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// SPDX-License-Identifier: GPL-2.0-or-later
/*
i2c Support for Via Technologies 82C586B South Bridge
Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <linux/io.h>
/* Power management registers */
#define PM_CFG_REVID 0x08 /* silicon revision code */
#define PM_CFG_IOBASE0 0x20
#define PM_CFG_IOBASE1 0x48
#define I2C_DIR (pm_io_base+0x40)
#define I2C_OUT (pm_io_base+0x42)
#define I2C_IN (pm_io_base+0x44)
#define I2C_SCL 0x02 /* clock bit in DIR/OUT/IN register */
#define I2C_SDA 0x04
/* io-region reservation */
#define IOSPACE 0x06
static struct pci_driver vt586b_driver;
static u16 pm_io_base;
/*
It does not appear from the datasheet that the GPIO pins are
open drain. So a we set a low value by setting the direction to
output and a high value by setting the direction to input and
relying on the required I2C pullup. The data value is initialized
to 0 in via_init() and never changed.
*/
static void bit_via_setscl(void *data, int state)
{
outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
}
static void bit_via_setsda(void *data, int state)
{
outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
}
static int bit_via_getscl(void *data)
{
return (0 != (inb(I2C_IN) & I2C_SCL));
}
static int bit_via_getsda(void *data)
{
return (0 != (inb(I2C_IN) & I2C_SDA));
}
static struct i2c_algo_bit_data bit_data = {
.setsda = bit_via_setsda,
.setscl = bit_via_setscl,
.getsda = bit_via_getsda,
.getscl = bit_via_getscl,
.udelay = 5,
.timeout = HZ
};
static struct i2c_adapter vt586b_adapter = {
.owner = THIS_MODULE,
.class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
.name = "VIA i2c",
.algo_data = &bit_data,
};
static const struct pci_device_id vt586b_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
{ 0, }
};
MODULE_DEVICE_TABLE (pci, vt586b_ids);
static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
u16 base;
u8 rev;
int res;
if (pm_io_base) {
dev_err(&dev->dev, "i2c-via: Will only support one host\n");
return -ENODEV;
}
pci_read_config_byte(dev, PM_CFG_REVID, &rev);
switch (rev) {
case 0x00:
base = PM_CFG_IOBASE0;
break;
case 0x01:
case 0x10:
base = PM_CFG_IOBASE1;
break;
default:
base = PM_CFG_IOBASE1;
/* later revision */
}
pci_read_config_word(dev, base, &pm_io_base);
pm_io_base &= (0xff << 8);
if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {
dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
return -ENODEV;
}
outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
/* set up the sysfs linkage to our parent device */
vt586b_adapter.dev.parent = &dev->dev;
res = i2c_bit_add_bus(&vt586b_adapter);
if ( res < 0 ) {
release_region(I2C_DIR, IOSPACE);
pm_io_base = 0;
return res;
}
return 0;
}
static void vt586b_remove(struct pci_dev *dev)
{
i2c_del_adapter(&vt586b_adapter);
release_region(I2C_DIR, IOSPACE);
pm_io_base = 0;
}
static struct pci_driver vt586b_driver = {
.name = "vt586b_smbus",
.id_table = vt586b_ids,
.probe = vt586b_probe,
.remove = vt586b_remove,
};
module_pci_driver(vt586b_driver);
MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
MODULE_LICENSE("GPL");
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