/*
i2c Support for Apple SMU Controller
Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp.
<benh@kernel.crashing.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
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.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <asm/prom.h>
#include <asm/of_device.h>
#include <asm/smu.h>
static int probe;
MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("I2C driver for Apple's SMU");
MODULE_LICENSE("GPL");
module_param(probe, bool, 0);
/* Physical interface */
struct smu_iface
{
struct i2c_adapter adapter;
struct completion complete;
u32 busid;
};
static void smu_i2c_done(struct smu_i2c_cmd *cmd, void *misc)
{
struct smu_iface *iface = misc;
complete(&iface->complete);
}
/*
* SMBUS-type transfer entrypoint
*/
static s32 smu_smbus_xfer( struct i2c_adapter* adap,
u16 addr,
unsigned short flags,
char read_write,
u8 command,
int size,
union i2c_smbus_data* data)
{
struct smu_iface *iface = i2c_get_adapdata(adap);
struct smu_i2c_cmd cmd;
int rc = 0;
int read = (read_write == I2C_SMBUS_READ);
cmd.info.bus = iface->busid;
cmd.info.devaddr = (addr << 1) | (read ? 0x01 : 0x00);
/* Prepare datas & select mode */
switch (size) {
case I2C_SMBUS_QUICK:
cmd.info.type = SMU_I2C_TRANSFER_SIMPLE;
cmd.info.datalen = 0;
break;
case I2C_SMBUS_BYTE:
cmd.info.type = SMU_I2C_TRANSFER_SIMPLE;
cmd.info.datalen = 1;
if (!read)
cmd.info.data[0] = data->byte;
break;
case I2C_SMBUS_BYTE_DATA:
cmd.info.type = SMU_I2C_TRANSFER_STDSUB;
cmd.info.datalen = 1;
cmd.info.sublen = 1;
cmd.info.subaddr[0] = command;
cmd.info.subaddr[1] = 0;
cmd.info.subaddr[2] = 0;
if (!read)
cmd.info.data[0] = data->byte;
break;
case I2C_SMBUS_WORD_DATA:
cmd.info.type = SMU_I2C_TRANSFER_STDSUB;
cmd.info.datalen = 2;
cmd.info.sublen = 1;
cmd.info.subaddr[0] = command;
cmd.info.subaddr[1] = 0;
cmd.info.subaddr[2] = 0;
if (!read) {
cmd.info.data[0] = data->byte & 0xff;
cmd.info.data[1] = (data->byte >> 8) & 0xff;
}
break;
/* Note that these are broken vs. the expected smbus API where
* on reads, the lenght is actually returned from the function,
* but I think the current API makes no sense and I don't want
* any driver that I haven't verified for correctness to go
* anywhere near a pmac i2c bus anyway ...
*/
case I2C_SMBUS_BLOCK_DATA:
cmd.info.type = SMU_I2C_TRANSFER_STDSUB;
cmd.info.datalen = data->block[0] + 1;
if (cmd.info.datalen > 6)
return -EINVAL;
if (!read)
memcpy(cmd.info.data, data->block, cmd.info.datalen);
cmd.info.sublen = 1;
cmd.info.subaddr[0] = command;
cmd.info.subaddr[1] = 0;
cmd.info.subaddr[2] = 0;
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
cmd.info.type = SMU_I2C_TRANSFER_STDSUB;
cmd.info.datalen = data->block[0];
if (cmd.info.datalen > 7)
return -EINVAL;
if (!read)
memcpy(cmd.info.data, &data->block[1],
cmd.info.datalen);
cmd.info.sublen = 1;
cmd.info.subaddr[0] = command;
cmd.info.subaddr[1] = 0;
cmd.info.subaddr[2] = 0;
break;
default:
return -EINVAL;
}
/* Turn a standardsub read into a combined mode access */
if (read_write == I2C_SMBUS_READ &&
cmd.info.type == SMU_I2C_TRANSFER_STDSUB)
cmd.info.type = SMU_I2C_TRANSFER_COMBINED;
/* Finish filling command and submit it */
cmd.done = smu_i2c_done;
cmd.misc = iface;
rc = smu_queue_i2c(&cmd);
if (rc < 0)
return rc;
wait_for_completion(&iface->complete);
rc = cmd.status;
if (!read || rc < 0)
return rc;
switch (size) {
case I2C_SMBUS_BYTE:
case I2C_SMBUS_BYTE_DATA:
data->byte = cmd.info.data[0];
break;
case I2C_SMBUS_WORD_DATA:
data->word = ((u16)cmd.info.data[1]) << 8;
data->word |= cmd.info.data[0];
break;
/* Note that these are broken vs. the expected smbus API where
* on reads, the lenght is actually returned from the function,
* but I think the current API makes no sense and I don't want
* any driver that I haven't verified for correctness to go
* anywhere near a pmac i2c bus anyway ...
*/
case I2C_SMBUS_BLOCK_DATA:
case I2C_SMBUS_I2C_BLOCK_DATA:
memcpy(&data->block[0], cmd.info.data, cmd.info.datalen);
break;
}
return rc;
}
static u32
smu_smbus_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;
}
/* For now, we only handle combined mode (smbus) */
static struct i2c_algorithm smu_algorithm = {
.smbus_xfer = smu_smbus_xfer,
.functionality = smu_smbus_func,
};
static int create_iface(struct device_node *np, struct device *dev)
{
struct smu_iface* iface;
u32 *reg, busid;
int rc;
reg = (u32 *)get_property(np, "reg", NULL);
if (reg == NULL) {
printk(KERN_ERR "i2c-pmac-smu: can't find bus number !\n");
return -ENXIO;
}
busid = *reg;
iface = kzalloc(sizeof(struct smu_iface), GFP_KERNEL);
if (iface == NULL) {
printk(KERN_ERR "i2c-pmac-smu: can't allocate inteface !\n");
return -ENOMEM;
}
init_completion(&iface->complete);
iface->busid = busid;
dev_set_drvdata(dev, iface);
sprintf(iface->adapter.name, "smu-i2c-%02x", busid);
iface->adapter.algo = &smu_algorithm;
iface->adapter.algo_data = NULL;
iface->adapter.client_register = NULL;
iface->adapter.client_unregister = NULL;
i2c_set_adapdata(&iface->adapter, iface);
iface->adapter.dev.parent = dev;
rc = i2c_add_adapter(&iface->adapter);
if (rc) {
printk(KERN_ERR "i2c-pamc-smu.c: Adapter %s registration "
"failed\n", iface->adapter.name);
i2c_set_adapdata(&iface->adapter, NULL);
}
if (probe) {
unsigned char addr;
printk("Probe: ");
for (addr = 0x00; addr <= 0x7f; addr++) {
if (i2c_smbus_xfer(&iface->adapter,addr,
0,0,0,I2C_SMBUS_QUICK,NULL) >= 0)
printk("%02x ", addr);
}
printk("\n");
}
printk(KERN_INFO "SMU i2c bus %x registered\n", busid);
return 0;
}
static int dispose_iface(struct device *dev)
{
struct smu_iface *iface = dev_get_drvdata(dev);
int rc;
rc = i2c_del_adapter(&iface->adapter);
i2c_set_adapdata(&iface->adapter, NULL);
/* We aren't that prepared to deal with this... */
if (rc)
printk("i2c-pmac-smu.c: Failed to remove bus %s !\n",
iface->adapter.name);
dev_set_drvdata(dev, NULL);
kfree(iface);
return 0;
}
static int create_iface_of_platform(struct of_device* dev,
const struct of_device_id *match)
{
return create_iface(dev->node, &dev->dev);
}
static int dispose_iface_of_platform(struct of_device* dev)
{
return dispose_iface(&dev->dev);
}
static struct of_device_id i2c_smu_match[] =
{
{
.compatible = "smu-i2c",
},
{},
};
static struct of_platform_driver i2c_smu_of_platform_driver =
{
.name = "i2c-smu",
.match_table = i2c_smu_match,
.probe = create_iface_of_platform,
.remove = dispose_iface_of_platform
};
static int __init i2c_pmac_smu_init(void)
{
of_register_driver(&i2c_smu_of_platform_driver);
return 0;
}
static void __exit i2c_pmac_smu_cleanup(void)
{
of_unregister_driver(&i2c_smu_of_platform_driver);
}
module_init(i2c_pmac_smu_init);
module_exit(i2c_pmac_smu_cleanup);
