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path: root/drivers/i2c/i2c-core.c
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Diffstat (limited to 'drivers/i2c/i2c-core.c')
-rw-r--r--drivers/i2c/i2c-core.c199
1 files changed, 72 insertions, 127 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index dda472e5e8b..82ea1b7ec91 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -19,7 +19,8 @@
/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
- SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> */
+ SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
+ Jean Delvare <khali@linux-fr.org> */
#include <linux/module.h>
#include <linux/kernel.h>
@@ -29,6 +30,7 @@
#include <linux/init.h>
#include <linux/idr.h>
#include <linux/seq_file.h>
+#include <linux/platform_device.h>
#include <asm/uaccess.h>
@@ -48,7 +50,7 @@ static int i2c_bus_suspend(struct device * dev, pm_message_t state)
int rc = 0;
if (dev->driver && dev->driver->suspend)
- rc = dev->driver->suspend(dev,state,0);
+ rc = dev->driver->suspend(dev, state);
return rc;
}
@@ -57,7 +59,7 @@ static int i2c_bus_resume(struct device * dev)
int rc = 0;
if (dev->driver && dev->driver->resume)
- rc = dev->driver->resume(dev,0);
+ rc = dev->driver->resume(dev);
return rc;
}
@@ -85,6 +87,7 @@ void i2c_adapter_dev_release(struct device *dev)
}
struct device_driver i2c_adapter_driver = {
+ .owner = THIS_MODULE,
.name = "i2c_adapter",
.bus = &i2c_bus_type,
.probe = i2c_device_probe,
@@ -98,6 +101,7 @@ static void i2c_adapter_class_dev_release(struct class_device *dev)
}
struct class i2c_adapter_class = {
+ .owner = THIS_MODULE,
.name = "i2c-adapter",
.release = &i2c_adapter_class_dev_release,
};
@@ -291,6 +295,7 @@ int i2c_add_driver(struct i2c_driver *driver)
down(&core_lists);
/* add the driver to the list of i2c drivers in the driver core */
+ driver->driver.owner = driver->owner;
driver->driver.name = driver->name;
driver->driver.bus = &i2c_bus_type;
driver->driver.probe = i2c_device_probe;
@@ -706,10 +711,6 @@ int i2c_probe(struct i2c_adapter *adapter,
int i, err;
int adap_id = i2c_adapter_id(adapter);
- /* Forget it if we can't probe using SMBUS_QUICK */
- if (! i2c_check_functionality(adapter,I2C_FUNC_SMBUS_QUICK))
- return -1;
-
/* Force entries are done first, and are not affected by ignore
entries */
if (address_data->forces) {
@@ -736,6 +737,17 @@ int i2c_probe(struct i2c_adapter *adapter,
}
}
+ /* Stop here if we can't use SMBUS_QUICK */
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_QUICK)) {
+ if (address_data->probe[0] == I2C_CLIENT_END
+ && address_data->normal_i2c[0] == I2C_CLIENT_END)
+ return 0;
+
+ dev_warn(&adapter->dev, "SMBus Quick command not supported, "
+ "can't probe for chips\n");
+ return -1;
+ }
+
/* Probe entries are done second, and are not affected by ignore
entries either */
for (i = 0; address_data->probe[i] != I2C_CLIENT_END; i += 2) {
@@ -820,101 +832,44 @@ crc8(u16 data)
return (u8)(data >> 8);
}
-/* CRC over count bytes in the first array plus the bytes in the rest
- array if it is non-null. rest[0] is the (length of rest) - 1
- and is included. */
-static u8 i2c_smbus_partial_pec(u8 crc, int count, u8 *first, u8 *rest)
+/* Incremental CRC8 over count bytes in the array pointed to by p */
+static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
{
int i;
for(i = 0; i < count; i++)
- crc = crc8((crc ^ first[i]) << 8);
- if(rest != NULL)
- for(i = 0; i <= rest[0]; i++)
- crc = crc8((crc ^ rest[i]) << 8);
+ crc = crc8((crc ^ p[i]) << 8);
return crc;
}
-static u8 i2c_smbus_pec(int count, u8 *first, u8 *rest)
+/* Assume a 7-bit address, which is reasonable for SMBus */
+static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
{
- return i2c_smbus_partial_pec(0, count, first, rest);
+ /* The address will be sent first */
+ u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
+ pec = i2c_smbus_pec(pec, &addr, 1);
+
+ /* The data buffer follows */
+ return i2c_smbus_pec(pec, msg->buf, msg->len);
}
-/* Returns new "size" (transaction type)
- Note that we convert byte to byte_data and byte_data to word_data
- rather than invent new xxx_PEC transactions. */
-static int i2c_smbus_add_pec(u16 addr, u8 command, int size,
- union i2c_smbus_data *data)
+/* Used for write only transactions */
+static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
{
- u8 buf[3];
-
- buf[0] = addr << 1;
- buf[1] = command;
- switch(size) {
- case I2C_SMBUS_BYTE:
- data->byte = i2c_smbus_pec(2, buf, NULL);
- size = I2C_SMBUS_BYTE_DATA;
- break;
- case I2C_SMBUS_BYTE_DATA:
- buf[2] = data->byte;
- data->word = buf[2] ||
- (i2c_smbus_pec(3, buf, NULL) << 8);
- size = I2C_SMBUS_WORD_DATA;
- break;
- case I2C_SMBUS_WORD_DATA:
- /* unsupported */
- break;
- case I2C_SMBUS_BLOCK_DATA:
- data->block[data->block[0] + 1] =
- i2c_smbus_pec(2, buf, data->block);
- size = I2C_SMBUS_BLOCK_DATA_PEC;
- break;
- }
- return size;
+ msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
+ msg->len++;
}
-static int i2c_smbus_check_pec(u16 addr, u8 command, int size, u8 partial,
- union i2c_smbus_data *data)
+/* Return <0 on CRC error
+ If there was a write before this read (most cases) we need to take the
+ partial CRC from the write part into account.
+ Note that this function does modify the message (we need to decrease the
+ message length to hide the CRC byte from the caller). */
+static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
{
- u8 buf[3], rpec, cpec;
+ u8 rpec = msg->buf[--msg->len];
+ cpec = i2c_smbus_msg_pec(cpec, msg);
- buf[1] = command;
- switch(size) {
- case I2C_SMBUS_BYTE_DATA:
- buf[0] = (addr << 1) | 1;
- cpec = i2c_smbus_pec(2, buf, NULL);
- rpec = data->byte;
- break;
- case I2C_SMBUS_WORD_DATA:
- buf[0] = (addr << 1) | 1;
- buf[2] = data->word & 0xff;
- cpec = i2c_smbus_pec(3, buf, NULL);
- rpec = data->word >> 8;
- break;
- case I2C_SMBUS_WORD_DATA_PEC:
- /* unsupported */
- cpec = rpec = 0;
- break;
- case I2C_SMBUS_PROC_CALL_PEC:
- /* unsupported */
- cpec = rpec = 0;
- break;
- case I2C_SMBUS_BLOCK_DATA_PEC:
- buf[0] = (addr << 1);
- buf[2] = (addr << 1) | 1;
- cpec = i2c_smbus_pec(3, buf, data->block);
- rpec = data->block[data->block[0] + 1];
- break;
- case I2C_SMBUS_BLOCK_PROC_CALL_PEC:
- buf[0] = (addr << 1) | 1;
- rpec = i2c_smbus_partial_pec(partial, 1,
- buf, data->block);
- cpec = data->block[data->block[0] + 1];
- break;
- default:
- cpec = rpec = 0;
- break;
- }
if (rpec != cpec) {
pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
rpec, cpec);
@@ -941,9 +896,8 @@ s32 i2c_smbus_read_byte(struct i2c_client *client)
s32 i2c_smbus_write_byte(struct i2c_client *client, u8 value)
{
- union i2c_smbus_data data; /* only for PEC */
return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
- I2C_SMBUS_WRITE,value, I2C_SMBUS_BYTE,&data);
+ I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
}
s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 command)
@@ -1026,13 +980,14 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
need to use only one message; when reading, we need two. We initialize
most things with sane defaults, to keep the code below somewhat
simpler. */
- unsigned char msgbuf0[34];
- unsigned char msgbuf1[34];
+ unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
+ unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
int num = read_write == I2C_SMBUS_READ?2:1;
struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 },
{ addr, flags | I2C_M_RD, 0, msgbuf1 }
};
int i;
+ u8 partial_pec = 0;
msgbuf0[0] = command;
switch(size) {
@@ -1075,7 +1030,6 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
msgbuf0[2] = (data->word >> 8) & 0xff;
break;
case I2C_SMBUS_BLOCK_DATA:
- case I2C_SMBUS_BLOCK_DATA_PEC:
if (read_write == I2C_SMBUS_READ) {
dev_err(&adapter->dev, "Block read not supported "
"under I2C emulation!\n");
@@ -1088,23 +1042,20 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
data->block[0]);
return -1;
}
- if(size == I2C_SMBUS_BLOCK_DATA_PEC)
- (msg[0].len)++;
- for (i = 1; i <= msg[0].len; i++)
+ for (i = 1; i < msg[0].len; i++)
msgbuf0[i] = data->block[i-1];
}
break;
case I2C_SMBUS_BLOCK_PROC_CALL:
- case I2C_SMBUS_BLOCK_PROC_CALL_PEC:
dev_dbg(&adapter->dev, "Block process call not supported "
"under I2C emulation!\n");
return -1;
case I2C_SMBUS_I2C_BLOCK_DATA:
if (read_write == I2C_SMBUS_READ) {
- msg[1].len = I2C_SMBUS_I2C_BLOCK_MAX;
+ msg[1].len = I2C_SMBUS_BLOCK_MAX;
} else {
msg[0].len = data->block[0] + 1;
- if (msg[0].len > I2C_SMBUS_I2C_BLOCK_MAX + 1) {
+ if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
dev_err(&adapter->dev, "i2c_smbus_xfer_emulated called with "
"invalid block write size (%d)\n",
data->block[0]);
@@ -1120,9 +1071,30 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
return -1;
}
+ i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
+ && size != I2C_SMBUS_I2C_BLOCK_DATA);
+ if (i) {
+ /* Compute PEC if first message is a write */
+ if (!(msg[0].flags & I2C_M_RD)) {
+ if (num == 1) /* Write only */
+ i2c_smbus_add_pec(&msg[0]);
+ else /* Write followed by read */
+ partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
+ }
+ /* Ask for PEC if last message is a read */
+ if (msg[num-1].flags & I2C_M_RD)
+ msg[num-1].len++;
+ }
+
if (i2c_transfer(adapter, msg, num) < 0)
return -1;
+ /* Check PEC if last message is a read */
+ if (i && (msg[num-1].flags & I2C_M_RD)) {
+ if (i2c_smbus_check_pec(partial_pec, &msg[num-1]) < 0)
+ return -1;
+ }
+
if (read_write == I2C_SMBUS_READ)
switch(size) {
case I2C_SMBUS_BYTE:
@@ -1137,8 +1109,8 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
/* fixed at 32 for now */
- data->block[0] = I2C_SMBUS_I2C_BLOCK_MAX;
- for (i = 0; i < I2C_SMBUS_I2C_BLOCK_MAX; i++)
+ data->block[0] = I2C_SMBUS_BLOCK_MAX;
+ for (i = 0; i < I2C_SMBUS_BLOCK_MAX; i++)
data->block[i+1] = msgbuf1[i];
break;
}
@@ -1151,28 +1123,8 @@ s32 i2c_smbus_xfer(struct i2c_adapter * adapter, u16 addr, unsigned short flags,
union i2c_smbus_data * data)
{
s32 res;
- int swpec = 0;
- u8 partial = 0;
flags &= I2C_M_TEN | I2C_CLIENT_PEC;
- if((flags & I2C_CLIENT_PEC) &&
- !(i2c_check_functionality(adapter, I2C_FUNC_SMBUS_HWPEC_CALC))) {
- swpec = 1;
- if(read_write == I2C_SMBUS_READ &&
- size == I2C_SMBUS_BLOCK_DATA)
- size = I2C_SMBUS_BLOCK_DATA_PEC;
- else if(size == I2C_SMBUS_PROC_CALL)
- size = I2C_SMBUS_PROC_CALL_PEC;
- else if(size == I2C_SMBUS_BLOCK_PROC_CALL) {
- i2c_smbus_add_pec(addr, command,
- I2C_SMBUS_BLOCK_DATA, data);
- partial = data->block[data->block[0] + 1];
- size = I2C_SMBUS_BLOCK_PROC_CALL_PEC;
- } else if(read_write == I2C_SMBUS_WRITE &&
- size != I2C_SMBUS_QUICK &&
- size != I2C_SMBUS_I2C_BLOCK_DATA)
- size = i2c_smbus_add_pec(addr, command, size, data);
- }
if (adapter->algo->smbus_xfer) {
down(&adapter->bus_lock);
@@ -1183,13 +1135,6 @@ s32 i2c_smbus_xfer(struct i2c_adapter * adapter, u16 addr, unsigned short flags,
res = i2c_smbus_xfer_emulated(adapter,addr,flags,read_write,
command,size,data);
- if(res >= 0 && swpec &&
- size != I2C_SMBUS_QUICK && size != I2C_SMBUS_I2C_BLOCK_DATA &&
- (read_write == I2C_SMBUS_READ || size == I2C_SMBUS_PROC_CALL_PEC ||
- size == I2C_SMBUS_BLOCK_PROC_CALL_PEC)) {
- if(i2c_smbus_check_pec(addr, command, size, partial, data))
- return -1;
- }
return res;
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-04 03:20:00 +0000