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i2c-i801: Implement I2C block read support
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I2C block read is supported since the ICH5. I couldn't get it to work
using the block buffer, so it's using the old-style byte-by-byte mode
for now.

Note: I'm also updating the driver author... The i2c-i801 driver was
really written by Mark Studebaker, even though he based his work on
the i2c-piix4 driver which was written by Philip Edelbrock.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
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Jean Delvare authored and Jean Delvare committed Jan 27, 2008
1 parent a0921b6 commit 6342064
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Showing 2 changed files with 56 additions and 28 deletions.
5 changes: 2 additions & 3 deletions Documentation/i2c/busses/i2c-i801
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Original file line number Diff line number Diff line change
Expand Up @@ -17,9 +17,8 @@ Supported adapters:
Datasheets: Publicly available at the Intel website

Authors:
Frodo Looijaard <frodol@dds.nl>,
Philip Edelbrock <phil@netroedge.com>,
Mark Studebaker <mdsxyz123@yahoo.com>
Jean Delvare <khali@linux-fr.org>


Module Parameters
Expand Down Expand Up @@ -62,7 +61,7 @@ Not supported.
I2C Block Read Support
----------------------

Not supported at the moment.
I2C block read is supported on the 82801EB (ICH5) and later chips.


SMBus 2.0 Support
Expand Down
79 changes: 54 additions & 25 deletions drivers/i2c/busses/i2c-i801.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
Copyright (c) 1998 - 2002 Frodo Looijaard <frodol@dds.nl>,
Philip Edelbrock <phil@netroedge.com>, and Mark D. Studebaker
<mdsxyz123@yahoo.com>
Copyright (C) 2007 Jean Delvare <khali@linux-fr.org>
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
Expand Down Expand Up @@ -46,7 +47,7 @@
Hardware PEC yes
Block buffer yes
Block process call transaction no
I2C block read transaction no
I2C block read transaction yes (doesn't use the block buffer)
See the file Documentation/i2c/busses/i2c-i801 for details.
*/
Expand Down Expand Up @@ -102,9 +103,9 @@
#define I801_WORD_DATA 0x0C
#define I801_PROC_CALL 0x10 /* unimplemented */
#define I801_BLOCK_DATA 0x14
#define I801_I2C_BLOCK_DATA 0x18 /* unimplemented */
#define I801_I2C_BLOCK_DATA 0x18 /* ICH5 and later */
#define I801_BLOCK_LAST 0x34
#define I801_I2C_BLOCK_LAST 0x38 /* unimplemented */
#define I801_I2C_BLOCK_LAST 0x38 /* ICH5 and later */
#define I801_START 0x40
#define I801_PEC_EN 0x80 /* ICH3 and later */

Expand Down Expand Up @@ -256,7 +257,8 @@ static int i801_block_transaction_by_block(union i2c_smbus_data *data,
}

static int i801_block_transaction_byte_by_byte(union i2c_smbus_data *data,
char read_write, int hwpec)
char read_write, int command,
int hwpec)
{
int i, len;
int smbcmd;
Expand All @@ -273,16 +275,24 @@ static int i801_block_transaction_byte_by_byte(union i2c_smbus_data *data,
}

for (i = 1; i <= len; i++) {
if (i == len && read_write == I2C_SMBUS_READ)
smbcmd = I801_BLOCK_LAST;
else
smbcmd = I801_BLOCK_DATA;
if (i == len && read_write == I2C_SMBUS_READ) {
if (command == I2C_SMBUS_I2C_BLOCK_DATA)
smbcmd = I801_I2C_BLOCK_LAST;
else
smbcmd = I801_BLOCK_LAST;
} else {
if (command == I2C_SMBUS_I2C_BLOCK_DATA
&& read_write == I2C_SMBUS_READ)
smbcmd = I801_I2C_BLOCK_DATA;
else
smbcmd = I801_BLOCK_DATA;
}
outb_p(smbcmd | ENABLE_INT9, SMBHSTCNT);

dev_dbg(&I801_dev->dev, "Block (pre %d): CNT=%02x, CMD=%02x, "
"ADD=%02x, DAT0=%02x, BLKDAT=%02x\n", i,
"ADD=%02x, DAT0=%02x, DAT1=%02x, BLKDAT=%02x\n", i,
inb_p(SMBHSTCNT), inb_p(SMBHSTCMD), inb_p(SMBHSTADD),
inb_p(SMBHSTDAT0), inb_p(SMBBLKDAT));
inb_p(SMBHSTDAT0), inb_p(SMBHSTDAT1), inb_p(SMBBLKDAT));

/* Make sure the SMBus host is ready to start transmitting */
temp = inb_p(SMBHSTSTS);
Expand Down Expand Up @@ -346,7 +356,8 @@ static int i801_block_transaction_byte_by_byte(union i2c_smbus_data *data,
dev_dbg(&I801_dev->dev, "Error: no response!\n");
}

if (i == 1 && read_write == I2C_SMBUS_READ) {
if (i == 1 && read_write == I2C_SMBUS_READ
&& command != I2C_SMBUS_I2C_BLOCK_DATA) {
len = inb_p(SMBHSTDAT0);
if (len < 1 || len > I2C_SMBUS_BLOCK_MAX)
return -1;
Expand All @@ -367,9 +378,9 @@ static int i801_block_transaction_byte_by_byte(union i2c_smbus_data *data,
temp);
}
dev_dbg(&I801_dev->dev, "Block (post %d): CNT=%02x, CMD=%02x, "
"ADD=%02x, DAT0=%02x, BLKDAT=%02x\n", i,
"ADD=%02x, DAT0=%02x, DAT1=%02x, BLKDAT=%02x\n", i,
inb_p(SMBHSTCNT), inb_p(SMBHSTCMD), inb_p(SMBHSTADD),
inb_p(SMBHSTDAT0), inb_p(SMBBLKDAT));
inb_p(SMBHSTDAT0), inb_p(SMBHSTDAT1), inb_p(SMBBLKDAT));

if (result < 0)
return result;
Expand Down Expand Up @@ -398,34 +409,38 @@ static int i801_block_transaction(union i2c_smbus_data *data, char read_write,
pci_read_config_byte(I801_dev, SMBHSTCFG, &hostc);
pci_write_config_byte(I801_dev, SMBHSTCFG,
hostc | SMBHSTCFG_I2C_EN);
} else {
} else if (!(i801_features & FEATURE_I2C_BLOCK_READ)) {
dev_err(&I801_dev->dev,
"I2C_SMBUS_I2C_BLOCK_READ not DB!\n");
"I2C block read is unsupported!\n");
return -1;
}
}

if (read_write == I2C_SMBUS_WRITE) {
if (read_write == I2C_SMBUS_WRITE
|| command == I2C_SMBUS_I2C_BLOCK_DATA) {
if (data->block[0] < 1)
data->block[0] = 1;
if (data->block[0] > I2C_SMBUS_BLOCK_MAX)
data->block[0] = I2C_SMBUS_BLOCK_MAX;
} else {
data->block[0] = 32; /* max for reads */
data->block[0] = 32; /* max for SMBus block reads */
}

if ((i801_features & FEATURE_BLOCK_BUFFER)
&& !(command == I2C_SMBUS_I2C_BLOCK_DATA
&& read_write == I2C_SMBUS_READ)
&& i801_set_block_buffer_mode() == 0)
result = i801_block_transaction_by_block(data, read_write,
hwpec);
else
result = i801_block_transaction_byte_by_byte(data, read_write,
hwpec);
command, hwpec);

if (result == 0 && hwpec)
i801_wait_hwpec();

if (command == I2C_SMBUS_I2C_BLOCK_DATA) {
if (command == I2C_SMBUS_I2C_BLOCK_DATA
&& read_write == I2C_SMBUS_WRITE) {
/* restore saved configuration register value */
pci_write_config_byte(I801_dev, SMBHSTCFG, hostc);
}
Expand Down Expand Up @@ -477,12 +492,23 @@ static s32 i801_access(struct i2c_adapter * adap, u16 addr,
xact = I801_WORD_DATA;
break;
case I2C_SMBUS_BLOCK_DATA:
case I2C_SMBUS_I2C_BLOCK_DATA:
outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
SMBHSTADD);
outb_p(command, SMBHSTCMD);
block = 1;
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
/* NB: page 240 of ICH5 datasheet shows that the R/#W
* bit should be cleared here, even when reading */
outb_p((addr & 0x7f) << 1, SMBHSTADD);
if (read_write == I2C_SMBUS_READ) {
/* NB: page 240 of ICH5 datasheet also shows
* that DATA1 is the cmd field when reading */
outb_p(command, SMBHSTDAT1);
} else
outb_p(command, SMBHSTCMD);
block = 1;
break;
case I2C_SMBUS_PROC_CALL:
default:
dev_err(&I801_dev->dev, "Unsupported transaction %d\n", size);
Expand Down Expand Up @@ -531,7 +557,9 @@ static u32 i801_func(struct i2c_adapter *adapter)
return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_WRITE_I2C_BLOCK |
((i801_features & FEATURE_SMBUS_PEC) ? I2C_FUNC_SMBUS_PEC : 0);
((i801_features & FEATURE_SMBUS_PEC) ? I2C_FUNC_SMBUS_PEC : 0) |
((i801_features & FEATURE_I2C_BLOCK_READ) ?
I2C_FUNC_SMBUS_READ_I2C_BLOCK : 0);
}

static const struct i2c_algorithm smbus_algorithm = {
Expand Down Expand Up @@ -573,14 +601,16 @@ static int __devinit i801_probe(struct pci_dev *dev, const struct pci_device_id
I801_dev = dev;
i801_features = 0;
switch (dev->device) {
case PCI_DEVICE_ID_INTEL_82801DB_3:
case PCI_DEVICE_ID_INTEL_82801EB_3:
case PCI_DEVICE_ID_INTEL_ESB_4:
case PCI_DEVICE_ID_INTEL_ICH6_16:
case PCI_DEVICE_ID_INTEL_ICH7_17:
case PCI_DEVICE_ID_INTEL_ESB2_17:
case PCI_DEVICE_ID_INTEL_ICH8_5:
case PCI_DEVICE_ID_INTEL_ICH9_6:
i801_features |= FEATURE_I2C_BLOCK_READ;
/* fall through */
case PCI_DEVICE_ID_INTEL_82801DB_3:
case PCI_DEVICE_ID_INTEL_TOLAPAI_1:
i801_features |= FEATURE_SMBUS_PEC;
i801_features |= FEATURE_BLOCK_BUFFER;
Expand Down Expand Up @@ -698,9 +728,8 @@ static void __exit i2c_i801_exit(void)
pci_unregister_driver(&i801_driver);
}

MODULE_AUTHOR ("Frodo Looijaard <frodol@dds.nl>, "
"Philip Edelbrock <phil@netroedge.com>, "
"and Mark D. Studebaker <mdsxyz123@yahoo.com>");
MODULE_AUTHOR("Mark D. Studebaker <mdsxyz123@yahoo.com>, "
"Jean Delvare <khali@linux-fr.org>");
MODULE_DESCRIPTION("I801 SMBus driver");
MODULE_LICENSE("GPL");

Expand Down

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