1 /* 2 i2c Support for Via Technologies 82C586B South Bridge 3 4 Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi> 5 6 This program is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2 of the License, or 9 (at your option) any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with this program; if not, write to the Free Software 18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 19 */ 20 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/pci.h> 24 #include <linux/ioport.h> 25 #include <linux/i2c.h> 26 #include <linux/i2c-algo-bit.h> 27 #include <linux/io.h> 28 29 /* Power management registers */ 30 #define PM_CFG_REVID 0x08 /* silicon revision code */ 31 #define PM_CFG_IOBASE0 0x20 32 #define PM_CFG_IOBASE1 0x48 33 34 #define I2C_DIR (pm_io_base+0x40) 35 #define I2C_OUT (pm_io_base+0x42) 36 #define I2C_IN (pm_io_base+0x44) 37 #define I2C_SCL 0x02 /* clock bit in DIR/OUT/IN register */ 38 #define I2C_SDA 0x04 39 40 /* io-region reservation */ 41 #define IOSPACE 0x06 42 43 static struct pci_driver vt586b_driver; 44 static u16 pm_io_base; 45 46 /* 47 It does not appear from the datasheet that the GPIO pins are 48 open drain. So a we set a low value by setting the direction to 49 output and a high value by setting the direction to input and 50 relying on the required I2C pullup. The data value is initialized 51 to 0 in via_init() and never changed. 52 */ 53 static void bit_via_setscl(void *data, int state) 54 { 55 outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR); 56 } 57 58 static void bit_via_setsda(void *data, int state) 59 { 60 outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR); 61 } 62 63 static int bit_via_getscl(void *data) 64 { 65 return (0 != (inb(I2C_IN) & I2C_SCL)); 66 } 67 68 static int bit_via_getsda(void *data) 69 { 70 return (0 != (inb(I2C_IN) & I2C_SDA)); 71 } 72 73 74 static struct i2c_algo_bit_data bit_data = { 75 .setsda = bit_via_setsda, 76 .setscl = bit_via_setscl, 77 .getsda = bit_via_getsda, 78 .getscl = bit_via_getscl, 79 .udelay = 5, 80 .timeout = HZ 81 }; 82 83 static struct i2c_adapter vt586b_adapter = { 84 .owner = THIS_MODULE, 85 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD, 86 .name = "VIA i2c", 87 .algo_data = &bit_data, 88 }; 89 90 91 static const struct pci_device_id vt586b_ids[] = { 92 { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) }, 93 { 0, } 94 }; 95 96 MODULE_DEVICE_TABLE (pci, vt586b_ids); 97 98 static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id) 99 { 100 u16 base; 101 u8 rev; 102 int res; 103 104 if (pm_io_base) { 105 dev_err(&dev->dev, "i2c-via: Will only support one host\n"); 106 return -ENODEV; 107 } 108 109 pci_read_config_byte(dev, PM_CFG_REVID, &rev); 110 111 switch (rev) { 112 case 0x00: 113 base = PM_CFG_IOBASE0; 114 break; 115 case 0x01: 116 case 0x10: 117 base = PM_CFG_IOBASE1; 118 break; 119 120 default: 121 base = PM_CFG_IOBASE1; 122 /* later revision */ 123 } 124 125 pci_read_config_word(dev, base, &pm_io_base); 126 pm_io_base &= (0xff << 8); 127 128 if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) { 129 dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE); 130 return -ENODEV; 131 } 132 133 outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR); 134 outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT); 135 136 /* set up the sysfs linkage to our parent device */ 137 vt586b_adapter.dev.parent = &dev->dev; 138 139 res = i2c_bit_add_bus(&vt586b_adapter); 140 if ( res < 0 ) { 141 release_region(I2C_DIR, IOSPACE); 142 pm_io_base = 0; 143 return res; 144 } 145 return 0; 146 } 147 148 static void vt586b_remove(struct pci_dev *dev) 149 { 150 i2c_del_adapter(&vt586b_adapter); 151 release_region(I2C_DIR, IOSPACE); 152 pm_io_base = 0; 153 } 154 155 156 static struct pci_driver vt586b_driver = { 157 .name = "vt586b_smbus", 158 .id_table = vt586b_ids, 159 .probe = vt586b_probe, 160 .remove = vt586b_remove, 161 }; 162 163 module_pci_driver(vt586b_driver); 164 165 MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>"); 166 MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge"); 167 MODULE_LICENSE("GPL"); 168