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