1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 i2c Support for Via Technologies 82C586B South Bridge 4 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 0x20 20 #define PM_CFG_IOBASE1 0x48 21 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 0x04 27 28 /* io-region reservation */ 29 #define IOSPACE 0x06 30 31 static struct pci_driver vt586b_driver; 32 static u16 pm_io_base; 33 34 /* 35 It does not appear from the datasheet that the GPIO pins are 36 open drain. So a we set a low value by setting the direction to 37 output and a high value by setting the direction to input and 38 relying on the required I2C pullup. The data value is initialized 39 to 0 in via_init() and never changed. 40 */ 41 static 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 46 static 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 51 static int bit_via_getscl(void *data) 52 { 53 return (0 != (inb(I2C_IN) & I2C_SCL)); 54 } 55 56 static int bit_via_getsda(void *data) 57 { 58 return (0 != (inb(I2C_IN) & I2C_SDA)); 59 } 60 61 62 static 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 = HZ 69 }; 70 71 static 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 79 static const struct pci_device_id vt586b_ids[] = { 80 { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) }, 81 { 0, } 82 }; 83 84 MODULE_DEVICE_TABLE (pci, vt586b_ids); 85 86 static 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 } 135 136 static 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 } 142 143 144 static struct pci_driver vt586b_driver = { 145 .name = "vt586b_smbus", 146 .id_table = vt586b_ids, 147 .probe = vt586b_probe, 148 .remove = vt586b_remove, 149 }; 150 151 module_pci_driver(vt586b_driver); 152 153 MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>"); 154 MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge"); 155 MODULE_LICENSE("GPL"); 156