; i >= 0; i--)
+ INIT_LIST_HEAD(&stub_chips[i].smbus_blocks);
ret = i2c_add_adapter(&stub_adapter);
if (ret)