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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 i2c Support for Via Technologies 82C586B South Bridge4 5 Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>6 7*/8 9#include <linux/kernel.h>10#include <linux/module.h>11#include <linux/pci.h>12#include <linux/ioport.h>13#include <linux/i2c.h>14#include <linux/i2c-algo-bit.h>15#include <linux/io.h>16 17/* Power management registers */18#define PM_CFG_REVID 0x08 /* silicon revision code */19#define PM_CFG_IOBASE0 0x2020#define PM_CFG_IOBASE1 0x4821 22#define I2C_DIR (pm_io_base+0x40)23#define I2C_OUT (pm_io_base+0x42)24#define I2C_IN (pm_io_base+0x44)25#define I2C_SCL 0x02 /* clock bit in DIR/OUT/IN register */26#define I2C_SDA 0x0427 28/* io-region reservation */29#define IOSPACE 0x0630 31static struct pci_driver vt586b_driver;32static u16 pm_io_base;33 34/*35 It does not appear from the datasheet that the GPIO pins are36 open drain. So a we set a low value by setting the direction to37 output and a high value by setting the direction to input and38 relying on the required I2C pullup. The data value is initialized39 to 0 in via_init() and never changed.40*/41static void bit_via_setscl(void *data, int state)42{43 outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);44}45 46static void bit_via_setsda(void *data, int state)47{48 outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);49}50 51static int bit_via_getscl(void *data)52{53 return (0 != (inb(I2C_IN) & I2C_SCL));54}55 56static int bit_via_getsda(void *data)57{58 return (0 != (inb(I2C_IN) & I2C_SDA));59}60 61 62static struct i2c_algo_bit_data bit_data = {63 .setsda = bit_via_setsda,64 .setscl = bit_via_setscl,65 .getsda = bit_via_getsda,66 .getscl = bit_via_getscl,67 .udelay = 5,68 .timeout = HZ69};70 71static struct i2c_adapter vt586b_adapter = {72 .owner = THIS_MODULE,73 .class = I2C_CLASS_HWMON,74 .name = "VIA i2c",75 .algo_data = &bit_data,76};77 78 79static const struct pci_device_id vt586b_ids[] = {80 { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },81 { 0, }82};83 84MODULE_DEVICE_TABLE (pci, vt586b_ids);85 86static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)87{88 u16 base;89 u8 rev;90 int res;91 92 if (pm_io_base) {93 dev_err(&dev->dev, "i2c-via: Will only support one host\n");94 return -ENODEV;95 }96 97 pci_read_config_byte(dev, PM_CFG_REVID, &rev);98 99 switch (rev) {100 case 0x00:101 base = PM_CFG_IOBASE0;102 break;103 case 0x01:104 case 0x10:105 base = PM_CFG_IOBASE1;106 break;107 108 default:109 base = PM_CFG_IOBASE1;110 /* later revision */111 }112 113 pci_read_config_word(dev, base, &pm_io_base);114 pm_io_base &= (0xff << 8);115 116 if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {117 dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);118 return -ENODEV;119 }120 121 outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);122 outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);123 124 /* set up the sysfs linkage to our parent device */125 vt586b_adapter.dev.parent = &dev->dev;126 127 res = i2c_bit_add_bus(&vt586b_adapter);128 if ( res < 0 ) {129 release_region(I2C_DIR, IOSPACE);130 pm_io_base = 0;131 return res;132 }133 return 0;134}135 136static void vt586b_remove(struct pci_dev *dev)137{138 i2c_del_adapter(&vt586b_adapter);139 release_region(I2C_DIR, IOSPACE);140 pm_io_base = 0;141}142 143 144static struct pci_driver vt586b_driver = {145 .name = "vt586b_smbus",146 .id_table = vt586b_ids,147 .probe = vt586b_probe,148 .remove = vt586b_remove,149};150 151module_pci_driver(vt586b_driver);152 153MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");154MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");155MODULE_LICENSE("GPL");156